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authorBen Cheng <bccheng@google.com>2014-03-25 22:37:19 -0700
committerBen Cheng <bccheng@google.com>2014-03-25 22:37:19 -0700
commit1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch)
treec607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/gcc/tree-vrp.c
parent283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff)
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Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/gcc/tree-vrp.c')
-rw-r--r--gcc-4.9/gcc/tree-vrp.c9915
1 files changed, 9915 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/tree-vrp.c b/gcc-4.9/gcc/tree-vrp.c
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+++ b/gcc-4.9/gcc/tree-vrp.c
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+/* Support routines for Value Range Propagation (VRP).
+ Copyright (C) 2005-2014 Free Software Foundation, Inc.
+ Contributed by Diego Novillo <dnovillo@redhat.com>.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "flags.h"
+#include "tree.h"
+#include "stor-layout.h"
+#include "calls.h"
+#include "basic-block.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "gimple-fold.h"
+#include "tree-eh.h"
+#include "gimple-expr.h"
+#include "is-a.h"
+#include "gimple.h"
+#include "gimple-iterator.h"
+#include "gimple-walk.h"
+#include "gimple-ssa.h"
+#include "tree-cfg.h"
+#include "tree-phinodes.h"
+#include "ssa-iterators.h"
+#include "stringpool.h"
+#include "tree-ssanames.h"
+#include "tree-ssa-loop-manip.h"
+#include "tree-ssa-loop-niter.h"
+#include "tree-ssa-loop.h"
+#include "tree-into-ssa.h"
+#include "tree-ssa.h"
+#include "tree-pass.h"
+#include "tree-dump.h"
+#include "gimple-pretty-print.h"
+#include "diagnostic-core.h"
+#include "intl.h"
+#include "cfgloop.h"
+#include "tree-scalar-evolution.h"
+#include "tree-ssa-propagate.h"
+#include "tree-chrec.h"
+#include "tree-ssa-threadupdate.h"
+#include "expr.h"
+#include "optabs.h"
+#include "tree-ssa-threadedge.h"
+
+
+
+/* Range of values that can be associated with an SSA_NAME after VRP
+ has executed. */
+struct value_range_d
+{
+ /* Lattice value represented by this range. */
+ enum value_range_type type;
+
+ /* Minimum and maximum values represented by this range. These
+ values should be interpreted as follows:
+
+ - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
+ be NULL.
+
+ - If TYPE == VR_RANGE then MIN holds the minimum value and
+ MAX holds the maximum value of the range [MIN, MAX].
+
+ - If TYPE == ANTI_RANGE the variable is known to NOT
+ take any values in the range [MIN, MAX]. */
+ tree min;
+ tree max;
+
+ /* Set of SSA names whose value ranges are equivalent to this one.
+ This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
+ bitmap equiv;
+};
+
+typedef struct value_range_d value_range_t;
+
+#define VR_INITIALIZER { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }
+
+/* Set of SSA names found live during the RPO traversal of the function
+ for still active basic-blocks. */
+static sbitmap *live;
+
+/* Return true if the SSA name NAME is live on the edge E. */
+
+static bool
+live_on_edge (edge e, tree name)
+{
+ return (live[e->dest->index]
+ && bitmap_bit_p (live[e->dest->index], SSA_NAME_VERSION (name)));
+}
+
+/* Local functions. */
+static int compare_values (tree val1, tree val2);
+static int compare_values_warnv (tree val1, tree val2, bool *);
+static void vrp_meet (value_range_t *, value_range_t *);
+static void vrp_intersect_ranges (value_range_t *, value_range_t *);
+static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
+ tree, tree, bool, bool *,
+ bool *);
+
+/* Location information for ASSERT_EXPRs. Each instance of this
+ structure describes an ASSERT_EXPR for an SSA name. Since a single
+ SSA name may have more than one assertion associated with it, these
+ locations are kept in a linked list attached to the corresponding
+ SSA name. */
+struct assert_locus_d
+{
+ /* Basic block where the assertion would be inserted. */
+ basic_block bb;
+
+ /* Some assertions need to be inserted on an edge (e.g., assertions
+ generated by COND_EXPRs). In those cases, BB will be NULL. */
+ edge e;
+
+ /* Pointer to the statement that generated this assertion. */
+ gimple_stmt_iterator si;
+
+ /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
+ enum tree_code comp_code;
+
+ /* Value being compared against. */
+ tree val;
+
+ /* Expression to compare. */
+ tree expr;
+
+ /* Next node in the linked list. */
+ struct assert_locus_d *next;
+};
+
+typedef struct assert_locus_d *assert_locus_t;
+
+/* If bit I is present, it means that SSA name N_i has a list of
+ assertions that should be inserted in the IL. */
+static bitmap need_assert_for;
+
+/* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
+ holds a list of ASSERT_LOCUS_T nodes that describe where
+ ASSERT_EXPRs for SSA name N_I should be inserted. */
+static assert_locus_t *asserts_for;
+
+/* Value range array. After propagation, VR_VALUE[I] holds the range
+ of values that SSA name N_I may take. */
+static unsigned num_vr_values;
+static value_range_t **vr_value;
+static bool values_propagated;
+
+/* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
+ number of executable edges we saw the last time we visited the
+ node. */
+static int *vr_phi_edge_counts;
+
+typedef struct {
+ gimple stmt;
+ tree vec;
+} switch_update;
+
+static vec<edge> to_remove_edges;
+static vec<switch_update> to_update_switch_stmts;
+
+
+/* Return the maximum value for TYPE. */
+
+static inline tree
+vrp_val_max (const_tree type)
+{
+ if (!INTEGRAL_TYPE_P (type))
+ return NULL_TREE;
+
+ return TYPE_MAX_VALUE (type);
+}
+
+/* Return the minimum value for TYPE. */
+
+static inline tree
+vrp_val_min (const_tree type)
+{
+ if (!INTEGRAL_TYPE_P (type))
+ return NULL_TREE;
+
+ return TYPE_MIN_VALUE (type);
+}
+
+/* Return whether VAL is equal to the maximum value of its type. This
+ will be true for a positive overflow infinity. We can't do a
+ simple equality comparison with TYPE_MAX_VALUE because C typedefs
+ and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
+ to the integer constant with the same value in the type. */
+
+static inline bool
+vrp_val_is_max (const_tree val)
+{
+ tree type_max = vrp_val_max (TREE_TYPE (val));
+ return (val == type_max
+ || (type_max != NULL_TREE
+ && operand_equal_p (val, type_max, 0)));
+}
+
+/* Return whether VAL is equal to the minimum value of its type. This
+ will be true for a negative overflow infinity. */
+
+static inline bool
+vrp_val_is_min (const_tree val)
+{
+ tree type_min = vrp_val_min (TREE_TYPE (val));
+ return (val == type_min
+ || (type_min != NULL_TREE
+ && operand_equal_p (val, type_min, 0)));
+}
+
+
+/* Return whether TYPE should use an overflow infinity distinct from
+ TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
+ represent a signed overflow during VRP computations. An infinity
+ is distinct from a half-range, which will go from some number to
+ TYPE_{MIN,MAX}_VALUE. */
+
+static inline bool
+needs_overflow_infinity (const_tree type)
+{
+ return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
+}
+
+/* Return whether TYPE can support our overflow infinity
+ representation: we use the TREE_OVERFLOW flag, which only exists
+ for constants. If TYPE doesn't support this, we don't optimize
+ cases which would require signed overflow--we drop them to
+ VARYING. */
+
+static inline bool
+supports_overflow_infinity (const_tree type)
+{
+ tree min = vrp_val_min (type), max = vrp_val_max (type);
+#ifdef ENABLE_CHECKING
+ gcc_assert (needs_overflow_infinity (type));
+#endif
+ return (min != NULL_TREE
+ && CONSTANT_CLASS_P (min)
+ && max != NULL_TREE
+ && CONSTANT_CLASS_P (max));
+}
+
+/* VAL is the maximum or minimum value of a type. Return a
+ corresponding overflow infinity. */
+
+static inline tree
+make_overflow_infinity (tree val)
+{
+ gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
+ val = copy_node (val);
+ TREE_OVERFLOW (val) = 1;
+ return val;
+}
+
+/* Return a negative overflow infinity for TYPE. */
+
+static inline tree
+negative_overflow_infinity (tree type)
+{
+ gcc_checking_assert (supports_overflow_infinity (type));
+ return make_overflow_infinity (vrp_val_min (type));
+}
+
+/* Return a positive overflow infinity for TYPE. */
+
+static inline tree
+positive_overflow_infinity (tree type)
+{
+ gcc_checking_assert (supports_overflow_infinity (type));
+ return make_overflow_infinity (vrp_val_max (type));
+}
+
+/* Return whether VAL is a negative overflow infinity. */
+
+static inline bool
+is_negative_overflow_infinity (const_tree val)
+{
+ return (needs_overflow_infinity (TREE_TYPE (val))
+ && CONSTANT_CLASS_P (val)
+ && TREE_OVERFLOW (val)
+ && vrp_val_is_min (val));
+}
+
+/* Return whether VAL is a positive overflow infinity. */
+
+static inline bool
+is_positive_overflow_infinity (const_tree val)
+{
+ return (needs_overflow_infinity (TREE_TYPE (val))
+ && CONSTANT_CLASS_P (val)
+ && TREE_OVERFLOW (val)
+ && vrp_val_is_max (val));
+}
+
+/* Return whether VAL is a positive or negative overflow infinity. */
+
+static inline bool
+is_overflow_infinity (const_tree val)
+{
+ return (needs_overflow_infinity (TREE_TYPE (val))
+ && CONSTANT_CLASS_P (val)
+ && TREE_OVERFLOW (val)
+ && (vrp_val_is_min (val) || vrp_val_is_max (val)));
+}
+
+/* Return whether STMT has a constant rhs that is_overflow_infinity. */
+
+static inline bool
+stmt_overflow_infinity (gimple stmt)
+{
+ if (is_gimple_assign (stmt)
+ && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
+ GIMPLE_SINGLE_RHS)
+ return is_overflow_infinity (gimple_assign_rhs1 (stmt));
+ return false;
+}
+
+/* If VAL is now an overflow infinity, return VAL. Otherwise, return
+ the same value with TREE_OVERFLOW clear. This can be used to avoid
+ confusing a regular value with an overflow value. */
+
+static inline tree
+avoid_overflow_infinity (tree val)
+{
+ if (!is_overflow_infinity (val))
+ return val;
+
+ if (vrp_val_is_max (val))
+ return vrp_val_max (TREE_TYPE (val));
+ else
+ {
+ gcc_checking_assert (vrp_val_is_min (val));
+ return vrp_val_min (TREE_TYPE (val));
+ }
+}
+
+
+/* Return true if ARG is marked with the nonnull attribute in the
+ current function signature. */
+
+static bool
+nonnull_arg_p (const_tree arg)
+{
+ tree t, attrs, fntype;
+ unsigned HOST_WIDE_INT arg_num;
+
+ gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
+
+ /* The static chain decl is always non null. */
+ if (arg == cfun->static_chain_decl)
+ return true;
+
+ fntype = TREE_TYPE (current_function_decl);
+ for (attrs = TYPE_ATTRIBUTES (fntype); attrs; attrs = TREE_CHAIN (attrs))
+ {
+ attrs = lookup_attribute ("nonnull", attrs);
+
+ /* If "nonnull" wasn't specified, we know nothing about the argument. */
+ if (attrs == NULL_TREE)
+ return false;
+
+ /* If "nonnull" applies to all the arguments, then ARG is non-null. */
+ if (TREE_VALUE (attrs) == NULL_TREE)
+ return true;
+
+ /* Get the position number for ARG in the function signature. */
+ for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
+ t;
+ t = DECL_CHAIN (t), arg_num++)
+ {
+ if (t == arg)
+ break;
+ }
+
+ gcc_assert (t == arg);
+
+ /* Now see if ARG_NUM is mentioned in the nonnull list. */
+ for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
+ {
+ if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
+ return true;
+ }
+ }
+
+ return false;
+}
+
+
+/* Set value range VR to VR_UNDEFINED. */
+
+static inline void
+set_value_range_to_undefined (value_range_t *vr)
+{
+ vr->type = VR_UNDEFINED;
+ vr->min = vr->max = NULL_TREE;
+ if (vr->equiv)
+ bitmap_clear (vr->equiv);
+}
+
+
+/* Set value range VR to VR_VARYING. */
+
+static inline void
+set_value_range_to_varying (value_range_t *vr)
+{
+ vr->type = VR_VARYING;
+ vr->min = vr->max = NULL_TREE;
+ if (vr->equiv)
+ bitmap_clear (vr->equiv);
+}
+
+
+/* Set value range VR to {T, MIN, MAX, EQUIV}. */
+
+static void
+set_value_range (value_range_t *vr, enum value_range_type t, tree min,
+ tree max, bitmap equiv)
+{
+#if defined ENABLE_CHECKING
+ /* Check the validity of the range. */
+ if (t == VR_RANGE || t == VR_ANTI_RANGE)
+ {
+ int cmp;
+
+ gcc_assert (min && max);
+
+ gcc_assert ((!TREE_OVERFLOW_P (min) || is_overflow_infinity (min))
+ && (!TREE_OVERFLOW_P (max) || is_overflow_infinity (max)));
+
+ if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
+ gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
+
+ cmp = compare_values (min, max);
+ gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
+
+ if (needs_overflow_infinity (TREE_TYPE (min)))
+ gcc_assert (!is_overflow_infinity (min)
+ || !is_overflow_infinity (max));
+ }
+
+ if (t == VR_UNDEFINED || t == VR_VARYING)
+ gcc_assert (min == NULL_TREE && max == NULL_TREE);
+
+ if (t == VR_UNDEFINED || t == VR_VARYING)
+ gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
+#endif
+
+ vr->type = t;
+ vr->min = min;
+ vr->max = max;
+
+ /* Since updating the equivalence set involves deep copying the
+ bitmaps, only do it if absolutely necessary. */
+ if (vr->equiv == NULL
+ && equiv != NULL)
+ vr->equiv = BITMAP_ALLOC (NULL);
+
+ if (equiv != vr->equiv)
+ {
+ if (equiv && !bitmap_empty_p (equiv))
+ bitmap_copy (vr->equiv, equiv);
+ else
+ bitmap_clear (vr->equiv);
+ }
+}
+
+
+/* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
+ This means adjusting T, MIN and MAX representing the case of a
+ wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
+ as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
+ In corner cases where MAX+1 or MIN-1 wraps this will fall back
+ to varying.
+ This routine exists to ease canonicalization in the case where we
+ extract ranges from var + CST op limit. */
+
+static void
+set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
+ tree min, tree max, bitmap equiv)
+{
+ /* Use the canonical setters for VR_UNDEFINED and VR_VARYING. */
+ if (t == VR_UNDEFINED)
+ {
+ set_value_range_to_undefined (vr);
+ return;
+ }
+ else if (t == VR_VARYING)
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* Nothing to canonicalize for symbolic ranges. */
+ if (TREE_CODE (min) != INTEGER_CST
+ || TREE_CODE (max) != INTEGER_CST)
+ {
+ set_value_range (vr, t, min, max, equiv);
+ return;
+ }
+
+ /* Wrong order for min and max, to swap them and the VR type we need
+ to adjust them. */
+ if (tree_int_cst_lt (max, min))
+ {
+ tree one, tmp;
+
+ /* For one bit precision if max < min, then the swapped
+ range covers all values, so for VR_RANGE it is varying and
+ for VR_ANTI_RANGE empty range, so drop to varying as well. */
+ if (TYPE_PRECISION (TREE_TYPE (min)) == 1)
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ one = build_int_cst (TREE_TYPE (min), 1);
+ tmp = int_const_binop (PLUS_EXPR, max, one);
+ max = int_const_binop (MINUS_EXPR, min, one);
+ min = tmp;
+
+ /* There's one corner case, if we had [C+1, C] before we now have
+ that again. But this represents an empty value range, so drop
+ to varying in this case. */
+ if (tree_int_cst_lt (max, min))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
+ }
+
+ /* Anti-ranges that can be represented as ranges should be so. */
+ if (t == VR_ANTI_RANGE)
+ {
+ bool is_min = vrp_val_is_min (min);
+ bool is_max = vrp_val_is_max (max);
+
+ if (is_min && is_max)
+ {
+ /* We cannot deal with empty ranges, drop to varying.
+ ??? This could be VR_UNDEFINED instead. */
+ set_value_range_to_varying (vr);
+ return;
+ }
+ else if (TYPE_PRECISION (TREE_TYPE (min)) == 1
+ && (is_min || is_max))
+ {
+ /* Non-empty boolean ranges can always be represented
+ as a singleton range. */
+ if (is_min)
+ min = max = vrp_val_max (TREE_TYPE (min));
+ else
+ min = max = vrp_val_min (TREE_TYPE (min));
+ t = VR_RANGE;
+ }
+ else if (is_min
+ /* As a special exception preserve non-null ranges. */
+ && !(TYPE_UNSIGNED (TREE_TYPE (min))
+ && integer_zerop (max)))
+ {
+ tree one = build_int_cst (TREE_TYPE (max), 1);
+ min = int_const_binop (PLUS_EXPR, max, one);
+ max = vrp_val_max (TREE_TYPE (max));
+ t = VR_RANGE;
+ }
+ else if (is_max)
+ {
+ tree one = build_int_cst (TREE_TYPE (min), 1);
+ max = int_const_binop (MINUS_EXPR, min, one);
+ min = vrp_val_min (TREE_TYPE (min));
+ t = VR_RANGE;
+ }
+ }
+
+ /* Drop [-INF(OVF), +INF(OVF)] to varying. */
+ if (needs_overflow_infinity (TREE_TYPE (min))
+ && is_overflow_infinity (min)
+ && is_overflow_infinity (max))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ set_value_range (vr, t, min, max, equiv);
+}
+
+/* Copy value range FROM into value range TO. */
+
+static inline void
+copy_value_range (value_range_t *to, value_range_t *from)
+{
+ set_value_range (to, from->type, from->min, from->max, from->equiv);
+}
+
+/* Set value range VR to a single value. This function is only called
+ with values we get from statements, and exists to clear the
+ TREE_OVERFLOW flag so that we don't think we have an overflow
+ infinity when we shouldn't. */
+
+static inline void
+set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
+{
+ gcc_assert (is_gimple_min_invariant (val));
+ if (TREE_OVERFLOW_P (val))
+ val = drop_tree_overflow (val);
+ set_value_range (vr, VR_RANGE, val, val, equiv);
+}
+
+/* Set value range VR to a non-negative range of type TYPE.
+ OVERFLOW_INFINITY indicates whether to use an overflow infinity
+ rather than TYPE_MAX_VALUE; this should be true if we determine
+ that the range is nonnegative based on the assumption that signed
+ overflow does not occur. */
+
+static inline void
+set_value_range_to_nonnegative (value_range_t *vr, tree type,
+ bool overflow_infinity)
+{
+ tree zero;
+
+ if (overflow_infinity && !supports_overflow_infinity (type))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ zero = build_int_cst (type, 0);
+ set_value_range (vr, VR_RANGE, zero,
+ (overflow_infinity
+ ? positive_overflow_infinity (type)
+ : TYPE_MAX_VALUE (type)),
+ vr->equiv);
+}
+
+/* Set value range VR to a non-NULL range of type TYPE. */
+
+static inline void
+set_value_range_to_nonnull (value_range_t *vr, tree type)
+{
+ tree zero = build_int_cst (type, 0);
+ set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
+}
+
+
+/* Set value range VR to a NULL range of type TYPE. */
+
+static inline void
+set_value_range_to_null (value_range_t *vr, tree type)
+{
+ set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
+}
+
+
+/* Set value range VR to a range of a truthvalue of type TYPE. */
+
+static inline void
+set_value_range_to_truthvalue (value_range_t *vr, tree type)
+{
+ if (TYPE_PRECISION (type) == 1)
+ set_value_range_to_varying (vr);
+ else
+ set_value_range (vr, VR_RANGE,
+ build_int_cst (type, 0), build_int_cst (type, 1),
+ vr->equiv);
+}
+
+
+/* If abs (min) < abs (max), set VR to [-max, max], if
+ abs (min) >= abs (max), set VR to [-min, min]. */
+
+static void
+abs_extent_range (value_range_t *vr, tree min, tree max)
+{
+ int cmp;
+
+ gcc_assert (TREE_CODE (min) == INTEGER_CST);
+ gcc_assert (TREE_CODE (max) == INTEGER_CST);
+ gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
+ gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
+ min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
+ max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
+ if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ cmp = compare_values (min, max);
+ if (cmp == -1)
+ min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
+ else if (cmp == 0 || cmp == 1)
+ {
+ max = min;
+ min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
+ }
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
+}
+
+
+/* Return value range information for VAR.
+
+ If we have no values ranges recorded (ie, VRP is not running), then
+ return NULL. Otherwise create an empty range if none existed for VAR. */
+
+static value_range_t *
+get_value_range (const_tree var)
+{
+ static const struct value_range_d vr_const_varying
+ = { VR_VARYING, NULL_TREE, NULL_TREE, NULL };
+ value_range_t *vr;
+ tree sym;
+ unsigned ver = SSA_NAME_VERSION (var);
+
+ /* If we have no recorded ranges, then return NULL. */
+ if (! vr_value)
+ return NULL;
+
+ /* If we query the range for a new SSA name return an unmodifiable VARYING.
+ We should get here at most from the substitute-and-fold stage which
+ will never try to change values. */
+ if (ver >= num_vr_values)
+ return CONST_CAST (value_range_t *, &vr_const_varying);
+
+ vr = vr_value[ver];
+ if (vr)
+ return vr;
+
+ /* After propagation finished do not allocate new value-ranges. */
+ if (values_propagated)
+ return CONST_CAST (value_range_t *, &vr_const_varying);
+
+ /* Create a default value range. */
+ vr_value[ver] = vr = XCNEW (value_range_t);
+
+ /* Defer allocating the equivalence set. */
+ vr->equiv = NULL;
+
+ /* If VAR is a default definition of a parameter, the variable can
+ take any value in VAR's type. */
+ if (SSA_NAME_IS_DEFAULT_DEF (var))
+ {
+ sym = SSA_NAME_VAR (var);
+ if (TREE_CODE (sym) == PARM_DECL)
+ {
+ /* Try to use the "nonnull" attribute to create ~[0, 0]
+ anti-ranges for pointers. Note that this is only valid with
+ default definitions of PARM_DECLs. */
+ if (POINTER_TYPE_P (TREE_TYPE (sym))
+ && nonnull_arg_p (sym))
+ set_value_range_to_nonnull (vr, TREE_TYPE (sym));
+ else
+ set_value_range_to_varying (vr);
+ }
+ else if (TREE_CODE (sym) == RESULT_DECL
+ && DECL_BY_REFERENCE (sym))
+ set_value_range_to_nonnull (vr, TREE_TYPE (sym));
+ }
+
+ return vr;
+}
+
+/* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
+
+static inline bool
+vrp_operand_equal_p (const_tree val1, const_tree val2)
+{
+ if (val1 == val2)
+ return true;
+ if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
+ return false;
+ if (is_overflow_infinity (val1))
+ return is_overflow_infinity (val2);
+ return true;
+}
+
+/* Return true, if the bitmaps B1 and B2 are equal. */
+
+static inline bool
+vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
+{
+ return (b1 == b2
+ || ((!b1 || bitmap_empty_p (b1))
+ && (!b2 || bitmap_empty_p (b2)))
+ || (b1 && b2
+ && bitmap_equal_p (b1, b2)));
+}
+
+/* Update the value range and equivalence set for variable VAR to
+ NEW_VR. Return true if NEW_VR is different from VAR's previous
+ value.
+
+ NOTE: This function assumes that NEW_VR is a temporary value range
+ object created for the sole purpose of updating VAR's range. The
+ storage used by the equivalence set from NEW_VR will be freed by
+ this function. Do not call update_value_range when NEW_VR
+ is the range object associated with another SSA name. */
+
+static inline bool
+update_value_range (const_tree var, value_range_t *new_vr)
+{
+ value_range_t *old_vr;
+ bool is_new;
+
+ /* Update the value range, if necessary. */
+ old_vr = get_value_range (var);
+ is_new = old_vr->type != new_vr->type
+ || !vrp_operand_equal_p (old_vr->min, new_vr->min)
+ || !vrp_operand_equal_p (old_vr->max, new_vr->max)
+ || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
+
+ if (is_new)
+ {
+ /* Do not allow transitions up the lattice. The following
+ is slightly more awkward than just new_vr->type < old_vr->type
+ because VR_RANGE and VR_ANTI_RANGE need to be considered
+ the same. We may not have is_new when transitioning to
+ UNDEFINED or from VARYING. */
+ if (new_vr->type == VR_UNDEFINED
+ || old_vr->type == VR_VARYING)
+ set_value_range_to_varying (old_vr);
+ else
+ set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
+ new_vr->equiv);
+ }
+
+ BITMAP_FREE (new_vr->equiv);
+
+ return is_new;
+}
+
+
+/* Add VAR and VAR's equivalence set to EQUIV. This is the central
+ point where equivalence processing can be turned on/off. */
+
+static void
+add_equivalence (bitmap *equiv, const_tree var)
+{
+ unsigned ver = SSA_NAME_VERSION (var);
+ value_range_t *vr = vr_value[ver];
+
+ if (*equiv == NULL)
+ *equiv = BITMAP_ALLOC (NULL);
+ bitmap_set_bit (*equiv, ver);
+ if (vr && vr->equiv)
+ bitmap_ior_into (*equiv, vr->equiv);
+}
+
+
+/* Return true if VR is ~[0, 0]. */
+
+static inline bool
+range_is_nonnull (value_range_t *vr)
+{
+ return vr->type == VR_ANTI_RANGE
+ && integer_zerop (vr->min)
+ && integer_zerop (vr->max);
+}
+
+
+/* Return true if VR is [0, 0]. */
+
+static inline bool
+range_is_null (value_range_t *vr)
+{
+ return vr->type == VR_RANGE
+ && integer_zerop (vr->min)
+ && integer_zerop (vr->max);
+}
+
+/* Return true if max and min of VR are INTEGER_CST. It's not necessary
+ a singleton. */
+
+static inline bool
+range_int_cst_p (value_range_t *vr)
+{
+ return (vr->type == VR_RANGE
+ && TREE_CODE (vr->max) == INTEGER_CST
+ && TREE_CODE (vr->min) == INTEGER_CST);
+}
+
+/* Return true if VR is a INTEGER_CST singleton. */
+
+static inline bool
+range_int_cst_singleton_p (value_range_t *vr)
+{
+ return (range_int_cst_p (vr)
+ && !is_overflow_infinity (vr->min)
+ && !is_overflow_infinity (vr->max)
+ && tree_int_cst_equal (vr->min, vr->max));
+}
+
+/* Return true if value range VR involves at least one symbol. */
+
+static inline bool
+symbolic_range_p (value_range_t *vr)
+{
+ return (!is_gimple_min_invariant (vr->min)
+ || !is_gimple_min_invariant (vr->max));
+}
+
+/* Return true if value range VR uses an overflow infinity. */
+
+static inline bool
+overflow_infinity_range_p (value_range_t *vr)
+{
+ return (vr->type == VR_RANGE
+ && (is_overflow_infinity (vr->min)
+ || is_overflow_infinity (vr->max)));
+}
+
+/* Return false if we can not make a valid comparison based on VR;
+ this will be the case if it uses an overflow infinity and overflow
+ is not undefined (i.e., -fno-strict-overflow is in effect).
+ Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
+ uses an overflow infinity. */
+
+static bool
+usable_range_p (value_range_t *vr, bool *strict_overflow_p)
+{
+ gcc_assert (vr->type == VR_RANGE);
+ if (is_overflow_infinity (vr->min))
+ {
+ *strict_overflow_p = true;
+ if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
+ return false;
+ }
+ if (is_overflow_infinity (vr->max))
+ {
+ *strict_overflow_p = true;
+ if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
+ return false;
+ }
+ return true;
+}
+
+
+/* Return true if the result of assignment STMT is know to be non-negative.
+ If the return value is based on the assumption that signed overflow is
+ undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
+ *STRICT_OVERFLOW_P.*/
+
+static bool
+gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
+{
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+ switch (get_gimple_rhs_class (code))
+ {
+ case GIMPLE_UNARY_RHS:
+ return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ gimple_assign_rhs1 (stmt),
+ strict_overflow_p);
+ case GIMPLE_BINARY_RHS:
+ return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt),
+ strict_overflow_p);
+ case GIMPLE_TERNARY_RHS:
+ return false;
+ case GIMPLE_SINGLE_RHS:
+ return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
+ strict_overflow_p);
+ case GIMPLE_INVALID_RHS:
+ gcc_unreachable ();
+ default:
+ gcc_unreachable ();
+ }
+}
+
+/* Return true if return value of call STMT is know to be non-negative.
+ If the return value is based on the assumption that signed overflow is
+ undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
+ *STRICT_OVERFLOW_P.*/
+
+static bool
+gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
+{
+ tree arg0 = gimple_call_num_args (stmt) > 0 ?
+ gimple_call_arg (stmt, 0) : NULL_TREE;
+ tree arg1 = gimple_call_num_args (stmt) > 1 ?
+ gimple_call_arg (stmt, 1) : NULL_TREE;
+
+ return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
+ gimple_call_fndecl (stmt),
+ arg0,
+ arg1,
+ strict_overflow_p);
+}
+
+/* Return true if STMT is know to to compute a non-negative value.
+ If the return value is based on the assumption that signed overflow is
+ undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
+ *STRICT_OVERFLOW_P.*/
+
+static bool
+gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
+{
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_ASSIGN:
+ return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
+ case GIMPLE_CALL:
+ return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
+ default:
+ gcc_unreachable ();
+ }
+}
+
+/* Return true if the result of assignment STMT is know to be non-zero.
+ If the return value is based on the assumption that signed overflow is
+ undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
+ *STRICT_OVERFLOW_P.*/
+
+static bool
+gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
+{
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+ switch (get_gimple_rhs_class (code))
+ {
+ case GIMPLE_UNARY_RHS:
+ return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ gimple_assign_rhs1 (stmt),
+ strict_overflow_p);
+ case GIMPLE_BINARY_RHS:
+ return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt),
+ strict_overflow_p);
+ case GIMPLE_TERNARY_RHS:
+ return false;
+ case GIMPLE_SINGLE_RHS:
+ return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
+ strict_overflow_p);
+ case GIMPLE_INVALID_RHS:
+ gcc_unreachable ();
+ default:
+ gcc_unreachable ();
+ }
+}
+
+/* Return true if STMT is known to compute a non-zero value.
+ If the return value is based on the assumption that signed overflow is
+ undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
+ *STRICT_OVERFLOW_P.*/
+
+static bool
+gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
+{
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_ASSIGN:
+ return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
+ case GIMPLE_CALL:
+ {
+ tree fndecl = gimple_call_fndecl (stmt);
+ if (!fndecl) return false;
+ if (flag_delete_null_pointer_checks && !flag_check_new
+ && DECL_IS_OPERATOR_NEW (fndecl)
+ && !TREE_NOTHROW (fndecl))
+ return true;
+ if (flag_delete_null_pointer_checks &&
+ lookup_attribute ("returns_nonnull",
+ TYPE_ATTRIBUTES (gimple_call_fntype (stmt))))
+ return true;
+ return gimple_alloca_call_p (stmt);
+ }
+ default:
+ gcc_unreachable ();
+ }
+}
+
+/* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
+ obtained so far. */
+
+static bool
+vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
+{
+ if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
+ return true;
+
+ /* If we have an expression of the form &X->a, then the expression
+ is nonnull if X is nonnull. */
+ if (is_gimple_assign (stmt)
+ && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
+ {
+ tree expr = gimple_assign_rhs1 (stmt);
+ tree base = get_base_address (TREE_OPERAND (expr, 0));
+
+ if (base != NULL_TREE
+ && TREE_CODE (base) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
+ {
+ value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
+ if (range_is_nonnull (vr))
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/* Returns true if EXPR is a valid value (as expected by compare_values) --
+ a gimple invariant, or SSA_NAME +- CST. */
+
+static bool
+valid_value_p (tree expr)
+{
+ if (TREE_CODE (expr) == SSA_NAME)
+ return true;
+
+ if (TREE_CODE (expr) == PLUS_EXPR
+ || TREE_CODE (expr) == MINUS_EXPR)
+ return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
+ && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
+
+ return is_gimple_min_invariant (expr);
+}
+
+/* Return
+ 1 if VAL < VAL2
+ 0 if !(VAL < VAL2)
+ -2 if those are incomparable. */
+static inline int
+operand_less_p (tree val, tree val2)
+{
+ /* LT is folded faster than GE and others. Inline the common case. */
+ if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
+ {
+ if (TYPE_UNSIGNED (TREE_TYPE (val)))
+ return INT_CST_LT_UNSIGNED (val, val2);
+ else
+ {
+ if (INT_CST_LT (val, val2))
+ return 1;
+ }
+ }
+ else
+ {
+ tree tcmp;
+
+ fold_defer_overflow_warnings ();
+
+ tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
+
+ fold_undefer_and_ignore_overflow_warnings ();
+
+ if (!tcmp
+ || TREE_CODE (tcmp) != INTEGER_CST)
+ return -2;
+
+ if (!integer_zerop (tcmp))
+ return 1;
+ }
+
+ /* val >= val2, not considering overflow infinity. */
+ if (is_negative_overflow_infinity (val))
+ return is_negative_overflow_infinity (val2) ? 0 : 1;
+ else if (is_positive_overflow_infinity (val2))
+ return is_positive_overflow_infinity (val) ? 0 : 1;
+
+ return 0;
+}
+
+/* Compare two values VAL1 and VAL2. Return
+
+ -2 if VAL1 and VAL2 cannot be compared at compile-time,
+ -1 if VAL1 < VAL2,
+ 0 if VAL1 == VAL2,
+ +1 if VAL1 > VAL2, and
+ +2 if VAL1 != VAL2
+
+ This is similar to tree_int_cst_compare but supports pointer values
+ and values that cannot be compared at compile time.
+
+ If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
+ true if the return value is only valid if we assume that signed
+ overflow is undefined. */
+
+static int
+compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
+{
+ if (val1 == val2)
+ return 0;
+
+ /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
+ both integers. */
+ gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
+ == POINTER_TYPE_P (TREE_TYPE (val2)));
+ /* Convert the two values into the same type. This is needed because
+ sizetype causes sign extension even for unsigned types. */
+ val2 = fold_convert (TREE_TYPE (val1), val2);
+ STRIP_USELESS_TYPE_CONVERSION (val2);
+
+ if ((TREE_CODE (val1) == SSA_NAME
+ || TREE_CODE (val1) == PLUS_EXPR
+ || TREE_CODE (val1) == MINUS_EXPR)
+ && (TREE_CODE (val2) == SSA_NAME
+ || TREE_CODE (val2) == PLUS_EXPR
+ || TREE_CODE (val2) == MINUS_EXPR))
+ {
+ tree n1, c1, n2, c2;
+ enum tree_code code1, code2;
+
+ /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
+ return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
+ same name, return -2. */
+ if (TREE_CODE (val1) == SSA_NAME)
+ {
+ code1 = SSA_NAME;
+ n1 = val1;
+ c1 = NULL_TREE;
+ }
+ else
+ {
+ code1 = TREE_CODE (val1);
+ n1 = TREE_OPERAND (val1, 0);
+ c1 = TREE_OPERAND (val1, 1);
+ if (tree_int_cst_sgn (c1) == -1)
+ {
+ if (is_negative_overflow_infinity (c1))
+ return -2;
+ c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
+ if (!c1)
+ return -2;
+ code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
+ }
+ }
+
+ if (TREE_CODE (val2) == SSA_NAME)
+ {
+ code2 = SSA_NAME;
+ n2 = val2;
+ c2 = NULL_TREE;
+ }
+ else
+ {
+ code2 = TREE_CODE (val2);
+ n2 = TREE_OPERAND (val2, 0);
+ c2 = TREE_OPERAND (val2, 1);
+ if (tree_int_cst_sgn (c2) == -1)
+ {
+ if (is_negative_overflow_infinity (c2))
+ return -2;
+ c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
+ if (!c2)
+ return -2;
+ code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
+ }
+ }
+
+ /* Both values must use the same name. */
+ if (n1 != n2)
+ return -2;
+
+ if (code1 == SSA_NAME
+ && code2 == SSA_NAME)
+ /* NAME == NAME */
+ return 0;
+
+ /* If overflow is defined we cannot simplify more. */
+ if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
+ return -2;
+
+ if (strict_overflow_p != NULL
+ && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
+ && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
+ *strict_overflow_p = true;
+
+ if (code1 == SSA_NAME)
+ {
+ if (code2 == PLUS_EXPR)
+ /* NAME < NAME + CST */
+ return -1;
+ else if (code2 == MINUS_EXPR)
+ /* NAME > NAME - CST */
+ return 1;
+ }
+ else if (code1 == PLUS_EXPR)
+ {
+ if (code2 == SSA_NAME)
+ /* NAME + CST > NAME */
+ return 1;
+ else if (code2 == PLUS_EXPR)
+ /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
+ return compare_values_warnv (c1, c2, strict_overflow_p);
+ else if (code2 == MINUS_EXPR)
+ /* NAME + CST1 > NAME - CST2 */
+ return 1;
+ }
+ else if (code1 == MINUS_EXPR)
+ {
+ if (code2 == SSA_NAME)
+ /* NAME - CST < NAME */
+ return -1;
+ else if (code2 == PLUS_EXPR)
+ /* NAME - CST1 < NAME + CST2 */
+ return -1;
+ else if (code2 == MINUS_EXPR)
+ /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
+ C1 and C2 are swapped in the call to compare_values. */
+ return compare_values_warnv (c2, c1, strict_overflow_p);
+ }
+
+ gcc_unreachable ();
+ }
+
+ /* We cannot compare non-constants. */
+ if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
+ return -2;
+
+ if (!POINTER_TYPE_P (TREE_TYPE (val1)))
+ {
+ /* We cannot compare overflowed values, except for overflow
+ infinities. */
+ if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
+ {
+ if (strict_overflow_p != NULL)
+ *strict_overflow_p = true;
+ if (is_negative_overflow_infinity (val1))
+ return is_negative_overflow_infinity (val2) ? 0 : -1;
+ else if (is_negative_overflow_infinity (val2))
+ return 1;
+ else if (is_positive_overflow_infinity (val1))
+ return is_positive_overflow_infinity (val2) ? 0 : 1;
+ else if (is_positive_overflow_infinity (val2))
+ return -1;
+ return -2;
+ }
+
+ return tree_int_cst_compare (val1, val2);
+ }
+ else
+ {
+ tree t;
+
+ /* First see if VAL1 and VAL2 are not the same. */
+ if (val1 == val2 || operand_equal_p (val1, val2, 0))
+ return 0;
+
+ /* If VAL1 is a lower address than VAL2, return -1. */
+ if (operand_less_p (val1, val2) == 1)
+ return -1;
+
+ /* If VAL1 is a higher address than VAL2, return +1. */
+ if (operand_less_p (val2, val1) == 1)
+ return 1;
+
+ /* If VAL1 is different than VAL2, return +2.
+ For integer constants we either have already returned -1 or 1
+ or they are equivalent. We still might succeed in proving
+ something about non-trivial operands. */
+ if (TREE_CODE (val1) != INTEGER_CST
+ || TREE_CODE (val2) != INTEGER_CST)
+ {
+ t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
+ if (t && integer_onep (t))
+ return 2;
+ }
+
+ return -2;
+ }
+}
+
+/* Compare values like compare_values_warnv, but treat comparisons of
+ nonconstants which rely on undefined overflow as incomparable. */
+
+static int
+compare_values (tree val1, tree val2)
+{
+ bool sop;
+ int ret;
+
+ sop = false;
+ ret = compare_values_warnv (val1, val2, &sop);
+ if (sop
+ && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
+ ret = -2;
+ return ret;
+}
+
+
+/* Return 1 if VAL is inside value range MIN <= VAL <= MAX,
+ 0 if VAL is not inside [MIN, MAX],
+ -2 if we cannot tell either way.
+
+ Benchmark compile/20001226-1.c compilation time after changing this
+ function. */
+
+static inline int
+value_inside_range (tree val, tree min, tree max)
+{
+ int cmp1, cmp2;
+
+ cmp1 = operand_less_p (val, min);
+ if (cmp1 == -2)
+ return -2;
+ if (cmp1 == 1)
+ return 0;
+
+ cmp2 = operand_less_p (max, val);
+ if (cmp2 == -2)
+ return -2;
+
+ return !cmp2;
+}
+
+
+/* Return true if value ranges VR0 and VR1 have a non-empty
+ intersection.
+
+ Benchmark compile/20001226-1.c compilation time after changing this
+ function.
+ */
+
+static inline bool
+value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
+{
+ /* The value ranges do not intersect if the maximum of the first range is
+ less than the minimum of the second range or vice versa.
+ When those relations are unknown, we can't do any better. */
+ if (operand_less_p (vr0->max, vr1->min) != 0)
+ return false;
+ if (operand_less_p (vr1->max, vr0->min) != 0)
+ return false;
+ return true;
+}
+
+
+/* Return 1 if [MIN, MAX] includes the value zero, 0 if it does not
+ include the value zero, -2 if we cannot tell. */
+
+static inline int
+range_includes_zero_p (tree min, tree max)
+{
+ tree zero = build_int_cst (TREE_TYPE (min), 0);
+ return value_inside_range (zero, min, max);
+}
+
+/* Return true if *VR is know to only contain nonnegative values. */
+
+static inline bool
+value_range_nonnegative_p (value_range_t *vr)
+{
+ /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
+ which would return a useful value should be encoded as a
+ VR_RANGE. */
+ if (vr->type == VR_RANGE)
+ {
+ int result = compare_values (vr->min, integer_zero_node);
+ return (result == 0 || result == 1);
+ }
+
+ return false;
+}
+
+/* If *VR has a value rante that is a single constant value return that,
+ otherwise return NULL_TREE. */
+
+static tree
+value_range_constant_singleton (value_range_t *vr)
+{
+ if (vr->type == VR_RANGE
+ && operand_equal_p (vr->min, vr->max, 0)
+ && is_gimple_min_invariant (vr->min))
+ return vr->min;
+
+ return NULL_TREE;
+}
+
+/* If OP has a value range with a single constant value return that,
+ otherwise return NULL_TREE. This returns OP itself if OP is a
+ constant. */
+
+static tree
+op_with_constant_singleton_value_range (tree op)
+{
+ if (is_gimple_min_invariant (op))
+ return op;
+
+ if (TREE_CODE (op) != SSA_NAME)
+ return NULL_TREE;
+
+ return value_range_constant_singleton (get_value_range (op));
+}
+
+/* Return true if op is in a boolean [0, 1] value-range. */
+
+static bool
+op_with_boolean_value_range_p (tree op)
+{
+ value_range_t *vr;
+
+ if (TYPE_PRECISION (TREE_TYPE (op)) == 1)
+ return true;
+
+ if (integer_zerop (op)
+ || integer_onep (op))
+ return true;
+
+ if (TREE_CODE (op) != SSA_NAME)
+ return false;
+
+ vr = get_value_range (op);
+ return (vr->type == VR_RANGE
+ && integer_zerop (vr->min)
+ && integer_onep (vr->max));
+}
+
+/* Extract value range information from an ASSERT_EXPR EXPR and store
+ it in *VR_P. */
+
+static void
+extract_range_from_assert (value_range_t *vr_p, tree expr)
+{
+ tree var, cond, limit, min, max, type;
+ value_range_t *limit_vr;
+ enum tree_code cond_code;
+
+ var = ASSERT_EXPR_VAR (expr);
+ cond = ASSERT_EXPR_COND (expr);
+
+ gcc_assert (COMPARISON_CLASS_P (cond));
+
+ /* Find VAR in the ASSERT_EXPR conditional. */
+ if (var == TREE_OPERAND (cond, 0)
+ || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
+ || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
+ {
+ /* If the predicate is of the form VAR COMP LIMIT, then we just
+ take LIMIT from the RHS and use the same comparison code. */
+ cond_code = TREE_CODE (cond);
+ limit = TREE_OPERAND (cond, 1);
+ cond = TREE_OPERAND (cond, 0);
+ }
+ else
+ {
+ /* If the predicate is of the form LIMIT COMP VAR, then we need
+ to flip around the comparison code to create the proper range
+ for VAR. */
+ cond_code = swap_tree_comparison (TREE_CODE (cond));
+ limit = TREE_OPERAND (cond, 0);
+ cond = TREE_OPERAND (cond, 1);
+ }
+
+ limit = avoid_overflow_infinity (limit);
+
+ type = TREE_TYPE (var);
+ gcc_assert (limit != var);
+
+ /* For pointer arithmetic, we only keep track of pointer equality
+ and inequality. */
+ if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
+ {
+ set_value_range_to_varying (vr_p);
+ return;
+ }
+
+ /* If LIMIT is another SSA name and LIMIT has a range of its own,
+ try to use LIMIT's range to avoid creating symbolic ranges
+ unnecessarily. */
+ limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
+
+ /* LIMIT's range is only interesting if it has any useful information. */
+ if (limit_vr
+ && (limit_vr->type == VR_UNDEFINED
+ || limit_vr->type == VR_VARYING
+ || symbolic_range_p (limit_vr)))
+ limit_vr = NULL;
+
+ /* Initially, the new range has the same set of equivalences of
+ VAR's range. This will be revised before returning the final
+ value. Since assertions may be chained via mutually exclusive
+ predicates, we will need to trim the set of equivalences before
+ we are done. */
+ gcc_assert (vr_p->equiv == NULL);
+ add_equivalence (&vr_p->equiv, var);
+
+ /* Extract a new range based on the asserted comparison for VAR and
+ LIMIT's value range. Notice that if LIMIT has an anti-range, we
+ will only use it for equality comparisons (EQ_EXPR). For any
+ other kind of assertion, we cannot derive a range from LIMIT's
+ anti-range that can be used to describe the new range. For
+ instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
+ then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
+ no single range for x_2 that could describe LE_EXPR, so we might
+ as well build the range [b_4, +INF] for it.
+ One special case we handle is extracting a range from a
+ range test encoded as (unsigned)var + CST <= limit. */
+ if (TREE_CODE (cond) == NOP_EXPR
+ || TREE_CODE (cond) == PLUS_EXPR)
+ {
+ if (TREE_CODE (cond) == PLUS_EXPR)
+ {
+ min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
+ TREE_OPERAND (cond, 1));
+ max = int_const_binop (PLUS_EXPR, limit, min);
+ cond = TREE_OPERAND (cond, 0);
+ }
+ else
+ {
+ min = build_int_cst (TREE_TYPE (var), 0);
+ max = limit;
+ }
+
+ /* Make sure to not set TREE_OVERFLOW on the final type
+ conversion. We are willingly interpreting large positive
+ unsigned values as negative singed values here. */
+ min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
+ 0, false);
+ max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
+ 0, false);
+
+ /* We can transform a max, min range to an anti-range or
+ vice-versa. Use set_and_canonicalize_value_range which does
+ this for us. */
+ if (cond_code == LE_EXPR)
+ set_and_canonicalize_value_range (vr_p, VR_RANGE,
+ min, max, vr_p->equiv);
+ else if (cond_code == GT_EXPR)
+ set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
+ min, max, vr_p->equiv);
+ else
+ gcc_unreachable ();
+ }
+ else if (cond_code == EQ_EXPR)
+ {
+ enum value_range_type range_type;
+
+ if (limit_vr)
+ {
+ range_type = limit_vr->type;
+ min = limit_vr->min;
+ max = limit_vr->max;
+ }
+ else
+ {
+ range_type = VR_RANGE;
+ min = limit;
+ max = limit;
+ }
+
+ set_value_range (vr_p, range_type, min, max, vr_p->equiv);
+
+ /* When asserting the equality VAR == LIMIT and LIMIT is another
+ SSA name, the new range will also inherit the equivalence set
+ from LIMIT. */
+ if (TREE_CODE (limit) == SSA_NAME)
+ add_equivalence (&vr_p->equiv, limit);
+ }
+ else if (cond_code == NE_EXPR)
+ {
+ /* As described above, when LIMIT's range is an anti-range and
+ this assertion is an inequality (NE_EXPR), then we cannot
+ derive anything from the anti-range. For instance, if
+ LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
+ not imply that VAR's range is [0, 0]. So, in the case of
+ anti-ranges, we just assert the inequality using LIMIT and
+ not its anti-range.
+
+ If LIMIT_VR is a range, we can only use it to build a new
+ anti-range if LIMIT_VR is a single-valued range. For
+ instance, if LIMIT_VR is [0, 1], the predicate
+ VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
+ Rather, it means that for value 0 VAR should be ~[0, 0]
+ and for value 1, VAR should be ~[1, 1]. We cannot
+ represent these ranges.
+
+ The only situation in which we can build a valid
+ anti-range is when LIMIT_VR is a single-valued range
+ (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
+ build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
+ if (limit_vr
+ && limit_vr->type == VR_RANGE
+ && compare_values (limit_vr->min, limit_vr->max) == 0)
+ {
+ min = limit_vr->min;
+ max = limit_vr->max;
+ }
+ else
+ {
+ /* In any other case, we cannot use LIMIT's range to build a
+ valid anti-range. */
+ min = max = limit;
+ }
+
+ /* If MIN and MAX cover the whole range for their type, then
+ just use the original LIMIT. */
+ if (INTEGRAL_TYPE_P (type)
+ && vrp_val_is_min (min)
+ && vrp_val_is_max (max))
+ min = max = limit;
+
+ set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
+ min, max, vr_p->equiv);
+ }
+ else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
+ {
+ min = TYPE_MIN_VALUE (type);
+
+ if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
+ max = limit;
+ else
+ {
+ /* If LIMIT_VR is of the form [N1, N2], we need to build the
+ range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
+ LT_EXPR. */
+ max = limit_vr->max;
+ }
+
+ /* If the maximum value forces us to be out of bounds, simply punt.
+ It would be pointless to try and do anything more since this
+ all should be optimized away above us. */
+ if ((cond_code == LT_EXPR
+ && compare_values (max, min) == 0)
+ || is_overflow_infinity (max))
+ set_value_range_to_varying (vr_p);
+ else
+ {
+ /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
+ if (cond_code == LT_EXPR)
+ {
+ if (TYPE_PRECISION (TREE_TYPE (max)) == 1
+ && !TYPE_UNSIGNED (TREE_TYPE (max)))
+ max = fold_build2 (PLUS_EXPR, TREE_TYPE (max), max,
+ build_int_cst (TREE_TYPE (max), -1));
+ else
+ max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max,
+ build_int_cst (TREE_TYPE (max), 1));
+ if (EXPR_P (max))
+ TREE_NO_WARNING (max) = 1;
+ }
+
+ set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
+ }
+ }
+ else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
+ {
+ max = TYPE_MAX_VALUE (type);
+
+ if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
+ min = limit;
+ else
+ {
+ /* If LIMIT_VR is of the form [N1, N2], we need to build the
+ range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
+ GT_EXPR. */
+ min = limit_vr->min;
+ }
+
+ /* If the minimum value forces us to be out of bounds, simply punt.
+ It would be pointless to try and do anything more since this
+ all should be optimized away above us. */
+ if ((cond_code == GT_EXPR
+ && compare_values (min, max) == 0)
+ || is_overflow_infinity (min))
+ set_value_range_to_varying (vr_p);
+ else
+ {
+ /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
+ if (cond_code == GT_EXPR)
+ {
+ if (TYPE_PRECISION (TREE_TYPE (min)) == 1
+ && !TYPE_UNSIGNED (TREE_TYPE (min)))
+ min = fold_build2 (MINUS_EXPR, TREE_TYPE (min), min,
+ build_int_cst (TREE_TYPE (min), -1));
+ else
+ min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min,
+ build_int_cst (TREE_TYPE (min), 1));
+ if (EXPR_P (min))
+ TREE_NO_WARNING (min) = 1;
+ }
+
+ set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
+ }
+ }
+ else
+ gcc_unreachable ();
+
+ /* Finally intersect the new range with what we already know about var. */
+ vrp_intersect_ranges (vr_p, get_value_range (var));
+}
+
+
+/* Extract range information from SSA name VAR and store it in VR. If
+ VAR has an interesting range, use it. Otherwise, create the
+ range [VAR, VAR] and return it. This is useful in situations where
+ we may have conditionals testing values of VARYING names. For
+ instance,
+
+ x_3 = y_5;
+ if (x_3 > y_5)
+ ...
+
+ Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
+ always false. */
+
+static void
+extract_range_from_ssa_name (value_range_t *vr, tree var)
+{
+ value_range_t *var_vr = get_value_range (var);
+
+ if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
+ copy_value_range (vr, var_vr);
+ else
+ set_value_range (vr, VR_RANGE, var, var, NULL);
+
+ add_equivalence (&vr->equiv, var);
+}
+
+
+/* Wrapper around int_const_binop. If the operation overflows and we
+ are not using wrapping arithmetic, then adjust the result to be
+ -INF or +INF depending on CODE, VAL1 and VAL2. This can return
+ NULL_TREE if we need to use an overflow infinity representation but
+ the type does not support it. */
+
+static tree
+vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
+{
+ tree res;
+
+ res = int_const_binop (code, val1, val2);
+
+ /* If we are using unsigned arithmetic, operate symbolically
+ on -INF and +INF as int_const_binop only handles signed overflow. */
+ if (TYPE_UNSIGNED (TREE_TYPE (val1)))
+ {
+ int checkz = compare_values (res, val1);
+ bool overflow = false;
+
+ /* Ensure that res = val1 [+*] val2 >= val1
+ or that res = val1 - val2 <= val1. */
+ if ((code == PLUS_EXPR
+ && !(checkz == 1 || checkz == 0))
+ || (code == MINUS_EXPR
+ && !(checkz == 0 || checkz == -1)))
+ {
+ overflow = true;
+ }
+ /* Checking for multiplication overflow is done by dividing the
+ output of the multiplication by the first input of the
+ multiplication. If the result of that division operation is
+ not equal to the second input of the multiplication, then the
+ multiplication overflowed. */
+ else if (code == MULT_EXPR && !integer_zerop (val1))
+ {
+ tree tmp = int_const_binop (TRUNC_DIV_EXPR,
+ res,
+ val1);
+ int check = compare_values (tmp, val2);
+
+ if (check != 0)
+ overflow = true;
+ }
+
+ if (overflow)
+ {
+ res = copy_node (res);
+ TREE_OVERFLOW (res) = 1;
+ }
+
+ }
+ else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
+ /* If the singed operation wraps then int_const_binop has done
+ everything we want. */
+ ;
+ else if ((TREE_OVERFLOW (res)
+ && !TREE_OVERFLOW (val1)
+ && !TREE_OVERFLOW (val2))
+ || is_overflow_infinity (val1)
+ || is_overflow_infinity (val2))
+ {
+ /* If the operation overflowed but neither VAL1 nor VAL2 are
+ overflown, return -INF or +INF depending on the operation
+ and the combination of signs of the operands. */
+ int sgn1 = tree_int_cst_sgn (val1);
+ int sgn2 = tree_int_cst_sgn (val2);
+
+ if (needs_overflow_infinity (TREE_TYPE (res))
+ && !supports_overflow_infinity (TREE_TYPE (res)))
+ return NULL_TREE;
+
+ /* We have to punt on adding infinities of different signs,
+ since we can't tell what the sign of the result should be.
+ Likewise for subtracting infinities of the same sign. */
+ if (((code == PLUS_EXPR && sgn1 != sgn2)
+ || (code == MINUS_EXPR && sgn1 == sgn2))
+ && is_overflow_infinity (val1)
+ && is_overflow_infinity (val2))
+ return NULL_TREE;
+
+ /* Don't try to handle division or shifting of infinities. */
+ if ((code == TRUNC_DIV_EXPR
+ || code == FLOOR_DIV_EXPR
+ || code == CEIL_DIV_EXPR
+ || code == EXACT_DIV_EXPR
+ || code == ROUND_DIV_EXPR
+ || code == RSHIFT_EXPR)
+ && (is_overflow_infinity (val1)
+ || is_overflow_infinity (val2)))
+ return NULL_TREE;
+
+ /* Notice that we only need to handle the restricted set of
+ operations handled by extract_range_from_binary_expr.
+ Among them, only multiplication, addition and subtraction
+ can yield overflow without overflown operands because we
+ are working with integral types only... except in the
+ case VAL1 = -INF and VAL2 = -1 which overflows to +INF
+ for division too. */
+
+ /* For multiplication, the sign of the overflow is given
+ by the comparison of the signs of the operands. */
+ if ((code == MULT_EXPR && sgn1 == sgn2)
+ /* For addition, the operands must be of the same sign
+ to yield an overflow. Its sign is therefore that
+ of one of the operands, for example the first. For
+ infinite operands X + -INF is negative, not positive. */
+ || (code == PLUS_EXPR
+ && (sgn1 >= 0
+ ? !is_negative_overflow_infinity (val2)
+ : is_positive_overflow_infinity (val2)))
+ /* For subtraction, non-infinite operands must be of
+ different signs to yield an overflow. Its sign is
+ therefore that of the first operand or the opposite of
+ that of the second operand. A first operand of 0 counts
+ as positive here, for the corner case 0 - (-INF), which
+ overflows, but must yield +INF. For infinite operands 0
+ - INF is negative, not positive. */
+ || (code == MINUS_EXPR
+ && (sgn1 >= 0
+ ? !is_positive_overflow_infinity (val2)
+ : is_negative_overflow_infinity (val2)))
+ /* We only get in here with positive shift count, so the
+ overflow direction is the same as the sign of val1.
+ Actually rshift does not overflow at all, but we only
+ handle the case of shifting overflowed -INF and +INF. */
+ || (code == RSHIFT_EXPR
+ && sgn1 >= 0)
+ /* For division, the only case is -INF / -1 = +INF. */
+ || code == TRUNC_DIV_EXPR
+ || code == FLOOR_DIV_EXPR
+ || code == CEIL_DIV_EXPR
+ || code == EXACT_DIV_EXPR
+ || code == ROUND_DIV_EXPR)
+ return (needs_overflow_infinity (TREE_TYPE (res))
+ ? positive_overflow_infinity (TREE_TYPE (res))
+ : TYPE_MAX_VALUE (TREE_TYPE (res)));
+ else
+ return (needs_overflow_infinity (TREE_TYPE (res))
+ ? negative_overflow_infinity (TREE_TYPE (res))
+ : TYPE_MIN_VALUE (TREE_TYPE (res)));
+ }
+
+ return res;
+}
+
+
+/* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
+ bitmask if some bit is unset, it means for all numbers in the range
+ the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
+ bitmask if some bit is set, it means for all numbers in the range
+ the bit is 1, otherwise it might be 0 or 1. */
+
+static bool
+zero_nonzero_bits_from_vr (value_range_t *vr,
+ double_int *may_be_nonzero,
+ double_int *must_be_nonzero)
+{
+ *may_be_nonzero = double_int_minus_one;
+ *must_be_nonzero = double_int_zero;
+ if (!range_int_cst_p (vr)
+ || is_overflow_infinity (vr->min)
+ || is_overflow_infinity (vr->max))
+ return false;
+
+ if (range_int_cst_singleton_p (vr))
+ {
+ *may_be_nonzero = tree_to_double_int (vr->min);
+ *must_be_nonzero = *may_be_nonzero;
+ }
+ else if (tree_int_cst_sgn (vr->min) >= 0
+ || tree_int_cst_sgn (vr->max) < 0)
+ {
+ double_int dmin = tree_to_double_int (vr->min);
+ double_int dmax = tree_to_double_int (vr->max);
+ double_int xor_mask = dmin ^ dmax;
+ *may_be_nonzero = dmin | dmax;
+ *must_be_nonzero = dmin & dmax;
+ if (xor_mask.high != 0)
+ {
+ unsigned HOST_WIDE_INT mask
+ = ((unsigned HOST_WIDE_INT) 1
+ << floor_log2 (xor_mask.high)) - 1;
+ may_be_nonzero->low = ALL_ONES;
+ may_be_nonzero->high |= mask;
+ must_be_nonzero->low = 0;
+ must_be_nonzero->high &= ~mask;
+ }
+ else if (xor_mask.low != 0)
+ {
+ unsigned HOST_WIDE_INT mask
+ = ((unsigned HOST_WIDE_INT) 1
+ << floor_log2 (xor_mask.low)) - 1;
+ may_be_nonzero->low |= mask;
+ must_be_nonzero->low &= ~mask;
+ }
+ }
+
+ return true;
+}
+
+/* Create two value-ranges in *VR0 and *VR1 from the anti-range *AR
+ so that *VR0 U *VR1 == *AR. Returns true if that is possible,
+ false otherwise. If *AR can be represented with a single range
+ *VR1 will be VR_UNDEFINED. */
+
+static bool
+ranges_from_anti_range (value_range_t *ar,
+ value_range_t *vr0, value_range_t *vr1)
+{
+ tree type = TREE_TYPE (ar->min);
+
+ vr0->type = VR_UNDEFINED;
+ vr1->type = VR_UNDEFINED;
+
+ if (ar->type != VR_ANTI_RANGE
+ || TREE_CODE (ar->min) != INTEGER_CST
+ || TREE_CODE (ar->max) != INTEGER_CST
+ || !vrp_val_min (type)
+ || !vrp_val_max (type))
+ return false;
+
+ if (!vrp_val_is_min (ar->min))
+ {
+ vr0->type = VR_RANGE;
+ vr0->min = vrp_val_min (type);
+ vr0->max
+ = double_int_to_tree (type,
+ tree_to_double_int (ar->min) - double_int_one);
+ }
+ if (!vrp_val_is_max (ar->max))
+ {
+ vr1->type = VR_RANGE;
+ vr1->min
+ = double_int_to_tree (type,
+ tree_to_double_int (ar->max) + double_int_one);
+ vr1->max = vrp_val_max (type);
+ }
+ if (vr0->type == VR_UNDEFINED)
+ {
+ *vr0 = *vr1;
+ vr1->type = VR_UNDEFINED;
+ }
+
+ return vr0->type != VR_UNDEFINED;
+}
+
+/* Helper to extract a value-range *VR for a multiplicative operation
+ *VR0 CODE *VR1. */
+
+static void
+extract_range_from_multiplicative_op_1 (value_range_t *vr,
+ enum tree_code code,
+ value_range_t *vr0, value_range_t *vr1)
+{
+ enum value_range_type type;
+ tree val[4];
+ size_t i;
+ tree min, max;
+ bool sop;
+ int cmp;
+
+ /* Multiplications, divisions and shifts are a bit tricky to handle,
+ depending on the mix of signs we have in the two ranges, we
+ need to operate on different values to get the minimum and
+ maximum values for the new range. One approach is to figure
+ out all the variations of range combinations and do the
+ operations.
+
+ However, this involves several calls to compare_values and it
+ is pretty convoluted. It's simpler to do the 4 operations
+ (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
+ MAX1) and then figure the smallest and largest values to form
+ the new range. */
+ gcc_assert (code == MULT_EXPR
+ || code == TRUNC_DIV_EXPR
+ || code == FLOOR_DIV_EXPR
+ || code == CEIL_DIV_EXPR
+ || code == EXACT_DIV_EXPR
+ || code == ROUND_DIV_EXPR
+ || code == RSHIFT_EXPR
+ || code == LSHIFT_EXPR);
+ gcc_assert ((vr0->type == VR_RANGE
+ || (code == MULT_EXPR && vr0->type == VR_ANTI_RANGE))
+ && vr0->type == vr1->type);
+
+ type = vr0->type;
+
+ /* Compute the 4 cross operations. */
+ sop = false;
+ val[0] = vrp_int_const_binop (code, vr0->min, vr1->min);
+ if (val[0] == NULL_TREE)
+ sop = true;
+
+ if (vr1->max == vr1->min)
+ val[1] = NULL_TREE;
+ else
+ {
+ val[1] = vrp_int_const_binop (code, vr0->min, vr1->max);
+ if (val[1] == NULL_TREE)
+ sop = true;
+ }
+
+ if (vr0->max == vr0->min)
+ val[2] = NULL_TREE;
+ else
+ {
+ val[2] = vrp_int_const_binop (code, vr0->max, vr1->min);
+ if (val[2] == NULL_TREE)
+ sop = true;
+ }
+
+ if (vr0->min == vr0->max || vr1->min == vr1->max)
+ val[3] = NULL_TREE;
+ else
+ {
+ val[3] = vrp_int_const_binop (code, vr0->max, vr1->max);
+ if (val[3] == NULL_TREE)
+ sop = true;
+ }
+
+ if (sop)
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* Set MIN to the minimum of VAL[i] and MAX to the maximum
+ of VAL[i]. */
+ min = val[0];
+ max = val[0];
+ for (i = 1; i < 4; i++)
+ {
+ if (!is_gimple_min_invariant (min)
+ || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
+ || !is_gimple_min_invariant (max)
+ || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
+ break;
+
+ if (val[i])
+ {
+ if (!is_gimple_min_invariant (val[i])
+ || (TREE_OVERFLOW (val[i])
+ && !is_overflow_infinity (val[i])))
+ {
+ /* If we found an overflowed value, set MIN and MAX
+ to it so that we set the resulting range to
+ VARYING. */
+ min = max = val[i];
+ break;
+ }
+
+ if (compare_values (val[i], min) == -1)
+ min = val[i];
+
+ if (compare_values (val[i], max) == 1)
+ max = val[i];
+ }
+ }
+
+ /* If either MIN or MAX overflowed, then set the resulting range to
+ VARYING. But we do accept an overflow infinity
+ representation. */
+ if (min == NULL_TREE
+ || !is_gimple_min_invariant (min)
+ || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
+ || max == NULL_TREE
+ || !is_gimple_min_invariant (max)
+ || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* We punt if:
+ 1) [-INF, +INF]
+ 2) [-INF, +-INF(OVF)]
+ 3) [+-INF(OVF), +INF]
+ 4) [+-INF(OVF), +-INF(OVF)]
+ We learn nothing when we have INF and INF(OVF) on both sides.
+ Note that we do accept [-INF, -INF] and [+INF, +INF] without
+ overflow. */
+ if ((vrp_val_is_min (min) || is_overflow_infinity (min))
+ && (vrp_val_is_max (max) || is_overflow_infinity (max)))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ cmp = compare_values (min, max);
+ if (cmp == -2 || cmp == 1)
+ {
+ /* If the new range has its limits swapped around (MIN > MAX),
+ then the operation caused one of them to wrap around, mark
+ the new range VARYING. */
+ set_value_range_to_varying (vr);
+ }
+ else
+ set_value_range (vr, type, min, max, NULL);
+}
+
+/* Some quadruple precision helpers. */
+static int
+quad_int_cmp (double_int l0, double_int h0,
+ double_int l1, double_int h1, bool uns)
+{
+ int c = h0.cmp (h1, uns);
+ if (c != 0) return c;
+ return l0.ucmp (l1);
+}
+
+static void
+quad_int_pair_sort (double_int *l0, double_int *h0,
+ double_int *l1, double_int *h1, bool uns)
+{
+ if (quad_int_cmp (*l0, *h0, *l1, *h1, uns) > 0)
+ {
+ double_int tmp;
+ tmp = *l0; *l0 = *l1; *l1 = tmp;
+ tmp = *h0; *h0 = *h1; *h1 = tmp;
+ }
+}
+
+/* Extract range information from a binary operation CODE based on
+ the ranges of each of its operands, *VR0 and *VR1 with resulting
+ type EXPR_TYPE. The resulting range is stored in *VR. */
+
+static void
+extract_range_from_binary_expr_1 (value_range_t *vr,
+ enum tree_code code, tree expr_type,
+ value_range_t *vr0_, value_range_t *vr1_)
+{
+ value_range_t vr0 = *vr0_, vr1 = *vr1_;
+ value_range_t vrtem0 = VR_INITIALIZER, vrtem1 = VR_INITIALIZER;
+ enum value_range_type type;
+ tree min = NULL_TREE, max = NULL_TREE;
+ int cmp;
+
+ if (!INTEGRAL_TYPE_P (expr_type)
+ && !POINTER_TYPE_P (expr_type))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* Not all binary expressions can be applied to ranges in a
+ meaningful way. Handle only arithmetic operations. */
+ if (code != PLUS_EXPR
+ && code != MINUS_EXPR
+ && code != POINTER_PLUS_EXPR
+ && code != MULT_EXPR
+ && code != TRUNC_DIV_EXPR
+ && code != FLOOR_DIV_EXPR
+ && code != CEIL_DIV_EXPR
+ && code != EXACT_DIV_EXPR
+ && code != ROUND_DIV_EXPR
+ && code != TRUNC_MOD_EXPR
+ && code != RSHIFT_EXPR
+ && code != LSHIFT_EXPR
+ && code != MIN_EXPR
+ && code != MAX_EXPR
+ && code != BIT_AND_EXPR
+ && code != BIT_IOR_EXPR
+ && code != BIT_XOR_EXPR)
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* If both ranges are UNDEFINED, so is the result. */
+ if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED)
+ {
+ set_value_range_to_undefined (vr);
+ return;
+ }
+ /* If one of the ranges is UNDEFINED drop it to VARYING for the following
+ code. At some point we may want to special-case operations that
+ have UNDEFINED result for all or some value-ranges of the not UNDEFINED
+ operand. */
+ else if (vr0.type == VR_UNDEFINED)
+ set_value_range_to_varying (&vr0);
+ else if (vr1.type == VR_UNDEFINED)
+ set_value_range_to_varying (&vr1);
+
+ /* Now canonicalize anti-ranges to ranges when they are not symbolic
+ and express ~[] op X as ([]' op X) U ([]'' op X). */
+ if (vr0.type == VR_ANTI_RANGE
+ && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1))
+ {
+ extract_range_from_binary_expr_1 (vr, code, expr_type, &vrtem0, vr1_);
+ if (vrtem1.type != VR_UNDEFINED)
+ {
+ value_range_t vrres = VR_INITIALIZER;
+ extract_range_from_binary_expr_1 (&vrres, code, expr_type,
+ &vrtem1, vr1_);
+ vrp_meet (vr, &vrres);
+ }
+ return;
+ }
+ /* Likewise for X op ~[]. */
+ if (vr1.type == VR_ANTI_RANGE
+ && ranges_from_anti_range (&vr1, &vrtem0, &vrtem1))
+ {
+ extract_range_from_binary_expr_1 (vr, code, expr_type, vr0_, &vrtem0);
+ if (vrtem1.type != VR_UNDEFINED)
+ {
+ value_range_t vrres = VR_INITIALIZER;
+ extract_range_from_binary_expr_1 (&vrres, code, expr_type,
+ vr0_, &vrtem1);
+ vrp_meet (vr, &vrres);
+ }
+ return;
+ }
+
+ /* The type of the resulting value range defaults to VR0.TYPE. */
+ type = vr0.type;
+
+ /* Refuse to operate on VARYING ranges, ranges of different kinds
+ and symbolic ranges. As an exception, we allow BIT_AND_EXPR
+ because we may be able to derive a useful range even if one of
+ the operands is VR_VARYING or symbolic range. Similarly for
+ divisions. TODO, we may be able to derive anti-ranges in
+ some cases. */
+ if (code != BIT_AND_EXPR
+ && code != BIT_IOR_EXPR
+ && code != TRUNC_DIV_EXPR
+ && code != FLOOR_DIV_EXPR
+ && code != CEIL_DIV_EXPR
+ && code != EXACT_DIV_EXPR
+ && code != ROUND_DIV_EXPR
+ && code != TRUNC_MOD_EXPR
+ && code != MIN_EXPR
+ && code != MAX_EXPR
+ && (vr0.type == VR_VARYING
+ || vr1.type == VR_VARYING
+ || vr0.type != vr1.type
+ || symbolic_range_p (&vr0)
+ || symbolic_range_p (&vr1)))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* Now evaluate the expression to determine the new range. */
+ if (POINTER_TYPE_P (expr_type))
+ {
+ if (code == MIN_EXPR || code == MAX_EXPR)
+ {
+ /* For MIN/MAX expressions with pointers, we only care about
+ nullness, if both are non null, then the result is nonnull.
+ If both are null, then the result is null. Otherwise they
+ are varying. */
+ if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
+ set_value_range_to_nonnull (vr, expr_type);
+ else if (range_is_null (&vr0) && range_is_null (&vr1))
+ set_value_range_to_null (vr, expr_type);
+ else
+ set_value_range_to_varying (vr);
+ }
+ else if (code == POINTER_PLUS_EXPR)
+ {
+ /* For pointer types, we are really only interested in asserting
+ whether the expression evaluates to non-NULL. */
+ if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
+ set_value_range_to_nonnull (vr, expr_type);
+ else if (range_is_null (&vr0) && range_is_null (&vr1))
+ set_value_range_to_null (vr, expr_type);
+ else
+ set_value_range_to_varying (vr);
+ }
+ else if (code == BIT_AND_EXPR)
+ {
+ /* For pointer types, we are really only interested in asserting
+ whether the expression evaluates to non-NULL. */
+ if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
+ set_value_range_to_nonnull (vr, expr_type);
+ else if (range_is_null (&vr0) || range_is_null (&vr1))
+ set_value_range_to_null (vr, expr_type);
+ else
+ set_value_range_to_varying (vr);
+ }
+ else
+ set_value_range_to_varying (vr);
+
+ return;
+ }
+
+ /* For integer ranges, apply the operation to each end of the
+ range and see what we end up with. */
+ if (code == PLUS_EXPR || code == MINUS_EXPR)
+ {
+ /* If we have a PLUS_EXPR with two VR_RANGE integer constant
+ ranges compute the precise range for such case if possible. */
+ if (range_int_cst_p (&vr0)
+ && range_int_cst_p (&vr1)
+ /* We need as many bits as the possibly unsigned inputs. */
+ && TYPE_PRECISION (expr_type) <= HOST_BITS_PER_DOUBLE_INT)
+ {
+ double_int min0 = tree_to_double_int (vr0.min);
+ double_int max0 = tree_to_double_int (vr0.max);
+ double_int min1 = tree_to_double_int (vr1.min);
+ double_int max1 = tree_to_double_int (vr1.max);
+ bool uns = TYPE_UNSIGNED (expr_type);
+ double_int type_min
+ = double_int::min_value (TYPE_PRECISION (expr_type), uns);
+ double_int type_max
+ = double_int::max_value (TYPE_PRECISION (expr_type), uns);
+ double_int dmin, dmax;
+ int min_ovf = 0;
+ int max_ovf = 0;
+
+ if (code == PLUS_EXPR)
+ {
+ dmin = min0 + min1;
+ dmax = max0 + max1;
+
+ /* Check for overflow in double_int. */
+ if (min1.cmp (double_int_zero, uns) != dmin.cmp (min0, uns))
+ min_ovf = min0.cmp (dmin, uns);
+ if (max1.cmp (double_int_zero, uns) != dmax.cmp (max0, uns))
+ max_ovf = max0.cmp (dmax, uns);
+ }
+ else /* if (code == MINUS_EXPR) */
+ {
+ dmin = min0 - max1;
+ dmax = max0 - min1;
+
+ if (double_int_zero.cmp (max1, uns) != dmin.cmp (min0, uns))
+ min_ovf = min0.cmp (max1, uns);
+ if (double_int_zero.cmp (min1, uns) != dmax.cmp (max0, uns))
+ max_ovf = max0.cmp (min1, uns);
+ }
+
+ /* For non-wrapping arithmetic look at possibly smaller
+ value-ranges of the type. */
+ if (!TYPE_OVERFLOW_WRAPS (expr_type))
+ {
+ if (vrp_val_min (expr_type))
+ type_min = tree_to_double_int (vrp_val_min (expr_type));
+ if (vrp_val_max (expr_type))
+ type_max = tree_to_double_int (vrp_val_max (expr_type));
+ }
+
+ /* Check for type overflow. */
+ if (min_ovf == 0)
+ {
+ if (dmin.cmp (type_min, uns) == -1)
+ min_ovf = -1;
+ else if (dmin.cmp (type_max, uns) == 1)
+ min_ovf = 1;
+ }
+ if (max_ovf == 0)
+ {
+ if (dmax.cmp (type_min, uns) == -1)
+ max_ovf = -1;
+ else if (dmax.cmp (type_max, uns) == 1)
+ max_ovf = 1;
+ }
+
+ if (TYPE_OVERFLOW_WRAPS (expr_type))
+ {
+ /* If overflow wraps, truncate the values and adjust the
+ range kind and bounds appropriately. */
+ double_int tmin
+ = dmin.ext (TYPE_PRECISION (expr_type), uns);
+ double_int tmax
+ = dmax.ext (TYPE_PRECISION (expr_type), uns);
+ if (min_ovf == max_ovf)
+ {
+ /* No overflow or both overflow or underflow. The
+ range kind stays VR_RANGE. */
+ min = double_int_to_tree (expr_type, tmin);
+ max = double_int_to_tree (expr_type, tmax);
+ }
+ else if (min_ovf == -1
+ && max_ovf == 1)
+ {
+ /* Underflow and overflow, drop to VR_VARYING. */
+ set_value_range_to_varying (vr);
+ return;
+ }
+ else
+ {
+ /* Min underflow or max overflow. The range kind
+ changes to VR_ANTI_RANGE. */
+ bool covers = false;
+ double_int tem = tmin;
+ gcc_assert ((min_ovf == -1 && max_ovf == 0)
+ || (max_ovf == 1 && min_ovf == 0));
+ type = VR_ANTI_RANGE;
+ tmin = tmax + double_int_one;
+ if (tmin.cmp (tmax, uns) < 0)
+ covers = true;
+ tmax = tem + double_int_minus_one;
+ if (tmax.cmp (tem, uns) > 0)
+ covers = true;
+ /* If the anti-range would cover nothing, drop to varying.
+ Likewise if the anti-range bounds are outside of the
+ types values. */
+ if (covers || tmin.cmp (tmax, uns) > 0)
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ min = double_int_to_tree (expr_type, tmin);
+ max = double_int_to_tree (expr_type, tmax);
+ }
+ }
+ else
+ {
+ /* If overflow does not wrap, saturate to the types min/max
+ value. */
+ if (min_ovf == -1)
+ {
+ if (needs_overflow_infinity (expr_type)
+ && supports_overflow_infinity (expr_type))
+ min = negative_overflow_infinity (expr_type);
+ else
+ min = double_int_to_tree (expr_type, type_min);
+ }
+ else if (min_ovf == 1)
+ {
+ if (needs_overflow_infinity (expr_type)
+ && supports_overflow_infinity (expr_type))
+ min = positive_overflow_infinity (expr_type);
+ else
+ min = double_int_to_tree (expr_type, type_max);
+ }
+ else
+ min = double_int_to_tree (expr_type, dmin);
+
+ if (max_ovf == -1)
+ {
+ if (needs_overflow_infinity (expr_type)
+ && supports_overflow_infinity (expr_type))
+ max = negative_overflow_infinity (expr_type);
+ else
+ max = double_int_to_tree (expr_type, type_min);
+ }
+ else if (max_ovf == 1)
+ {
+ if (needs_overflow_infinity (expr_type)
+ && supports_overflow_infinity (expr_type))
+ max = positive_overflow_infinity (expr_type);
+ else
+ max = double_int_to_tree (expr_type, type_max);
+ }
+ else
+ max = double_int_to_tree (expr_type, dmax);
+ }
+ if (needs_overflow_infinity (expr_type)
+ && supports_overflow_infinity (expr_type))
+ {
+ if (is_negative_overflow_infinity (vr0.min)
+ || (code == PLUS_EXPR
+ ? is_negative_overflow_infinity (vr1.min)
+ : is_positive_overflow_infinity (vr1.max)))
+ min = negative_overflow_infinity (expr_type);
+ if (is_positive_overflow_infinity (vr0.max)
+ || (code == PLUS_EXPR
+ ? is_positive_overflow_infinity (vr1.max)
+ : is_negative_overflow_infinity (vr1.min)))
+ max = positive_overflow_infinity (expr_type);
+ }
+ }
+ else
+ {
+ /* For other cases, for example if we have a PLUS_EXPR with two
+ VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort
+ to compute a precise range for such a case.
+ ??? General even mixed range kind operations can be expressed
+ by for example transforming ~[3, 5] + [1, 2] to range-only
+ operations and a union primitive:
+ [-INF, 2] + [1, 2] U [5, +INF] + [1, 2]
+ [-INF+1, 4] U [6, +INF(OVF)]
+ though usually the union is not exactly representable with
+ a single range or anti-range as the above is
+ [-INF+1, +INF(OVF)] intersected with ~[5, 5]
+ but one could use a scheme similar to equivalences for this. */
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+ else if (code == MIN_EXPR
+ || code == MAX_EXPR)
+ {
+ if (vr0.type == VR_RANGE
+ && !symbolic_range_p (&vr0))
+ {
+ type = VR_RANGE;
+ if (vr1.type == VR_RANGE
+ && !symbolic_range_p (&vr1))
+ {
+ /* For operations that make the resulting range directly
+ proportional to the original ranges, apply the operation to
+ the same end of each range. */
+ min = vrp_int_const_binop (code, vr0.min, vr1.min);
+ max = vrp_int_const_binop (code, vr0.max, vr1.max);
+ }
+ else if (code == MIN_EXPR)
+ {
+ min = vrp_val_min (expr_type);
+ max = vr0.max;
+ }
+ else if (code == MAX_EXPR)
+ {
+ min = vr0.min;
+ max = vrp_val_max (expr_type);
+ }
+ }
+ else if (vr1.type == VR_RANGE
+ && !symbolic_range_p (&vr1))
+ {
+ type = VR_RANGE;
+ if (code == MIN_EXPR)
+ {
+ min = vrp_val_min (expr_type);
+ max = vr1.max;
+ }
+ else if (code == MAX_EXPR)
+ {
+ min = vr1.min;
+ max = vrp_val_max (expr_type);
+ }
+ }
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+ else if (code == MULT_EXPR)
+ {
+ /* Fancy code so that with unsigned, [-3,-1]*[-3,-1] does not
+ drop to varying. */
+ if (range_int_cst_p (&vr0)
+ && range_int_cst_p (&vr1)
+ && TYPE_OVERFLOW_WRAPS (expr_type))
+ {
+ double_int min0, max0, min1, max1, sizem1, size;
+ double_int prod0l, prod0h, prod1l, prod1h,
+ prod2l, prod2h, prod3l, prod3h;
+ bool uns0, uns1, uns;
+
+ sizem1 = double_int::max_value (TYPE_PRECISION (expr_type), true);
+ size = sizem1 + double_int_one;
+
+ min0 = tree_to_double_int (vr0.min);
+ max0 = tree_to_double_int (vr0.max);
+ min1 = tree_to_double_int (vr1.min);
+ max1 = tree_to_double_int (vr1.max);
+
+ uns0 = TYPE_UNSIGNED (expr_type);
+ uns1 = uns0;
+
+ /* Canonicalize the intervals. */
+ if (TYPE_UNSIGNED (expr_type))
+ {
+ double_int min2 = size - min0;
+ if (!min2.is_zero () && min2.cmp (max0, true) < 0)
+ {
+ min0 = -min2;
+ max0 -= size;
+ uns0 = false;
+ }
+
+ min2 = size - min1;
+ if (!min2.is_zero () && min2.cmp (max1, true) < 0)
+ {
+ min1 = -min2;
+ max1 -= size;
+ uns1 = false;
+ }
+ }
+ uns = uns0 & uns1;
+
+ bool overflow;
+ prod0l = min0.wide_mul_with_sign (min1, true, &prod0h, &overflow);
+ if (!uns0 && min0.is_negative ())
+ prod0h -= min1;
+ if (!uns1 && min1.is_negative ())
+ prod0h -= min0;
+
+ prod1l = min0.wide_mul_with_sign (max1, true, &prod1h, &overflow);
+ if (!uns0 && min0.is_negative ())
+ prod1h -= max1;
+ if (!uns1 && max1.is_negative ())
+ prod1h -= min0;
+
+ prod2l = max0.wide_mul_with_sign (min1, true, &prod2h, &overflow);
+ if (!uns0 && max0.is_negative ())
+ prod2h -= min1;
+ if (!uns1 && min1.is_negative ())
+ prod2h -= max0;
+
+ prod3l = max0.wide_mul_with_sign (max1, true, &prod3h, &overflow);
+ if (!uns0 && max0.is_negative ())
+ prod3h -= max1;
+ if (!uns1 && max1.is_negative ())
+ prod3h -= max0;
+
+ /* Sort the 4 products. */
+ quad_int_pair_sort (&prod0l, &prod0h, &prod3l, &prod3h, uns);
+ quad_int_pair_sort (&prod1l, &prod1h, &prod2l, &prod2h, uns);
+ quad_int_pair_sort (&prod0l, &prod0h, &prod1l, &prod1h, uns);
+ quad_int_pair_sort (&prod2l, &prod2h, &prod3l, &prod3h, uns);
+
+ /* Max - min. */
+ if (prod0l.is_zero ())
+ {
+ prod1l = double_int_zero;
+ prod1h = -prod0h;
+ }
+ else
+ {
+ prod1l = -prod0l;
+ prod1h = ~prod0h;
+ }
+ prod2l = prod3l + prod1l;
+ prod2h = prod3h + prod1h;
+ if (prod2l.ult (prod3l))
+ prod2h += double_int_one; /* carry */
+
+ if (!prod2h.is_zero ()
+ || prod2l.cmp (sizem1, true) >= 0)
+ {
+ /* the range covers all values. */
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* The following should handle the wrapping and selecting
+ VR_ANTI_RANGE for us. */
+ min = double_int_to_tree (expr_type, prod0l);
+ max = double_int_to_tree (expr_type, prod3l);
+ set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
+ return;
+ }
+
+ /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
+ drop to VR_VARYING. It would take more effort to compute a
+ precise range for such a case. For example, if we have
+ op0 == 65536 and op1 == 65536 with their ranges both being
+ ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
+ we cannot claim that the product is in ~[0,0]. Note that we
+ are guaranteed to have vr0.type == vr1.type at this
+ point. */
+ if (vr0.type == VR_ANTI_RANGE
+ && !TYPE_OVERFLOW_UNDEFINED (expr_type))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
+ return;
+ }
+ else if (code == RSHIFT_EXPR
+ || code == LSHIFT_EXPR)
+ {
+ /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
+ then drop to VR_VARYING. Outside of this range we get undefined
+ behavior from the shift operation. We cannot even trust
+ SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
+ shifts, and the operation at the tree level may be widened. */
+ if (range_int_cst_p (&vr1)
+ && compare_tree_int (vr1.min, 0) >= 0
+ && compare_tree_int (vr1.max, TYPE_PRECISION (expr_type)) == -1)
+ {
+ if (code == RSHIFT_EXPR)
+ {
+ extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
+ return;
+ }
+ /* We can map lshifts by constants to MULT_EXPR handling. */
+ else if (code == LSHIFT_EXPR
+ && range_int_cst_singleton_p (&vr1))
+ {
+ bool saved_flag_wrapv;
+ value_range_t vr1p = VR_INITIALIZER;
+ vr1p.type = VR_RANGE;
+ vr1p.min
+ = double_int_to_tree (expr_type,
+ double_int_one
+ .llshift (TREE_INT_CST_LOW (vr1.min),
+ TYPE_PRECISION (expr_type)));
+ vr1p.max = vr1p.min;
+ /* We have to use a wrapping multiply though as signed overflow
+ on lshifts is implementation defined in C89. */
+ saved_flag_wrapv = flag_wrapv;
+ flag_wrapv = 1;
+ extract_range_from_binary_expr_1 (vr, MULT_EXPR, expr_type,
+ &vr0, &vr1p);
+ flag_wrapv = saved_flag_wrapv;
+ return;
+ }
+ else if (code == LSHIFT_EXPR
+ && range_int_cst_p (&vr0))
+ {
+ int prec = TYPE_PRECISION (expr_type);
+ int overflow_pos = prec;
+ int bound_shift;
+ double_int bound, complement, low_bound, high_bound;
+ bool uns = TYPE_UNSIGNED (expr_type);
+ bool in_bounds = false;
+
+ if (!uns)
+ overflow_pos -= 1;
+
+ bound_shift = overflow_pos - TREE_INT_CST_LOW (vr1.max);
+ /* If bound_shift == HOST_BITS_PER_DOUBLE_INT, the llshift can
+ overflow. However, for that to happen, vr1.max needs to be
+ zero, which means vr1 is a singleton range of zero, which
+ means it should be handled by the previous LSHIFT_EXPR
+ if-clause. */
+ bound = double_int_one.llshift (bound_shift, prec);
+ complement = ~(bound - double_int_one);
+
+ if (uns)
+ {
+ low_bound = bound.zext (prec);
+ high_bound = complement.zext (prec);
+ if (tree_to_double_int (vr0.max).ult (low_bound))
+ {
+ /* [5, 6] << [1, 2] == [10, 24]. */
+ /* We're shifting out only zeroes, the value increases
+ monotonically. */
+ in_bounds = true;
+ }
+ else if (high_bound.ult (tree_to_double_int (vr0.min)))
+ {
+ /* [0xffffff00, 0xffffffff] << [1, 2]
+ == [0xfffffc00, 0xfffffffe]. */
+ /* We're shifting out only ones, the value decreases
+ monotonically. */
+ in_bounds = true;
+ }
+ }
+ else
+ {
+ /* [-1, 1] << [1, 2] == [-4, 4]. */
+ low_bound = complement.sext (prec);
+ high_bound = bound;
+ if (tree_to_double_int (vr0.max).slt (high_bound)
+ && low_bound.slt (tree_to_double_int (vr0.min)))
+ {
+ /* For non-negative numbers, we're shifting out only
+ zeroes, the value increases monotonically.
+ For negative numbers, we're shifting out only ones, the
+ value decreases monotomically. */
+ in_bounds = true;
+ }
+ }
+
+ if (in_bounds)
+ {
+ extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
+ return;
+ }
+ }
+ }
+ set_value_range_to_varying (vr);
+ return;
+ }
+ else if (code == TRUNC_DIV_EXPR
+ || code == FLOOR_DIV_EXPR
+ || code == CEIL_DIV_EXPR
+ || code == EXACT_DIV_EXPR
+ || code == ROUND_DIV_EXPR)
+ {
+ if (vr0.type != VR_RANGE || symbolic_range_p (&vr0))
+ {
+ /* For division, if op1 has VR_RANGE but op0 does not, something
+ can be deduced just from that range. Say [min, max] / [4, max]
+ gives [min / 4, max / 4] range. */
+ if (vr1.type == VR_RANGE
+ && !symbolic_range_p (&vr1)
+ && range_includes_zero_p (vr1.min, vr1.max) == 0)
+ {
+ vr0.type = type = VR_RANGE;
+ vr0.min = vrp_val_min (expr_type);
+ vr0.max = vrp_val_max (expr_type);
+ }
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+
+ /* For divisions, if flag_non_call_exceptions is true, we must
+ not eliminate a division by zero. */
+ if (cfun->can_throw_non_call_exceptions
+ && (vr1.type != VR_RANGE
+ || range_includes_zero_p (vr1.min, vr1.max) != 0))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* For divisions, if op0 is VR_RANGE, we can deduce a range
+ even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
+ include 0. */
+ if (vr0.type == VR_RANGE
+ && (vr1.type != VR_RANGE
+ || range_includes_zero_p (vr1.min, vr1.max) != 0))
+ {
+ tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
+ int cmp;
+
+ min = NULL_TREE;
+ max = NULL_TREE;
+ if (TYPE_UNSIGNED (expr_type)
+ || value_range_nonnegative_p (&vr1))
+ {
+ /* For unsigned division or when divisor is known
+ to be non-negative, the range has to cover
+ all numbers from 0 to max for positive max
+ and all numbers from min to 0 for negative min. */
+ cmp = compare_values (vr0.max, zero);
+ if (cmp == -1)
+ max = zero;
+ else if (cmp == 0 || cmp == 1)
+ max = vr0.max;
+ else
+ type = VR_VARYING;
+ cmp = compare_values (vr0.min, zero);
+ if (cmp == 1)
+ min = zero;
+ else if (cmp == 0 || cmp == -1)
+ min = vr0.min;
+ else
+ type = VR_VARYING;
+ }
+ else
+ {
+ /* Otherwise the range is -max .. max or min .. -min
+ depending on which bound is bigger in absolute value,
+ as the division can change the sign. */
+ abs_extent_range (vr, vr0.min, vr0.max);
+ return;
+ }
+ if (type == VR_VARYING)
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+ else
+ {
+ extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
+ return;
+ }
+ }
+ else if (code == TRUNC_MOD_EXPR)
+ {
+ if (vr1.type != VR_RANGE
+ || range_includes_zero_p (vr1.min, vr1.max) != 0
+ || vrp_val_is_min (vr1.min))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ type = VR_RANGE;
+ /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
+ max = fold_unary_to_constant (ABS_EXPR, expr_type, vr1.min);
+ if (tree_int_cst_lt (max, vr1.max))
+ max = vr1.max;
+ max = int_const_binop (MINUS_EXPR, max, integer_one_node);
+ /* If the dividend is non-negative the modulus will be
+ non-negative as well. */
+ if (TYPE_UNSIGNED (expr_type)
+ || value_range_nonnegative_p (&vr0))
+ min = build_int_cst (TREE_TYPE (max), 0);
+ else
+ min = fold_unary_to_constant (NEGATE_EXPR, expr_type, max);
+ }
+ else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR)
+ {
+ bool int_cst_range0, int_cst_range1;
+ double_int may_be_nonzero0, may_be_nonzero1;
+ double_int must_be_nonzero0, must_be_nonzero1;
+
+ int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
+ &must_be_nonzero0);
+ int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
+ &must_be_nonzero1);
+
+ type = VR_RANGE;
+ if (code == BIT_AND_EXPR)
+ {
+ double_int dmax;
+ min = double_int_to_tree (expr_type,
+ must_be_nonzero0 & must_be_nonzero1);
+ dmax = may_be_nonzero0 & may_be_nonzero1;
+ /* If both input ranges contain only negative values we can
+ truncate the result range maximum to the minimum of the
+ input range maxima. */
+ if (int_cst_range0 && int_cst_range1
+ && tree_int_cst_sgn (vr0.max) < 0
+ && tree_int_cst_sgn (vr1.max) < 0)
+ {
+ dmax = dmax.min (tree_to_double_int (vr0.max),
+ TYPE_UNSIGNED (expr_type));
+ dmax = dmax.min (tree_to_double_int (vr1.max),
+ TYPE_UNSIGNED (expr_type));
+ }
+ /* If either input range contains only non-negative values
+ we can truncate the result range maximum to the respective
+ maximum of the input range. */
+ if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
+ dmax = dmax.min (tree_to_double_int (vr0.max),
+ TYPE_UNSIGNED (expr_type));
+ if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
+ dmax = dmax.min (tree_to_double_int (vr1.max),
+ TYPE_UNSIGNED (expr_type));
+ max = double_int_to_tree (expr_type, dmax);
+ }
+ else if (code == BIT_IOR_EXPR)
+ {
+ double_int dmin;
+ max = double_int_to_tree (expr_type,
+ may_be_nonzero0 | may_be_nonzero1);
+ dmin = must_be_nonzero0 | must_be_nonzero1;
+ /* If the input ranges contain only positive values we can
+ truncate the minimum of the result range to the maximum
+ of the input range minima. */
+ if (int_cst_range0 && int_cst_range1
+ && tree_int_cst_sgn (vr0.min) >= 0
+ && tree_int_cst_sgn (vr1.min) >= 0)
+ {
+ dmin = dmin.max (tree_to_double_int (vr0.min),
+ TYPE_UNSIGNED (expr_type));
+ dmin = dmin.max (tree_to_double_int (vr1.min),
+ TYPE_UNSIGNED (expr_type));
+ }
+ /* If either input range contains only negative values
+ we can truncate the minimum of the result range to the
+ respective minimum range. */
+ if (int_cst_range0 && tree_int_cst_sgn (vr0.max) < 0)
+ dmin = dmin.max (tree_to_double_int (vr0.min),
+ TYPE_UNSIGNED (expr_type));
+ if (int_cst_range1 && tree_int_cst_sgn (vr1.max) < 0)
+ dmin = dmin.max (tree_to_double_int (vr1.min),
+ TYPE_UNSIGNED (expr_type));
+ min = double_int_to_tree (expr_type, dmin);
+ }
+ else if (code == BIT_XOR_EXPR)
+ {
+ double_int result_zero_bits, result_one_bits;
+ result_zero_bits = (must_be_nonzero0 & must_be_nonzero1)
+ | ~(may_be_nonzero0 | may_be_nonzero1);
+ result_one_bits = must_be_nonzero0.and_not (may_be_nonzero1)
+ | must_be_nonzero1.and_not (may_be_nonzero0);
+ max = double_int_to_tree (expr_type, ~result_zero_bits);
+ min = double_int_to_tree (expr_type, result_one_bits);
+ /* If the range has all positive or all negative values the
+ result is better than VARYING. */
+ if (tree_int_cst_sgn (min) < 0
+ || tree_int_cst_sgn (max) >= 0)
+ ;
+ else
+ max = min = NULL_TREE;
+ }
+ }
+ else
+ gcc_unreachable ();
+
+ /* If either MIN or MAX overflowed, then set the resulting range to
+ VARYING. But we do accept an overflow infinity
+ representation. */
+ if (min == NULL_TREE
+ || !is_gimple_min_invariant (min)
+ || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
+ || max == NULL_TREE
+ || !is_gimple_min_invariant (max)
+ || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* We punt if:
+ 1) [-INF, +INF]
+ 2) [-INF, +-INF(OVF)]
+ 3) [+-INF(OVF), +INF]
+ 4) [+-INF(OVF), +-INF(OVF)]
+ We learn nothing when we have INF and INF(OVF) on both sides.
+ Note that we do accept [-INF, -INF] and [+INF, +INF] without
+ overflow. */
+ if ((vrp_val_is_min (min) || is_overflow_infinity (min))
+ && (vrp_val_is_max (max) || is_overflow_infinity (max)))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ cmp = compare_values (min, max);
+ if (cmp == -2 || cmp == 1)
+ {
+ /* If the new range has its limits swapped around (MIN > MAX),
+ then the operation caused one of them to wrap around, mark
+ the new range VARYING. */
+ set_value_range_to_varying (vr);
+ }
+ else
+ set_value_range (vr, type, min, max, NULL);
+}
+
+/* Extract range information from a binary expression OP0 CODE OP1 based on
+ the ranges of each of its operands with resulting type EXPR_TYPE.
+ The resulting range is stored in *VR. */
+
+static void
+extract_range_from_binary_expr (value_range_t *vr,
+ enum tree_code code,
+ tree expr_type, tree op0, tree op1)
+{
+ value_range_t vr0 = VR_INITIALIZER;
+ value_range_t vr1 = VR_INITIALIZER;
+
+ /* Get value ranges for each operand. For constant operands, create
+ a new value range with the operand to simplify processing. */
+ if (TREE_CODE (op0) == SSA_NAME)
+ vr0 = *(get_value_range (op0));
+ else if (is_gimple_min_invariant (op0))
+ set_value_range_to_value (&vr0, op0, NULL);
+ else
+ set_value_range_to_varying (&vr0);
+
+ if (TREE_CODE (op1) == SSA_NAME)
+ vr1 = *(get_value_range (op1));
+ else if (is_gimple_min_invariant (op1))
+ set_value_range_to_value (&vr1, op1, NULL);
+ else
+ set_value_range_to_varying (&vr1);
+
+ extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1);
+}
+
+/* Extract range information from a unary operation CODE based on
+ the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
+ The The resulting range is stored in *VR. */
+
+static void
+extract_range_from_unary_expr_1 (value_range_t *vr,
+ enum tree_code code, tree type,
+ value_range_t *vr0_, tree op0_type)
+{
+ value_range_t vr0 = *vr0_, vrtem0 = VR_INITIALIZER, vrtem1 = VR_INITIALIZER;
+
+ /* VRP only operates on integral and pointer types. */
+ if (!(INTEGRAL_TYPE_P (op0_type)
+ || POINTER_TYPE_P (op0_type))
+ || !(INTEGRAL_TYPE_P (type)
+ || POINTER_TYPE_P (type)))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* If VR0 is UNDEFINED, so is the result. */
+ if (vr0.type == VR_UNDEFINED)
+ {
+ set_value_range_to_undefined (vr);
+ return;
+ }
+
+ /* Handle operations that we express in terms of others. */
+ if (code == PAREN_EXPR || code == OBJ_TYPE_REF)
+ {
+ /* PAREN_EXPR and OBJ_TYPE_REF are simple copies. */
+ copy_value_range (vr, &vr0);
+ return;
+ }
+ else if (code == NEGATE_EXPR)
+ {
+ /* -X is simply 0 - X, so re-use existing code that also handles
+ anti-ranges fine. */
+ value_range_t zero = VR_INITIALIZER;
+ set_value_range_to_value (&zero, build_int_cst (type, 0), NULL);
+ extract_range_from_binary_expr_1 (vr, MINUS_EXPR, type, &zero, &vr0);
+ return;
+ }
+ else if (code == BIT_NOT_EXPR)
+ {
+ /* ~X is simply -1 - X, so re-use existing code that also handles
+ anti-ranges fine. */
+ value_range_t minusone = VR_INITIALIZER;
+ set_value_range_to_value (&minusone, build_int_cst (type, -1), NULL);
+ extract_range_from_binary_expr_1 (vr, MINUS_EXPR,
+ type, &minusone, &vr0);
+ return;
+ }
+
+ /* Now canonicalize anti-ranges to ranges when they are not symbolic
+ and express op ~[] as (op []') U (op []''). */
+ if (vr0.type == VR_ANTI_RANGE
+ && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1))
+ {
+ extract_range_from_unary_expr_1 (vr, code, type, &vrtem0, op0_type);
+ if (vrtem1.type != VR_UNDEFINED)
+ {
+ value_range_t vrres = VR_INITIALIZER;
+ extract_range_from_unary_expr_1 (&vrres, code, type,
+ &vrtem1, op0_type);
+ vrp_meet (vr, &vrres);
+ }
+ return;
+ }
+
+ if (CONVERT_EXPR_CODE_P (code))
+ {
+ tree inner_type = op0_type;
+ tree outer_type = type;
+
+ /* If the expression evaluates to a pointer, we are only interested in
+ determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
+ if (POINTER_TYPE_P (type))
+ {
+ if (range_is_nonnull (&vr0))
+ set_value_range_to_nonnull (vr, type);
+ else if (range_is_null (&vr0))
+ set_value_range_to_null (vr, type);
+ else
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* If VR0 is varying and we increase the type precision, assume
+ a full range for the following transformation. */
+ if (vr0.type == VR_VARYING
+ && INTEGRAL_TYPE_P (inner_type)
+ && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
+ {
+ vr0.type = VR_RANGE;
+ vr0.min = TYPE_MIN_VALUE (inner_type);
+ vr0.max = TYPE_MAX_VALUE (inner_type);
+ }
+
+ /* If VR0 is a constant range or anti-range and the conversion is
+ not truncating we can convert the min and max values and
+ canonicalize the resulting range. Otherwise we can do the
+ conversion if the size of the range is less than what the
+ precision of the target type can represent and the range is
+ not an anti-range. */
+ if ((vr0.type == VR_RANGE
+ || vr0.type == VR_ANTI_RANGE)
+ && TREE_CODE (vr0.min) == INTEGER_CST
+ && TREE_CODE (vr0.max) == INTEGER_CST
+ && (!is_overflow_infinity (vr0.min)
+ || (vr0.type == VR_RANGE
+ && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
+ && needs_overflow_infinity (outer_type)
+ && supports_overflow_infinity (outer_type)))
+ && (!is_overflow_infinity (vr0.max)
+ || (vr0.type == VR_RANGE
+ && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
+ && needs_overflow_infinity (outer_type)
+ && supports_overflow_infinity (outer_type)))
+ && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
+ || (vr0.type == VR_RANGE
+ && integer_zerop (int_const_binop (RSHIFT_EXPR,
+ int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
+ size_int (TYPE_PRECISION (outer_type)))))))
+ {
+ tree new_min, new_max;
+ if (is_overflow_infinity (vr0.min))
+ new_min = negative_overflow_infinity (outer_type);
+ else
+ new_min = force_fit_type_double (outer_type,
+ tree_to_double_int (vr0.min),
+ 0, false);
+ if (is_overflow_infinity (vr0.max))
+ new_max = positive_overflow_infinity (outer_type);
+ else
+ new_max = force_fit_type_double (outer_type,
+ tree_to_double_int (vr0.max),
+ 0, false);
+ set_and_canonicalize_value_range (vr, vr0.type,
+ new_min, new_max, NULL);
+ return;
+ }
+
+ set_value_range_to_varying (vr);
+ return;
+ }
+ else if (code == ABS_EXPR)
+ {
+ tree min, max;
+ int cmp;
+
+ /* Pass through vr0 in the easy cases. */
+ if (TYPE_UNSIGNED (type)
+ || value_range_nonnegative_p (&vr0))
+ {
+ copy_value_range (vr, &vr0);
+ return;
+ }
+
+ /* For the remaining varying or symbolic ranges we can't do anything
+ useful. */
+ if (vr0.type == VR_VARYING
+ || symbolic_range_p (&vr0))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
+ useful range. */
+ if (!TYPE_OVERFLOW_UNDEFINED (type)
+ && ((vr0.type == VR_RANGE
+ && vrp_val_is_min (vr0.min))
+ || (vr0.type == VR_ANTI_RANGE
+ && !vrp_val_is_min (vr0.min))))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ /* ABS_EXPR may flip the range around, if the original range
+ included negative values. */
+ if (is_overflow_infinity (vr0.min))
+ min = positive_overflow_infinity (type);
+ else if (!vrp_val_is_min (vr0.min))
+ min = fold_unary_to_constant (code, type, vr0.min);
+ else if (!needs_overflow_infinity (type))
+ min = TYPE_MAX_VALUE (type);
+ else if (supports_overflow_infinity (type))
+ min = positive_overflow_infinity (type);
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ if (is_overflow_infinity (vr0.max))
+ max = positive_overflow_infinity (type);
+ else if (!vrp_val_is_min (vr0.max))
+ max = fold_unary_to_constant (code, type, vr0.max);
+ else if (!needs_overflow_infinity (type))
+ max = TYPE_MAX_VALUE (type);
+ else if (supports_overflow_infinity (type)
+ /* We shouldn't generate [+INF, +INF] as set_value_range
+ doesn't like this and ICEs. */
+ && !is_positive_overflow_infinity (min))
+ max = positive_overflow_infinity (type);
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+
+ cmp = compare_values (min, max);
+
+ /* If a VR_ANTI_RANGEs contains zero, then we have
+ ~[-INF, min(MIN, MAX)]. */
+ if (vr0.type == VR_ANTI_RANGE)
+ {
+ if (range_includes_zero_p (vr0.min, vr0.max) == 1)
+ {
+ /* Take the lower of the two values. */
+ if (cmp != 1)
+ max = min;
+
+ /* Create ~[-INF, min (abs(MIN), abs(MAX))]
+ or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
+ flag_wrapv is set and the original anti-range doesn't include
+ TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
+ if (TYPE_OVERFLOW_WRAPS (type))
+ {
+ tree type_min_value = TYPE_MIN_VALUE (type);
+
+ min = (vr0.min != type_min_value
+ ? int_const_binop (PLUS_EXPR, type_min_value,
+ integer_one_node)
+ : type_min_value);
+ }
+ else
+ {
+ if (overflow_infinity_range_p (&vr0))
+ min = negative_overflow_infinity (type);
+ else
+ min = TYPE_MIN_VALUE (type);
+ }
+ }
+ else
+ {
+ /* All else has failed, so create the range [0, INF], even for
+ flag_wrapv since TYPE_MIN_VALUE is in the original
+ anti-range. */
+ vr0.type = VR_RANGE;
+ min = build_int_cst (type, 0);
+ if (needs_overflow_infinity (type))
+ {
+ if (supports_overflow_infinity (type))
+ max = positive_overflow_infinity (type);
+ else
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+ else
+ max = TYPE_MAX_VALUE (type);
+ }
+ }
+
+ /* If the range contains zero then we know that the minimum value in the
+ range will be zero. */
+ else if (range_includes_zero_p (vr0.min, vr0.max) == 1)
+ {
+ if (cmp == 1)
+ max = min;
+ min = build_int_cst (type, 0);
+ }
+ else
+ {
+ /* If the range was reversed, swap MIN and MAX. */
+ if (cmp == 1)
+ {
+ tree t = min;
+ min = max;
+ max = t;
+ }
+ }
+
+ cmp = compare_values (min, max);
+ if (cmp == -2 || cmp == 1)
+ {
+ /* If the new range has its limits swapped around (MIN > MAX),
+ then the operation caused one of them to wrap around, mark
+ the new range VARYING. */
+ set_value_range_to_varying (vr);
+ }
+ else
+ set_value_range (vr, vr0.type, min, max, NULL);
+ return;
+ }
+
+ /* For unhandled operations fall back to varying. */
+ set_value_range_to_varying (vr);
+ return;
+}
+
+
+/* Extract range information from a unary expression CODE OP0 based on
+ the range of its operand with resulting type TYPE.
+ The resulting range is stored in *VR. */
+
+static void
+extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
+ tree type, tree op0)
+{
+ value_range_t vr0 = VR_INITIALIZER;
+
+ /* Get value ranges for the operand. For constant operands, create
+ a new value range with the operand to simplify processing. */
+ if (TREE_CODE (op0) == SSA_NAME)
+ vr0 = *(get_value_range (op0));
+ else if (is_gimple_min_invariant (op0))
+ set_value_range_to_value (&vr0, op0, NULL);
+ else
+ set_value_range_to_varying (&vr0);
+
+ extract_range_from_unary_expr_1 (vr, code, type, &vr0, TREE_TYPE (op0));
+}
+
+
+/* Extract range information from a conditional expression STMT based on
+ the ranges of each of its operands and the expression code. */
+
+static void
+extract_range_from_cond_expr (value_range_t *vr, gimple stmt)
+{
+ tree op0, op1;
+ value_range_t vr0 = VR_INITIALIZER;
+ value_range_t vr1 = VR_INITIALIZER;
+
+ /* Get value ranges for each operand. For constant operands, create
+ a new value range with the operand to simplify processing. */
+ op0 = gimple_assign_rhs2 (stmt);
+ if (TREE_CODE (op0) == SSA_NAME)
+ vr0 = *(get_value_range (op0));
+ else if (is_gimple_min_invariant (op0))
+ set_value_range_to_value (&vr0, op0, NULL);
+ else
+ set_value_range_to_varying (&vr0);
+
+ op1 = gimple_assign_rhs3 (stmt);
+ if (TREE_CODE (op1) == SSA_NAME)
+ vr1 = *(get_value_range (op1));
+ else if (is_gimple_min_invariant (op1))
+ set_value_range_to_value (&vr1, op1, NULL);
+ else
+ set_value_range_to_varying (&vr1);
+
+ /* The resulting value range is the union of the operand ranges */
+ copy_value_range (vr, &vr0);
+ vrp_meet (vr, &vr1);
+}
+
+
+/* Extract range information from a comparison expression EXPR based
+ on the range of its operand and the expression code. */
+
+static void
+extract_range_from_comparison (value_range_t *vr, enum tree_code code,
+ tree type, tree op0, tree op1)
+{
+ bool sop = false;
+ tree val;
+
+ val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
+ NULL);
+
+ /* A disadvantage of using a special infinity as an overflow
+ representation is that we lose the ability to record overflow
+ when we don't have an infinity. So we have to ignore a result
+ which relies on overflow. */
+
+ if (val && !is_overflow_infinity (val) && !sop)
+ {
+ /* Since this expression was found on the RHS of an assignment,
+ its type may be different from _Bool. Convert VAL to EXPR's
+ type. */
+ val = fold_convert (type, val);
+ if (is_gimple_min_invariant (val))
+ set_value_range_to_value (vr, val, vr->equiv);
+ else
+ set_value_range (vr, VR_RANGE, val, val, vr->equiv);
+ }
+ else
+ /* The result of a comparison is always true or false. */
+ set_value_range_to_truthvalue (vr, type);
+}
+
+/* Try to derive a nonnegative or nonzero range out of STMT relying
+ primarily on generic routines in fold in conjunction with range data.
+ Store the result in *VR */
+
+static void
+extract_range_basic (value_range_t *vr, gimple stmt)
+{
+ bool sop = false;
+ tree type = gimple_expr_type (stmt);
+
+ if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
+ {
+ tree fndecl = gimple_call_fndecl (stmt), arg;
+ int mini, maxi, zerov = 0, prec;
+
+ switch (DECL_FUNCTION_CODE (fndecl))
+ {
+ case BUILT_IN_CONSTANT_P:
+ /* If the call is __builtin_constant_p and the argument is a
+ function parameter resolve it to false. This avoids bogus
+ array bound warnings.
+ ??? We could do this as early as inlining is finished. */
+ arg = gimple_call_arg (stmt, 0);
+ if (TREE_CODE (arg) == SSA_NAME
+ && SSA_NAME_IS_DEFAULT_DEF (arg)
+ && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL)
+ {
+ set_value_range_to_null (vr, type);
+ return;
+ }
+ break;
+ /* Both __builtin_ffs* and __builtin_popcount return
+ [0, prec]. */
+ CASE_INT_FN (BUILT_IN_FFS):
+ CASE_INT_FN (BUILT_IN_POPCOUNT):
+ arg = gimple_call_arg (stmt, 0);
+ prec = TYPE_PRECISION (TREE_TYPE (arg));
+ mini = 0;
+ maxi = prec;
+ if (TREE_CODE (arg) == SSA_NAME)
+ {
+ value_range_t *vr0 = get_value_range (arg);
+ /* If arg is non-zero, then ffs or popcount
+ are non-zero. */
+ if (((vr0->type == VR_RANGE
+ && integer_nonzerop (vr0->min))
+ || (vr0->type == VR_ANTI_RANGE
+ && integer_zerop (vr0->min)))
+ && !is_overflow_infinity (vr0->min))
+ mini = 1;
+ /* If some high bits are known to be zero,
+ we can decrease the maximum. */
+ if (vr0->type == VR_RANGE
+ && TREE_CODE (vr0->max) == INTEGER_CST
+ && !is_overflow_infinity (vr0->max))
+ maxi = tree_floor_log2 (vr0->max) + 1;
+ }
+ goto bitop_builtin;
+ /* __builtin_parity* returns [0, 1]. */
+ CASE_INT_FN (BUILT_IN_PARITY):
+ mini = 0;
+ maxi = 1;
+ goto bitop_builtin;
+ /* __builtin_c[lt]z* return [0, prec-1], except for
+ when the argument is 0, but that is undefined behavior.
+ On many targets where the CLZ RTL or optab value is defined
+ for 0 the value is prec, so include that in the range
+ by default. */
+ CASE_INT_FN (BUILT_IN_CLZ):
+ arg = gimple_call_arg (stmt, 0);
+ prec = TYPE_PRECISION (TREE_TYPE (arg));
+ mini = 0;
+ maxi = prec;
+ if (optab_handler (clz_optab, TYPE_MODE (TREE_TYPE (arg)))
+ != CODE_FOR_nothing
+ && CLZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)),
+ zerov)
+ /* Handle only the single common value. */
+ && zerov != prec)
+ /* Magic value to give up, unless vr0 proves
+ arg is non-zero. */
+ mini = -2;
+ if (TREE_CODE (arg) == SSA_NAME)
+ {
+ value_range_t *vr0 = get_value_range (arg);
+ /* From clz of VR_RANGE minimum we can compute
+ result maximum. */
+ if (vr0->type == VR_RANGE
+ && TREE_CODE (vr0->min) == INTEGER_CST
+ && !is_overflow_infinity (vr0->min))
+ {
+ maxi = prec - 1 - tree_floor_log2 (vr0->min);
+ if (maxi != prec)
+ mini = 0;
+ }
+ else if (vr0->type == VR_ANTI_RANGE
+ && integer_zerop (vr0->min)
+ && !is_overflow_infinity (vr0->min))
+ {
+ maxi = prec - 1;
+ mini = 0;
+ }
+ if (mini == -2)
+ break;
+ /* From clz of VR_RANGE maximum we can compute
+ result minimum. */
+ if (vr0->type == VR_RANGE
+ && TREE_CODE (vr0->max) == INTEGER_CST
+ && !is_overflow_infinity (vr0->max))
+ {
+ mini = prec - 1 - tree_floor_log2 (vr0->max);
+ if (mini == prec)
+ break;
+ }
+ }
+ if (mini == -2)
+ break;
+ goto bitop_builtin;
+ /* __builtin_ctz* return [0, prec-1], except for
+ when the argument is 0, but that is undefined behavior.
+ If there is a ctz optab for this mode and
+ CTZ_DEFINED_VALUE_AT_ZERO, include that in the range,
+ otherwise just assume 0 won't be seen. */
+ CASE_INT_FN (BUILT_IN_CTZ):
+ arg = gimple_call_arg (stmt, 0);
+ prec = TYPE_PRECISION (TREE_TYPE (arg));
+ mini = 0;
+ maxi = prec - 1;
+ if (optab_handler (ctz_optab, TYPE_MODE (TREE_TYPE (arg)))
+ != CODE_FOR_nothing
+ && CTZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)),
+ zerov))
+ {
+ /* Handle only the two common values. */
+ if (zerov == -1)
+ mini = -1;
+ else if (zerov == prec)
+ maxi = prec;
+ else
+ /* Magic value to give up, unless vr0 proves
+ arg is non-zero. */
+ mini = -2;
+ }
+ if (TREE_CODE (arg) == SSA_NAME)
+ {
+ value_range_t *vr0 = get_value_range (arg);
+ /* If arg is non-zero, then use [0, prec - 1]. */
+ if (((vr0->type == VR_RANGE
+ && integer_nonzerop (vr0->min))
+ || (vr0->type == VR_ANTI_RANGE
+ && integer_zerop (vr0->min)))
+ && !is_overflow_infinity (vr0->min))
+ {
+ mini = 0;
+ maxi = prec - 1;
+ }
+ /* If some high bits are known to be zero,
+ we can decrease the result maximum. */
+ if (vr0->type == VR_RANGE
+ && TREE_CODE (vr0->max) == INTEGER_CST
+ && !is_overflow_infinity (vr0->max))
+ {
+ maxi = tree_floor_log2 (vr0->max);
+ /* For vr0 [0, 0] give up. */
+ if (maxi == -1)
+ break;
+ }
+ }
+ if (mini == -2)
+ break;
+ goto bitop_builtin;
+ /* __builtin_clrsb* returns [0, prec-1]. */
+ CASE_INT_FN (BUILT_IN_CLRSB):
+ arg = gimple_call_arg (stmt, 0);
+ prec = TYPE_PRECISION (TREE_TYPE (arg));
+ mini = 0;
+ maxi = prec - 1;
+ goto bitop_builtin;
+ bitop_builtin:
+ set_value_range (vr, VR_RANGE, build_int_cst (type, mini),
+ build_int_cst (type, maxi), NULL);
+ return;
+ default:
+ break;
+ }
+ }
+ else if (is_gimple_call (stmt)
+ && gimple_call_internal_p (stmt))
+ {
+ enum tree_code subcode = ERROR_MARK;
+ switch (gimple_call_internal_fn (stmt))
+ {
+ case IFN_UBSAN_CHECK_ADD:
+ subcode = PLUS_EXPR;
+ break;
+ case IFN_UBSAN_CHECK_SUB:
+ subcode = MINUS_EXPR;
+ break;
+ case IFN_UBSAN_CHECK_MUL:
+ subcode = MULT_EXPR;
+ break;
+ default:
+ break;
+ }
+ if (subcode != ERROR_MARK)
+ {
+ bool saved_flag_wrapv = flag_wrapv;
+ /* Pretend the arithmetics is wrapping. If there is
+ any overflow, we'll complain, but will actually do
+ wrapping operation. */
+ flag_wrapv = 1;
+ extract_range_from_binary_expr (vr, subcode, type,
+ gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 1));
+ flag_wrapv = saved_flag_wrapv;
+
+ /* If for both arguments vrp_valueize returned non-NULL,
+ this should have been already folded and if not, it
+ wasn't folded because of overflow. Avoid removing the
+ UBSAN_CHECK_* calls in that case. */
+ if (vr->type == VR_RANGE
+ && (vr->min == vr->max
+ || operand_equal_p (vr->min, vr->max, 0)))
+ set_value_range_to_varying (vr);
+ return;
+ }
+ }
+ if (INTEGRAL_TYPE_P (type)
+ && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
+ set_value_range_to_nonnegative (vr, type,
+ sop || stmt_overflow_infinity (stmt));
+ else if (vrp_stmt_computes_nonzero (stmt, &sop)
+ && !sop)
+ set_value_range_to_nonnull (vr, type);
+ else
+ set_value_range_to_varying (vr);
+}
+
+
+/* Try to compute a useful range out of assignment STMT and store it
+ in *VR. */
+
+static void
+extract_range_from_assignment (value_range_t *vr, gimple stmt)
+{
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+
+ if (code == ASSERT_EXPR)
+ extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
+ else if (code == SSA_NAME)
+ extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
+ else if (TREE_CODE_CLASS (code) == tcc_binary)
+ extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt));
+ else if (TREE_CODE_CLASS (code) == tcc_unary)
+ extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ gimple_assign_rhs1 (stmt));
+ else if (code == COND_EXPR)
+ extract_range_from_cond_expr (vr, stmt);
+ else if (TREE_CODE_CLASS (code) == tcc_comparison)
+ extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
+ gimple_expr_type (stmt),
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt));
+ else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
+ && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
+ set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
+ else
+ set_value_range_to_varying (vr);
+
+ if (vr->type == VR_VARYING)
+ extract_range_basic (vr, stmt);
+}
+
+/* Given a range VR, a LOOP and a variable VAR, determine whether it
+ would be profitable to adjust VR using scalar evolution information
+ for VAR. If so, update VR with the new limits. */
+
+static void
+adjust_range_with_scev (value_range_t *vr, struct loop *loop,
+ gimple stmt, tree var)
+{
+ tree init, step, chrec, tmin, tmax, min, max, type, tem;
+ enum ev_direction dir;
+
+ /* TODO. Don't adjust anti-ranges. An anti-range may provide
+ better opportunities than a regular range, but I'm not sure. */
+ if (vr->type == VR_ANTI_RANGE)
+ return;
+
+ chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
+
+ /* Like in PR19590, scev can return a constant function. */
+ if (is_gimple_min_invariant (chrec))
+ {
+ set_value_range_to_value (vr, chrec, vr->equiv);
+ return;
+ }
+
+ if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
+ return;
+
+ init = initial_condition_in_loop_num (chrec, loop->num);
+ tem = op_with_constant_singleton_value_range (init);
+ if (tem)
+ init = tem;
+ step = evolution_part_in_loop_num (chrec, loop->num);
+ tem = op_with_constant_singleton_value_range (step);
+ if (tem)
+ step = tem;
+
+ /* If STEP is symbolic, we can't know whether INIT will be the
+ minimum or maximum value in the range. Also, unless INIT is
+ a simple expression, compare_values and possibly other functions
+ in tree-vrp won't be able to handle it. */
+ if (step == NULL_TREE
+ || !is_gimple_min_invariant (step)
+ || !valid_value_p (init))
+ return;
+
+ dir = scev_direction (chrec);
+ if (/* Do not adjust ranges if we do not know whether the iv increases
+ or decreases, ... */
+ dir == EV_DIR_UNKNOWN
+ /* ... or if it may wrap. */
+ || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
+ true))
+ return;
+
+ /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
+ negative_overflow_infinity and positive_overflow_infinity,
+ because we have concluded that the loop probably does not
+ wrap. */
+
+ type = TREE_TYPE (var);
+ if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
+ tmin = lower_bound_in_type (type, type);
+ else
+ tmin = TYPE_MIN_VALUE (type);
+ if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
+ tmax = upper_bound_in_type (type, type);
+ else
+ tmax = TYPE_MAX_VALUE (type);
+
+ /* Try to use estimated number of iterations for the loop to constrain the
+ final value in the evolution. */
+ if (TREE_CODE (step) == INTEGER_CST
+ && is_gimple_val (init)
+ && (TREE_CODE (init) != SSA_NAME
+ || get_value_range (init)->type == VR_RANGE))
+ {
+ double_int nit;
+
+ /* We are only entering here for loop header PHI nodes, so using
+ the number of latch executions is the correct thing to use. */
+ if (max_loop_iterations (loop, &nit))
+ {
+ value_range_t maxvr = VR_INITIALIZER;
+ double_int dtmp;
+ bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
+ bool overflow = false;
+
+ dtmp = tree_to_double_int (step)
+ .mul_with_sign (nit, unsigned_p, &overflow);
+ /* If the multiplication overflowed we can't do a meaningful
+ adjustment. Likewise if the result doesn't fit in the type
+ of the induction variable. For a signed type we have to
+ check whether the result has the expected signedness which
+ is that of the step as number of iterations is unsigned. */
+ if (!overflow
+ && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
+ && (unsigned_p
+ || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
+ {
+ tem = double_int_to_tree (TREE_TYPE (init), dtmp);
+ extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
+ TREE_TYPE (init), init, tem);
+ /* Likewise if the addition did. */
+ if (maxvr.type == VR_RANGE)
+ {
+ tmin = maxvr.min;
+ tmax = maxvr.max;
+ }
+ }
+ }
+ }
+
+ if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
+ {
+ min = tmin;
+ max = tmax;
+
+ /* For VARYING or UNDEFINED ranges, just about anything we get
+ from scalar evolutions should be better. */
+
+ if (dir == EV_DIR_DECREASES)
+ max = init;
+ else
+ min = init;
+
+ /* If we would create an invalid range, then just assume we
+ know absolutely nothing. This may be over-conservative,
+ but it's clearly safe, and should happen only in unreachable
+ parts of code, or for invalid programs. */
+ if (compare_values (min, max) == 1)
+ return;
+
+ set_value_range (vr, VR_RANGE, min, max, vr->equiv);
+ }
+ else if (vr->type == VR_RANGE)
+ {
+ min = vr->min;
+ max = vr->max;
+
+ if (dir == EV_DIR_DECREASES)
+ {
+ /* INIT is the maximum value. If INIT is lower than VR->MAX
+ but no smaller than VR->MIN, set VR->MAX to INIT. */
+ if (compare_values (init, max) == -1)
+ max = init;
+
+ /* According to the loop information, the variable does not
+ overflow. If we think it does, probably because of an
+ overflow due to arithmetic on a different INF value,
+ reset now. */
+ if (is_negative_overflow_infinity (min)
+ || compare_values (min, tmin) == -1)
+ min = tmin;
+
+ }
+ else
+ {
+ /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
+ if (compare_values (init, min) == 1)
+ min = init;
+
+ if (is_positive_overflow_infinity (max)
+ || compare_values (tmax, max) == -1)
+ max = tmax;
+ }
+
+ /* If we just created an invalid range with the minimum
+ greater than the maximum, we fail conservatively.
+ This should happen only in unreachable
+ parts of code, or for invalid programs. */
+ if (compare_values (min, max) == 1)
+ return;
+
+ set_value_range (vr, VR_RANGE, min, max, vr->equiv);
+ }
+}
+
+/* Return true if VAR may overflow at STMT. This checks any available
+ loop information to see if we can determine that VAR does not
+ overflow. */
+
+static bool
+vrp_var_may_overflow (tree var, gimple stmt)
+{
+ struct loop *l;
+ tree chrec, init, step;
+
+ if (current_loops == NULL)
+ return true;
+
+ l = loop_containing_stmt (stmt);
+ if (l == NULL
+ || !loop_outer (l))
+ return true;
+
+ chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
+ if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
+ return true;
+
+ init = initial_condition_in_loop_num (chrec, l->num);
+ step = evolution_part_in_loop_num (chrec, l->num);
+
+ if (step == NULL_TREE
+ || !is_gimple_min_invariant (step)
+ || !valid_value_p (init))
+ return true;
+
+ /* If we get here, we know something useful about VAR based on the
+ loop information. If it wraps, it may overflow. */
+
+ if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
+ true))
+ return true;
+
+ if (dump_file && (dump_flags & TDF_DETAILS) != 0)
+ {
+ print_generic_expr (dump_file, var, 0);
+ fprintf (dump_file, ": loop information indicates does not overflow\n");
+ }
+
+ return false;
+}
+
+
+/* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
+
+ - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
+ all the values in the ranges.
+
+ - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
+
+ - Return NULL_TREE if it is not always possible to determine the
+ value of the comparison.
+
+ Also set *STRICT_OVERFLOW_P to indicate whether a range with an
+ overflow infinity was used in the test. */
+
+
+static tree
+compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
+ bool *strict_overflow_p)
+{
+ /* VARYING or UNDEFINED ranges cannot be compared. */
+ if (vr0->type == VR_VARYING
+ || vr0->type == VR_UNDEFINED
+ || vr1->type == VR_VARYING
+ || vr1->type == VR_UNDEFINED)
+ return NULL_TREE;
+
+ /* Anti-ranges need to be handled separately. */
+ if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
+ {
+ /* If both are anti-ranges, then we cannot compute any
+ comparison. */
+ if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
+ return NULL_TREE;
+
+ /* These comparisons are never statically computable. */
+ if (comp == GT_EXPR
+ || comp == GE_EXPR
+ || comp == LT_EXPR
+ || comp == LE_EXPR)
+ return NULL_TREE;
+
+ /* Equality can be computed only between a range and an
+ anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
+ if (vr0->type == VR_RANGE)
+ {
+ /* To simplify processing, make VR0 the anti-range. */
+ value_range_t *tmp = vr0;
+ vr0 = vr1;
+ vr1 = tmp;
+ }
+
+ gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
+
+ if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
+ && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
+ return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
+
+ return NULL_TREE;
+ }
+
+ if (!usable_range_p (vr0, strict_overflow_p)
+ || !usable_range_p (vr1, strict_overflow_p))
+ return NULL_TREE;
+
+ /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
+ operands around and change the comparison code. */
+ if (comp == GT_EXPR || comp == GE_EXPR)
+ {
+ value_range_t *tmp;
+ comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
+ tmp = vr0;
+ vr0 = vr1;
+ vr1 = tmp;
+ }
+
+ if (comp == EQ_EXPR)
+ {
+ /* Equality may only be computed if both ranges represent
+ exactly one value. */
+ if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
+ && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
+ {
+ int cmp_min = compare_values_warnv (vr0->min, vr1->min,
+ strict_overflow_p);
+ int cmp_max = compare_values_warnv (vr0->max, vr1->max,
+ strict_overflow_p);
+ if (cmp_min == 0 && cmp_max == 0)
+ return boolean_true_node;
+ else if (cmp_min != -2 && cmp_max != -2)
+ return boolean_false_node;
+ }
+ /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
+ else if (compare_values_warnv (vr0->min, vr1->max,
+ strict_overflow_p) == 1
+ || compare_values_warnv (vr1->min, vr0->max,
+ strict_overflow_p) == 1)
+ return boolean_false_node;
+
+ return NULL_TREE;
+ }
+ else if (comp == NE_EXPR)
+ {
+ int cmp1, cmp2;
+
+ /* If VR0 is completely to the left or completely to the right
+ of VR1, they are always different. Notice that we need to
+ make sure that both comparisons yield similar results to
+ avoid comparing values that cannot be compared at
+ compile-time. */
+ cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
+ cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
+ if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
+ return boolean_true_node;
+
+ /* If VR0 and VR1 represent a single value and are identical,
+ return false. */
+ else if (compare_values_warnv (vr0->min, vr0->max,
+ strict_overflow_p) == 0
+ && compare_values_warnv (vr1->min, vr1->max,
+ strict_overflow_p) == 0
+ && compare_values_warnv (vr0->min, vr1->min,
+ strict_overflow_p) == 0
+ && compare_values_warnv (vr0->max, vr1->max,
+ strict_overflow_p) == 0)
+ return boolean_false_node;
+
+ /* Otherwise, they may or may not be different. */
+ else
+ return NULL_TREE;
+ }
+ else if (comp == LT_EXPR || comp == LE_EXPR)
+ {
+ int tst;
+
+ /* If VR0 is to the left of VR1, return true. */
+ tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
+ if ((comp == LT_EXPR && tst == -1)
+ || (comp == LE_EXPR && (tst == -1 || tst == 0)))
+ {
+ if (overflow_infinity_range_p (vr0)
+ || overflow_infinity_range_p (vr1))
+ *strict_overflow_p = true;
+ return boolean_true_node;
+ }
+
+ /* If VR0 is to the right of VR1, return false. */
+ tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
+ if ((comp == LT_EXPR && (tst == 0 || tst == 1))
+ || (comp == LE_EXPR && tst == 1))
+ {
+ if (overflow_infinity_range_p (vr0)
+ || overflow_infinity_range_p (vr1))
+ *strict_overflow_p = true;
+ return boolean_false_node;
+ }
+
+ /* Otherwise, we don't know. */
+ return NULL_TREE;
+ }
+
+ gcc_unreachable ();
+}
+
+
+/* Given a value range VR, a value VAL and a comparison code COMP, return
+ BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
+ values in VR. Return BOOLEAN_FALSE_NODE if the comparison
+ always returns false. Return NULL_TREE if it is not always
+ possible to determine the value of the comparison. Also set
+ *STRICT_OVERFLOW_P to indicate whether a range with an overflow
+ infinity was used in the test. */
+
+static tree
+compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
+ bool *strict_overflow_p)
+{
+ if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
+ return NULL_TREE;
+
+ /* Anti-ranges need to be handled separately. */
+ if (vr->type == VR_ANTI_RANGE)
+ {
+ /* For anti-ranges, the only predicates that we can compute at
+ compile time are equality and inequality. */
+ if (comp == GT_EXPR
+ || comp == GE_EXPR
+ || comp == LT_EXPR
+ || comp == LE_EXPR)
+ return NULL_TREE;
+
+ /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
+ if (value_inside_range (val, vr->min, vr->max) == 1)
+ return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
+
+ return NULL_TREE;
+ }
+
+ if (!usable_range_p (vr, strict_overflow_p))
+ return NULL_TREE;
+
+ if (comp == EQ_EXPR)
+ {
+ /* EQ_EXPR may only be computed if VR represents exactly
+ one value. */
+ if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
+ {
+ int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
+ if (cmp == 0)
+ return boolean_true_node;
+ else if (cmp == -1 || cmp == 1 || cmp == 2)
+ return boolean_false_node;
+ }
+ else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
+ || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
+ return boolean_false_node;
+
+ return NULL_TREE;
+ }
+ else if (comp == NE_EXPR)
+ {
+ /* If VAL is not inside VR, then they are always different. */
+ if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
+ || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
+ return boolean_true_node;
+
+ /* If VR represents exactly one value equal to VAL, then return
+ false. */
+ if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
+ && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
+ return boolean_false_node;
+
+ /* Otherwise, they may or may not be different. */
+ return NULL_TREE;
+ }
+ else if (comp == LT_EXPR || comp == LE_EXPR)
+ {
+ int tst;
+
+ /* If VR is to the left of VAL, return true. */
+ tst = compare_values_warnv (vr->max, val, strict_overflow_p);
+ if ((comp == LT_EXPR && tst == -1)
+ || (comp == LE_EXPR && (tst == -1 || tst == 0)))
+ {
+ if (overflow_infinity_range_p (vr))
+ *strict_overflow_p = true;
+ return boolean_true_node;
+ }
+
+ /* If VR is to the right of VAL, return false. */
+ tst = compare_values_warnv (vr->min, val, strict_overflow_p);
+ if ((comp == LT_EXPR && (tst == 0 || tst == 1))
+ || (comp == LE_EXPR && tst == 1))
+ {
+ if (overflow_infinity_range_p (vr))
+ *strict_overflow_p = true;
+ return boolean_false_node;
+ }
+
+ /* Otherwise, we don't know. */
+ return NULL_TREE;
+ }
+ else if (comp == GT_EXPR || comp == GE_EXPR)
+ {
+ int tst;
+
+ /* If VR is to the right of VAL, return true. */
+ tst = compare_values_warnv (vr->min, val, strict_overflow_p);
+ if ((comp == GT_EXPR && tst == 1)
+ || (comp == GE_EXPR && (tst == 0 || tst == 1)))
+ {
+ if (overflow_infinity_range_p (vr))
+ *strict_overflow_p = true;
+ return boolean_true_node;
+ }
+
+ /* If VR is to the left of VAL, return false. */
+ tst = compare_values_warnv (vr->max, val, strict_overflow_p);
+ if ((comp == GT_EXPR && (tst == -1 || tst == 0))
+ || (comp == GE_EXPR && tst == -1))
+ {
+ if (overflow_infinity_range_p (vr))
+ *strict_overflow_p = true;
+ return boolean_false_node;
+ }
+
+ /* Otherwise, we don't know. */
+ return NULL_TREE;
+ }
+
+ gcc_unreachable ();
+}
+
+
+/* Debugging dumps. */
+
+void dump_value_range (FILE *, value_range_t *);
+void debug_value_range (value_range_t *);
+void dump_all_value_ranges (FILE *);
+void debug_all_value_ranges (void);
+void dump_vr_equiv (FILE *, bitmap);
+void debug_vr_equiv (bitmap);
+
+
+/* Dump value range VR to FILE. */
+
+void
+dump_value_range (FILE *file, value_range_t *vr)
+{
+ if (vr == NULL)
+ fprintf (file, "[]");
+ else if (vr->type == VR_UNDEFINED)
+ fprintf (file, "UNDEFINED");
+ else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
+ {
+ tree type = TREE_TYPE (vr->min);
+
+ fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
+
+ if (is_negative_overflow_infinity (vr->min))
+ fprintf (file, "-INF(OVF)");
+ else if (INTEGRAL_TYPE_P (type)
+ && !TYPE_UNSIGNED (type)
+ && vrp_val_is_min (vr->min))
+ fprintf (file, "-INF");
+ else
+ print_generic_expr (file, vr->min, 0);
+
+ fprintf (file, ", ");
+
+ if (is_positive_overflow_infinity (vr->max))
+ fprintf (file, "+INF(OVF)");
+ else if (INTEGRAL_TYPE_P (type)
+ && vrp_val_is_max (vr->max))
+ fprintf (file, "+INF");
+ else
+ print_generic_expr (file, vr->max, 0);
+
+ fprintf (file, "]");
+
+ if (vr->equiv)
+ {
+ bitmap_iterator bi;
+ unsigned i, c = 0;
+
+ fprintf (file, " EQUIVALENCES: { ");
+
+ EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
+ {
+ print_generic_expr (file, ssa_name (i), 0);
+ fprintf (file, " ");
+ c++;
+ }
+
+ fprintf (file, "} (%u elements)", c);
+ }
+ }
+ else if (vr->type == VR_VARYING)
+ fprintf (file, "VARYING");
+ else
+ fprintf (file, "INVALID RANGE");
+}
+
+
+/* Dump value range VR to stderr. */
+
+DEBUG_FUNCTION void
+debug_value_range (value_range_t *vr)
+{
+ dump_value_range (stderr, vr);
+ fprintf (stderr, "\n");
+}
+
+
+/* Dump value ranges of all SSA_NAMEs to FILE. */
+
+void
+dump_all_value_ranges (FILE *file)
+{
+ size_t i;
+
+ for (i = 0; i < num_vr_values; i++)
+ {
+ if (vr_value[i])
+ {
+ print_generic_expr (file, ssa_name (i), 0);
+ fprintf (file, ": ");
+ dump_value_range (file, vr_value[i]);
+ fprintf (file, "\n");
+ }
+ }
+
+ fprintf (file, "\n");
+}
+
+
+/* Dump all value ranges to stderr. */
+
+DEBUG_FUNCTION void
+debug_all_value_ranges (void)
+{
+ dump_all_value_ranges (stderr);
+}
+
+
+/* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
+ create a new SSA name N and return the assertion assignment
+ 'V = ASSERT_EXPR <V, V OP W>'. */
+
+static gimple
+build_assert_expr_for (tree cond, tree v)
+{
+ tree a;
+ gimple assertion;
+
+ gcc_assert (TREE_CODE (v) == SSA_NAME
+ && COMPARISON_CLASS_P (cond));
+
+ a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
+ assertion = gimple_build_assign (NULL_TREE, a);
+
+ /* The new ASSERT_EXPR, creates a new SSA name that replaces the
+ operand of the ASSERT_EXPR. Create it so the new name and the old one
+ are registered in the replacement table so that we can fix the SSA web
+ after adding all the ASSERT_EXPRs. */
+ create_new_def_for (v, assertion, NULL);
+
+ return assertion;
+}
+
+
+/* Return false if EXPR is a predicate expression involving floating
+ point values. */
+
+static inline bool
+fp_predicate (gimple stmt)
+{
+ GIMPLE_CHECK (stmt, GIMPLE_COND);
+
+ return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
+}
+
+/* If the range of values taken by OP can be inferred after STMT executes,
+ return the comparison code (COMP_CODE_P) and value (VAL_P) that
+ describes the inferred range. Return true if a range could be
+ inferred. */
+
+static bool
+infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
+{
+ *val_p = NULL_TREE;
+ *comp_code_p = ERROR_MARK;
+
+ /* Do not attempt to infer anything in names that flow through
+ abnormal edges. */
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
+ return false;
+
+ /* Similarly, don't infer anything from statements that may throw
+ exceptions. ??? Relax this requirement? */
+ if (stmt_could_throw_p (stmt))
+ return false;
+
+ /* If STMT is the last statement of a basic block with no normal
+ successors, there is no point inferring anything about any of its
+ operands. We would not be able to find a proper insertion point
+ for the assertion, anyway. */
+ if (stmt_ends_bb_p (stmt))
+ {
+ edge_iterator ei;
+ edge e;
+
+ FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
+ if (!(e->flags & EDGE_ABNORMAL))
+ break;
+ if (e == NULL)
+ return false;
+ }
+
+ if (infer_nonnull_range (stmt, op, true, true))
+ {
+ *val_p = build_int_cst (TREE_TYPE (op), 0);
+ *comp_code_p = NE_EXPR;
+ return true;
+ }
+
+ return false;
+}
+
+
+void dump_asserts_for (FILE *, tree);
+void debug_asserts_for (tree);
+void dump_all_asserts (FILE *);
+void debug_all_asserts (void);
+
+/* Dump all the registered assertions for NAME to FILE. */
+
+void
+dump_asserts_for (FILE *file, tree name)
+{
+ assert_locus_t loc;
+
+ fprintf (file, "Assertions to be inserted for ");
+ print_generic_expr (file, name, 0);
+ fprintf (file, "\n");
+
+ loc = asserts_for[SSA_NAME_VERSION (name)];
+ while (loc)
+ {
+ fprintf (file, "\t");
+ print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
+ fprintf (file, "\n\tBB #%d", loc->bb->index);
+ if (loc->e)
+ {
+ fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
+ loc->e->dest->index);
+ dump_edge_info (file, loc->e, dump_flags, 0);
+ }
+ fprintf (file, "\n\tPREDICATE: ");
+ print_generic_expr (file, name, 0);
+ fprintf (file, " %s ", get_tree_code_name (loc->comp_code));
+ print_generic_expr (file, loc->val, 0);
+ fprintf (file, "\n\n");
+ loc = loc->next;
+ }
+
+ fprintf (file, "\n");
+}
+
+
+/* Dump all the registered assertions for NAME to stderr. */
+
+DEBUG_FUNCTION void
+debug_asserts_for (tree name)
+{
+ dump_asserts_for (stderr, name);
+}
+
+
+/* Dump all the registered assertions for all the names to FILE. */
+
+void
+dump_all_asserts (FILE *file)
+{
+ unsigned i;
+ bitmap_iterator bi;
+
+ fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
+ EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
+ dump_asserts_for (file, ssa_name (i));
+ fprintf (file, "\n");
+}
+
+
+/* Dump all the registered assertions for all the names to stderr. */
+
+DEBUG_FUNCTION void
+debug_all_asserts (void)
+{
+ dump_all_asserts (stderr);
+}
+
+
+/* If NAME doesn't have an ASSERT_EXPR registered for asserting
+ 'EXPR COMP_CODE VAL' at a location that dominates block BB or
+ E->DEST, then register this location as a possible insertion point
+ for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
+
+ BB, E and SI provide the exact insertion point for the new
+ ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
+ on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
+ BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
+ must not be NULL. */
+
+static void
+register_new_assert_for (tree name, tree expr,
+ enum tree_code comp_code,
+ tree val,
+ basic_block bb,
+ edge e,
+ gimple_stmt_iterator si)
+{
+ assert_locus_t n, loc, last_loc;
+ basic_block dest_bb;
+
+ gcc_checking_assert (bb == NULL || e == NULL);
+
+ if (e == NULL)
+ gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
+ && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
+
+ /* Never build an assert comparing against an integer constant with
+ TREE_OVERFLOW set. This confuses our undefined overflow warning
+ machinery. */
+ if (TREE_OVERFLOW_P (val))
+ val = drop_tree_overflow (val);
+
+ /* The new assertion A will be inserted at BB or E. We need to
+ determine if the new location is dominated by a previously
+ registered location for A. If we are doing an edge insertion,
+ assume that A will be inserted at E->DEST. Note that this is not
+ necessarily true.
+
+ If E is a critical edge, it will be split. But even if E is
+ split, the new block will dominate the same set of blocks that
+ E->DEST dominates.
+
+ The reverse, however, is not true, blocks dominated by E->DEST
+ will not be dominated by the new block created to split E. So,
+ if the insertion location is on a critical edge, we will not use
+ the new location to move another assertion previously registered
+ at a block dominated by E->DEST. */
+ dest_bb = (bb) ? bb : e->dest;
+
+ /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
+ VAL at a block dominating DEST_BB, then we don't need to insert a new
+ one. Similarly, if the same assertion already exists at a block
+ dominated by DEST_BB and the new location is not on a critical
+ edge, then update the existing location for the assertion (i.e.,
+ move the assertion up in the dominance tree).
+
+ Note, this is implemented as a simple linked list because there
+ should not be more than a handful of assertions registered per
+ name. If this becomes a performance problem, a table hashed by
+ COMP_CODE and VAL could be implemented. */
+ loc = asserts_for[SSA_NAME_VERSION (name)];
+ last_loc = loc;
+ while (loc)
+ {
+ if (loc->comp_code == comp_code
+ && (loc->val == val
+ || operand_equal_p (loc->val, val, 0))
+ && (loc->expr == expr
+ || operand_equal_p (loc->expr, expr, 0)))
+ {
+ /* If E is not a critical edge and DEST_BB
+ dominates the existing location for the assertion, move
+ the assertion up in the dominance tree by updating its
+ location information. */
+ if ((e == NULL || !EDGE_CRITICAL_P (e))
+ && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
+ {
+ loc->bb = dest_bb;
+ loc->e = e;
+ loc->si = si;
+ return;
+ }
+ }
+
+ /* Update the last node of the list and move to the next one. */
+ last_loc = loc;
+ loc = loc->next;
+ }
+
+ /* If we didn't find an assertion already registered for
+ NAME COMP_CODE VAL, add a new one at the end of the list of
+ assertions associated with NAME. */
+ n = XNEW (struct assert_locus_d);
+ n->bb = dest_bb;
+ n->e = e;
+ n->si = si;
+ n->comp_code = comp_code;
+ n->val = val;
+ n->expr = expr;
+ n->next = NULL;
+
+ if (last_loc)
+ last_loc->next = n;
+ else
+ asserts_for[SSA_NAME_VERSION (name)] = n;
+
+ bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
+}
+
+/* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
+ Extract a suitable test code and value and store them into *CODE_P and
+ *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
+
+ If no extraction was possible, return FALSE, otherwise return TRUE.
+
+ If INVERT is true, then we invert the result stored into *CODE_P. */
+
+static bool
+extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
+ tree cond_op0, tree cond_op1,
+ bool invert, enum tree_code *code_p,
+ tree *val_p)
+{
+ enum tree_code comp_code;
+ tree val;
+
+ /* Otherwise, we have a comparison of the form NAME COMP VAL
+ or VAL COMP NAME. */
+ if (name == cond_op1)
+ {
+ /* If the predicate is of the form VAL COMP NAME, flip
+ COMP around because we need to register NAME as the
+ first operand in the predicate. */
+ comp_code = swap_tree_comparison (cond_code);
+ val = cond_op0;
+ }
+ else
+ {
+ /* The comparison is of the form NAME COMP VAL, so the
+ comparison code remains unchanged. */
+ comp_code = cond_code;
+ val = cond_op1;
+ }
+
+ /* Invert the comparison code as necessary. */
+ if (invert)
+ comp_code = invert_tree_comparison (comp_code, 0);
+
+ /* VRP does not handle float types. */
+ if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
+ return false;
+
+ /* Do not register always-false predicates.
+ FIXME: this works around a limitation in fold() when dealing with
+ enumerations. Given 'enum { N1, N2 } x;', fold will not
+ fold 'if (x > N2)' to 'if (0)'. */
+ if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
+ && INTEGRAL_TYPE_P (TREE_TYPE (val)))
+ {
+ tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
+ tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
+
+ if (comp_code == GT_EXPR
+ && (!max
+ || compare_values (val, max) == 0))
+ return false;
+
+ if (comp_code == LT_EXPR
+ && (!min
+ || compare_values (val, min) == 0))
+ return false;
+ }
+ *code_p = comp_code;
+ *val_p = val;
+ return true;
+}
+
+/* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any
+ (otherwise return VAL). VAL and MASK must be zero-extended for
+ precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT
+ (to transform signed values into unsigned) and at the end xor
+ SGNBIT back. */
+
+static double_int
+masked_increment (double_int val, double_int mask, double_int sgnbit,
+ unsigned int prec)
+{
+ double_int bit = double_int_one, res;
+ unsigned int i;
+
+ val ^= sgnbit;
+ for (i = 0; i < prec; i++, bit += bit)
+ {
+ res = mask;
+ if ((res & bit).is_zero ())
+ continue;
+ res = bit - double_int_one;
+ res = (val + bit).and_not (res);
+ res &= mask;
+ if (res.ugt (val))
+ return res ^ sgnbit;
+ }
+ return val ^ sgnbit;
+}
+
+/* Try to register an edge assertion for SSA name NAME on edge E for
+ the condition COND contributing to the conditional jump pointed to by BSI.
+ Invert the condition COND if INVERT is true.
+ Return true if an assertion for NAME could be registered. */
+
+static bool
+register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
+ enum tree_code cond_code,
+ tree cond_op0, tree cond_op1, bool invert)
+{
+ tree val;
+ enum tree_code comp_code;
+ bool retval = false;
+
+ if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
+ cond_op0,
+ cond_op1,
+ invert, &comp_code, &val))
+ return false;
+
+ /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
+ reachable from E. */
+ if (live_on_edge (e, name)
+ && !has_single_use (name))
+ {
+ register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
+ retval = true;
+ }
+
+ /* In the case of NAME <= CST and NAME being defined as
+ NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
+ and NAME2 <= CST - CST2. We can do the same for NAME > CST.
+ This catches range and anti-range tests. */
+ if ((comp_code == LE_EXPR
+ || comp_code == GT_EXPR)
+ && TREE_CODE (val) == INTEGER_CST
+ && TYPE_UNSIGNED (TREE_TYPE (val)))
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (name);
+ tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
+
+ /* Extract CST2 from the (optional) addition. */
+ if (is_gimple_assign (def_stmt)
+ && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
+ {
+ name2 = gimple_assign_rhs1 (def_stmt);
+ cst2 = gimple_assign_rhs2 (def_stmt);
+ if (TREE_CODE (name2) == SSA_NAME
+ && TREE_CODE (cst2) == INTEGER_CST)
+ def_stmt = SSA_NAME_DEF_STMT (name2);
+ }
+
+ /* Extract NAME2 from the (optional) sign-changing cast. */
+ if (gimple_assign_cast_p (def_stmt))
+ {
+ if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
+ && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
+ && (TYPE_PRECISION (gimple_expr_type (def_stmt))
+ == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
+ name3 = gimple_assign_rhs1 (def_stmt);
+ }
+
+ /* If name3 is used later, create an ASSERT_EXPR for it. */
+ if (name3 != NULL_TREE
+ && TREE_CODE (name3) == SSA_NAME
+ && (cst2 == NULL_TREE
+ || TREE_CODE (cst2) == INTEGER_CST)
+ && INTEGRAL_TYPE_P (TREE_TYPE (name3))
+ && live_on_edge (e, name3)
+ && !has_single_use (name3))
+ {
+ tree tmp;
+
+ /* Build an expression for the range test. */
+ tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
+ if (cst2 != NULL_TREE)
+ tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Adding assert for ");
+ print_generic_expr (dump_file, name3, 0);
+ fprintf (dump_file, " from ");
+ print_generic_expr (dump_file, tmp, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
+
+ retval = true;
+ }
+
+ /* If name2 is used later, create an ASSERT_EXPR for it. */
+ if (name2 != NULL_TREE
+ && TREE_CODE (name2) == SSA_NAME
+ && TREE_CODE (cst2) == INTEGER_CST
+ && INTEGRAL_TYPE_P (TREE_TYPE (name2))
+ && live_on_edge (e, name2)
+ && !has_single_use (name2))
+ {
+ tree tmp;
+
+ /* Build an expression for the range test. */
+ tmp = name2;
+ if (TREE_TYPE (name) != TREE_TYPE (name2))
+ tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
+ if (cst2 != NULL_TREE)
+ tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Adding assert for ");
+ print_generic_expr (dump_file, name2, 0);
+ fprintf (dump_file, " from ");
+ print_generic_expr (dump_file, tmp, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
+
+ retval = true;
+ }
+ }
+
+ /* In the case of post-in/decrement tests like if (i++) ... and uses
+ of the in/decremented value on the edge the extra name we want to
+ assert for is not on the def chain of the name compared. Instead
+ it is in the set of use stmts. */
+ if ((comp_code == NE_EXPR
+ || comp_code == EQ_EXPR)
+ && TREE_CODE (val) == INTEGER_CST)
+ {
+ imm_use_iterator ui;
+ gimple use_stmt;
+ FOR_EACH_IMM_USE_STMT (use_stmt, ui, name)
+ {
+ /* Cut off to use-stmts that are in the predecessor. */
+ if (gimple_bb (use_stmt) != e->src)
+ continue;
+
+ if (!is_gimple_assign (use_stmt))
+ continue;
+
+ enum tree_code code = gimple_assign_rhs_code (use_stmt);
+ if (code != PLUS_EXPR
+ && code != MINUS_EXPR)
+ continue;
+
+ tree cst = gimple_assign_rhs2 (use_stmt);
+ if (TREE_CODE (cst) != INTEGER_CST)
+ continue;
+
+ tree name2 = gimple_assign_lhs (use_stmt);
+ if (live_on_edge (e, name2))
+ {
+ cst = int_const_binop (code, val, cst);
+ register_new_assert_for (name2, name2, comp_code, cst,
+ NULL, e, bsi);
+ retval = true;
+ }
+ }
+ }
+
+ if (TREE_CODE_CLASS (comp_code) == tcc_comparison
+ && TREE_CODE (val) == INTEGER_CST)
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (name);
+ tree name2 = NULL_TREE, names[2], cst2 = NULL_TREE;
+ tree val2 = NULL_TREE;
+ double_int mask = double_int_zero;
+ unsigned int prec = TYPE_PRECISION (TREE_TYPE (val));
+ unsigned int nprec = prec;
+ enum tree_code rhs_code = ERROR_MARK;
+
+ if (is_gimple_assign (def_stmt))
+ rhs_code = gimple_assign_rhs_code (def_stmt);
+
+ /* Add asserts for NAME cmp CST and NAME being defined
+ as NAME = (int) NAME2. */
+ if (!TYPE_UNSIGNED (TREE_TYPE (val))
+ && (comp_code == LE_EXPR || comp_code == LT_EXPR
+ || comp_code == GT_EXPR || comp_code == GE_EXPR)
+ && gimple_assign_cast_p (def_stmt))
+ {
+ name2 = gimple_assign_rhs1 (def_stmt);
+ if (CONVERT_EXPR_CODE_P (rhs_code)
+ && INTEGRAL_TYPE_P (TREE_TYPE (name2))
+ && TYPE_UNSIGNED (TREE_TYPE (name2))
+ && prec == TYPE_PRECISION (TREE_TYPE (name2))
+ && (comp_code == LE_EXPR || comp_code == GT_EXPR
+ || !tree_int_cst_equal (val,
+ TYPE_MIN_VALUE (TREE_TYPE (val))))
+ && live_on_edge (e, name2)
+ && !has_single_use (name2))
+ {
+ tree tmp, cst;
+ enum tree_code new_comp_code = comp_code;
+
+ cst = fold_convert (TREE_TYPE (name2),
+ TYPE_MIN_VALUE (TREE_TYPE (val)));
+ /* Build an expression for the range test. */
+ tmp = build2 (PLUS_EXPR, TREE_TYPE (name2), name2, cst);
+ cst = fold_build2 (PLUS_EXPR, TREE_TYPE (name2), cst,
+ fold_convert (TREE_TYPE (name2), val));
+ if (comp_code == LT_EXPR || comp_code == GE_EXPR)
+ {
+ new_comp_code = comp_code == LT_EXPR ? LE_EXPR : GT_EXPR;
+ cst = fold_build2 (MINUS_EXPR, TREE_TYPE (name2), cst,
+ build_int_cst (TREE_TYPE (name2), 1));
+ }
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Adding assert for ");
+ print_generic_expr (dump_file, name2, 0);
+ fprintf (dump_file, " from ");
+ print_generic_expr (dump_file, tmp, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ register_new_assert_for (name2, tmp, new_comp_code, cst, NULL,
+ e, bsi);
+
+ retval = true;
+ }
+ }
+
+ /* Add asserts for NAME cmp CST and NAME being defined as
+ NAME = NAME2 >> CST2.
+
+ Extract CST2 from the right shift. */
+ if (rhs_code == RSHIFT_EXPR)
+ {
+ name2 = gimple_assign_rhs1 (def_stmt);
+ cst2 = gimple_assign_rhs2 (def_stmt);
+ if (TREE_CODE (name2) == SSA_NAME
+ && tree_fits_uhwi_p (cst2)
+ && INTEGRAL_TYPE_P (TREE_TYPE (name2))
+ && IN_RANGE (tree_to_uhwi (cst2), 1, prec - 1)
+ && prec <= HOST_BITS_PER_DOUBLE_INT
+ && prec == GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (val)))
+ && live_on_edge (e, name2)
+ && !has_single_use (name2))
+ {
+ mask = double_int::mask (tree_to_uhwi (cst2));
+ val2 = fold_binary (LSHIFT_EXPR, TREE_TYPE (val), val, cst2);
+ }
+ }
+ if (val2 != NULL_TREE
+ && TREE_CODE (val2) == INTEGER_CST
+ && simple_cst_equal (fold_build2 (RSHIFT_EXPR,
+ TREE_TYPE (val),
+ val2, cst2), val))
+ {
+ enum tree_code new_comp_code = comp_code;
+ tree tmp, new_val;
+
+ tmp = name2;
+ if (comp_code == EQ_EXPR || comp_code == NE_EXPR)
+ {
+ if (!TYPE_UNSIGNED (TREE_TYPE (val)))
+ {
+ tree type = build_nonstandard_integer_type (prec, 1);
+ tmp = build1 (NOP_EXPR, type, name2);
+ val2 = fold_convert (type, val2);
+ }
+ tmp = fold_build2 (MINUS_EXPR, TREE_TYPE (tmp), tmp, val2);
+ new_val = double_int_to_tree (TREE_TYPE (tmp), mask);
+ new_comp_code = comp_code == EQ_EXPR ? LE_EXPR : GT_EXPR;
+ }
+ else if (comp_code == LT_EXPR || comp_code == GE_EXPR)
+ {
+ double_int minval
+ = double_int::min_value (prec, TYPE_UNSIGNED (TREE_TYPE (val)));
+ new_val = val2;
+ if (minval == tree_to_double_int (new_val))
+ new_val = NULL_TREE;
+ }
+ else
+ {
+ double_int maxval
+ = double_int::max_value (prec, TYPE_UNSIGNED (TREE_TYPE (val)));
+ mask |= tree_to_double_int (val2);
+ if (mask == maxval)
+ new_val = NULL_TREE;
+ else
+ new_val = double_int_to_tree (TREE_TYPE (val2), mask);
+ }
+
+ if (new_val)
+ {
+ if (dump_file)
+ {
+ fprintf (dump_file, "Adding assert for ");
+ print_generic_expr (dump_file, name2, 0);
+ fprintf (dump_file, " from ");
+ print_generic_expr (dump_file, tmp, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ register_new_assert_for (name2, tmp, new_comp_code, new_val,
+ NULL, e, bsi);
+ retval = true;
+ }
+ }
+
+ /* Add asserts for NAME cmp CST and NAME being defined as
+ NAME = NAME2 & CST2.
+
+ Extract CST2 from the and.
+
+ Also handle
+ NAME = (unsigned) NAME2;
+ casts where NAME's type is unsigned and has smaller precision
+ than NAME2's type as if it was NAME = NAME2 & MASK. */
+ names[0] = NULL_TREE;
+ names[1] = NULL_TREE;
+ cst2 = NULL_TREE;
+ if (rhs_code == BIT_AND_EXPR
+ || (CONVERT_EXPR_CODE_P (rhs_code)
+ && TREE_CODE (TREE_TYPE (val)) == INTEGER_TYPE
+ && TYPE_UNSIGNED (TREE_TYPE (val))
+ && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
+ > prec
+ && !retval))
+ {
+ name2 = gimple_assign_rhs1 (def_stmt);
+ if (rhs_code == BIT_AND_EXPR)
+ cst2 = gimple_assign_rhs2 (def_stmt);
+ else
+ {
+ cst2 = TYPE_MAX_VALUE (TREE_TYPE (val));
+ nprec = TYPE_PRECISION (TREE_TYPE (name2));
+ }
+ if (TREE_CODE (name2) == SSA_NAME
+ && INTEGRAL_TYPE_P (TREE_TYPE (name2))
+ && TREE_CODE (cst2) == INTEGER_CST
+ && !integer_zerop (cst2)
+ && nprec <= HOST_BITS_PER_DOUBLE_INT
+ && (nprec > 1
+ || TYPE_UNSIGNED (TREE_TYPE (val))))
+ {
+ gimple def_stmt2 = SSA_NAME_DEF_STMT (name2);
+ if (gimple_assign_cast_p (def_stmt2))
+ {
+ names[1] = gimple_assign_rhs1 (def_stmt2);
+ if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2))
+ || !INTEGRAL_TYPE_P (TREE_TYPE (names[1]))
+ || (TYPE_PRECISION (TREE_TYPE (name2))
+ != TYPE_PRECISION (TREE_TYPE (names[1])))
+ || !live_on_edge (e, names[1])
+ || has_single_use (names[1]))
+ names[1] = NULL_TREE;
+ }
+ if (live_on_edge (e, name2)
+ && !has_single_use (name2))
+ names[0] = name2;
+ }
+ }
+ if (names[0] || names[1])
+ {
+ double_int minv, maxv = double_int_zero, valv, cst2v;
+ double_int tem, sgnbit;
+ bool valid_p = false, valn = false, cst2n = false;
+ enum tree_code ccode = comp_code;
+
+ valv = tree_to_double_int (val).zext (nprec);
+ cst2v = tree_to_double_int (cst2).zext (nprec);
+ if (!TYPE_UNSIGNED (TREE_TYPE (val)))
+ {
+ valn = valv.sext (nprec).is_negative ();
+ cst2n = cst2v.sext (nprec).is_negative ();
+ }
+ /* If CST2 doesn't have most significant bit set,
+ but VAL is negative, we have comparison like
+ if ((x & 0x123) > -4) (always true). Just give up. */
+ if (!cst2n && valn)
+ ccode = ERROR_MARK;
+ if (cst2n)
+ sgnbit = double_int_one.llshift (nprec - 1, nprec).zext (nprec);
+ else
+ sgnbit = double_int_zero;
+ minv = valv & cst2v;
+ switch (ccode)
+ {
+ case EQ_EXPR:
+ /* Minimum unsigned value for equality is VAL & CST2
+ (should be equal to VAL, otherwise we probably should
+ have folded the comparison into false) and
+ maximum unsigned value is VAL | ~CST2. */
+ maxv = valv | ~cst2v;
+ maxv = maxv.zext (nprec);
+ valid_p = true;
+ break;
+ case NE_EXPR:
+ tem = valv | ~cst2v;
+ tem = tem.zext (nprec);
+ /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */
+ if (valv.is_zero ())
+ {
+ cst2n = false;
+ sgnbit = double_int_zero;
+ goto gt_expr;
+ }
+ /* If (VAL | ~CST2) is all ones, handle it as
+ (X & CST2) < VAL. */
+ if (tem == double_int::mask (nprec))
+ {
+ cst2n = false;
+ valn = false;
+ sgnbit = double_int_zero;
+ goto lt_expr;
+ }
+ if (!cst2n
+ && cst2v.sext (nprec).is_negative ())
+ sgnbit
+ = double_int_one.llshift (nprec - 1, nprec).zext (nprec);
+ if (!sgnbit.is_zero ())
+ {
+ if (valv == sgnbit)
+ {
+ cst2n = true;
+ valn = true;
+ goto gt_expr;
+ }
+ if (tem == double_int::mask (nprec - 1))
+ {
+ cst2n = true;
+ goto lt_expr;
+ }
+ if (!cst2n)
+ sgnbit = double_int_zero;
+ }
+ break;
+ case GE_EXPR:
+ /* Minimum unsigned value for >= if (VAL & CST2) == VAL
+ is VAL and maximum unsigned value is ~0. For signed
+ comparison, if CST2 doesn't have most significant bit
+ set, handle it similarly. If CST2 has MSB set,
+ the minimum is the same, and maximum is ~0U/2. */
+ if (minv != valv)
+ {
+ /* If (VAL & CST2) != VAL, X & CST2 can't be equal to
+ VAL. */
+ minv = masked_increment (valv, cst2v, sgnbit, nprec);
+ if (minv == valv)
+ break;
+ }
+ maxv = double_int::mask (nprec - (cst2n ? 1 : 0));
+ valid_p = true;
+ break;
+ case GT_EXPR:
+ gt_expr:
+ /* Find out smallest MINV where MINV > VAL
+ && (MINV & CST2) == MINV, if any. If VAL is signed and
+ CST2 has MSB set, compute it biased by 1 << (nprec - 1). */
+ minv = masked_increment (valv, cst2v, sgnbit, nprec);
+ if (minv == valv)
+ break;
+ maxv = double_int::mask (nprec - (cst2n ? 1 : 0));
+ valid_p = true;
+ break;
+ case LE_EXPR:
+ /* Minimum unsigned value for <= is 0 and maximum
+ unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL.
+ Otherwise, find smallest VAL2 where VAL2 > VAL
+ && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
+ as maximum.
+ For signed comparison, if CST2 doesn't have most
+ significant bit set, handle it similarly. If CST2 has
+ MSB set, the maximum is the same and minimum is INT_MIN. */
+ if (minv == valv)
+ maxv = valv;
+ else
+ {
+ maxv = masked_increment (valv, cst2v, sgnbit, nprec);
+ if (maxv == valv)
+ break;
+ maxv -= double_int_one;
+ }
+ maxv |= ~cst2v;
+ maxv = maxv.zext (nprec);
+ minv = sgnbit;
+ valid_p = true;
+ break;
+ case LT_EXPR:
+ lt_expr:
+ /* Minimum unsigned value for < is 0 and maximum
+ unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL.
+ Otherwise, find smallest VAL2 where VAL2 > VAL
+ && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
+ as maximum.
+ For signed comparison, if CST2 doesn't have most
+ significant bit set, handle it similarly. If CST2 has
+ MSB set, the maximum is the same and minimum is INT_MIN. */
+ if (minv == valv)
+ {
+ if (valv == sgnbit)
+ break;
+ maxv = valv;
+ }
+ else
+ {
+ maxv = masked_increment (valv, cst2v, sgnbit, nprec);
+ if (maxv == valv)
+ break;
+ }
+ maxv -= double_int_one;
+ maxv |= ~cst2v;
+ maxv = maxv.zext (nprec);
+ minv = sgnbit;
+ valid_p = true;
+ break;
+ default:
+ break;
+ }
+ if (valid_p
+ && (maxv - minv).zext (nprec) != double_int::mask (nprec))
+ {
+ tree tmp, new_val, type;
+ int i;
+
+ for (i = 0; i < 2; i++)
+ if (names[i])
+ {
+ double_int maxv2 = maxv;
+ tmp = names[i];
+ type = TREE_TYPE (names[i]);
+ if (!TYPE_UNSIGNED (type))
+ {
+ type = build_nonstandard_integer_type (nprec, 1);
+ tmp = build1 (NOP_EXPR, type, names[i]);
+ }
+ if (!minv.is_zero ())
+ {
+ tmp = build2 (PLUS_EXPR, type, tmp,
+ double_int_to_tree (type, -minv));
+ maxv2 = maxv - minv;
+ }
+ new_val = double_int_to_tree (type, maxv2);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Adding assert for ");
+ print_generic_expr (dump_file, names[i], 0);
+ fprintf (dump_file, " from ");
+ print_generic_expr (dump_file, tmp, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ register_new_assert_for (names[i], tmp, LE_EXPR,
+ new_val, NULL, e, bsi);
+ retval = true;
+ }
+ }
+ }
+ }
+
+ return retval;
+}
+
+/* OP is an operand of a truth value expression which is known to have
+ a particular value. Register any asserts for OP and for any
+ operands in OP's defining statement.
+
+ If CODE is EQ_EXPR, then we want to register OP is zero (false),
+ if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
+
+static bool
+register_edge_assert_for_1 (tree op, enum tree_code code,
+ edge e, gimple_stmt_iterator bsi)
+{
+ bool retval = false;
+ gimple op_def;
+ tree val;
+ enum tree_code rhs_code;
+
+ /* We only care about SSA_NAMEs. */
+ if (TREE_CODE (op) != SSA_NAME)
+ return false;
+
+ /* We know that OP will have a zero or nonzero value. If OP is used
+ more than once go ahead and register an assert for OP. */
+ if (live_on_edge (e, op)
+ && !has_single_use (op))
+ {
+ val = build_int_cst (TREE_TYPE (op), 0);
+ register_new_assert_for (op, op, code, val, NULL, e, bsi);
+ retval = true;
+ }
+
+ /* Now look at how OP is set. If it's set from a comparison,
+ a truth operation or some bit operations, then we may be able
+ to register information about the operands of that assignment. */
+ op_def = SSA_NAME_DEF_STMT (op);
+ if (gimple_code (op_def) != GIMPLE_ASSIGN)
+ return retval;
+
+ rhs_code = gimple_assign_rhs_code (op_def);
+
+ if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
+ {
+ bool invert = (code == EQ_EXPR ? true : false);
+ tree op0 = gimple_assign_rhs1 (op_def);
+ tree op1 = gimple_assign_rhs2 (op_def);
+
+ if (TREE_CODE (op0) == SSA_NAME)
+ retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
+ invert);
+ if (TREE_CODE (op1) == SSA_NAME)
+ retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
+ invert);
+ }
+ else if ((code == NE_EXPR
+ && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
+ || (code == EQ_EXPR
+ && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
+ {
+ /* Recurse on each operand. */
+ tree op0 = gimple_assign_rhs1 (op_def);
+ tree op1 = gimple_assign_rhs2 (op_def);
+ if (TREE_CODE (op0) == SSA_NAME
+ && has_single_use (op0))
+ retval |= register_edge_assert_for_1 (op0, code, e, bsi);
+ if (TREE_CODE (op1) == SSA_NAME
+ && has_single_use (op1))
+ retval |= register_edge_assert_for_1 (op1, code, e, bsi);
+ }
+ else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
+ && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1)
+ {
+ /* Recurse, flipping CODE. */
+ code = invert_tree_comparison (code, false);
+ retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
+ code, e, bsi);
+ }
+ else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
+ {
+ /* Recurse through the copy. */
+ retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
+ code, e, bsi);
+ }
+ else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
+ {
+ /* Recurse through the type conversion, unless it is a narrowing
+ conversion or conversion from non-integral type. */
+ tree rhs = gimple_assign_rhs1 (op_def);
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs))
+ && (TYPE_PRECISION (TREE_TYPE (rhs))
+ <= TYPE_PRECISION (TREE_TYPE (op))))
+ retval |= register_edge_assert_for_1 (rhs, code, e, bsi);
+ }
+
+ return retval;
+}
+
+/* Try to register an edge assertion for SSA name NAME on edge E for
+ the condition COND contributing to the conditional jump pointed to by SI.
+ Return true if an assertion for NAME could be registered. */
+
+static bool
+register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
+ enum tree_code cond_code, tree cond_op0,
+ tree cond_op1)
+{
+ tree val;
+ enum tree_code comp_code;
+ bool retval = false;
+ bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
+
+ /* Do not attempt to infer anything in names that flow through
+ abnormal edges. */
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
+ return false;
+
+ if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
+ cond_op0, cond_op1,
+ is_else_edge,
+ &comp_code, &val))
+ return false;
+
+ /* Register ASSERT_EXPRs for name. */
+ retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
+ cond_op1, is_else_edge);
+
+
+ /* If COND is effectively an equality test of an SSA_NAME against
+ the value zero or one, then we may be able to assert values
+ for SSA_NAMEs which flow into COND. */
+
+ /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
+ statement of NAME we can assert both operands of the BIT_AND_EXPR
+ have nonzero value. */
+ if (((comp_code == EQ_EXPR && integer_onep (val))
+ || (comp_code == NE_EXPR && integer_zerop (val))))
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (name);
+
+ if (is_gimple_assign (def_stmt)
+ && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
+ {
+ tree op0 = gimple_assign_rhs1 (def_stmt);
+ tree op1 = gimple_assign_rhs2 (def_stmt);
+ retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
+ retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
+ }
+ }
+
+ /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
+ statement of NAME we can assert both operands of the BIT_IOR_EXPR
+ have zero value. */
+ if (((comp_code == EQ_EXPR && integer_zerop (val))
+ || (comp_code == NE_EXPR && integer_onep (val))))
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (name);
+
+ /* For BIT_IOR_EXPR only if NAME == 0 both operands have
+ necessarily zero value, or if type-precision is one. */
+ if (is_gimple_assign (def_stmt)
+ && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
+ && (TYPE_PRECISION (TREE_TYPE (name)) == 1
+ || comp_code == EQ_EXPR)))
+ {
+ tree op0 = gimple_assign_rhs1 (def_stmt);
+ tree op1 = gimple_assign_rhs2 (def_stmt);
+ retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
+ retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
+ }
+ }
+
+ return retval;
+}
+
+
+/* Determine whether the outgoing edges of BB should receive an
+ ASSERT_EXPR for each of the operands of BB's LAST statement.
+ The last statement of BB must be a COND_EXPR.
+
+ If any of the sub-graphs rooted at BB have an interesting use of
+ the predicate operands, an assert location node is added to the
+ list of assertions for the corresponding operands. */
+
+static bool
+find_conditional_asserts (basic_block bb, gimple last)
+{
+ bool need_assert;
+ gimple_stmt_iterator bsi;
+ tree op;
+ edge_iterator ei;
+ edge e;
+ ssa_op_iter iter;
+
+ need_assert = false;
+ bsi = gsi_for_stmt (last);
+
+ /* Look for uses of the operands in each of the sub-graphs
+ rooted at BB. We need to check each of the outgoing edges
+ separately, so that we know what kind of ASSERT_EXPR to
+ insert. */
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if (e->dest == bb)
+ continue;
+
+ /* Register the necessary assertions for each operand in the
+ conditional predicate. */
+ FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
+ {
+ need_assert |= register_edge_assert_for (op, e, bsi,
+ gimple_cond_code (last),
+ gimple_cond_lhs (last),
+ gimple_cond_rhs (last));
+ }
+ }
+
+ return need_assert;
+}
+
+struct case_info
+{
+ tree expr;
+ basic_block bb;
+};
+
+/* Compare two case labels sorting first by the destination bb index
+ and then by the case value. */
+
+static int
+compare_case_labels (const void *p1, const void *p2)
+{
+ const struct case_info *ci1 = (const struct case_info *) p1;
+ const struct case_info *ci2 = (const struct case_info *) p2;
+ int idx1 = ci1->bb->index;
+ int idx2 = ci2->bb->index;
+
+ if (idx1 < idx2)
+ return -1;
+ else if (idx1 == idx2)
+ {
+ /* Make sure the default label is first in a group. */
+ if (!CASE_LOW (ci1->expr))
+ return -1;
+ else if (!CASE_LOW (ci2->expr))
+ return 1;
+ else
+ return tree_int_cst_compare (CASE_LOW (ci1->expr),
+ CASE_LOW (ci2->expr));
+ }
+ else
+ return 1;
+}
+
+/* Determine whether the outgoing edges of BB should receive an
+ ASSERT_EXPR for each of the operands of BB's LAST statement.
+ The last statement of BB must be a SWITCH_EXPR.
+
+ If any of the sub-graphs rooted at BB have an interesting use of
+ the predicate operands, an assert location node is added to the
+ list of assertions for the corresponding operands. */
+
+static bool
+find_switch_asserts (basic_block bb, gimple last)
+{
+ bool need_assert;
+ gimple_stmt_iterator bsi;
+ tree op;
+ edge e;
+ struct case_info *ci;
+ size_t n = gimple_switch_num_labels (last);
+#if GCC_VERSION >= 4000
+ unsigned int idx;
+#else
+ /* Work around GCC 3.4 bug (PR 37086). */
+ volatile unsigned int idx;
+#endif
+
+ need_assert = false;
+ bsi = gsi_for_stmt (last);
+ op = gimple_switch_index (last);
+ if (TREE_CODE (op) != SSA_NAME)
+ return false;
+
+ /* Build a vector of case labels sorted by destination label. */
+ ci = XNEWVEC (struct case_info, n);
+ for (idx = 0; idx < n; ++idx)
+ {
+ ci[idx].expr = gimple_switch_label (last, idx);
+ ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
+ }
+ qsort (ci, n, sizeof (struct case_info), compare_case_labels);
+
+ for (idx = 0; idx < n; ++idx)
+ {
+ tree min, max;
+ tree cl = ci[idx].expr;
+ basic_block cbb = ci[idx].bb;
+
+ min = CASE_LOW (cl);
+ max = CASE_HIGH (cl);
+
+ /* If there are multiple case labels with the same destination
+ we need to combine them to a single value range for the edge. */
+ if (idx + 1 < n && cbb == ci[idx + 1].bb)
+ {
+ /* Skip labels until the last of the group. */
+ do {
+ ++idx;
+ } while (idx < n && cbb == ci[idx].bb);
+ --idx;
+
+ /* Pick up the maximum of the case label range. */
+ if (CASE_HIGH (ci[idx].expr))
+ max = CASE_HIGH (ci[idx].expr);
+ else
+ max = CASE_LOW (ci[idx].expr);
+ }
+
+ /* Nothing to do if the range includes the default label until we
+ can register anti-ranges. */
+ if (min == NULL_TREE)
+ continue;
+
+ /* Find the edge to register the assert expr on. */
+ e = find_edge (bb, cbb);
+
+ /* Register the necessary assertions for the operand in the
+ SWITCH_EXPR. */
+ need_assert |= register_edge_assert_for (op, e, bsi,
+ max ? GE_EXPR : EQ_EXPR,
+ op,
+ fold_convert (TREE_TYPE (op),
+ min));
+ if (max)
+ {
+ need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
+ op,
+ fold_convert (TREE_TYPE (op),
+ max));
+ }
+ }
+
+ XDELETEVEC (ci);
+ return need_assert;
+}
+
+
+/* Traverse all the statements in block BB looking for statements that
+ may generate useful assertions for the SSA names in their operand.
+ If a statement produces a useful assertion A for name N_i, then the
+ list of assertions already generated for N_i is scanned to
+ determine if A is actually needed.
+
+ If N_i already had the assertion A at a location dominating the
+ current location, then nothing needs to be done. Otherwise, the
+ new location for A is recorded instead.
+
+ 1- For every statement S in BB, all the variables used by S are
+ added to bitmap FOUND_IN_SUBGRAPH.
+
+ 2- If statement S uses an operand N in a way that exposes a known
+ value range for N, then if N was not already generated by an
+ ASSERT_EXPR, create a new assert location for N. For instance,
+ if N is a pointer and the statement dereferences it, we can
+ assume that N is not NULL.
+
+ 3- COND_EXPRs are a special case of #2. We can derive range
+ information from the predicate but need to insert different
+ ASSERT_EXPRs for each of the sub-graphs rooted at the
+ conditional block. If the last statement of BB is a conditional
+ expression of the form 'X op Y', then
+
+ a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
+
+ b) If the conditional is the only entry point to the sub-graph
+ corresponding to the THEN_CLAUSE, recurse into it. On
+ return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
+ an ASSERT_EXPR is added for the corresponding variable.
+
+ c) Repeat step (b) on the ELSE_CLAUSE.
+
+ d) Mark X and Y in FOUND_IN_SUBGRAPH.
+
+ For instance,
+
+ if (a == 9)
+ b = a;
+ else
+ b = c + 1;
+
+ In this case, an assertion on the THEN clause is useful to
+ determine that 'a' is always 9 on that edge. However, an assertion
+ on the ELSE clause would be unnecessary.
+
+ 4- If BB does not end in a conditional expression, then we recurse
+ into BB's dominator children.
+
+ At the end of the recursive traversal, every SSA name will have a
+ list of locations where ASSERT_EXPRs should be added. When a new
+ location for name N is found, it is registered by calling
+ register_new_assert_for. That function keeps track of all the
+ registered assertions to prevent adding unnecessary assertions.
+ For instance, if a pointer P_4 is dereferenced more than once in a
+ dominator tree, only the location dominating all the dereference of
+ P_4 will receive an ASSERT_EXPR.
+
+ If this function returns true, then it means that there are names
+ for which we need to generate ASSERT_EXPRs. Those assertions are
+ inserted by process_assert_insertions. */
+
+static bool
+find_assert_locations_1 (basic_block bb, sbitmap live)
+{
+ gimple_stmt_iterator si;
+ gimple last;
+ bool need_assert;
+
+ need_assert = false;
+ last = last_stmt (bb);
+
+ /* If BB's last statement is a conditional statement involving integer
+ operands, determine if we need to add ASSERT_EXPRs. */
+ if (last
+ && gimple_code (last) == GIMPLE_COND
+ && !fp_predicate (last)
+ && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
+ need_assert |= find_conditional_asserts (bb, last);
+
+ /* If BB's last statement is a switch statement involving integer
+ operands, determine if we need to add ASSERT_EXPRs. */
+ if (last
+ && gimple_code (last) == GIMPLE_SWITCH
+ && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
+ need_assert |= find_switch_asserts (bb, last);
+
+ /* Traverse all the statements in BB marking used names and looking
+ for statements that may infer assertions for their used operands. */
+ for (si = gsi_last_bb (bb); !gsi_end_p (si); gsi_prev (&si))
+ {
+ gimple stmt;
+ tree op;
+ ssa_op_iter i;
+
+ stmt = gsi_stmt (si);
+
+ if (is_gimple_debug (stmt))
+ continue;
+
+ /* See if we can derive an assertion for any of STMT's operands. */
+ FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
+ {
+ tree value;
+ enum tree_code comp_code;
+
+ /* If op is not live beyond this stmt, do not bother to insert
+ asserts for it. */
+ if (!bitmap_bit_p (live, SSA_NAME_VERSION (op)))
+ continue;
+
+ /* If OP is used in such a way that we can infer a value
+ range for it, and we don't find a previous assertion for
+ it, create a new assertion location node for OP. */
+ if (infer_value_range (stmt, op, &comp_code, &value))
+ {
+ /* If we are able to infer a nonzero value range for OP,
+ then walk backwards through the use-def chain to see if OP
+ was set via a typecast.
+
+ If so, then we can also infer a nonzero value range
+ for the operand of the NOP_EXPR. */
+ if (comp_code == NE_EXPR && integer_zerop (value))
+ {
+ tree t = op;
+ gimple def_stmt = SSA_NAME_DEF_STMT (t);
+
+ while (is_gimple_assign (def_stmt)
+ && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
+ && TREE_CODE
+ (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
+ && POINTER_TYPE_P
+ (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
+ {
+ t = gimple_assign_rhs1 (def_stmt);
+ def_stmt = SSA_NAME_DEF_STMT (t);
+
+ /* Note we want to register the assert for the
+ operand of the NOP_EXPR after SI, not after the
+ conversion. */
+ if (! has_single_use (t))
+ {
+ register_new_assert_for (t, t, comp_code, value,
+ bb, NULL, si);
+ need_assert = true;
+ }
+ }
+ }
+
+ register_new_assert_for (op, op, comp_code, value, bb, NULL, si);
+ need_assert = true;
+ }
+ }
+
+ /* Update live. */
+ FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
+ bitmap_set_bit (live, SSA_NAME_VERSION (op));
+ FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_DEF)
+ bitmap_clear_bit (live, SSA_NAME_VERSION (op));
+ }
+
+ /* Traverse all PHI nodes in BB, updating live. */
+ for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
+ {
+ use_operand_p arg_p;
+ ssa_op_iter i;
+ gimple phi = gsi_stmt (si);
+ tree res = gimple_phi_result (phi);
+
+ if (virtual_operand_p (res))
+ continue;
+
+ FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
+ {
+ tree arg = USE_FROM_PTR (arg_p);
+ if (TREE_CODE (arg) == SSA_NAME)
+ bitmap_set_bit (live, SSA_NAME_VERSION (arg));
+ }
+
+ bitmap_clear_bit (live, SSA_NAME_VERSION (res));
+ }
+
+ return need_assert;
+}
+
+/* Do an RPO walk over the function computing SSA name liveness
+ on-the-fly and deciding on assert expressions to insert.
+ Returns true if there are assert expressions to be inserted. */
+
+static bool
+find_assert_locations (void)
+{
+ int *rpo = XNEWVEC (int, last_basic_block_for_fn (cfun));
+ int *bb_rpo = XNEWVEC (int, last_basic_block_for_fn (cfun));
+ int *last_rpo = XCNEWVEC (int, last_basic_block_for_fn (cfun));
+ int rpo_cnt, i;
+ bool need_asserts;
+
+ live = XCNEWVEC (sbitmap, last_basic_block_for_fn (cfun));
+ rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
+ for (i = 0; i < rpo_cnt; ++i)
+ bb_rpo[rpo[i]] = i;
+
+ /* Pre-seed loop latch liveness from loop header PHI nodes. Due to
+ the order we compute liveness and insert asserts we otherwise
+ fail to insert asserts into the loop latch. */
+ loop_p loop;
+ FOR_EACH_LOOP (loop, 0)
+ {
+ i = loop->latch->index;
+ unsigned int j = single_succ_edge (loop->latch)->dest_idx;
+ for (gimple_stmt_iterator gsi = gsi_start_phis (loop->header);
+ !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple phi = gsi_stmt (gsi);
+ if (virtual_operand_p (gimple_phi_result (phi)))
+ continue;
+ tree arg = gimple_phi_arg_def (phi, j);
+ if (TREE_CODE (arg) == SSA_NAME)
+ {
+ if (live[i] == NULL)
+ {
+ live[i] = sbitmap_alloc (num_ssa_names);
+ bitmap_clear (live[i]);
+ }
+ bitmap_set_bit (live[i], SSA_NAME_VERSION (arg));
+ }
+ }
+ }
+
+ need_asserts = false;
+ for (i = rpo_cnt - 1; i >= 0; --i)
+ {
+ basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]);
+ edge e;
+ edge_iterator ei;
+
+ if (!live[rpo[i]])
+ {
+ live[rpo[i]] = sbitmap_alloc (num_ssa_names);
+ bitmap_clear (live[rpo[i]]);
+ }
+
+ /* Process BB and update the live information with uses in
+ this block. */
+ need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
+
+ /* Merge liveness into the predecessor blocks and free it. */
+ if (!bitmap_empty_p (live[rpo[i]]))
+ {
+ int pred_rpo = i;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ int pred = e->src->index;
+ if ((e->flags & EDGE_DFS_BACK) || pred == ENTRY_BLOCK)
+ continue;
+
+ if (!live[pred])
+ {
+ live[pred] = sbitmap_alloc (num_ssa_names);
+ bitmap_clear (live[pred]);
+ }
+ bitmap_ior (live[pred], live[pred], live[rpo[i]]);
+
+ if (bb_rpo[pred] < pred_rpo)
+ pred_rpo = bb_rpo[pred];
+ }
+
+ /* Record the RPO number of the last visited block that needs
+ live information from this block. */
+ last_rpo[rpo[i]] = pred_rpo;
+ }
+ else
+ {
+ sbitmap_free (live[rpo[i]]);
+ live[rpo[i]] = NULL;
+ }
+
+ /* We can free all successors live bitmaps if all their
+ predecessors have been visited already. */
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ if (last_rpo[e->dest->index] == i
+ && live[e->dest->index])
+ {
+ sbitmap_free (live[e->dest->index]);
+ live[e->dest->index] = NULL;
+ }
+ }
+
+ XDELETEVEC (rpo);
+ XDELETEVEC (bb_rpo);
+ XDELETEVEC (last_rpo);
+ for (i = 0; i < last_basic_block_for_fn (cfun); ++i)
+ if (live[i])
+ sbitmap_free (live[i]);
+ XDELETEVEC (live);
+
+ return need_asserts;
+}
+
+/* Create an ASSERT_EXPR for NAME and insert it in the location
+ indicated by LOC. Return true if we made any edge insertions. */
+
+static bool
+process_assert_insertions_for (tree name, assert_locus_t loc)
+{
+ /* Build the comparison expression NAME_i COMP_CODE VAL. */
+ gimple stmt;
+ tree cond;
+ gimple assert_stmt;
+ edge_iterator ei;
+ edge e;
+
+ /* If we have X <=> X do not insert an assert expr for that. */
+ if (loc->expr == loc->val)
+ return false;
+
+ cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
+ assert_stmt = build_assert_expr_for (cond, name);
+ if (loc->e)
+ {
+ /* We have been asked to insert the assertion on an edge. This
+ is used only by COND_EXPR and SWITCH_EXPR assertions. */
+ gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
+ || (gimple_code (gsi_stmt (loc->si))
+ == GIMPLE_SWITCH));
+
+ gsi_insert_on_edge (loc->e, assert_stmt);
+ return true;
+ }
+
+ /* Otherwise, we can insert right after LOC->SI iff the
+ statement must not be the last statement in the block. */
+ stmt = gsi_stmt (loc->si);
+ if (!stmt_ends_bb_p (stmt))
+ {
+ gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
+ return false;
+ }
+
+ /* If STMT must be the last statement in BB, we can only insert new
+ assertions on the non-abnormal edge out of BB. Note that since
+ STMT is not control flow, there may only be one non-abnormal edge
+ out of BB. */
+ FOR_EACH_EDGE (e, ei, loc->bb->succs)
+ if (!(e->flags & EDGE_ABNORMAL))
+ {
+ gsi_insert_on_edge (e, assert_stmt);
+ return true;
+ }
+
+ gcc_unreachable ();
+}
+
+
+/* Process all the insertions registered for every name N_i registered
+ in NEED_ASSERT_FOR. The list of assertions to be inserted are
+ found in ASSERTS_FOR[i]. */
+
+static void
+process_assert_insertions (void)
+{
+ unsigned i;
+ bitmap_iterator bi;
+ bool update_edges_p = false;
+ int num_asserts = 0;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ dump_all_asserts (dump_file);
+
+ EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
+ {
+ assert_locus_t loc = asserts_for[i];
+ gcc_assert (loc);
+
+ while (loc)
+ {
+ assert_locus_t next = loc->next;
+ update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
+ free (loc);
+ loc = next;
+ num_asserts++;
+ }
+ }
+
+ if (update_edges_p)
+ gsi_commit_edge_inserts ();
+
+ statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
+ num_asserts);
+}
+
+
+/* Traverse the flowgraph looking for conditional jumps to insert range
+ expressions. These range expressions are meant to provide information
+ to optimizations that need to reason in terms of value ranges. They
+ will not be expanded into RTL. For instance, given:
+
+ x = ...
+ y = ...
+ if (x < y)
+ y = x - 2;
+ else
+ x = y + 3;
+
+ this pass will transform the code into:
+
+ x = ...
+ y = ...
+ if (x < y)
+ {
+ x = ASSERT_EXPR <x, x < y>
+ y = x - 2
+ }
+ else
+ {
+ y = ASSERT_EXPR <y, x <= y>
+ x = y + 3
+ }
+
+ The idea is that once copy and constant propagation have run, other
+ optimizations will be able to determine what ranges of values can 'x'
+ take in different paths of the code, simply by checking the reaching
+ definition of 'x'. */
+
+static void
+insert_range_assertions (void)
+{
+ need_assert_for = BITMAP_ALLOC (NULL);
+ asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
+
+ calculate_dominance_info (CDI_DOMINATORS);
+
+ if (find_assert_locations ())
+ {
+ process_assert_insertions ();
+ update_ssa (TODO_update_ssa_no_phi);
+ }
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
+ dump_function_to_file (current_function_decl, dump_file, dump_flags);
+ }
+
+ free (asserts_for);
+ BITMAP_FREE (need_assert_for);
+}
+
+/* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
+ and "struct" hacks. If VRP can determine that the
+ array subscript is a constant, check if it is outside valid
+ range. If the array subscript is a RANGE, warn if it is
+ non-overlapping with valid range.
+ IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
+
+static void
+check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
+{
+ value_range_t* vr = NULL;
+ tree low_sub, up_sub;
+ tree low_bound, up_bound, up_bound_p1;
+ tree base;
+
+ if (TREE_NO_WARNING (ref))
+ return;
+
+ low_sub = up_sub = TREE_OPERAND (ref, 1);
+ up_bound = array_ref_up_bound (ref);
+
+ /* Can not check flexible arrays. */
+ if (!up_bound
+ || TREE_CODE (up_bound) != INTEGER_CST)
+ return;
+
+ /* Accesses to trailing arrays via pointers may access storage
+ beyond the types array bounds. */
+ base = get_base_address (ref);
+ if (base && TREE_CODE (base) == MEM_REF)
+ {
+ tree cref, next = NULL_TREE;
+
+ if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
+ return;
+
+ cref = TREE_OPERAND (ref, 0);
+ if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
+ for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
+ next && TREE_CODE (next) != FIELD_DECL;
+ next = DECL_CHAIN (next))
+ ;
+
+ /* If this is the last field in a struct type or a field in a
+ union type do not warn. */
+ if (!next)
+ return;
+ }
+
+ low_bound = array_ref_low_bound (ref);
+ up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
+
+ if (TREE_CODE (low_sub) == SSA_NAME)
+ {
+ vr = get_value_range (low_sub);
+ if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
+ {
+ low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
+ up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
+ }
+ }
+
+ if (vr && vr->type == VR_ANTI_RANGE)
+ {
+ if (TREE_CODE (up_sub) == INTEGER_CST
+ && tree_int_cst_lt (up_bound, up_sub)
+ && TREE_CODE (low_sub) == INTEGER_CST
+ && tree_int_cst_lt (low_sub, low_bound))
+ {
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is outside array bounds");
+ TREE_NO_WARNING (ref) = 1;
+ }
+ }
+ else if (TREE_CODE (up_sub) == INTEGER_CST
+ && (ignore_off_by_one
+ ? (tree_int_cst_lt (up_bound, up_sub)
+ && !tree_int_cst_equal (up_bound_p1, up_sub))
+ : (tree_int_cst_lt (up_bound, up_sub)
+ || tree_int_cst_equal (up_bound_p1, up_sub))))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Array bound warning for ");
+ dump_generic_expr (MSG_NOTE, TDF_SLIM, ref);
+ fprintf (dump_file, "\n");
+ }
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is above array bounds");
+ TREE_NO_WARNING (ref) = 1;
+ }
+ else if (TREE_CODE (low_sub) == INTEGER_CST
+ && tree_int_cst_lt (low_sub, low_bound))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Array bound warning for ");
+ dump_generic_expr (MSG_NOTE, TDF_SLIM, ref);
+ fprintf (dump_file, "\n");
+ }
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is below array bounds");
+ TREE_NO_WARNING (ref) = 1;
+ }
+}
+
+/* Searches if the expr T, located at LOCATION computes
+ address of an ARRAY_REF, and call check_array_ref on it. */
+
+static void
+search_for_addr_array (tree t, location_t location)
+{
+ while (TREE_CODE (t) == SSA_NAME)
+ {
+ gimple g = SSA_NAME_DEF_STMT (t);
+
+ if (gimple_code (g) != GIMPLE_ASSIGN)
+ return;
+
+ if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
+ != GIMPLE_SINGLE_RHS)
+ return;
+
+ t = gimple_assign_rhs1 (g);
+ }
+
+
+ /* We are only interested in addresses of ARRAY_REF's. */
+ if (TREE_CODE (t) != ADDR_EXPR)
+ return;
+
+ /* Check each ARRAY_REFs in the reference chain. */
+ do
+ {
+ if (TREE_CODE (t) == ARRAY_REF)
+ check_array_ref (location, t, true /*ignore_off_by_one*/);
+
+ t = TREE_OPERAND (t, 0);
+ }
+ while (handled_component_p (t));
+
+ if (TREE_CODE (t) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
+ && !TREE_NO_WARNING (t))
+ {
+ tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
+ tree low_bound, up_bound, el_sz;
+ double_int idx;
+ if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
+ || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
+ || !TYPE_DOMAIN (TREE_TYPE (tem)))
+ return;
+
+ low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
+ up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
+ el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
+ if (!low_bound
+ || TREE_CODE (low_bound) != INTEGER_CST
+ || !up_bound
+ || TREE_CODE (up_bound) != INTEGER_CST
+ || !el_sz
+ || TREE_CODE (el_sz) != INTEGER_CST)
+ return;
+
+ idx = mem_ref_offset (t);
+ idx = idx.sdiv (tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
+ if (idx.slt (double_int_zero))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Array bound warning for ");
+ dump_generic_expr (MSG_NOTE, TDF_SLIM, t);
+ fprintf (dump_file, "\n");
+ }
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is below array bounds");
+ TREE_NO_WARNING (t) = 1;
+ }
+ else if (idx.sgt (tree_to_double_int (up_bound)
+ - tree_to_double_int (low_bound)
+ + double_int_one))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Array bound warning for ");
+ dump_generic_expr (MSG_NOTE, TDF_SLIM, t);
+ fprintf (dump_file, "\n");
+ }
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is above array bounds");
+ TREE_NO_WARNING (t) = 1;
+ }
+ }
+}
+
+/* walk_tree() callback that checks if *TP is
+ an ARRAY_REF inside an ADDR_EXPR (in which an array
+ subscript one outside the valid range is allowed). Call
+ check_array_ref for each ARRAY_REF found. The location is
+ passed in DATA. */
+
+static tree
+check_array_bounds (tree *tp, int *walk_subtree, void *data)
+{
+ tree t = *tp;
+ struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
+ location_t location;
+
+ if (EXPR_HAS_LOCATION (t))
+ location = EXPR_LOCATION (t);
+ else
+ {
+ location_t *locp = (location_t *) wi->info;
+ location = *locp;
+ }
+
+ *walk_subtree = TRUE;
+
+ if (TREE_CODE (t) == ARRAY_REF)
+ check_array_ref (location, t, false /*ignore_off_by_one*/);
+
+ if (TREE_CODE (t) == MEM_REF
+ || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
+ search_for_addr_array (TREE_OPERAND (t, 0), location);
+
+ if (TREE_CODE (t) == ADDR_EXPR)
+ *walk_subtree = FALSE;
+
+ return NULL_TREE;
+}
+
+/* Walk over all statements of all reachable BBs and call check_array_bounds
+ on them. */
+
+static void
+check_all_array_refs (void)
+{
+ basic_block bb;
+ gimple_stmt_iterator si;
+
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ edge_iterator ei;
+ edge e;
+ bool executable = false;
+
+ /* Skip blocks that were found to be unreachable. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ executable |= !!(e->flags & EDGE_EXECUTABLE);
+ if (!executable)
+ continue;
+
+ for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
+ {
+ gimple stmt = gsi_stmt (si);
+ struct walk_stmt_info wi;
+ if (!gimple_has_location (stmt))
+ continue;
+
+ if (is_gimple_call (stmt))
+ {
+ size_t i;
+ size_t n = gimple_call_num_args (stmt);
+ for (i = 0; i < n; i++)
+ {
+ tree arg = gimple_call_arg (stmt, i);
+ search_for_addr_array (arg, gimple_location (stmt));
+ }
+ }
+ else
+ {
+ memset (&wi, 0, sizeof (wi));
+ wi.info = CONST_CAST (void *, (const void *)
+ gimple_location_ptr (stmt));
+
+ walk_gimple_op (gsi_stmt (si),
+ check_array_bounds,
+ &wi);
+ }
+ }
+ }
+}
+
+/* Return true if all imm uses of VAR are either in STMT, or
+ feed (optionally through a chain of single imm uses) GIMPLE_COND
+ in basic block COND_BB. */
+
+static bool
+all_imm_uses_in_stmt_or_feed_cond (tree var, gimple stmt, basic_block cond_bb)
+{
+ use_operand_p use_p, use2_p;
+ imm_use_iterator iter;
+
+ FOR_EACH_IMM_USE_FAST (use_p, iter, var)
+ if (USE_STMT (use_p) != stmt)
+ {
+ gimple use_stmt = USE_STMT (use_p), use_stmt2;
+ if (is_gimple_debug (use_stmt))
+ continue;
+ while (is_gimple_assign (use_stmt)
+ && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
+ && single_imm_use (gimple_assign_lhs (use_stmt),
+ &use2_p, &use_stmt2))
+ use_stmt = use_stmt2;
+ if (gimple_code (use_stmt) != GIMPLE_COND
+ || gimple_bb (use_stmt) != cond_bb)
+ return false;
+ }
+ return true;
+}
+
+/* Handle
+ _4 = x_3 & 31;
+ if (_4 != 0)
+ goto <bb 6>;
+ else
+ goto <bb 7>;
+ <bb 6>:
+ __builtin_unreachable ();
+ <bb 7>:
+ x_5 = ASSERT_EXPR <x_3, ...>;
+ If x_3 has no other immediate uses (checked by caller),
+ var is the x_3 var from ASSERT_EXPR, we can clear low 5 bits
+ from the non-zero bitmask. */
+
+static void
+maybe_set_nonzero_bits (basic_block bb, tree var)
+{
+ edge e = single_pred_edge (bb);
+ basic_block cond_bb = e->src;
+ gimple stmt = last_stmt (cond_bb);
+ tree cst;
+
+ if (stmt == NULL
+ || gimple_code (stmt) != GIMPLE_COND
+ || gimple_cond_code (stmt) != ((e->flags & EDGE_TRUE_VALUE)
+ ? EQ_EXPR : NE_EXPR)
+ || TREE_CODE (gimple_cond_lhs (stmt)) != SSA_NAME
+ || !integer_zerop (gimple_cond_rhs (stmt)))
+ return;
+
+ stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt));
+ if (!is_gimple_assign (stmt)
+ || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR
+ || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)
+ return;
+ if (gimple_assign_rhs1 (stmt) != var)
+ {
+ gimple stmt2;
+
+ if (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME)
+ return;
+ stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));
+ if (!gimple_assign_cast_p (stmt2)
+ || gimple_assign_rhs1 (stmt2) != var
+ || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2))
+ || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt)))
+ != TYPE_PRECISION (TREE_TYPE (var))))
+ return;
+ }
+ cst = gimple_assign_rhs2 (stmt);
+ set_nonzero_bits (var, (get_nonzero_bits (var)
+ & ~tree_to_double_int (cst)));
+}
+
+/* Convert range assertion expressions into the implied copies and
+ copy propagate away the copies. Doing the trivial copy propagation
+ here avoids the need to run the full copy propagation pass after
+ VRP.
+
+ FIXME, this will eventually lead to copy propagation removing the
+ names that had useful range information attached to them. For
+ instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
+ then N_i will have the range [3, +INF].
+
+ However, by converting the assertion into the implied copy
+ operation N_i = N_j, we will then copy-propagate N_j into the uses
+ of N_i and lose the range information. We may want to hold on to
+ ASSERT_EXPRs a little while longer as the ranges could be used in
+ things like jump threading.
+
+ The problem with keeping ASSERT_EXPRs around is that passes after
+ VRP need to handle them appropriately.
+
+ Another approach would be to make the range information a first
+ class property of the SSA_NAME so that it can be queried from
+ any pass. This is made somewhat more complex by the need for
+ multiple ranges to be associated with one SSA_NAME. */
+
+static void
+remove_range_assertions (void)
+{
+ basic_block bb;
+ gimple_stmt_iterator si;
+ /* 1 if looking at ASSERT_EXPRs immediately at the beginning of
+ a basic block preceeded by GIMPLE_COND branching to it and
+ __builtin_trap, -1 if not yet checked, 0 otherwise. */
+ int is_unreachable;
+
+ /* Note that the BSI iterator bump happens at the bottom of the
+ loop and no bump is necessary if we're removing the statement
+ referenced by the current BSI. */
+ FOR_EACH_BB_FN (bb, cfun)
+ for (si = gsi_after_labels (bb), is_unreachable = -1; !gsi_end_p (si);)
+ {
+ gimple stmt = gsi_stmt (si);
+ gimple use_stmt;
+
+ if (is_gimple_assign (stmt)
+ && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
+ {
+ tree lhs = gimple_assign_lhs (stmt);
+ tree rhs = gimple_assign_rhs1 (stmt);
+ tree var;
+ tree cond = fold (ASSERT_EXPR_COND (rhs));
+ use_operand_p use_p;
+ imm_use_iterator iter;
+
+ gcc_assert (cond != boolean_false_node);
+
+ var = ASSERT_EXPR_VAR (rhs);
+ gcc_assert (TREE_CODE (var) == SSA_NAME);
+
+ if (!POINTER_TYPE_P (TREE_TYPE (lhs))
+ && SSA_NAME_RANGE_INFO (lhs))
+ {
+ if (is_unreachable == -1)
+ {
+ is_unreachable = 0;
+ if (single_pred_p (bb)
+ && assert_unreachable_fallthru_edge_p
+ (single_pred_edge (bb)))
+ is_unreachable = 1;
+ }
+ /* Handle
+ if (x_7 >= 10 && x_7 < 20)
+ __builtin_unreachable ();
+ x_8 = ASSERT_EXPR <x_7, ...>;
+ if the only uses of x_7 are in the ASSERT_EXPR and
+ in the condition. In that case, we can copy the
+ range info from x_8 computed in this pass also
+ for x_7. */
+ if (is_unreachable
+ && all_imm_uses_in_stmt_or_feed_cond (var, stmt,
+ single_pred (bb)))
+ {
+ set_range_info (var, SSA_NAME_RANGE_TYPE (lhs),
+ SSA_NAME_RANGE_INFO (lhs)->min,
+ SSA_NAME_RANGE_INFO (lhs)->max);
+ maybe_set_nonzero_bits (bb, var);
+ }
+ }
+
+ /* Propagate the RHS into every use of the LHS. */
+ FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
+ FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+ SET_USE (use_p, var);
+
+ /* And finally, remove the copy, it is not needed. */
+ gsi_remove (&si, true);
+ release_defs (stmt);
+ }
+ else
+ {
+ gsi_next (&si);
+ is_unreachable = 0;
+ }
+ }
+}
+
+
+/* Return true if STMT is interesting for VRP. */
+
+static bool
+stmt_interesting_for_vrp (gimple stmt)
+{
+ if (gimple_code (stmt) == GIMPLE_PHI)
+ {
+ tree res = gimple_phi_result (stmt);
+ return (!virtual_operand_p (res)
+ && (INTEGRAL_TYPE_P (TREE_TYPE (res))
+ || POINTER_TYPE_P (TREE_TYPE (res))));
+ }
+ else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
+ {
+ tree lhs = gimple_get_lhs (stmt);
+
+ /* In general, assignments with virtual operands are not useful
+ for deriving ranges, with the obvious exception of calls to
+ builtin functions. */
+ if (lhs && TREE_CODE (lhs) == SSA_NAME
+ && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ || POINTER_TYPE_P (TREE_TYPE (lhs)))
+ && (is_gimple_call (stmt)
+ || !gimple_vuse (stmt)))
+ return true;
+ }
+ else if (gimple_code (stmt) == GIMPLE_COND
+ || gimple_code (stmt) == GIMPLE_SWITCH)
+ return true;
+
+ return false;
+}
+
+
+/* Initialize local data structures for VRP. */
+
+static void
+vrp_initialize (void)
+{
+ basic_block bb;
+
+ values_propagated = false;
+ num_vr_values = num_ssa_names;
+ vr_value = XCNEWVEC (value_range_t *, num_vr_values);
+ vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
+
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ gimple_stmt_iterator si;
+
+ for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
+ {
+ gimple phi = gsi_stmt (si);
+ if (!stmt_interesting_for_vrp (phi))
+ {
+ tree lhs = PHI_RESULT (phi);
+ set_value_range_to_varying (get_value_range (lhs));
+ prop_set_simulate_again (phi, false);
+ }
+ else
+ prop_set_simulate_again (phi, true);
+ }
+
+ for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
+ {
+ gimple stmt = gsi_stmt (si);
+
+ /* If the statement is a control insn, then we do not
+ want to avoid simulating the statement once. Failure
+ to do so means that those edges will never get added. */
+ if (stmt_ends_bb_p (stmt))
+ prop_set_simulate_again (stmt, true);
+ else if (!stmt_interesting_for_vrp (stmt))
+ {
+ ssa_op_iter i;
+ tree def;
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
+ set_value_range_to_varying (get_value_range (def));
+ prop_set_simulate_again (stmt, false);
+ }
+ else
+ prop_set_simulate_again (stmt, true);
+ }
+ }
+}
+
+/* Return the singleton value-range for NAME or NAME. */
+
+static inline tree
+vrp_valueize (tree name)
+{
+ if (TREE_CODE (name) == SSA_NAME)
+ {
+ value_range_t *vr = get_value_range (name);
+ if (vr->type == VR_RANGE
+ && (vr->min == vr->max
+ || operand_equal_p (vr->min, vr->max, 0)))
+ return vr->min;
+ }
+ return name;
+}
+
+/* Visit assignment STMT. If it produces an interesting range, record
+ the SSA name in *OUTPUT_P. */
+
+static enum ssa_prop_result
+vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
+{
+ tree def, lhs;
+ ssa_op_iter iter;
+ enum gimple_code code = gimple_code (stmt);
+ lhs = gimple_get_lhs (stmt);
+
+ /* We only keep track of ranges in integral and pointer types. */
+ if (TREE_CODE (lhs) == SSA_NAME
+ && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ /* It is valid to have NULL MIN/MAX values on a type. See
+ build_range_type. */
+ && TYPE_MIN_VALUE (TREE_TYPE (lhs))
+ && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
+ || POINTER_TYPE_P (TREE_TYPE (lhs))))
+ {
+ value_range_t new_vr = VR_INITIALIZER;
+
+ /* Try folding the statement to a constant first. */
+ tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
+ if (tem)
+ set_value_range_to_value (&new_vr, tem, NULL);
+ /* Then dispatch to value-range extracting functions. */
+ else if (code == GIMPLE_CALL)
+ extract_range_basic (&new_vr, stmt);
+ else
+ extract_range_from_assignment (&new_vr, stmt);
+
+ if (update_value_range (lhs, &new_vr))
+ {
+ *output_p = lhs;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Found new range for ");
+ print_generic_expr (dump_file, lhs, 0);
+ fprintf (dump_file, ": ");
+ dump_value_range (dump_file, &new_vr);
+ fprintf (dump_file, "\n\n");
+ }
+
+ if (new_vr.type == VR_VARYING)
+ return SSA_PROP_VARYING;
+
+ return SSA_PROP_INTERESTING;
+ }
+
+ return SSA_PROP_NOT_INTERESTING;
+ }
+
+ /* Every other statement produces no useful ranges. */
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
+ set_value_range_to_varying (get_value_range (def));
+
+ return SSA_PROP_VARYING;
+}
+
+/* Helper that gets the value range of the SSA_NAME with version I
+ or a symbolic range containing the SSA_NAME only if the value range
+ is varying or undefined. */
+
+static inline value_range_t
+get_vr_for_comparison (int i)
+{
+ value_range_t vr = *get_value_range (ssa_name (i));
+
+ /* If name N_i does not have a valid range, use N_i as its own
+ range. This allows us to compare against names that may
+ have N_i in their ranges. */
+ if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
+ {
+ vr.type = VR_RANGE;
+ vr.min = ssa_name (i);
+ vr.max = ssa_name (i);
+ }
+
+ return vr;
+}
+
+/* Compare all the value ranges for names equivalent to VAR with VAL
+ using comparison code COMP. Return the same value returned by
+ compare_range_with_value, including the setting of
+ *STRICT_OVERFLOW_P. */
+
+static tree
+compare_name_with_value (enum tree_code comp, tree var, tree val,
+ bool *strict_overflow_p)
+{
+ bitmap_iterator bi;
+ unsigned i;
+ bitmap e;
+ tree retval, t;
+ int used_strict_overflow;
+ bool sop;
+ value_range_t equiv_vr;
+
+ /* Get the set of equivalences for VAR. */
+ e = get_value_range (var)->equiv;
+
+ /* Start at -1. Set it to 0 if we do a comparison without relying
+ on overflow, or 1 if all comparisons rely on overflow. */
+ used_strict_overflow = -1;
+
+ /* Compare vars' value range with val. */
+ equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
+ sop = false;
+ retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
+ if (retval)
+ used_strict_overflow = sop ? 1 : 0;
+
+ /* If the equiv set is empty we have done all work we need to do. */
+ if (e == NULL)
+ {
+ if (retval
+ && used_strict_overflow > 0)
+ *strict_overflow_p = true;
+ return retval;
+ }
+
+ EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
+ {
+ equiv_vr = get_vr_for_comparison (i);
+ sop = false;
+ t = compare_range_with_value (comp, &equiv_vr, val, &sop);
+ if (t)
+ {
+ /* If we get different answers from different members
+ of the equivalence set this check must be in a dead
+ code region. Folding it to a trap representation
+ would be correct here. For now just return don't-know. */
+ if (retval != NULL
+ && t != retval)
+ {
+ retval = NULL_TREE;
+ break;
+ }
+ retval = t;
+
+ if (!sop)
+ used_strict_overflow = 0;
+ else if (used_strict_overflow < 0)
+ used_strict_overflow = 1;
+ }
+ }
+
+ if (retval
+ && used_strict_overflow > 0)
+ *strict_overflow_p = true;
+
+ return retval;
+}
+
+
+/* Given a comparison code COMP and names N1 and N2, compare all the
+ ranges equivalent to N1 against all the ranges equivalent to N2
+ to determine the value of N1 COMP N2. Return the same value
+ returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
+ whether we relied on an overflow infinity in the comparison. */
+
+
+static tree
+compare_names (enum tree_code comp, tree n1, tree n2,
+ bool *strict_overflow_p)
+{
+ tree t, retval;
+ bitmap e1, e2;
+ bitmap_iterator bi1, bi2;
+ unsigned i1, i2;
+ int used_strict_overflow;
+ static bitmap_obstack *s_obstack = NULL;
+ static bitmap s_e1 = NULL, s_e2 = NULL;
+
+ /* Compare the ranges of every name equivalent to N1 against the
+ ranges of every name equivalent to N2. */
+ e1 = get_value_range (n1)->equiv;
+ e2 = get_value_range (n2)->equiv;
+
+ /* Use the fake bitmaps if e1 or e2 are not available. */
+ if (s_obstack == NULL)
+ {
+ s_obstack = XNEW (bitmap_obstack);
+ bitmap_obstack_initialize (s_obstack);
+ s_e1 = BITMAP_ALLOC (s_obstack);
+ s_e2 = BITMAP_ALLOC (s_obstack);
+ }
+ if (e1 == NULL)
+ e1 = s_e1;
+ if (e2 == NULL)
+ e2 = s_e2;
+
+ /* Add N1 and N2 to their own set of equivalences to avoid
+ duplicating the body of the loop just to check N1 and N2
+ ranges. */
+ bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
+ bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
+
+ /* If the equivalence sets have a common intersection, then the two
+ names can be compared without checking their ranges. */
+ if (bitmap_intersect_p (e1, e2))
+ {
+ bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
+ bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
+
+ return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
+ ? boolean_true_node
+ : boolean_false_node;
+ }
+
+ /* Start at -1. Set it to 0 if we do a comparison without relying
+ on overflow, or 1 if all comparisons rely on overflow. */
+ used_strict_overflow = -1;
+
+ /* Otherwise, compare all the equivalent ranges. First, add N1 and
+ N2 to their own set of equivalences to avoid duplicating the body
+ of the loop just to check N1 and N2 ranges. */
+ EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
+ {
+ value_range_t vr1 = get_vr_for_comparison (i1);
+
+ t = retval = NULL_TREE;
+ EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
+ {
+ bool sop = false;
+
+ value_range_t vr2 = get_vr_for_comparison (i2);
+
+ t = compare_ranges (comp, &vr1, &vr2, &sop);
+ if (t)
+ {
+ /* If we get different answers from different members
+ of the equivalence set this check must be in a dead
+ code region. Folding it to a trap representation
+ would be correct here. For now just return don't-know. */
+ if (retval != NULL
+ && t != retval)
+ {
+ bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
+ bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
+ return NULL_TREE;
+ }
+ retval = t;
+
+ if (!sop)
+ used_strict_overflow = 0;
+ else if (used_strict_overflow < 0)
+ used_strict_overflow = 1;
+ }
+ }
+
+ if (retval)
+ {
+ bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
+ bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
+ if (used_strict_overflow > 0)
+ *strict_overflow_p = true;
+ return retval;
+ }
+ }
+
+ /* None of the equivalent ranges are useful in computing this
+ comparison. */
+ bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
+ bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
+ return NULL_TREE;
+}
+
+/* Helper function for vrp_evaluate_conditional_warnv. */
+
+static tree
+vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
+ tree op0, tree op1,
+ bool * strict_overflow_p)
+{
+ value_range_t *vr0, *vr1;
+
+ vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
+ vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
+
+ if (vr0 && vr1)
+ return compare_ranges (code, vr0, vr1, strict_overflow_p);
+ else if (vr0 && vr1 == NULL)
+ return compare_range_with_value (code, vr0, op1, strict_overflow_p);
+ else if (vr0 == NULL && vr1)
+ return (compare_range_with_value
+ (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
+ return NULL;
+}
+
+/* Helper function for vrp_evaluate_conditional_warnv. */
+
+static tree
+vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
+ tree op1, bool use_equiv_p,
+ bool *strict_overflow_p, bool *only_ranges)
+{
+ tree ret;
+ if (only_ranges)
+ *only_ranges = true;
+
+ /* We only deal with integral and pointer types. */
+ if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
+ && !POINTER_TYPE_P (TREE_TYPE (op0)))
+ return NULL_TREE;
+
+ if (use_equiv_p)
+ {
+ if (only_ranges
+ && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
+ (code, op0, op1, strict_overflow_p)))
+ return ret;
+ *only_ranges = false;
+ if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
+ return compare_names (code, op0, op1, strict_overflow_p);
+ else if (TREE_CODE (op0) == SSA_NAME)
+ return compare_name_with_value (code, op0, op1, strict_overflow_p);
+ else if (TREE_CODE (op1) == SSA_NAME)
+ return (compare_name_with_value
+ (swap_tree_comparison (code), op1, op0, strict_overflow_p));
+ }
+ else
+ return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
+ strict_overflow_p);
+ return NULL_TREE;
+}
+
+/* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
+ information. Return NULL if the conditional can not be evaluated.
+ The ranges of all the names equivalent with the operands in COND
+ will be used when trying to compute the value. If the result is
+ based on undefined signed overflow, issue a warning if
+ appropriate. */
+
+static tree
+vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
+{
+ bool sop;
+ tree ret;
+ bool only_ranges;
+
+ /* Some passes and foldings leak constants with overflow flag set
+ into the IL. Avoid doing wrong things with these and bail out. */
+ if ((TREE_CODE (op0) == INTEGER_CST
+ && TREE_OVERFLOW (op0))
+ || (TREE_CODE (op1) == INTEGER_CST
+ && TREE_OVERFLOW (op1)))
+ return NULL_TREE;
+
+ sop = false;
+ ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
+ &only_ranges);
+
+ if (ret && sop)
+ {
+ enum warn_strict_overflow_code wc;
+ const char* warnmsg;
+
+ if (is_gimple_min_invariant (ret))
+ {
+ wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
+ warnmsg = G_("assuming signed overflow does not occur when "
+ "simplifying conditional to constant");
+ }
+ else
+ {
+ wc = WARN_STRICT_OVERFLOW_COMPARISON;
+ warnmsg = G_("assuming signed overflow does not occur when "
+ "simplifying conditional");
+ }
+
+ if (issue_strict_overflow_warning (wc))
+ {
+ location_t location;
+
+ if (!gimple_has_location (stmt))
+ location = input_location;
+ else
+ location = gimple_location (stmt);
+ warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
+ }
+ }
+
+ if (warn_type_limits
+ && ret && only_ranges
+ && TREE_CODE_CLASS (code) == tcc_comparison
+ && TREE_CODE (op0) == SSA_NAME)
+ {
+ /* If the comparison is being folded and the operand on the LHS
+ is being compared against a constant value that is outside of
+ the natural range of OP0's type, then the predicate will
+ always fold regardless of the value of OP0. If -Wtype-limits
+ was specified, emit a warning. */
+ tree type = TREE_TYPE (op0);
+ value_range_t *vr0 = get_value_range (op0);
+
+ if (vr0->type != VR_VARYING
+ && INTEGRAL_TYPE_P (type)
+ && vrp_val_is_min (vr0->min)
+ && vrp_val_is_max (vr0->max)
+ && is_gimple_min_invariant (op1))
+ {
+ location_t location;
+
+ if (!gimple_has_location (stmt))
+ location = input_location;
+ else
+ location = gimple_location (stmt);
+
+ warning_at (location, OPT_Wtype_limits,
+ integer_zerop (ret)
+ ? G_("comparison always false "
+ "due to limited range of data type")
+ : G_("comparison always true "
+ "due to limited range of data type"));
+ }
+ }
+
+ return ret;
+}
+
+
+/* Visit conditional statement STMT. If we can determine which edge
+ will be taken out of STMT's basic block, record it in
+ *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
+ SSA_PROP_VARYING. */
+
+static enum ssa_prop_result
+vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
+{
+ tree val;
+ bool sop;
+
+ *taken_edge_p = NULL;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ tree use;
+ ssa_op_iter i;
+
+ fprintf (dump_file, "\nVisiting conditional with predicate: ");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ fprintf (dump_file, "\nWith known ranges\n");
+
+ FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
+ {
+ fprintf (dump_file, "\t");
+ print_generic_expr (dump_file, use, 0);
+ fprintf (dump_file, ": ");
+ dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
+ }
+
+ fprintf (dump_file, "\n");
+ }
+
+ /* Compute the value of the predicate COND by checking the known
+ ranges of each of its operands.
+
+ Note that we cannot evaluate all the equivalent ranges here
+ because those ranges may not yet be final and with the current
+ propagation strategy, we cannot determine when the value ranges
+ of the names in the equivalence set have changed.
+
+ For instance, given the following code fragment
+
+ i_5 = PHI <8, i_13>
+ ...
+ i_14 = ASSERT_EXPR <i_5, i_5 != 0>
+ if (i_14 == 1)
+ ...
+
+ Assume that on the first visit to i_14, i_5 has the temporary
+ range [8, 8] because the second argument to the PHI function is
+ not yet executable. We derive the range ~[0, 0] for i_14 and the
+ equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
+ the first time, since i_14 is equivalent to the range [8, 8], we
+ determine that the predicate is always false.
+
+ On the next round of propagation, i_13 is determined to be
+ VARYING, which causes i_5 to drop down to VARYING. So, another
+ visit to i_14 is scheduled. In this second visit, we compute the
+ exact same range and equivalence set for i_14, namely ~[0, 0] and
+ { i_5 }. But we did not have the previous range for i_5
+ registered, so vrp_visit_assignment thinks that the range for
+ i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
+ is not visited again, which stops propagation from visiting
+ statements in the THEN clause of that if().
+
+ To properly fix this we would need to keep the previous range
+ value for the names in the equivalence set. This way we would've
+ discovered that from one visit to the other i_5 changed from
+ range [8, 8] to VR_VARYING.
+
+ However, fixing this apparent limitation may not be worth the
+ additional checking. Testing on several code bases (GCC, DLV,
+ MICO, TRAMP3D and SPEC2000) showed that doing this results in
+ 4 more predicates folded in SPEC. */
+ sop = false;
+
+ val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
+ gimple_cond_lhs (stmt),
+ gimple_cond_rhs (stmt),
+ false, &sop, NULL);
+ if (val)
+ {
+ if (!sop)
+ *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
+ else
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file,
+ "\nIgnoring predicate evaluation because "
+ "it assumes that signed overflow is undefined");
+ val = NULL_TREE;
+ }
+ }
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\nPredicate evaluates to: ");
+ if (val == NULL_TREE)
+ fprintf (dump_file, "DON'T KNOW\n");
+ else
+ print_generic_stmt (dump_file, val, 0);
+ }
+
+ return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
+}
+
+/* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
+ that includes the value VAL. The search is restricted to the range
+ [START_IDX, n - 1] where n is the size of VEC.
+
+ If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
+ returned.
+
+ If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
+ it is placed in IDX and false is returned.
+
+ If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
+ returned. */
+
+static bool
+find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
+{
+ size_t n = gimple_switch_num_labels (stmt);
+ size_t low, high;
+
+ /* Find case label for minimum of the value range or the next one.
+ At each iteration we are searching in [low, high - 1]. */
+
+ for (low = start_idx, high = n; high != low; )
+ {
+ tree t;
+ int cmp;
+ /* Note that i != high, so we never ask for n. */
+ size_t i = (high + low) / 2;
+ t = gimple_switch_label (stmt, i);
+
+ /* Cache the result of comparing CASE_LOW and val. */
+ cmp = tree_int_cst_compare (CASE_LOW (t), val);
+
+ if (cmp == 0)
+ {
+ /* Ranges cannot be empty. */
+ *idx = i;
+ return true;
+ }
+ else if (cmp > 0)
+ high = i;
+ else
+ {
+ low = i + 1;
+ if (CASE_HIGH (t) != NULL
+ && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
+ {
+ *idx = i;
+ return true;
+ }
+ }
+ }
+
+ *idx = high;
+ return false;
+}
+
+/* Searches the case label vector VEC for the range of CASE_LABELs that is used
+ for values between MIN and MAX. The first index is placed in MIN_IDX. The
+ last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
+ then MAX_IDX < MIN_IDX.
+ Returns true if the default label is not needed. */
+
+static bool
+find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
+ size_t *max_idx)
+{
+ size_t i, j;
+ bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
+ bool max_take_default = !find_case_label_index (stmt, i, max, &j);
+
+ if (i == j
+ && min_take_default
+ && max_take_default)
+ {
+ /* Only the default case label reached.
+ Return an empty range. */
+ *min_idx = 1;
+ *max_idx = 0;
+ return false;
+ }
+ else
+ {
+ bool take_default = min_take_default || max_take_default;
+ tree low, high;
+ size_t k;
+
+ if (max_take_default)
+ j--;
+
+ /* If the case label range is continuous, we do not need
+ the default case label. Verify that. */
+ high = CASE_LOW (gimple_switch_label (stmt, i));
+ if (CASE_HIGH (gimple_switch_label (stmt, i)))
+ high = CASE_HIGH (gimple_switch_label (stmt, i));
+ for (k = i + 1; k <= j; ++k)
+ {
+ low = CASE_LOW (gimple_switch_label (stmt, k));
+ if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
+ {
+ take_default = true;
+ break;
+ }
+ high = low;
+ if (CASE_HIGH (gimple_switch_label (stmt, k)))
+ high = CASE_HIGH (gimple_switch_label (stmt, k));
+ }
+
+ *min_idx = i;
+ *max_idx = j;
+ return !take_default;
+ }
+}
+
+/* Searches the case label vector VEC for the ranges of CASE_LABELs that are
+ used in range VR. The indices are placed in MIN_IDX1, MAX_IDX, MIN_IDX2 and
+ MAX_IDX2. If the ranges of CASE_LABELs are empty then MAX_IDX1 < MIN_IDX1.
+ Returns true if the default label is not needed. */
+
+static bool
+find_case_label_ranges (gimple stmt, value_range_t *vr, size_t *min_idx1,
+ size_t *max_idx1, size_t *min_idx2,
+ size_t *max_idx2)
+{
+ size_t i, j, k, l;
+ unsigned int n = gimple_switch_num_labels (stmt);
+ bool take_default;
+ tree case_low, case_high;
+ tree min = vr->min, max = vr->max;
+
+ gcc_checking_assert (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE);
+
+ take_default = !find_case_label_range (stmt, min, max, &i, &j);
+
+ /* Set second range to emtpy. */
+ *min_idx2 = 1;
+ *max_idx2 = 0;
+
+ if (vr->type == VR_RANGE)
+ {
+ *min_idx1 = i;
+ *max_idx1 = j;
+ return !take_default;
+ }
+
+ /* Set first range to all case labels. */
+ *min_idx1 = 1;
+ *max_idx1 = n - 1;
+
+ if (i > j)
+ return false;
+
+ /* Make sure all the values of case labels [i , j] are contained in
+ range [MIN, MAX]. */
+ case_low = CASE_LOW (gimple_switch_label (stmt, i));
+ case_high = CASE_HIGH (gimple_switch_label (stmt, j));
+ if (tree_int_cst_compare (case_low, min) < 0)
+ i += 1;
+ if (case_high != NULL_TREE
+ && tree_int_cst_compare (max, case_high) < 0)
+ j -= 1;
+
+ if (i > j)
+ return false;
+
+ /* If the range spans case labels [i, j], the corresponding anti-range spans
+ the labels [1, i - 1] and [j + 1, n - 1]. */
+ k = j + 1;
+ l = n - 1;
+ if (k > l)
+ {
+ k = 1;
+ l = 0;
+ }
+
+ j = i - 1;
+ i = 1;
+ if (i > j)
+ {
+ i = k;
+ j = l;
+ k = 1;
+ l = 0;
+ }
+
+ *min_idx1 = i;
+ *max_idx1 = j;
+ *min_idx2 = k;
+ *max_idx2 = l;
+ return false;
+}
+
+/* Visit switch statement STMT. If we can determine which edge
+ will be taken out of STMT's basic block, record it in
+ *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
+ SSA_PROP_VARYING. */
+
+static enum ssa_prop_result
+vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
+{
+ tree op, val;
+ value_range_t *vr;
+ size_t i = 0, j = 0, k, l;
+ bool take_default;
+
+ *taken_edge_p = NULL;
+ op = gimple_switch_index (stmt);
+ if (TREE_CODE (op) != SSA_NAME)
+ return SSA_PROP_VARYING;
+
+ vr = get_value_range (op);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\nVisiting switch expression with operand ");
+ print_generic_expr (dump_file, op, 0);
+ fprintf (dump_file, " with known range ");
+ dump_value_range (dump_file, vr);
+ fprintf (dump_file, "\n");
+ }
+
+ if ((vr->type != VR_RANGE
+ && vr->type != VR_ANTI_RANGE)
+ || symbolic_range_p (vr))
+ return SSA_PROP_VARYING;
+
+ /* Find the single edge that is taken from the switch expression. */
+ take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l);
+
+ /* Check if the range spans no CASE_LABEL. If so, we only reach the default
+ label */
+ if (j < i)
+ {
+ gcc_assert (take_default);
+ val = gimple_switch_default_label (stmt);
+ }
+ else
+ {
+ /* Check if labels with index i to j and maybe the default label
+ are all reaching the same label. */
+
+ val = gimple_switch_label (stmt, i);
+ if (take_default
+ && CASE_LABEL (gimple_switch_default_label (stmt))
+ != CASE_LABEL (val))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " not a single destination for this "
+ "range\n");
+ return SSA_PROP_VARYING;
+ }
+ for (++i; i <= j; ++i)
+ {
+ if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " not a single destination for this "
+ "range\n");
+ return SSA_PROP_VARYING;
+ }
+ }
+ for (; k <= l; ++k)
+ {
+ if (CASE_LABEL (gimple_switch_label (stmt, k)) != CASE_LABEL (val))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " not a single destination for this "
+ "range\n");
+ return SSA_PROP_VARYING;
+ }
+ }
+ }
+
+ *taken_edge_p = find_edge (gimple_bb (stmt),
+ label_to_block (CASE_LABEL (val)));
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, " will take edge to ");
+ print_generic_stmt (dump_file, CASE_LABEL (val), 0);
+ }
+
+ return SSA_PROP_INTERESTING;
+}
+
+
+/* Evaluate statement STMT. If the statement produces a useful range,
+ return SSA_PROP_INTERESTING and record the SSA name with the
+ interesting range into *OUTPUT_P.
+
+ If STMT is a conditional branch and we can determine its truth
+ value, the taken edge is recorded in *TAKEN_EDGE_P.
+
+ If STMT produces a varying value, return SSA_PROP_VARYING. */
+
+static enum ssa_prop_result
+vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
+{
+ tree def;
+ ssa_op_iter iter;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\nVisiting statement:\n");
+ print_gimple_stmt (dump_file, stmt, 0, dump_flags);
+ fprintf (dump_file, "\n");
+ }
+
+ if (!stmt_interesting_for_vrp (stmt))
+ gcc_assert (stmt_ends_bb_p (stmt));
+ else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
+ return vrp_visit_assignment_or_call (stmt, output_p);
+ else if (gimple_code (stmt) == GIMPLE_COND)
+ return vrp_visit_cond_stmt (stmt, taken_edge_p);
+ else if (gimple_code (stmt) == GIMPLE_SWITCH)
+ return vrp_visit_switch_stmt (stmt, taken_edge_p);
+
+ /* All other statements produce nothing of interest for VRP, so mark
+ their outputs varying and prevent further simulation. */
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
+ set_value_range_to_varying (get_value_range (def));
+
+ return SSA_PROP_VARYING;
+}
+
+/* Union the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and
+ { VR1TYPE, VR0MIN, VR0MAX } and store the result
+ in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest
+ possible such range. The resulting range is not canonicalized. */
+
+static void
+union_ranges (enum value_range_type *vr0type,
+ tree *vr0min, tree *vr0max,
+ enum value_range_type vr1type,
+ tree vr1min, tree vr1max)
+{
+ bool mineq = operand_equal_p (*vr0min, vr1min, 0);
+ bool maxeq = operand_equal_p (*vr0max, vr1max, 0);
+
+ /* [] is vr0, () is vr1 in the following classification comments. */
+ if (mineq && maxeq)
+ {
+ /* [( )] */
+ if (*vr0type == vr1type)
+ /* Nothing to do for equal ranges. */
+ ;
+ else if ((*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ || (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE))
+ {
+ /* For anti-range with range union the result is varying. */
+ goto give_up;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else if (operand_less_p (*vr0max, vr1min) == 1
+ || operand_less_p (vr1max, *vr0min) == 1)
+ {
+ /* [ ] ( ) or ( ) [ ]
+ If the ranges have an empty intersection, result of the union
+ operation is the anti-range or if both are anti-ranges
+ it covers all. */
+ if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ goto give_up;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ ;
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ {
+ /* The result is the convex hull of both ranges. */
+ if (operand_less_p (*vr0max, vr1min) == 1)
+ {
+ /* If the result can be an anti-range, create one. */
+ if (TREE_CODE (*vr0max) == INTEGER_CST
+ && TREE_CODE (vr1min) == INTEGER_CST
+ && vrp_val_is_min (*vr0min)
+ && vrp_val_is_max (vr1max))
+ {
+ tree min = int_const_binop (PLUS_EXPR,
+ *vr0max, integer_one_node);
+ tree max = int_const_binop (MINUS_EXPR,
+ vr1min, integer_one_node);
+ if (!operand_less_p (max, min))
+ {
+ *vr0type = VR_ANTI_RANGE;
+ *vr0min = min;
+ *vr0max = max;
+ }
+ else
+ *vr0max = vr1max;
+ }
+ else
+ *vr0max = vr1max;
+ }
+ else
+ {
+ /* If the result can be an anti-range, create one. */
+ if (TREE_CODE (vr1max) == INTEGER_CST
+ && TREE_CODE (*vr0min) == INTEGER_CST
+ && vrp_val_is_min (vr1min)
+ && vrp_val_is_max (*vr0max))
+ {
+ tree min = int_const_binop (PLUS_EXPR,
+ vr1max, integer_one_node);
+ tree max = int_const_binop (MINUS_EXPR,
+ *vr0min, integer_one_node);
+ if (!operand_less_p (max, min))
+ {
+ *vr0type = VR_ANTI_RANGE;
+ *vr0min = min;
+ *vr0max = max;
+ }
+ else
+ *vr0min = vr1min;
+ }
+ else
+ *vr0min = vr1min;
+ }
+ }
+ else
+ gcc_unreachable ();
+ }
+ else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1)
+ && (mineq || operand_less_p (*vr0min, vr1min) == 1))
+ {
+ /* [ ( ) ] or [( ) ] or [ ( )] */
+ if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ ;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ /* Arbitrarily choose the right or left gap. */
+ if (!mineq && TREE_CODE (vr1min) == INTEGER_CST)
+ *vr0max = int_const_binop (MINUS_EXPR, vr1min, integer_one_node);
+ else if (!maxeq && TREE_CODE (vr1max) == INTEGER_CST)
+ *vr0min = int_const_binop (PLUS_EXPR, vr1max, integer_one_node);
+ else
+ goto give_up;
+ }
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ /* The result covers everything. */
+ goto give_up;
+ else
+ gcc_unreachable ();
+ }
+ else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1)
+ && (mineq || operand_less_p (vr1min, *vr0min) == 1))
+ {
+ /* ( [ ] ) or ([ ] ) or ( [ ]) */
+ if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ ;
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ *vr0type = VR_ANTI_RANGE;
+ if (!mineq && TREE_CODE (*vr0min) == INTEGER_CST)
+ {
+ *vr0max = int_const_binop (MINUS_EXPR, *vr0min, integer_one_node);
+ *vr0min = vr1min;
+ }
+ else if (!maxeq && TREE_CODE (*vr0max) == INTEGER_CST)
+ {
+ *vr0min = int_const_binop (PLUS_EXPR, *vr0max, integer_one_node);
+ *vr0max = vr1max;
+ }
+ else
+ goto give_up;
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ /* The result covers everything. */
+ goto give_up;
+ else
+ gcc_unreachable ();
+ }
+ else if ((operand_less_p (vr1min, *vr0max) == 1
+ || operand_equal_p (vr1min, *vr0max, 0))
+ && operand_less_p (*vr0min, vr1min) == 1
+ && operand_less_p (*vr0max, vr1max) == 1)
+ {
+ /* [ ( ] ) or [ ]( ) */
+ if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ *vr0max = vr1max;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ *vr0min = vr1min;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ if (TREE_CODE (vr1min) == INTEGER_CST)
+ *vr0max = int_const_binop (MINUS_EXPR, vr1min, integer_one_node);
+ else
+ goto give_up;
+ }
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ if (TREE_CODE (*vr0max) == INTEGER_CST)
+ {
+ *vr0type = vr1type;
+ *vr0min = int_const_binop (PLUS_EXPR, *vr0max, integer_one_node);
+ *vr0max = vr1max;
+ }
+ else
+ goto give_up;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else if ((operand_less_p (*vr0min, vr1max) == 1
+ || operand_equal_p (*vr0min, vr1max, 0))
+ && operand_less_p (vr1min, *vr0min) == 1
+ && operand_less_p (vr1max, *vr0max) == 1)
+ {
+ /* ( [ ) ] or ( )[ ] */
+ if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ *vr0min = vr1min;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ *vr0max = vr1max;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ if (TREE_CODE (vr1max) == INTEGER_CST)
+ *vr0min = int_const_binop (PLUS_EXPR, vr1max, integer_one_node);
+ else
+ goto give_up;
+ }
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ if (TREE_CODE (*vr0min) == INTEGER_CST)
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = int_const_binop (MINUS_EXPR, *vr0min, integer_one_node);
+ }
+ else
+ goto give_up;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else
+ goto give_up;
+
+ return;
+
+give_up:
+ *vr0type = VR_VARYING;
+ *vr0min = NULL_TREE;
+ *vr0max = NULL_TREE;
+}
+
+/* Intersect the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and
+ { VR1TYPE, VR0MIN, VR0MAX } and store the result
+ in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest
+ possible such range. The resulting range is not canonicalized. */
+
+static void
+intersect_ranges (enum value_range_type *vr0type,
+ tree *vr0min, tree *vr0max,
+ enum value_range_type vr1type,
+ tree vr1min, tree vr1max)
+{
+ bool mineq = operand_equal_p (*vr0min, vr1min, 0);
+ bool maxeq = operand_equal_p (*vr0max, vr1max, 0);
+
+ /* [] is vr0, () is vr1 in the following classification comments. */
+ if (mineq && maxeq)
+ {
+ /* [( )] */
+ if (*vr0type == vr1type)
+ /* Nothing to do for equal ranges. */
+ ;
+ else if ((*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ || (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE))
+ {
+ /* For anti-range with range intersection the result is empty. */
+ *vr0type = VR_UNDEFINED;
+ *vr0min = NULL_TREE;
+ *vr0max = NULL_TREE;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else if (operand_less_p (*vr0max, vr1min) == 1
+ || operand_less_p (vr1max, *vr0min) == 1)
+ {
+ /* [ ] ( ) or ( ) [ ]
+ If the ranges have an empty intersection, the result of the
+ intersect operation is the range for intersecting an
+ anti-range with a range or empty when intersecting two ranges. */
+ if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ ;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ {
+ *vr0type = VR_UNDEFINED;
+ *vr0min = NULL_TREE;
+ *vr0max = NULL_TREE;
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ /* If the anti-ranges are adjacent to each other merge them. */
+ if (TREE_CODE (*vr0max) == INTEGER_CST
+ && TREE_CODE (vr1min) == INTEGER_CST
+ && operand_less_p (*vr0max, vr1min) == 1
+ && integer_onep (int_const_binop (MINUS_EXPR,
+ vr1min, *vr0max)))
+ *vr0max = vr1max;
+ else if (TREE_CODE (vr1max) == INTEGER_CST
+ && TREE_CODE (*vr0min) == INTEGER_CST
+ && operand_less_p (vr1max, *vr0min) == 1
+ && integer_onep (int_const_binop (MINUS_EXPR,
+ *vr0min, vr1max)))
+ *vr0min = vr1min;
+ /* Else arbitrarily take VR0. */
+ }
+ }
+ else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1)
+ && (mineq || operand_less_p (*vr0min, vr1min) == 1))
+ {
+ /* [ ( ) ] or [( ) ] or [ ( )] */
+ if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ {
+ /* If both are ranges the result is the inner one. */
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ /* Choose the right gap if the left one is empty. */
+ if (mineq)
+ {
+ if (TREE_CODE (vr1max) == INTEGER_CST)
+ *vr0min = int_const_binop (PLUS_EXPR, vr1max, integer_one_node);
+ else
+ *vr0min = vr1max;
+ }
+ /* Choose the left gap if the right one is empty. */
+ else if (maxeq)
+ {
+ if (TREE_CODE (vr1min) == INTEGER_CST)
+ *vr0max = int_const_binop (MINUS_EXPR, vr1min,
+ integer_one_node);
+ else
+ *vr0max = vr1min;
+ }
+ /* Choose the anti-range if the range is effectively varying. */
+ else if (vrp_val_is_min (*vr0min)
+ && vrp_val_is_max (*vr0max))
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ /* Else choose the range. */
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ /* If both are anti-ranges the result is the outer one. */
+ ;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ /* The intersection is empty. */
+ *vr0type = VR_UNDEFINED;
+ *vr0min = NULL_TREE;
+ *vr0max = NULL_TREE;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1)
+ && (mineq || operand_less_p (vr1min, *vr0min) == 1))
+ {
+ /* ( [ ] ) or ([ ] ) or ( [ ]) */
+ if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ /* Choose the inner range. */
+ ;
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ /* Choose the right gap if the left is empty. */
+ if (mineq)
+ {
+ *vr0type = VR_RANGE;
+ if (TREE_CODE (*vr0max) == INTEGER_CST)
+ *vr0min = int_const_binop (PLUS_EXPR, *vr0max,
+ integer_one_node);
+ else
+ *vr0min = *vr0max;
+ *vr0max = vr1max;
+ }
+ /* Choose the left gap if the right is empty. */
+ else if (maxeq)
+ {
+ *vr0type = VR_RANGE;
+ if (TREE_CODE (*vr0min) == INTEGER_CST)
+ *vr0max = int_const_binop (MINUS_EXPR, *vr0min,
+ integer_one_node);
+ else
+ *vr0max = *vr0min;
+ *vr0min = vr1min;
+ }
+ /* Choose the anti-range if the range is effectively varying. */
+ else if (vrp_val_is_min (vr1min)
+ && vrp_val_is_max (vr1max))
+ ;
+ /* Else choose the range. */
+ else
+ {
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ /* If both are anti-ranges the result is the outer one. */
+ *vr0type = vr1type;
+ *vr0min = vr1min;
+ *vr0max = vr1max;
+ }
+ else if (vr1type == VR_ANTI_RANGE
+ && *vr0type == VR_RANGE)
+ {
+ /* The intersection is empty. */
+ *vr0type = VR_UNDEFINED;
+ *vr0min = NULL_TREE;
+ *vr0max = NULL_TREE;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else if ((operand_less_p (vr1min, *vr0max) == 1
+ || operand_equal_p (vr1min, *vr0max, 0))
+ && operand_less_p (*vr0min, vr1min) == 1)
+ {
+ /* [ ( ] ) or [ ]( ) */
+ if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ *vr0max = vr1max;
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ *vr0min = vr1min;
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ if (TREE_CODE (vr1min) == INTEGER_CST)
+ *vr0max = int_const_binop (MINUS_EXPR, vr1min,
+ integer_one_node);
+ else
+ *vr0max = vr1min;
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ *vr0type = VR_RANGE;
+ if (TREE_CODE (*vr0max) == INTEGER_CST)
+ *vr0min = int_const_binop (PLUS_EXPR, *vr0max,
+ integer_one_node);
+ else
+ *vr0min = *vr0max;
+ *vr0max = vr1max;
+ }
+ else
+ gcc_unreachable ();
+ }
+ else if ((operand_less_p (*vr0min, vr1max) == 1
+ || operand_equal_p (*vr0min, vr1max, 0))
+ && operand_less_p (vr1min, *vr0min) == 1)
+ {
+ /* ( [ ) ] or ( )[ ] */
+ if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ *vr0min = vr1min;
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_RANGE)
+ *vr0max = vr1max;
+ else if (*vr0type == VR_RANGE
+ && vr1type == VR_ANTI_RANGE)
+ {
+ if (TREE_CODE (vr1max) == INTEGER_CST)
+ *vr0min = int_const_binop (PLUS_EXPR, vr1max,
+ integer_one_node);
+ else
+ *vr0min = vr1max;
+ }
+ else if (*vr0type == VR_ANTI_RANGE
+ && vr1type == VR_RANGE)
+ {
+ *vr0type = VR_RANGE;
+ if (TREE_CODE (*vr0min) == INTEGER_CST)
+ *vr0max = int_const_binop (MINUS_EXPR, *vr0min,
+ integer_one_node);
+ else
+ *vr0max = *vr0min;
+ *vr0min = vr1min;
+ }
+ else
+ gcc_unreachable ();
+ }
+
+ /* As a fallback simply use { *VRTYPE, *VR0MIN, *VR0MAX } as
+ result for the intersection. That's always a conservative
+ correct estimate. */
+
+ return;
+}
+
+
+/* Intersect the two value-ranges *VR0 and *VR1 and store the result
+ in *VR0. This may not be the smallest possible such range. */
+
+static void
+vrp_intersect_ranges_1 (value_range_t *vr0, value_range_t *vr1)
+{
+ value_range_t saved;
+
+ /* If either range is VR_VARYING the other one wins. */
+ if (vr1->type == VR_VARYING)
+ return;
+ if (vr0->type == VR_VARYING)
+ {
+ copy_value_range (vr0, vr1);
+ return;
+ }
+
+ /* When either range is VR_UNDEFINED the resulting range is
+ VR_UNDEFINED, too. */
+ if (vr0->type == VR_UNDEFINED)
+ return;
+ if (vr1->type == VR_UNDEFINED)
+ {
+ set_value_range_to_undefined (vr0);
+ return;
+ }
+
+ /* Save the original vr0 so we can return it as conservative intersection
+ result when our worker turns things to varying. */
+ saved = *vr0;
+ intersect_ranges (&vr0->type, &vr0->min, &vr0->max,
+ vr1->type, vr1->min, vr1->max);
+ /* Make sure to canonicalize the result though as the inversion of a
+ VR_RANGE can still be a VR_RANGE. */
+ set_and_canonicalize_value_range (vr0, vr0->type,
+ vr0->min, vr0->max, vr0->equiv);
+ /* If that failed, use the saved original VR0. */
+ if (vr0->type == VR_VARYING)
+ {
+ *vr0 = saved;
+ return;
+ }
+ /* If the result is VR_UNDEFINED there is no need to mess with
+ the equivalencies. */
+ if (vr0->type == VR_UNDEFINED)
+ return;
+
+ /* The resulting set of equivalences for range intersection is the union of
+ the two sets. */
+ if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
+ bitmap_ior_into (vr0->equiv, vr1->equiv);
+ else if (vr1->equiv && !vr0->equiv)
+ bitmap_copy (vr0->equiv, vr1->equiv);
+}
+
+static void
+vrp_intersect_ranges (value_range_t *vr0, value_range_t *vr1)
+{
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Intersecting\n ");
+ dump_value_range (dump_file, vr0);
+ fprintf (dump_file, "\nand\n ");
+ dump_value_range (dump_file, vr1);
+ fprintf (dump_file, "\n");
+ }
+ vrp_intersect_ranges_1 (vr0, vr1);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "to\n ");
+ dump_value_range (dump_file, vr0);
+ fprintf (dump_file, "\n");
+ }
+}
+
+/* Meet operation for value ranges. Given two value ranges VR0 and
+ VR1, store in VR0 a range that contains both VR0 and VR1. This
+ may not be the smallest possible such range. */
+
+static void
+vrp_meet_1 (value_range_t *vr0, value_range_t *vr1)
+{
+ value_range_t saved;
+
+ if (vr0->type == VR_UNDEFINED)
+ {
+ set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr1->equiv);
+ return;
+ }
+
+ if (vr1->type == VR_UNDEFINED)
+ {
+ /* VR0 already has the resulting range. */
+ return;
+ }
+
+ if (vr0->type == VR_VARYING)
+ {
+ /* Nothing to do. VR0 already has the resulting range. */
+ return;
+ }
+
+ if (vr1->type == VR_VARYING)
+ {
+ set_value_range_to_varying (vr0);
+ return;
+ }
+
+ saved = *vr0;
+ union_ranges (&vr0->type, &vr0->min, &vr0->max,
+ vr1->type, vr1->min, vr1->max);
+ if (vr0->type == VR_VARYING)
+ {
+ /* Failed to find an efficient meet. Before giving up and setting
+ the result to VARYING, see if we can at least derive a useful
+ anti-range. FIXME, all this nonsense about distinguishing
+ anti-ranges from ranges is necessary because of the odd
+ semantics of range_includes_zero_p and friends. */
+ if (((saved.type == VR_RANGE
+ && range_includes_zero_p (saved.min, saved.max) == 0)
+ || (saved.type == VR_ANTI_RANGE
+ && range_includes_zero_p (saved.min, saved.max) == 1))
+ && ((vr1->type == VR_RANGE
+ && range_includes_zero_p (vr1->min, vr1->max) == 0)
+ || (vr1->type == VR_ANTI_RANGE
+ && range_includes_zero_p (vr1->min, vr1->max) == 1)))
+ {
+ set_value_range_to_nonnull (vr0, TREE_TYPE (saved.min));
+
+ /* Since this meet operation did not result from the meeting of
+ two equivalent names, VR0 cannot have any equivalences. */
+ if (vr0->equiv)
+ bitmap_clear (vr0->equiv);
+ return;
+ }
+
+ set_value_range_to_varying (vr0);
+ return;
+ }
+ set_and_canonicalize_value_range (vr0, vr0->type, vr0->min, vr0->max,
+ vr0->equiv);
+ if (vr0->type == VR_VARYING)
+ return;
+
+ /* The resulting set of equivalences is always the intersection of
+ the two sets. */
+ if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
+ bitmap_and_into (vr0->equiv, vr1->equiv);
+ else if (vr0->equiv && !vr1->equiv)
+ bitmap_clear (vr0->equiv);
+}
+
+static void
+vrp_meet (value_range_t *vr0, value_range_t *vr1)
+{
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Meeting\n ");
+ dump_value_range (dump_file, vr0);
+ fprintf (dump_file, "\nand\n ");
+ dump_value_range (dump_file, vr1);
+ fprintf (dump_file, "\n");
+ }
+ vrp_meet_1 (vr0, vr1);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "to\n ");
+ dump_value_range (dump_file, vr0);
+ fprintf (dump_file, "\n");
+ }
+}
+
+
+/* Visit all arguments for PHI node PHI that flow through executable
+ edges. If a valid value range can be derived from all the incoming
+ value ranges, set a new range for the LHS of PHI. */
+
+static enum ssa_prop_result
+vrp_visit_phi_node (gimple phi)
+{
+ size_t i;
+ tree lhs = PHI_RESULT (phi);
+ value_range_t *lhs_vr = get_value_range (lhs);
+ value_range_t vr_result = VR_INITIALIZER;
+ bool first = true;
+ int edges, old_edges;
+ struct loop *l;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\nVisiting PHI node: ");
+ print_gimple_stmt (dump_file, phi, 0, dump_flags);
+ }
+
+ edges = 0;
+ for (i = 0; i < gimple_phi_num_args (phi); i++)
+ {
+ edge e = gimple_phi_arg_edge (phi, i);
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file,
+ "\n Argument #%d (%d -> %d %sexecutable)\n",
+ (int) i, e->src->index, e->dest->index,
+ (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
+ }
+
+ if (e->flags & EDGE_EXECUTABLE)
+ {
+ tree arg = PHI_ARG_DEF (phi, i);
+ value_range_t vr_arg;
+
+ ++edges;
+
+ if (TREE_CODE (arg) == SSA_NAME)
+ {
+ vr_arg = *(get_value_range (arg));
+ /* Do not allow equivalences or symbolic ranges to leak in from
+ backedges. That creates invalid equivalencies.
+ See PR53465 and PR54767. */
+ if (e->flags & EDGE_DFS_BACK
+ && (vr_arg.type == VR_RANGE
+ || vr_arg.type == VR_ANTI_RANGE))
+ {
+ vr_arg.equiv = NULL;
+ if (symbolic_range_p (&vr_arg))
+ {
+ vr_arg.type = VR_VARYING;
+ vr_arg.min = NULL_TREE;
+ vr_arg.max = NULL_TREE;
+ }
+ }
+ }
+ else
+ {
+ if (TREE_OVERFLOW_P (arg))
+ arg = drop_tree_overflow (arg);
+
+ vr_arg.type = VR_RANGE;
+ vr_arg.min = arg;
+ vr_arg.max = arg;
+ vr_arg.equiv = NULL;
+ }
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\t");
+ print_generic_expr (dump_file, arg, dump_flags);
+ fprintf (dump_file, "\n\tValue: ");
+ dump_value_range (dump_file, &vr_arg);
+ fprintf (dump_file, "\n");
+ }
+
+ if (first)
+ copy_value_range (&vr_result, &vr_arg);
+ else
+ vrp_meet (&vr_result, &vr_arg);
+ first = false;
+
+ if (vr_result.type == VR_VARYING)
+ break;
+ }
+ }
+
+ if (vr_result.type == VR_VARYING)
+ goto varying;
+ else if (vr_result.type == VR_UNDEFINED)
+ goto update_range;
+
+ old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
+ vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
+
+ /* To prevent infinite iterations in the algorithm, derive ranges
+ when the new value is slightly bigger or smaller than the
+ previous one. We don't do this if we have seen a new executable
+ edge; this helps us avoid an overflow infinity for conditionals
+ which are not in a loop. If the old value-range was VR_UNDEFINED
+ use the updated range and iterate one more time. */
+ if (edges > 0
+ && gimple_phi_num_args (phi) > 1
+ && edges == old_edges
+ && lhs_vr->type != VR_UNDEFINED)
+ {
+ int cmp_min = compare_values (lhs_vr->min, vr_result.min);
+ int cmp_max = compare_values (lhs_vr->max, vr_result.max);
+
+ /* For non VR_RANGE or for pointers fall back to varying if
+ the range changed. */
+ if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
+ || POINTER_TYPE_P (TREE_TYPE (lhs)))
+ && (cmp_min != 0 || cmp_max != 0))
+ goto varying;
+
+ /* If the new minimum is smaller or larger than the previous
+ one, go all the way to -INF. In the first case, to avoid
+ iterating millions of times to reach -INF, and in the
+ other case to avoid infinite bouncing between different
+ minimums. */
+ if (cmp_min > 0 || cmp_min < 0)
+ {
+ if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
+ || !vrp_var_may_overflow (lhs, phi))
+ vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
+ else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
+ vr_result.min =
+ negative_overflow_infinity (TREE_TYPE (vr_result.min));
+ }
+
+ /* Similarly, if the new maximum is smaller or larger than
+ the previous one, go all the way to +INF. */
+ if (cmp_max < 0 || cmp_max > 0)
+ {
+ if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
+ || !vrp_var_may_overflow (lhs, phi))
+ vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
+ else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
+ vr_result.max =
+ positive_overflow_infinity (TREE_TYPE (vr_result.max));
+ }
+
+ /* If we dropped either bound to +-INF then if this is a loop
+ PHI node SCEV may known more about its value-range. */
+ if ((cmp_min > 0 || cmp_min < 0
+ || cmp_max < 0 || cmp_max > 0)
+ && current_loops
+ && (l = loop_containing_stmt (phi))
+ && l->header == gimple_bb (phi))
+ adjust_range_with_scev (&vr_result, l, phi, lhs);
+
+ /* If we will end up with a (-INF, +INF) range, set it to
+ VARYING. Same if the previous max value was invalid for
+ the type and we end up with vr_result.min > vr_result.max. */
+ if ((vrp_val_is_max (vr_result.max)
+ && vrp_val_is_min (vr_result.min))
+ || compare_values (vr_result.min,
+ vr_result.max) > 0)
+ goto varying;
+ }
+
+ /* If the new range is different than the previous value, keep
+ iterating. */
+update_range:
+ if (update_value_range (lhs, &vr_result))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Found new range for ");
+ print_generic_expr (dump_file, lhs, 0);
+ fprintf (dump_file, ": ");
+ dump_value_range (dump_file, &vr_result);
+ fprintf (dump_file, "\n\n");
+ }
+
+ return SSA_PROP_INTERESTING;
+ }
+
+ /* Nothing changed, don't add outgoing edges. */
+ return SSA_PROP_NOT_INTERESTING;
+
+ /* No match found. Set the LHS to VARYING. */
+varying:
+ set_value_range_to_varying (lhs_vr);
+ return SSA_PROP_VARYING;
+}
+
+/* Simplify boolean operations if the source is known
+ to be already a boolean. */
+static bool
+simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
+{
+ enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
+ tree lhs, op0, op1;
+ bool need_conversion;
+
+ /* We handle only !=/== case here. */
+ gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR);
+
+ op0 = gimple_assign_rhs1 (stmt);
+ if (!op_with_boolean_value_range_p (op0))
+ return false;
+
+ op1 = gimple_assign_rhs2 (stmt);
+ if (!op_with_boolean_value_range_p (op1))
+ return false;
+
+ /* Reduce number of cases to handle to NE_EXPR. As there is no
+ BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
+ if (rhs_code == EQ_EXPR)
+ {
+ if (TREE_CODE (op1) == INTEGER_CST)
+ op1 = int_const_binop (BIT_XOR_EXPR, op1, integer_one_node);
+ else
+ return false;
+ }
+
+ lhs = gimple_assign_lhs (stmt);
+ need_conversion
+ = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0));
+
+ /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
+ if (need_conversion
+ && !TYPE_UNSIGNED (TREE_TYPE (op0))
+ && TYPE_PRECISION (TREE_TYPE (op0)) == 1
+ && TYPE_PRECISION (TREE_TYPE (lhs)) > 1)
+ return false;
+
+ /* For A != 0 we can substitute A itself. */
+ if (integer_zerop (op1))
+ gimple_assign_set_rhs_with_ops (gsi,
+ need_conversion
+ ? NOP_EXPR : TREE_CODE (op0),
+ op0, NULL_TREE);
+ /* For A != B we substitute A ^ B. Either with conversion. */
+ else if (need_conversion)
+ {
+ tree tem = make_ssa_name (TREE_TYPE (op0), NULL);
+ gimple newop = gimple_build_assign_with_ops (BIT_XOR_EXPR, tem, op0, op1);
+ gsi_insert_before (gsi, newop, GSI_SAME_STMT);
+ gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem, NULL_TREE);
+ }
+ /* Or without. */
+ else
+ gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1);
+ update_stmt (gsi_stmt (*gsi));
+
+ return true;
+}
+
+/* Simplify a division or modulo operator to a right shift or
+ bitwise and if the first operand is unsigned or is greater
+ than zero and the second operand is an exact power of two. */
+
+static bool
+simplify_div_or_mod_using_ranges (gimple stmt)
+{
+ enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
+ tree val = NULL;
+ tree op0 = gimple_assign_rhs1 (stmt);
+ tree op1 = gimple_assign_rhs2 (stmt);
+ value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
+
+ if (TYPE_UNSIGNED (TREE_TYPE (op0)))
+ {
+ val = integer_one_node;
+ }
+ else
+ {
+ bool sop = false;
+
+ val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
+
+ if (val
+ && sop
+ && integer_onep (val)
+ && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
+ {
+ location_t location;
+
+ if (!gimple_has_location (stmt))
+ location = input_location;
+ else
+ location = gimple_location (stmt);
+ warning_at (location, OPT_Wstrict_overflow,
+ "assuming signed overflow does not occur when "
+ "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
+ }
+ }
+
+ if (val && integer_onep (val))
+ {
+ tree t;
+
+ if (rhs_code == TRUNC_DIV_EXPR)
+ {
+ t = build_int_cst (integer_type_node, tree_log2 (op1));
+ gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
+ gimple_assign_set_rhs1 (stmt, op0);
+ gimple_assign_set_rhs2 (stmt, t);
+ }
+ else
+ {
+ t = build_int_cst (TREE_TYPE (op1), 1);
+ t = int_const_binop (MINUS_EXPR, op1, t);
+ t = fold_convert (TREE_TYPE (op0), t);
+
+ gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
+ gimple_assign_set_rhs1 (stmt, op0);
+ gimple_assign_set_rhs2 (stmt, t);
+ }
+
+ update_stmt (stmt);
+ return true;
+ }
+
+ return false;
+}
+
+/* If the operand to an ABS_EXPR is >= 0, then eliminate the
+ ABS_EXPR. If the operand is <= 0, then simplify the
+ ABS_EXPR into a NEGATE_EXPR. */
+
+static bool
+simplify_abs_using_ranges (gimple stmt)
+{
+ tree val = NULL;
+ tree op = gimple_assign_rhs1 (stmt);
+ tree type = TREE_TYPE (op);
+ value_range_t *vr = get_value_range (op);
+
+ if (TYPE_UNSIGNED (type))
+ {
+ val = integer_zero_node;
+ }
+ else if (vr)
+ {
+ bool sop = false;
+
+ val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
+ if (!val)
+ {
+ sop = false;
+ val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
+ &sop);
+
+ if (val)
+ {
+ if (integer_zerop (val))
+ val = integer_one_node;
+ else if (integer_onep (val))
+ val = integer_zero_node;
+ }
+ }
+
+ if (val
+ && (integer_onep (val) || integer_zerop (val)))
+ {
+ if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
+ {
+ location_t location;
+
+ if (!gimple_has_location (stmt))
+ location = input_location;
+ else
+ location = gimple_location (stmt);
+ warning_at (location, OPT_Wstrict_overflow,
+ "assuming signed overflow does not occur when "
+ "simplifying %<abs (X)%> to %<X%> or %<-X%>");
+ }
+
+ gimple_assign_set_rhs1 (stmt, op);
+ if (integer_onep (val))
+ gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
+ else
+ gimple_assign_set_rhs_code (stmt, SSA_NAME);
+ update_stmt (stmt);
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
+ If all the bits that are being cleared by & are already
+ known to be zero from VR, or all the bits that are being
+ set by | are already known to be one from VR, the bit
+ operation is redundant. */
+
+static bool
+simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
+{
+ tree op0 = gimple_assign_rhs1 (stmt);
+ tree op1 = gimple_assign_rhs2 (stmt);
+ tree op = NULL_TREE;
+ value_range_t vr0 = VR_INITIALIZER;
+ value_range_t vr1 = VR_INITIALIZER;
+ double_int may_be_nonzero0, may_be_nonzero1;
+ double_int must_be_nonzero0, must_be_nonzero1;
+ double_int mask;
+
+ if (TREE_CODE (op0) == SSA_NAME)
+ vr0 = *(get_value_range (op0));
+ else if (is_gimple_min_invariant (op0))
+ set_value_range_to_value (&vr0, op0, NULL);
+ else
+ return false;
+
+ if (TREE_CODE (op1) == SSA_NAME)
+ vr1 = *(get_value_range (op1));
+ else if (is_gimple_min_invariant (op1))
+ set_value_range_to_value (&vr1, op1, NULL);
+ else
+ return false;
+
+ if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
+ return false;
+ if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
+ return false;
+
+ switch (gimple_assign_rhs_code (stmt))
+ {
+ case BIT_AND_EXPR:
+ mask = may_be_nonzero0.and_not (must_be_nonzero1);
+ if (mask.is_zero ())
+ {
+ op = op0;
+ break;
+ }
+ mask = may_be_nonzero1.and_not (must_be_nonzero0);
+ if (mask.is_zero ())
+ {
+ op = op1;
+ break;
+ }
+ break;
+ case BIT_IOR_EXPR:
+ mask = may_be_nonzero0.and_not (must_be_nonzero1);
+ if (mask.is_zero ())
+ {
+ op = op1;
+ break;
+ }
+ mask = may_be_nonzero1.and_not (must_be_nonzero0);
+ if (mask.is_zero ())
+ {
+ op = op0;
+ break;
+ }
+ break;
+ default:
+ gcc_unreachable ();
+ }
+
+ if (op == NULL_TREE)
+ return false;
+
+ gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
+ update_stmt (gsi_stmt (*gsi));
+ return true;
+}
+
+/* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
+ a known value range VR.
+
+ If there is one and only one value which will satisfy the
+ conditional, then return that value. Else return NULL. */
+
+static tree
+test_for_singularity (enum tree_code cond_code, tree op0,
+ tree op1, value_range_t *vr)
+{
+ tree min = NULL;
+ tree max = NULL;
+
+ /* Extract minimum/maximum values which satisfy the
+ the conditional as it was written. */
+ if (cond_code == LE_EXPR || cond_code == LT_EXPR)
+ {
+ /* This should not be negative infinity; there is no overflow
+ here. */
+ min = TYPE_MIN_VALUE (TREE_TYPE (op0));
+
+ max = op1;
+ if (cond_code == LT_EXPR && !is_overflow_infinity (max))
+ {
+ tree one = build_int_cst (TREE_TYPE (op0), 1);
+ max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
+ if (EXPR_P (max))
+ TREE_NO_WARNING (max) = 1;
+ }
+ }
+ else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
+ {
+ /* This should not be positive infinity; there is no overflow
+ here. */
+ max = TYPE_MAX_VALUE (TREE_TYPE (op0));
+
+ min = op1;
+ if (cond_code == GT_EXPR && !is_overflow_infinity (min))
+ {
+ tree one = build_int_cst (TREE_TYPE (op0), 1);
+ min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
+ if (EXPR_P (min))
+ TREE_NO_WARNING (min) = 1;
+ }
+ }
+
+ /* Now refine the minimum and maximum values using any
+ value range information we have for op0. */
+ if (min && max)
+ {
+ if (compare_values (vr->min, min) == 1)
+ min = vr->min;
+ if (compare_values (vr->max, max) == -1)
+ max = vr->max;
+
+ /* If the new min/max values have converged to a single value,
+ then there is only one value which can satisfy the condition,
+ return that value. */
+ if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
+ return min;
+ }
+ return NULL;
+}
+
+/* Return whether the value range *VR fits in an integer type specified
+ by PRECISION and UNSIGNED_P. */
+
+static bool
+range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
+{
+ tree src_type;
+ unsigned src_precision;
+ double_int tem;
+
+ /* We can only handle integral and pointer types. */
+ src_type = TREE_TYPE (vr->min);
+ if (!INTEGRAL_TYPE_P (src_type)
+ && !POINTER_TYPE_P (src_type))
+ return false;
+
+ /* An extension is fine unless VR is signed and unsigned_p,
+ and so is an identity transform. */
+ src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
+ if ((src_precision < precision
+ && !(unsigned_p && !TYPE_UNSIGNED (src_type)))
+ || (src_precision == precision
+ && TYPE_UNSIGNED (src_type) == unsigned_p))
+ return true;
+
+ /* Now we can only handle ranges with constant bounds. */
+ if (vr->type != VR_RANGE
+ || TREE_CODE (vr->min) != INTEGER_CST
+ || TREE_CODE (vr->max) != INTEGER_CST)
+ return false;
+
+ /* For sign changes, the MSB of the double_int has to be clear.
+ An unsigned value with its MSB set cannot be represented by
+ a signed double_int, while a negative value cannot be represented
+ by an unsigned double_int. */
+ if (TYPE_UNSIGNED (src_type) != unsigned_p
+ && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
+ return false;
+
+ /* Then we can perform the conversion on both ends and compare
+ the result for equality. */
+ tem = tree_to_double_int (vr->min).ext (precision, unsigned_p);
+ if (tree_to_double_int (vr->min) != tem)
+ return false;
+ tem = tree_to_double_int (vr->max).ext (precision, unsigned_p);
+ if (tree_to_double_int (vr->max) != tem)
+ return false;
+
+ return true;
+}
+
+/* Simplify a conditional using a relational operator to an equality
+ test if the range information indicates only one value can satisfy
+ the original conditional. */
+
+static bool
+simplify_cond_using_ranges (gimple stmt)
+{
+ tree op0 = gimple_cond_lhs (stmt);
+ tree op1 = gimple_cond_rhs (stmt);
+ enum tree_code cond_code = gimple_cond_code (stmt);
+
+ if (cond_code != NE_EXPR
+ && cond_code != EQ_EXPR
+ && TREE_CODE (op0) == SSA_NAME
+ && INTEGRAL_TYPE_P (TREE_TYPE (op0))
+ && is_gimple_min_invariant (op1))
+ {
+ value_range_t *vr = get_value_range (op0);
+
+ /* If we have range information for OP0, then we might be
+ able to simplify this conditional. */
+ if (vr->type == VR_RANGE)
+ {
+ tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
+
+ if (new_tree)
+ {
+ if (dump_file)
+ {
+ fprintf (dump_file, "Simplified relational ");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ fprintf (dump_file, " into ");
+ }
+
+ gimple_cond_set_code (stmt, EQ_EXPR);
+ gimple_cond_set_lhs (stmt, op0);
+ gimple_cond_set_rhs (stmt, new_tree);
+
+ update_stmt (stmt);
+
+ if (dump_file)
+ {
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ return true;
+ }
+
+ /* Try again after inverting the condition. We only deal
+ with integral types here, so no need to worry about
+ issues with inverting FP comparisons. */
+ cond_code = invert_tree_comparison (cond_code, false);
+ new_tree = test_for_singularity (cond_code, op0, op1, vr);
+
+ if (new_tree)
+ {
+ if (dump_file)
+ {
+ fprintf (dump_file, "Simplified relational ");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ fprintf (dump_file, " into ");
+ }
+
+ gimple_cond_set_code (stmt, NE_EXPR);
+ gimple_cond_set_lhs (stmt, op0);
+ gimple_cond_set_rhs (stmt, new_tree);
+
+ update_stmt (stmt);
+
+ if (dump_file)
+ {
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ return true;
+ }
+ }
+ }
+
+ /* If we have a comparison of an SSA_NAME (OP0) against a constant,
+ see if OP0 was set by a type conversion where the source of
+ the conversion is another SSA_NAME with a range that fits
+ into the range of OP0's type.
+
+ If so, the conversion is redundant as the earlier SSA_NAME can be
+ used for the comparison directly if we just massage the constant in the
+ comparison. */
+ if (TREE_CODE (op0) == SSA_NAME
+ && TREE_CODE (op1) == INTEGER_CST)
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (op0);
+ tree innerop;
+
+ if (!is_gimple_assign (def_stmt)
+ || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
+ return false;
+
+ innerop = gimple_assign_rhs1 (def_stmt);
+
+ if (TREE_CODE (innerop) == SSA_NAME
+ && !POINTER_TYPE_P (TREE_TYPE (innerop)))
+ {
+ value_range_t *vr = get_value_range (innerop);
+
+ if (range_int_cst_p (vr)
+ && range_fits_type_p (vr,
+ TYPE_PRECISION (TREE_TYPE (op0)),
+ TYPE_UNSIGNED (TREE_TYPE (op0)))
+ && int_fits_type_p (op1, TREE_TYPE (innerop))
+ /* The range must not have overflowed, or if it did overflow
+ we must not be wrapping/trapping overflow and optimizing
+ with strict overflow semantics. */
+ && ((!is_negative_overflow_infinity (vr->min)
+ && !is_positive_overflow_infinity (vr->max))
+ || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (innerop))))
+ {
+ /* If the range overflowed and the user has asked for warnings
+ when strict overflow semantics were used to optimize code,
+ issue an appropriate warning. */
+ if ((is_negative_overflow_infinity (vr->min)
+ || is_positive_overflow_infinity (vr->max))
+ && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_CONDITIONAL))
+ {
+ location_t location;
+
+ if (!gimple_has_location (stmt))
+ location = input_location;
+ else
+ location = gimple_location (stmt);
+ warning_at (location, OPT_Wstrict_overflow,
+ "assuming signed overflow does not occur when "
+ "simplifying conditional");
+ }
+
+ tree newconst = fold_convert (TREE_TYPE (innerop), op1);
+ gimple_cond_set_lhs (stmt, innerop);
+ gimple_cond_set_rhs (stmt, newconst);
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
+/* Simplify a switch statement using the value range of the switch
+ argument. */
+
+static bool
+simplify_switch_using_ranges (gimple stmt)
+{
+ tree op = gimple_switch_index (stmt);
+ value_range_t *vr;
+ bool take_default;
+ edge e;
+ edge_iterator ei;
+ size_t i = 0, j = 0, n, n2;
+ tree vec2;
+ switch_update su;
+ size_t k = 1, l = 0;
+
+ if (TREE_CODE (op) == SSA_NAME)
+ {
+ vr = get_value_range (op);
+
+ /* We can only handle integer ranges. */
+ if ((vr->type != VR_RANGE
+ && vr->type != VR_ANTI_RANGE)
+ || symbolic_range_p (vr))
+ return false;
+
+ /* Find case label for min/max of the value range. */
+ take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l);
+ }
+ else if (TREE_CODE (op) == INTEGER_CST)
+ {
+ take_default = !find_case_label_index (stmt, 1, op, &i);
+ if (take_default)
+ {
+ i = 1;
+ j = 0;
+ }
+ else
+ {
+ j = i;
+ }
+ }
+ else
+ return false;
+
+ n = gimple_switch_num_labels (stmt);
+
+ /* Bail out if this is just all edges taken. */
+ if (i == 1
+ && j == n - 1
+ && take_default)
+ return false;
+
+ /* Build a new vector of taken case labels. */
+ vec2 = make_tree_vec (j - i + 1 + l - k + 1 + (int)take_default);
+ n2 = 0;
+
+ /* Add the default edge, if necessary. */
+ if (take_default)
+ TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
+
+ for (; i <= j; ++i, ++n2)
+ TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
+
+ for (; k <= l; ++k, ++n2)
+ TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, k);
+
+ /* Mark needed edges. */
+ for (i = 0; i < n2; ++i)
+ {
+ e = find_edge (gimple_bb (stmt),
+ label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
+ e->aux = (void *)-1;
+ }
+
+ /* Queue not needed edges for later removal. */
+ FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
+ {
+ if (e->aux == (void *)-1)
+ {
+ e->aux = NULL;
+ continue;
+ }
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "removing unreachable case label\n");
+ }
+ to_remove_edges.safe_push (e);
+ e->flags &= ~EDGE_EXECUTABLE;
+ }
+
+ /* And queue an update for the stmt. */
+ su.stmt = stmt;
+ su.vec = vec2;
+ to_update_switch_stmts.safe_push (su);
+ return false;
+}
+
+/* Simplify an integral conversion from an SSA name in STMT. */
+
+static bool
+simplify_conversion_using_ranges (gimple stmt)
+{
+ tree innerop, middleop, finaltype;
+ gimple def_stmt;
+ value_range_t *innervr;
+ bool inner_unsigned_p, middle_unsigned_p, final_unsigned_p;
+ unsigned inner_prec, middle_prec, final_prec;
+ double_int innermin, innermed, innermax, middlemin, middlemed, middlemax;
+
+ finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
+ if (!INTEGRAL_TYPE_P (finaltype))
+ return false;
+ middleop = gimple_assign_rhs1 (stmt);
+ def_stmt = SSA_NAME_DEF_STMT (middleop);
+ if (!is_gimple_assign (def_stmt)
+ || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
+ return false;
+ innerop = gimple_assign_rhs1 (def_stmt);
+ if (TREE_CODE (innerop) != SSA_NAME
+ || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop))
+ return false;
+
+ /* Get the value-range of the inner operand. */
+ innervr = get_value_range (innerop);
+ if (innervr->type != VR_RANGE
+ || TREE_CODE (innervr->min) != INTEGER_CST
+ || TREE_CODE (innervr->max) != INTEGER_CST)
+ return false;
+
+ /* Simulate the conversion chain to check if the result is equal if
+ the middle conversion is removed. */
+ innermin = tree_to_double_int (innervr->min);
+ innermax = tree_to_double_int (innervr->max);
+
+ inner_prec = TYPE_PRECISION (TREE_TYPE (innerop));
+ middle_prec = TYPE_PRECISION (TREE_TYPE (middleop));
+ final_prec = TYPE_PRECISION (finaltype);
+
+ /* If the first conversion is not injective, the second must not
+ be widening. */
+ if ((innermax - innermin).ugt (double_int::mask (middle_prec))
+ && middle_prec < final_prec)
+ return false;
+ /* We also want a medium value so that we can track the effect that
+ narrowing conversions with sign change have. */
+ inner_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (innerop));
+ if (inner_unsigned_p)
+ innermed = double_int::mask (inner_prec).lrshift (1, inner_prec);
+ else
+ innermed = double_int_zero;
+ if (innermin.cmp (innermed, inner_unsigned_p) >= 0
+ || innermed.cmp (innermax, inner_unsigned_p) >= 0)
+ innermed = innermin;
+
+ middle_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (middleop));
+ middlemin = innermin.ext (middle_prec, middle_unsigned_p);
+ middlemed = innermed.ext (middle_prec, middle_unsigned_p);
+ middlemax = innermax.ext (middle_prec, middle_unsigned_p);
+
+ /* Require that the final conversion applied to both the original
+ and the intermediate range produces the same result. */
+ final_unsigned_p = TYPE_UNSIGNED (finaltype);
+ if (middlemin.ext (final_prec, final_unsigned_p)
+ != innermin.ext (final_prec, final_unsigned_p)
+ || middlemed.ext (final_prec, final_unsigned_p)
+ != innermed.ext (final_prec, final_unsigned_p)
+ || middlemax.ext (final_prec, final_unsigned_p)
+ != innermax.ext (final_prec, final_unsigned_p))
+ return false;
+
+ gimple_assign_set_rhs1 (stmt, innerop);
+ update_stmt (stmt);
+ return true;
+}
+
+/* Simplify a conversion from integral SSA name to float in STMT. */
+
+static bool
+simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
+{
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ value_range_t *vr = get_value_range (rhs1);
+ enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
+ enum machine_mode mode;
+ tree tem;
+ gimple conv;
+
+ /* We can only handle constant ranges. */
+ if (vr->type != VR_RANGE
+ || TREE_CODE (vr->min) != INTEGER_CST
+ || TREE_CODE (vr->max) != INTEGER_CST)
+ return false;
+
+ /* First check if we can use a signed type in place of an unsigned. */
+ if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
+ && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
+ != CODE_FOR_nothing)
+ && range_fits_type_p (vr, GET_MODE_PRECISION
+ (TYPE_MODE (TREE_TYPE (rhs1))), 0))
+ mode = TYPE_MODE (TREE_TYPE (rhs1));
+ /* If we can do the conversion in the current input mode do nothing. */
+ else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
+ TYPE_UNSIGNED (TREE_TYPE (rhs1))) != CODE_FOR_nothing)
+ return false;
+ /* Otherwise search for a mode we can use, starting from the narrowest
+ integer mode available. */
+ else
+ {
+ mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
+ do
+ {
+ /* If we cannot do a signed conversion to float from mode
+ or if the value-range does not fit in the signed type
+ try with a wider mode. */
+ if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
+ && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
+ break;
+
+ mode = GET_MODE_WIDER_MODE (mode);
+ /* But do not widen the input. Instead leave that to the
+ optabs expansion code. */
+ if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
+ return false;
+ }
+ while (mode != VOIDmode);
+ if (mode == VOIDmode)
+ return false;
+ }
+
+ /* It works, insert a truncation or sign-change before the
+ float conversion. */
+ tem = make_ssa_name (build_nonstandard_integer_type
+ (GET_MODE_PRECISION (mode), 0), NULL);
+ conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
+ gsi_insert_before (gsi, conv, GSI_SAME_STMT);
+ gimple_assign_set_rhs1 (stmt, tem);
+ update_stmt (stmt);
+
+ return true;
+}
+
+/* Simplify an internal fn call using ranges if possible. */
+
+static bool
+simplify_internal_call_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
+{
+ enum tree_code subcode;
+ switch (gimple_call_internal_fn (stmt))
+ {
+ case IFN_UBSAN_CHECK_ADD:
+ subcode = PLUS_EXPR;
+ break;
+ case IFN_UBSAN_CHECK_SUB:
+ subcode = MINUS_EXPR;
+ break;
+ case IFN_UBSAN_CHECK_MUL:
+ subcode = MULT_EXPR;
+ break;
+ default:
+ return false;
+ }
+
+ value_range_t vr0 = VR_INITIALIZER;
+ value_range_t vr1 = VR_INITIALIZER;
+ tree op0 = gimple_call_arg (stmt, 0);
+ tree op1 = gimple_call_arg (stmt, 1);
+
+ if (TREE_CODE (op0) == SSA_NAME)
+ vr0 = *get_value_range (op0);
+ else if (TREE_CODE (op0) == INTEGER_CST)
+ set_value_range_to_value (&vr0, op0, NULL);
+ else
+ return false;
+
+ if (TREE_CODE (op1) == SSA_NAME)
+ vr1 = *get_value_range (op1);
+ else if (TREE_CODE (op1) == INTEGER_CST)
+ set_value_range_to_value (&vr1, op1, NULL);
+ else
+ return false;
+
+ if (!range_int_cst_p (&vr0) || !range_int_cst_p (&vr1))
+ return false;
+
+ tree r1 = int_const_binop (subcode, vr0.min, vr1.min);
+ tree r2 = int_const_binop (subcode, vr0.max, vr1.max);
+ if (r1 == NULL_TREE || TREE_OVERFLOW (r1)
+ || r2 == NULL_TREE || TREE_OVERFLOW (r2))
+ return false;
+ if (subcode == MULT_EXPR)
+ {
+ tree r3 = int_const_binop (subcode, vr0.min, vr1.max);
+ tree r4 = int_const_binop (subcode, vr0.max, vr1.min);
+ if (r3 == NULL_TREE || TREE_OVERFLOW (r3)
+ || r4 == NULL_TREE || TREE_OVERFLOW (r4))
+ return false;
+ }
+ gimple g = gimple_build_assign_with_ops (subcode, gimple_call_lhs (stmt),
+ op0, op1);
+ gsi_replace (gsi, g, false);
+ return true;
+}
+
+/* Simplify STMT using ranges if possible. */
+
+static bool
+simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
+{
+ gimple stmt = gsi_stmt (*gsi);
+ if (is_gimple_assign (stmt))
+ {
+ enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+
+ switch (rhs_code)
+ {
+ case EQ_EXPR:
+ case NE_EXPR:
+ /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
+ if the RHS is zero or one, and the LHS are known to be boolean
+ values. */
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
+ return simplify_truth_ops_using_ranges (gsi, stmt);
+ break;
+
+ /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
+ and BIT_AND_EXPR respectively if the first operand is greater
+ than zero and the second operand is an exact power of two. */
+ case TRUNC_DIV_EXPR:
+ case TRUNC_MOD_EXPR:
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
+ && integer_pow2p (gimple_assign_rhs2 (stmt)))
+ return simplify_div_or_mod_using_ranges (stmt);
+ break;
+
+ /* Transform ABS (X) into X or -X as appropriate. */
+ case ABS_EXPR:
+ if (TREE_CODE (rhs1) == SSA_NAME
+ && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
+ return simplify_abs_using_ranges (stmt);
+ break;
+
+ case BIT_AND_EXPR:
+ case BIT_IOR_EXPR:
+ /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
+ if all the bits being cleared are already cleared or
+ all the bits being set are already set. */
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
+ return simplify_bit_ops_using_ranges (gsi, stmt);
+ break;
+
+ CASE_CONVERT:
+ if (TREE_CODE (rhs1) == SSA_NAME
+ && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
+ return simplify_conversion_using_ranges (stmt);
+ break;
+
+ case FLOAT_EXPR:
+ if (TREE_CODE (rhs1) == SSA_NAME
+ && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
+ return simplify_float_conversion_using_ranges (gsi, stmt);
+ break;
+
+ default:
+ break;
+ }
+ }
+ else if (gimple_code (stmt) == GIMPLE_COND)
+ return simplify_cond_using_ranges (stmt);
+ else if (gimple_code (stmt) == GIMPLE_SWITCH)
+ return simplify_switch_using_ranges (stmt);
+ else if (is_gimple_call (stmt)
+ && gimple_call_internal_p (stmt))
+ return simplify_internal_call_using_ranges (gsi, stmt);
+
+ return false;
+}
+
+/* If the statement pointed by SI has a predicate whose value can be
+ computed using the value range information computed by VRP, compute
+ its value and return true. Otherwise, return false. */
+
+static bool
+fold_predicate_in (gimple_stmt_iterator *si)
+{
+ bool assignment_p = false;
+ tree val;
+ gimple stmt = gsi_stmt (*si);
+
+ if (is_gimple_assign (stmt)
+ && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
+ {
+ assignment_p = true;
+ val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt),
+ stmt);
+ }
+ else if (gimple_code (stmt) == GIMPLE_COND)
+ val = vrp_evaluate_conditional (gimple_cond_code (stmt),
+ gimple_cond_lhs (stmt),
+ gimple_cond_rhs (stmt),
+ stmt);
+ else
+ return false;
+
+ if (val)
+ {
+ if (assignment_p)
+ val = fold_convert (gimple_expr_type (stmt), val);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Folding predicate ");
+ print_gimple_expr (dump_file, stmt, 0, 0);
+ fprintf (dump_file, " to ");
+ print_generic_expr (dump_file, val, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ if (is_gimple_assign (stmt))
+ gimple_assign_set_rhs_from_tree (si, val);
+ else
+ {
+ gcc_assert (gimple_code (stmt) == GIMPLE_COND);
+ if (integer_zerop (val))
+ gimple_cond_make_false (stmt);
+ else if (integer_onep (val))
+ gimple_cond_make_true (stmt);
+ else
+ gcc_unreachable ();
+ }
+
+ return true;
+ }
+
+ return false;
+}
+
+/* Callback for substitute_and_fold folding the stmt at *SI. */
+
+static bool
+vrp_fold_stmt (gimple_stmt_iterator *si)
+{
+ if (fold_predicate_in (si))
+ return true;
+
+ return simplify_stmt_using_ranges (si);
+}
+
+/* Stack of dest,src equivalency pairs that need to be restored after
+ each attempt to thread a block's incoming edge to an outgoing edge.
+
+ A NULL entry is used to mark the end of pairs which need to be
+ restored. */
+static vec<tree> equiv_stack;
+
+/* A trivial wrapper so that we can present the generic jump threading
+ code with a simple API for simplifying statements. STMT is the
+ statement we want to simplify, WITHIN_STMT provides the location
+ for any overflow warnings. */
+
+static tree
+simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
+{
+ if (gimple_code (stmt) == GIMPLE_COND)
+ return vrp_evaluate_conditional (gimple_cond_code (stmt),
+ gimple_cond_lhs (stmt),
+ gimple_cond_rhs (stmt), within_stmt);
+
+ if (gimple_code (stmt) == GIMPLE_ASSIGN)
+ {
+ value_range_t new_vr = VR_INITIALIZER;
+ tree lhs = gimple_assign_lhs (stmt);
+
+ if (TREE_CODE (lhs) == SSA_NAME
+ && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ || POINTER_TYPE_P (TREE_TYPE (lhs))))
+ {
+ extract_range_from_assignment (&new_vr, stmt);
+ if (range_int_cst_singleton_p (&new_vr))
+ return new_vr.min;
+ }
+ }
+
+ return NULL_TREE;
+}
+
+/* Blocks which have more than one predecessor and more than
+ one successor present jump threading opportunities, i.e.,
+ when the block is reached from a specific predecessor, we
+ may be able to determine which of the outgoing edges will
+ be traversed. When this optimization applies, we are able
+ to avoid conditionals at runtime and we may expose secondary
+ optimization opportunities.
+
+ This routine is effectively a driver for the generic jump
+ threading code. It basically just presents the generic code
+ with edges that may be suitable for jump threading.
+
+ Unlike DOM, we do not iterate VRP if jump threading was successful.
+ While iterating may expose new opportunities for VRP, it is expected
+ those opportunities would be very limited and the compile time cost
+ to expose those opportunities would be significant.
+
+ As jump threading opportunities are discovered, they are registered
+ for later realization. */
+
+static void
+identify_jump_threads (void)
+{
+ basic_block bb;
+ gimple dummy;
+ int i;
+ edge e;
+
+ /* Ugh. When substituting values earlier in this pass we can
+ wipe the dominance information. So rebuild the dominator
+ information as we need it within the jump threading code. */
+ calculate_dominance_info (CDI_DOMINATORS);
+
+ /* We do not allow VRP information to be used for jump threading
+ across a back edge in the CFG. Otherwise it becomes too
+ difficult to avoid eliminating loop exit tests. Of course
+ EDGE_DFS_BACK is not accurate at this time so we have to
+ recompute it. */
+ mark_dfs_back_edges ();
+
+ /* Do not thread across edges we are about to remove. Just marking
+ them as EDGE_DFS_BACK will do. */
+ FOR_EACH_VEC_ELT (to_remove_edges, i, e)
+ e->flags |= EDGE_DFS_BACK;
+
+ /* Allocate our unwinder stack to unwind any temporary equivalences
+ that might be recorded. */
+ equiv_stack.create (20);
+
+ /* To avoid lots of silly node creation, we create a single
+ conditional and just modify it in-place when attempting to
+ thread jumps. */
+ dummy = gimple_build_cond (EQ_EXPR,
+ integer_zero_node, integer_zero_node,
+ NULL, NULL);
+
+ /* Walk through all the blocks finding those which present a
+ potential jump threading opportunity. We could set this up
+ as a dominator walker and record data during the walk, but
+ I doubt it's worth the effort for the classes of jump
+ threading opportunities we are trying to identify at this
+ point in compilation. */
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ gimple last;
+
+ /* If the generic jump threading code does not find this block
+ interesting, then there is nothing to do. */
+ if (! potentially_threadable_block (bb))
+ continue;
+
+ /* We only care about blocks ending in a COND_EXPR. While there
+ may be some value in handling SWITCH_EXPR here, I doubt it's
+ terribly important. */
+ last = gsi_stmt (gsi_last_bb (bb));
+
+ /* We're basically looking for a switch or any kind of conditional with
+ integral or pointer type arguments. Note the type of the second
+ argument will be the same as the first argument, so no need to
+ check it explicitly. */
+ if (gimple_code (last) == GIMPLE_SWITCH
+ || (gimple_code (last) == GIMPLE_COND
+ && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
+ && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
+ || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
+ && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
+ || is_gimple_min_invariant (gimple_cond_rhs (last)))))
+ {
+ edge_iterator ei;
+
+ /* We've got a block with multiple predecessors and multiple
+ successors which also ends in a suitable conditional or
+ switch statement. For each predecessor, see if we can thread
+ it to a specific successor. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ /* Do not thread across back edges or abnormal edges
+ in the CFG. */
+ if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
+ continue;
+
+ thread_across_edge (dummy, e, true, &equiv_stack,
+ simplify_stmt_for_jump_threading);
+ }
+ }
+ }
+
+ /* We do not actually update the CFG or SSA graphs at this point as
+ ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
+ handle ASSERT_EXPRs gracefully. */
+}
+
+/* We identified all the jump threading opportunities earlier, but could
+ not transform the CFG at that time. This routine transforms the
+ CFG and arranges for the dominator tree to be rebuilt if necessary.
+
+ Note the SSA graph update will occur during the normal TODO
+ processing by the pass manager. */
+static void
+finalize_jump_threads (void)
+{
+ thread_through_all_blocks (false);
+ equiv_stack.release ();
+}
+
+
+/* Traverse all the blocks folding conditionals with known ranges. */
+
+static void
+vrp_finalize (void)
+{
+ size_t i;
+
+ values_propagated = true;
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "\nValue ranges after VRP:\n\n");
+ dump_all_value_ranges (dump_file);
+ fprintf (dump_file, "\n");
+ }
+
+ substitute_and_fold (op_with_constant_singleton_value_range,
+ vrp_fold_stmt, false);
+
+ if (warn_array_bounds)
+ check_all_array_refs ();
+
+ /* We must identify jump threading opportunities before we release
+ the datastructures built by VRP. */
+ identify_jump_threads ();
+
+ /* Set value range to non pointer SSA_NAMEs. */
+ for (i = 0; i < num_vr_values; i++)
+ if (vr_value[i])
+ {
+ tree name = ssa_name (i);
+
+ if (!name
+ || POINTER_TYPE_P (TREE_TYPE (name))
+ || (vr_value[i]->type == VR_VARYING)
+ || (vr_value[i]->type == VR_UNDEFINED))
+ continue;
+
+ if ((TREE_CODE (vr_value[i]->min) == INTEGER_CST)
+ && (TREE_CODE (vr_value[i]->max) == INTEGER_CST)
+ && (vr_value[i]->type == VR_RANGE
+ || vr_value[i]->type == VR_ANTI_RANGE))
+ set_range_info (name, vr_value[i]->type,
+ tree_to_double_int (vr_value[i]->min),
+ tree_to_double_int (vr_value[i]->max));
+ }
+
+ /* Free allocated memory. */
+ for (i = 0; i < num_vr_values; i++)
+ if (vr_value[i])
+ {
+ BITMAP_FREE (vr_value[i]->equiv);
+ free (vr_value[i]);
+ }
+
+ free (vr_value);
+ free (vr_phi_edge_counts);
+
+ /* So that we can distinguish between VRP data being available
+ and not available. */
+ vr_value = NULL;
+ vr_phi_edge_counts = NULL;
+}
+
+
+/* Main entry point to VRP (Value Range Propagation). This pass is
+ loosely based on J. R. C. Patterson, ``Accurate Static Branch
+ Prediction by Value Range Propagation,'' in SIGPLAN Conference on
+ Programming Language Design and Implementation, pp. 67-78, 1995.
+ Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
+
+ This is essentially an SSA-CCP pass modified to deal with ranges
+ instead of constants.
+
+ While propagating ranges, we may find that two or more SSA name
+ have equivalent, though distinct ranges. For instance,
+
+ 1 x_9 = p_3->a;
+ 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
+ 3 if (p_4 == q_2)
+ 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
+ 5 endif
+ 6 if (q_2)
+
+ In the code above, pointer p_5 has range [q_2, q_2], but from the
+ code we can also determine that p_5 cannot be NULL and, if q_2 had
+ a non-varying range, p_5's range should also be compatible with it.
+
+ These equivalences are created by two expressions: ASSERT_EXPR and
+ copy operations. Since p_5 is an assertion on p_4, and p_4 was the
+ result of another assertion, then we can use the fact that p_5 and
+ p_4 are equivalent when evaluating p_5's range.
+
+ Together with value ranges, we also propagate these equivalences
+ between names so that we can take advantage of information from
+ multiple ranges when doing final replacement. Note that this
+ equivalency relation is transitive but not symmetric.
+
+ In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
+ cannot assert that q_2 is equivalent to p_5 because q_2 may be used
+ in contexts where that assertion does not hold (e.g., in line 6).
+
+ TODO, the main difference between this pass and Patterson's is that
+ we do not propagate edge probabilities. We only compute whether
+ edges can be taken or not. That is, instead of having a spectrum
+ of jump probabilities between 0 and 1, we only deal with 0, 1 and
+ DON'T KNOW. In the future, it may be worthwhile to propagate
+ probabilities to aid branch prediction. */
+
+static unsigned int
+execute_vrp (void)
+{
+ int i;
+ edge e;
+ switch_update *su;
+
+ loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
+ rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
+ scev_initialize ();
+
+ /* ??? This ends up using stale EDGE_DFS_BACK for liveness computation.
+ Inserting assertions may split edges which will invalidate
+ EDGE_DFS_BACK. */
+ insert_range_assertions ();
+
+ to_remove_edges.create (10);
+ to_update_switch_stmts.create (5);
+ threadedge_initialize_values ();
+
+ /* For visiting PHI nodes we need EDGE_DFS_BACK computed. */
+ mark_dfs_back_edges ();
+
+ vrp_initialize ();
+ ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
+ vrp_finalize ();
+
+ free_numbers_of_iterations_estimates ();
+
+ /* ASSERT_EXPRs must be removed before finalizing jump threads
+ as finalizing jump threads calls the CFG cleanup code which
+ does not properly handle ASSERT_EXPRs. */
+ remove_range_assertions ();
+
+ /* If we exposed any new variables, go ahead and put them into
+ SSA form now, before we handle jump threading. This simplifies
+ interactions between rewriting of _DECL nodes into SSA form
+ and rewriting SSA_NAME nodes into SSA form after block
+ duplication and CFG manipulation. */
+ update_ssa (TODO_update_ssa);
+
+ finalize_jump_threads ();
+
+ /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
+ CFG in a broken state and requires a cfg_cleanup run. */
+ FOR_EACH_VEC_ELT (to_remove_edges, i, e)
+ remove_edge (e);
+ /* Update SWITCH_EXPR case label vector. */
+ FOR_EACH_VEC_ELT (to_update_switch_stmts, i, su)
+ {
+ size_t j;
+ size_t n = TREE_VEC_LENGTH (su->vec);
+ tree label;
+ gimple_switch_set_num_labels (su->stmt, n);
+ for (j = 0; j < n; j++)
+ gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
+ /* As we may have replaced the default label with a regular one
+ make sure to make it a real default label again. This ensures
+ optimal expansion. */
+ label = gimple_switch_label (su->stmt, 0);
+ CASE_LOW (label) = NULL_TREE;
+ CASE_HIGH (label) = NULL_TREE;
+ }
+
+ if (to_remove_edges.length () > 0)
+ {
+ free_dominance_info (CDI_DOMINATORS);
+ if (current_loops)
+ loops_state_set (LOOPS_NEED_FIXUP);
+ }
+
+ to_remove_edges.release ();
+ to_update_switch_stmts.release ();
+ threadedge_finalize_values ();
+
+ scev_finalize ();
+ loop_optimizer_finalize ();
+ return 0;
+}
+
+static bool
+gate_vrp (void)
+{
+ return flag_tree_vrp != 0;
+}
+
+namespace {
+
+const pass_data pass_data_vrp =
+{
+ GIMPLE_PASS, /* type */
+ "vrp", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ true, /* has_gate */
+ true, /* has_execute */
+ TV_TREE_VRP, /* tv_id */
+ PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ ( TODO_cleanup_cfg | TODO_update_ssa
+ | TODO_verify_ssa
+ | TODO_verify_flow ), /* todo_flags_finish */
+};
+
+class pass_vrp : public gimple_opt_pass
+{
+public:
+ pass_vrp (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_vrp, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ opt_pass * clone () { return new pass_vrp (m_ctxt); }
+ bool gate () { return gate_vrp (); }
+ unsigned int execute () { return execute_vrp (); }
+
+}; // class pass_vrp
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_vrp (gcc::context *ctxt)
+{
+ return new pass_vrp (ctxt);
+}