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author | Ben Cheng <bccheng@google.com> | 2013-03-28 11:14:20 -0700 |
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committer | Ben Cheng <bccheng@google.com> | 2013-03-28 12:40:33 -0700 |
commit | af0c51ac87ab2a87caa03fa108f0d164987a2764 (patch) | |
tree | 4b8b470f7c5b69642fdab8d0aa1fbc148d02196b /gcc-4.8/gcc/gimple-fold.c | |
parent | d87cae247d39ebf4f5a6bf25c932a14d2fdb9384 (diff) | |
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[GCC 4.8] Initial check-in of GCC 4.8.0
Change-Id: I0719d8a6d0f69b367a6ab6f10eb75622dbf12771
Diffstat (limited to 'gcc-4.8/gcc/gimple-fold.c')
-rw-r--r-- | gcc-4.8/gcc/gimple-fold.c | 3283 |
1 files changed, 3283 insertions, 0 deletions
diff --git a/gcc-4.8/gcc/gimple-fold.c b/gcc-4.8/gcc/gimple-fold.c new file mode 100644 index 000000000..b9211a9ad --- /dev/null +++ b/gcc-4.8/gcc/gimple-fold.c @@ -0,0 +1,3283 @@ +/* Statement simplification on GIMPLE. + Copyright (C) 2010-2013 Free Software Foundation, Inc. + Split out from tree-ssa-ccp.c. + +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 "tree.h" +#include "flags.h" +#include "function.h" +#include "dumpfile.h" +#include "tree-flow.h" +#include "tree-ssa-propagate.h" +#include "target.h" +#include "gimple-fold.h" + +/* Return true when DECL can be referenced from current unit. + FROM_DECL (if non-null) specify constructor of variable DECL was taken from. + We can get declarations that are not possible to reference for various + reasons: + + 1) When analyzing C++ virtual tables. + C++ virtual tables do have known constructors even + when they are keyed to other compilation unit. + Those tables can contain pointers to methods and vars + in other units. Those methods have both STATIC and EXTERNAL + set. + 2) In WHOPR mode devirtualization might lead to reference + to method that was partitioned elsehwere. + In this case we have static VAR_DECL or FUNCTION_DECL + that has no corresponding callgraph/varpool node + declaring the body. + 3) COMDAT functions referred by external vtables that + we devirtualize only during final copmilation stage. + At this time we already decided that we will not output + the function body and thus we can't reference the symbol + directly. */ + +static bool +can_refer_decl_in_current_unit_p (tree decl, tree from_decl) +{ + struct varpool_node *vnode; + struct cgraph_node *node; + symtab_node snode; + + /* We will later output the initializer, so we can refer to it. + So we are concerned only when DECL comes from initializer of + external var. */ + if (!from_decl + || TREE_CODE (from_decl) != VAR_DECL + || !DECL_EXTERNAL (from_decl) + || (flag_ltrans + && symtab_get_node (from_decl)->symbol.in_other_partition)) + return true; + /* We are concerned only about static/external vars and functions. */ + if ((!TREE_STATIC (decl) && !DECL_EXTERNAL (decl)) + || (TREE_CODE (decl) != VAR_DECL && TREE_CODE (decl) != FUNCTION_DECL)) + return true; + /* Weakrefs have somewhat confusing DECL_EXTERNAL flag set; they + are always safe. */ + if (DECL_EXTERNAL (decl) + && lookup_attribute ("weakref", DECL_ATTRIBUTES (decl))) + return true; + /* We are folding reference from external vtable. The vtable may reffer + to a symbol keyed to other compilation unit. The other compilation + unit may be in separate DSO and the symbol may be hidden. */ + if (DECL_VISIBILITY_SPECIFIED (decl) + && DECL_EXTERNAL (decl) + && (!(snode = symtab_get_node (decl)) || !snode->symbol.in_other_partition)) + return false; + /* When function is public, we always can introduce new reference. + Exception are the COMDAT functions where introducing a direct + reference imply need to include function body in the curren tunit. */ + if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl)) + return true; + /* We are not at ltrans stage; so don't worry about WHOPR. + Also when still gimplifying all referred comdat functions will be + produced. + + As observed in PR20991 for already optimized out comdat virtual functions + it may be tempting to not necessarily give up because the copy will be + output elsewhere when corresponding vtable is output. + This is however not possible - ABI specify that COMDATs are output in + units where they are used and when the other unit was compiled with LTO + it is possible that vtable was kept public while the function itself + was privatized. */ + if (!flag_ltrans && (!DECL_COMDAT (decl) || !cgraph_function_flags_ready)) + return true; + + /* OK we are seeing either COMDAT or static variable. In this case we must + check that the definition is still around so we can refer it. */ + if (TREE_CODE (decl) == FUNCTION_DECL) + { + node = cgraph_get_node (decl); + /* Check that we still have function body and that we didn't took + the decision to eliminate offline copy of the function yet. + The second is important when devirtualization happens during final + compilation stage when making a new reference no longer makes callee + to be compiled. */ + if (!node || !node->analyzed || node->global.inlined_to) + { + gcc_checking_assert (!TREE_ASM_WRITTEN (decl)); + return false; + } + } + else if (TREE_CODE (decl) == VAR_DECL) + { + vnode = varpool_get_node (decl); + if (!vnode || !vnode->analyzed) + { + gcc_checking_assert (!TREE_ASM_WRITTEN (decl)); + return false; + } + } + return true; +} + +/* CVAL is value taken from DECL_INITIAL of variable. Try to transform it into + acceptable form for is_gimple_min_invariant. + FROM_DECL (if non-NULL) specify variable whose constructor contains CVAL. */ + +tree +canonicalize_constructor_val (tree cval, tree from_decl) +{ + tree orig_cval = cval; + STRIP_NOPS (cval); + if (TREE_CODE (cval) == POINTER_PLUS_EXPR + && TREE_CODE (TREE_OPERAND (cval, 1)) == INTEGER_CST) + { + tree ptr = TREE_OPERAND (cval, 0); + if (is_gimple_min_invariant (ptr)) + cval = build1_loc (EXPR_LOCATION (cval), + ADDR_EXPR, TREE_TYPE (ptr), + fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (ptr)), + ptr, + fold_convert (ptr_type_node, + TREE_OPERAND (cval, 1)))); + } + if (TREE_CODE (cval) == ADDR_EXPR) + { + tree base = NULL_TREE; + if (TREE_CODE (TREE_OPERAND (cval, 0)) == COMPOUND_LITERAL_EXPR) + { + base = COMPOUND_LITERAL_EXPR_DECL (TREE_OPERAND (cval, 0)); + if (base) + TREE_OPERAND (cval, 0) = base; + } + else + base = get_base_address (TREE_OPERAND (cval, 0)); + if (!base) + return NULL_TREE; + + if ((TREE_CODE (base) == VAR_DECL + || TREE_CODE (base) == FUNCTION_DECL) + && !can_refer_decl_in_current_unit_p (base, from_decl)) + return NULL_TREE; + if (TREE_CODE (base) == VAR_DECL) + TREE_ADDRESSABLE (base) = 1; + else if (TREE_CODE (base) == FUNCTION_DECL) + { + /* Make sure we create a cgraph node for functions we'll reference. + They can be non-existent if the reference comes from an entry + of an external vtable for example. */ + cgraph_get_create_node (base); + } + /* Fixup types in global initializers. */ + if (TREE_TYPE (TREE_TYPE (cval)) != TREE_TYPE (TREE_OPERAND (cval, 0))) + cval = build_fold_addr_expr (TREE_OPERAND (cval, 0)); + + if (!useless_type_conversion_p (TREE_TYPE (orig_cval), TREE_TYPE (cval))) + cval = fold_convert (TREE_TYPE (orig_cval), cval); + return cval; + } + return orig_cval; +} + +/* If SYM is a constant variable with known value, return the value. + NULL_TREE is returned otherwise. */ + +tree +get_symbol_constant_value (tree sym) +{ + if (const_value_known_p (sym)) + { + tree val = DECL_INITIAL (sym); + if (val) + { + val = canonicalize_constructor_val (unshare_expr (val), sym); + if (val && is_gimple_min_invariant (val)) + return val; + else + return NULL_TREE; + } + /* Variables declared 'const' without an initializer + have zero as the initializer if they may not be + overridden at link or run time. */ + if (!val + && (INTEGRAL_TYPE_P (TREE_TYPE (sym)) + || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym)))) + return build_zero_cst (TREE_TYPE (sym)); + } + + return NULL_TREE; +} + + + +/* Subroutine of fold_stmt. We perform several simplifications of the + memory reference tree EXPR and make sure to re-gimplify them properly + after propagation of constant addresses. IS_LHS is true if the + reference is supposed to be an lvalue. */ + +static tree +maybe_fold_reference (tree expr, bool is_lhs) +{ + tree *t = &expr; + tree result; + + if ((TREE_CODE (expr) == VIEW_CONVERT_EXPR + || TREE_CODE (expr) == REALPART_EXPR + || TREE_CODE (expr) == IMAGPART_EXPR) + && CONSTANT_CLASS_P (TREE_OPERAND (expr, 0))) + return fold_unary_loc (EXPR_LOCATION (expr), + TREE_CODE (expr), + TREE_TYPE (expr), + TREE_OPERAND (expr, 0)); + else if (TREE_CODE (expr) == BIT_FIELD_REF + && CONSTANT_CLASS_P (TREE_OPERAND (expr, 0))) + return fold_ternary_loc (EXPR_LOCATION (expr), + TREE_CODE (expr), + TREE_TYPE (expr), + TREE_OPERAND (expr, 0), + TREE_OPERAND (expr, 1), + TREE_OPERAND (expr, 2)); + + while (handled_component_p (*t)) + t = &TREE_OPERAND (*t, 0); + + /* Canonicalize MEM_REFs invariant address operand. Do this first + to avoid feeding non-canonical MEM_REFs elsewhere. */ + if (TREE_CODE (*t) == MEM_REF + && !is_gimple_mem_ref_addr (TREE_OPERAND (*t, 0))) + { + bool volatile_p = TREE_THIS_VOLATILE (*t); + tree tem = fold_binary (MEM_REF, TREE_TYPE (*t), + TREE_OPERAND (*t, 0), + TREE_OPERAND (*t, 1)); + if (tem) + { + TREE_THIS_VOLATILE (tem) = volatile_p; + *t = tem; + tem = maybe_fold_reference (expr, is_lhs); + if (tem) + return tem; + return expr; + } + } + + if (!is_lhs + && (result = fold_const_aggregate_ref (expr)) + && is_gimple_min_invariant (result)) + return result; + + /* Fold back MEM_REFs to reference trees. */ + if (TREE_CODE (*t) == MEM_REF + && TREE_CODE (TREE_OPERAND (*t, 0)) == ADDR_EXPR + && integer_zerop (TREE_OPERAND (*t, 1)) + && (TREE_THIS_VOLATILE (*t) + == TREE_THIS_VOLATILE (TREE_OPERAND (TREE_OPERAND (*t, 0), 0))) + && !TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (TREE_OPERAND (*t, 1))) + && (TYPE_MAIN_VARIANT (TREE_TYPE (*t)) + == TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (TREE_OPERAND (*t, 1))))) + /* We have to look out here to not drop a required conversion + from the rhs to the lhs if is_lhs, but we don't have the + rhs here to verify that. Thus require strict type + compatibility. */ + && types_compatible_p (TREE_TYPE (*t), + TREE_TYPE (TREE_OPERAND + (TREE_OPERAND (*t, 0), 0)))) + { + tree tem; + *t = TREE_OPERAND (TREE_OPERAND (*t, 0), 0); + tem = maybe_fold_reference (expr, is_lhs); + if (tem) + return tem; + return expr; + } + else if (TREE_CODE (*t) == TARGET_MEM_REF) + { + tree tem = maybe_fold_tmr (*t); + if (tem) + { + *t = tem; + tem = maybe_fold_reference (expr, is_lhs); + if (tem) + return tem; + return expr; + } + } + + return NULL_TREE; +} + + +/* Attempt to fold an assignment statement pointed-to by SI. Returns a + replacement rhs for the statement or NULL_TREE if no simplification + could be made. It is assumed that the operands have been previously + folded. */ + +static tree +fold_gimple_assign (gimple_stmt_iterator *si) +{ + gimple stmt = gsi_stmt (*si); + enum tree_code subcode = gimple_assign_rhs_code (stmt); + location_t loc = gimple_location (stmt); + + tree result = NULL_TREE; + + switch (get_gimple_rhs_class (subcode)) + { + case GIMPLE_SINGLE_RHS: + { + tree rhs = gimple_assign_rhs1 (stmt); + + if (REFERENCE_CLASS_P (rhs)) + return maybe_fold_reference (rhs, false); + + else if (TREE_CODE (rhs) == ADDR_EXPR) + { + tree ref = TREE_OPERAND (rhs, 0); + tree tem = maybe_fold_reference (ref, true); + if (tem + && TREE_CODE (tem) == MEM_REF + && integer_zerop (TREE_OPERAND (tem, 1))) + result = fold_convert (TREE_TYPE (rhs), TREE_OPERAND (tem, 0)); + else if (tem) + result = fold_convert (TREE_TYPE (rhs), + build_fold_addr_expr_loc (loc, tem)); + else if (TREE_CODE (ref) == MEM_REF + && integer_zerop (TREE_OPERAND (ref, 1))) + result = fold_convert (TREE_TYPE (rhs), TREE_OPERAND (ref, 0)); + } + + else if (TREE_CODE (rhs) == CONSTRUCTOR + && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE + && (CONSTRUCTOR_NELTS (rhs) + == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs)))) + { + /* Fold a constant vector CONSTRUCTOR to VECTOR_CST. */ + unsigned i; + tree val; + + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val) + if (TREE_CODE (val) != INTEGER_CST + && TREE_CODE (val) != REAL_CST + && TREE_CODE (val) != FIXED_CST) + return NULL_TREE; + + return build_vector_from_ctor (TREE_TYPE (rhs), + CONSTRUCTOR_ELTS (rhs)); + } + + else if (DECL_P (rhs)) + return get_symbol_constant_value (rhs); + + /* If we couldn't fold the RHS, hand over to the generic + fold routines. */ + if (result == NULL_TREE) + result = fold (rhs); + + /* Strip away useless type conversions. Both the NON_LVALUE_EXPR + that may have been added by fold, and "useless" type + conversions that might now be apparent due to propagation. */ + STRIP_USELESS_TYPE_CONVERSION (result); + + if (result != rhs && valid_gimple_rhs_p (result)) + return result; + + return NULL_TREE; + } + break; + + case GIMPLE_UNARY_RHS: + { + tree rhs = gimple_assign_rhs1 (stmt); + + result = fold_unary_loc (loc, subcode, gimple_expr_type (stmt), rhs); + if (result) + { + /* If the operation was a conversion do _not_ mark a + resulting constant with TREE_OVERFLOW if the original + constant was not. These conversions have implementation + defined behavior and retaining the TREE_OVERFLOW flag + here would confuse later passes such as VRP. */ + if (CONVERT_EXPR_CODE_P (subcode) + && TREE_CODE (result) == INTEGER_CST + && TREE_CODE (rhs) == INTEGER_CST) + TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs); + + STRIP_USELESS_TYPE_CONVERSION (result); + if (valid_gimple_rhs_p (result)) + return result; + } + } + break; + + case GIMPLE_BINARY_RHS: + /* Try to canonicalize for boolean-typed X the comparisons + X == 0, X == 1, X != 0, and X != 1. */ + if (gimple_assign_rhs_code (stmt) == EQ_EXPR + || gimple_assign_rhs_code (stmt) == NE_EXPR) + { + tree lhs = gimple_assign_lhs (stmt); + tree op1 = gimple_assign_rhs1 (stmt); + tree op2 = gimple_assign_rhs2 (stmt); + tree type = TREE_TYPE (op1); + + /* Check whether the comparison operands are of the same boolean + type as the result type is. + Check that second operand is an integer-constant with value + one or zero. */ + if (TREE_CODE (op2) == INTEGER_CST + && (integer_zerop (op2) || integer_onep (op2)) + && useless_type_conversion_p (TREE_TYPE (lhs), type)) + { + enum tree_code cmp_code = gimple_assign_rhs_code (stmt); + bool is_logical_not = false; + + /* X == 0 and X != 1 is a logical-not.of X + X == 1 and X != 0 is X */ + if ((cmp_code == EQ_EXPR && integer_zerop (op2)) + || (cmp_code == NE_EXPR && integer_onep (op2))) + is_logical_not = true; + + if (is_logical_not == false) + result = op1; + /* Only for one-bit precision typed X the transformation + !X -> ~X is valied. */ + else if (TYPE_PRECISION (type) == 1) + result = build1_loc (gimple_location (stmt), BIT_NOT_EXPR, + type, op1); + /* Otherwise we use !X -> X ^ 1. */ + else + result = build2_loc (gimple_location (stmt), BIT_XOR_EXPR, + type, op1, build_int_cst (type, 1)); + + } + } + + if (!result) + result = fold_binary_loc (loc, subcode, + TREE_TYPE (gimple_assign_lhs (stmt)), + gimple_assign_rhs1 (stmt), + gimple_assign_rhs2 (stmt)); + + if (result) + { + STRIP_USELESS_TYPE_CONVERSION (result); + if (valid_gimple_rhs_p (result)) + return result; + } + break; + + case GIMPLE_TERNARY_RHS: + /* Try to fold a conditional expression. */ + if (gimple_assign_rhs_code (stmt) == COND_EXPR) + { + tree op0 = gimple_assign_rhs1 (stmt); + tree tem; + bool set = false; + location_t cond_loc = gimple_location (stmt); + + if (COMPARISON_CLASS_P (op0)) + { + fold_defer_overflow_warnings (); + tem = fold_binary_loc (cond_loc, + TREE_CODE (op0), TREE_TYPE (op0), + TREE_OPERAND (op0, 0), + TREE_OPERAND (op0, 1)); + /* This is actually a conditional expression, not a GIMPLE + conditional statement, however, the valid_gimple_rhs_p + test still applies. */ + set = (tem && is_gimple_condexpr (tem) + && valid_gimple_rhs_p (tem)); + fold_undefer_overflow_warnings (set, stmt, 0); + } + else if (is_gimple_min_invariant (op0)) + { + tem = op0; + set = true; + } + else + return NULL_TREE; + + if (set) + result = fold_build3_loc (cond_loc, COND_EXPR, + TREE_TYPE (gimple_assign_lhs (stmt)), tem, + gimple_assign_rhs2 (stmt), + gimple_assign_rhs3 (stmt)); + } + + if (!result) + result = fold_ternary_loc (loc, subcode, + TREE_TYPE (gimple_assign_lhs (stmt)), + gimple_assign_rhs1 (stmt), + gimple_assign_rhs2 (stmt), + gimple_assign_rhs3 (stmt)); + + if (result) + { + STRIP_USELESS_TYPE_CONVERSION (result); + if (valid_gimple_rhs_p (result)) + return result; + } + break; + + case GIMPLE_INVALID_RHS: + gcc_unreachable (); + } + + return NULL_TREE; +} + +/* Attempt to fold a conditional statement. Return true if any changes were + made. We only attempt to fold the condition expression, and do not perform + any transformation that would require alteration of the cfg. It is + assumed that the operands have been previously folded. */ + +static bool +fold_gimple_cond (gimple stmt) +{ + tree result = fold_binary_loc (gimple_location (stmt), + gimple_cond_code (stmt), + boolean_type_node, + gimple_cond_lhs (stmt), + gimple_cond_rhs (stmt)); + + if (result) + { + STRIP_USELESS_TYPE_CONVERSION (result); + if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result)) + { + gimple_cond_set_condition_from_tree (stmt, result); + return true; + } + } + + return false; +} + +/* Convert EXPR into a GIMPLE value suitable for substitution on the + RHS of an assignment. Insert the necessary statements before + iterator *SI_P. The statement at *SI_P, which must be a GIMPLE_CALL + is replaced. If the call is expected to produces a result, then it + is replaced by an assignment of the new RHS to the result variable. + If the result is to be ignored, then the call is replaced by a + GIMPLE_NOP. A proper VDEF chain is retained by making the first + VUSE and the last VDEF of the whole sequence be the same as the replaced + statement and using new SSA names for stores in between. */ + +void +gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr) +{ + tree lhs; + gimple stmt, new_stmt; + gimple_stmt_iterator i; + gimple_seq stmts = NULL; + struct gimplify_ctx gctx; + gimple laststore; + tree reaching_vuse; + + stmt = gsi_stmt (*si_p); + + gcc_assert (is_gimple_call (stmt)); + + push_gimplify_context (&gctx); + gctx.into_ssa = gimple_in_ssa_p (cfun); + + lhs = gimple_call_lhs (stmt); + if (lhs == NULL_TREE) + { + gimplify_and_add (expr, &stmts); + /* We can end up with folding a memcpy of an empty class assignment + which gets optimized away by C++ gimplification. */ + if (gimple_seq_empty_p (stmts)) + { + pop_gimplify_context (NULL); + if (gimple_in_ssa_p (cfun)) + { + unlink_stmt_vdef (stmt); + release_defs (stmt); + } + gsi_replace (si_p, gimple_build_nop (), true); + return; + } + } + else + { + tree tmp = get_initialized_tmp_var (expr, &stmts, NULL); + new_stmt = gimple_build_assign (lhs, tmp); + i = gsi_last (stmts); + gsi_insert_after_without_update (&i, new_stmt, + GSI_CONTINUE_LINKING); + } + + pop_gimplify_context (NULL); + + if (gimple_has_location (stmt)) + annotate_all_with_location (stmts, gimple_location (stmt)); + + /* First iterate over the replacement statements backward, assigning + virtual operands to their defining statements. */ + laststore = NULL; + for (i = gsi_last (stmts); !gsi_end_p (i); gsi_prev (&i)) + { + new_stmt = gsi_stmt (i); + if ((gimple_assign_single_p (new_stmt) + && !is_gimple_reg (gimple_assign_lhs (new_stmt))) + || (is_gimple_call (new_stmt) + && (gimple_call_flags (new_stmt) + & (ECF_NOVOPS | ECF_PURE | ECF_CONST | ECF_NORETURN)) == 0)) + { + tree vdef; + if (!laststore) + vdef = gimple_vdef (stmt); + else + vdef = make_ssa_name (gimple_vop (cfun), new_stmt); + gimple_set_vdef (new_stmt, vdef); + if (vdef && TREE_CODE (vdef) == SSA_NAME) + SSA_NAME_DEF_STMT (vdef) = new_stmt; + laststore = new_stmt; + } + } + + /* Second iterate over the statements forward, assigning virtual + operands to their uses. */ + reaching_vuse = gimple_vuse (stmt); + for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i)) + { + new_stmt = gsi_stmt (i); + /* If the new statement possibly has a VUSE, update it with exact SSA + name we know will reach this one. */ + if (gimple_has_mem_ops (new_stmt)) + gimple_set_vuse (new_stmt, reaching_vuse); + gimple_set_modified (new_stmt, true); + if (gimple_vdef (new_stmt)) + reaching_vuse = gimple_vdef (new_stmt); + } + + /* If the new sequence does not do a store release the virtual + definition of the original statement. */ + if (reaching_vuse + && reaching_vuse == gimple_vuse (stmt)) + { + tree vdef = gimple_vdef (stmt); + if (vdef + && TREE_CODE (vdef) == SSA_NAME) + { + unlink_stmt_vdef (stmt); + release_ssa_name (vdef); + } + } + + /* Finally replace the original statement with the sequence. */ + gsi_replace_with_seq (si_p, stmts, false); +} + +/* Return the string length, maximum string length or maximum value of + ARG in LENGTH. + If ARG is an SSA name variable, follow its use-def chains. If LENGTH + is not NULL and, for TYPE == 0, its value is not equal to the length + we determine or if we are unable to determine the length or value, + return false. VISITED is a bitmap of visited variables. + TYPE is 0 if string length should be returned, 1 for maximum string + length and 2 for maximum value ARG can have. */ + +static bool +get_maxval_strlen (tree arg, tree *length, bitmap visited, int type) +{ + tree var, val; + gimple def_stmt; + + if (TREE_CODE (arg) != SSA_NAME) + { + /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */ + if (TREE_CODE (arg) == ADDR_EXPR + && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF + && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1))) + { + tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0); + if (TREE_CODE (aop0) == INDIRECT_REF + && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME) + return get_maxval_strlen (TREE_OPERAND (aop0, 0), + length, visited, type); + } + + if (type == 2) + { + val = arg; + if (TREE_CODE (val) != INTEGER_CST + || tree_int_cst_sgn (val) < 0) + return false; + } + else + val = c_strlen (arg, 1); + if (!val) + return false; + + if (*length) + { + if (type > 0) + { + if (TREE_CODE (*length) != INTEGER_CST + || TREE_CODE (val) != INTEGER_CST) + return false; + + if (tree_int_cst_lt (*length, val)) + *length = val; + return true; + } + else if (simple_cst_equal (val, *length) != 1) + return false; + } + + *length = val; + return true; + } + + /* If ARG is registered for SSA update we cannot look at its defining + statement. */ + if (name_registered_for_update_p (arg)) + return false; + + /* If we were already here, break the infinite cycle. */ + if (!bitmap_set_bit (visited, SSA_NAME_VERSION (arg))) + return true; + + var = arg; + def_stmt = SSA_NAME_DEF_STMT (var); + + switch (gimple_code (def_stmt)) + { + case GIMPLE_ASSIGN: + /* The RHS of the statement defining VAR must either have a + constant length or come from another SSA_NAME with a constant + length. */ + if (gimple_assign_single_p (def_stmt) + || gimple_assign_unary_nop_p (def_stmt)) + { + tree rhs = gimple_assign_rhs1 (def_stmt); + return get_maxval_strlen (rhs, length, visited, type); + } + else if (gimple_assign_rhs_code (def_stmt) == COND_EXPR) + { + tree op2 = gimple_assign_rhs2 (def_stmt); + tree op3 = gimple_assign_rhs3 (def_stmt); + return get_maxval_strlen (op2, length, visited, type) + && get_maxval_strlen (op3, length, visited, type); + } + return false; + + case GIMPLE_PHI: + { + /* All the arguments of the PHI node must have the same constant + length. */ + unsigned i; + + for (i = 0; i < gimple_phi_num_args (def_stmt); i++) + { + tree arg = gimple_phi_arg (def_stmt, i)->def; + + /* If this PHI has itself as an argument, we cannot + determine the string length of this argument. However, + if we can find a constant string length for the other + PHI args then we can still be sure that this is a + constant string length. So be optimistic and just + continue with the next argument. */ + if (arg == gimple_phi_result (def_stmt)) + continue; + + if (!get_maxval_strlen (arg, length, visited, type)) + return false; + } + } + return true; + + default: + return false; + } +} + + +/* Fold builtin call in statement STMT. Returns a simplified tree. + We may return a non-constant expression, including another call + to a different function and with different arguments, e.g., + substituting memcpy for strcpy when the string length is known. + Note that some builtins expand into inline code that may not + be valid in GIMPLE. Callers must take care. */ + +tree +gimple_fold_builtin (gimple stmt) +{ + tree result, val[3]; + tree callee, a; + int arg_idx, type; + bitmap visited; + bool ignore; + int nargs; + location_t loc = gimple_location (stmt); + + gcc_assert (is_gimple_call (stmt)); + + ignore = (gimple_call_lhs (stmt) == NULL); + + /* First try the generic builtin folder. If that succeeds, return the + result directly. */ + result = fold_call_stmt (stmt, ignore); + if (result) + { + if (ignore) + STRIP_NOPS (result); + return result; + } + + /* Ignore MD builtins. */ + callee = gimple_call_fndecl (stmt); + if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD) + return NULL_TREE; + + /* Give up for always_inline inline builtins until they are + inlined. */ + if (avoid_folding_inline_builtin (callee)) + return NULL_TREE; + + /* If the builtin could not be folded, and it has no argument list, + we're done. */ + nargs = gimple_call_num_args (stmt); + if (nargs == 0) + return NULL_TREE; + + /* Limit the work only for builtins we know how to simplify. */ + switch (DECL_FUNCTION_CODE (callee)) + { + case BUILT_IN_STRLEN: + case BUILT_IN_FPUTS: + case BUILT_IN_FPUTS_UNLOCKED: + arg_idx = 0; + type = 0; + break; + case BUILT_IN_STRCPY: + case BUILT_IN_STRNCPY: + arg_idx = 1; + type = 0; + break; + case BUILT_IN_MEMCPY_CHK: + case BUILT_IN_MEMPCPY_CHK: + case BUILT_IN_MEMMOVE_CHK: + case BUILT_IN_MEMSET_CHK: + case BUILT_IN_STRNCPY_CHK: + case BUILT_IN_STPNCPY_CHK: + arg_idx = 2; + type = 2; + break; + case BUILT_IN_STRCPY_CHK: + case BUILT_IN_STPCPY_CHK: + arg_idx = 1; + type = 1; + break; + case BUILT_IN_SNPRINTF_CHK: + case BUILT_IN_VSNPRINTF_CHK: + arg_idx = 1; + type = 2; + break; + default: + return NULL_TREE; + } + + if (arg_idx >= nargs) + return NULL_TREE; + + /* Try to use the dataflow information gathered by the CCP process. */ + visited = BITMAP_ALLOC (NULL); + bitmap_clear (visited); + + memset (val, 0, sizeof (val)); + a = gimple_call_arg (stmt, arg_idx); + if (!get_maxval_strlen (a, &val[arg_idx], visited, type)) + val[arg_idx] = NULL_TREE; + + BITMAP_FREE (visited); + + result = NULL_TREE; + switch (DECL_FUNCTION_CODE (callee)) + { + case BUILT_IN_STRLEN: + if (val[0] && nargs == 1) + { + tree new_val = + fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]); + + /* If the result is not a valid gimple value, or not a cast + of a valid gimple value, then we cannot use the result. */ + if (is_gimple_val (new_val) + || (CONVERT_EXPR_P (new_val) + && is_gimple_val (TREE_OPERAND (new_val, 0)))) + return new_val; + } + break; + + case BUILT_IN_STRCPY: + if (val[1] && is_gimple_val (val[1]) && nargs == 2) + result = fold_builtin_strcpy (loc, callee, + gimple_call_arg (stmt, 0), + gimple_call_arg (stmt, 1), + val[1]); + break; + + case BUILT_IN_STRNCPY: + if (val[1] && is_gimple_val (val[1]) && nargs == 3) + result = fold_builtin_strncpy (loc, callee, + gimple_call_arg (stmt, 0), + gimple_call_arg (stmt, 1), + gimple_call_arg (stmt, 2), + val[1]); + break; + + case BUILT_IN_FPUTS: + if (nargs == 2) + result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0), + gimple_call_arg (stmt, 1), + ignore, false, val[0]); + break; + + case BUILT_IN_FPUTS_UNLOCKED: + if (nargs == 2) + result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0), + gimple_call_arg (stmt, 1), + ignore, true, val[0]); + break; + + case BUILT_IN_MEMCPY_CHK: + case BUILT_IN_MEMPCPY_CHK: + case BUILT_IN_MEMMOVE_CHK: + case BUILT_IN_MEMSET_CHK: + if (val[2] && is_gimple_val (val[2]) && nargs == 4) + result = fold_builtin_memory_chk (loc, callee, + gimple_call_arg (stmt, 0), + gimple_call_arg (stmt, 1), + gimple_call_arg (stmt, 2), + gimple_call_arg (stmt, 3), + val[2], ignore, + DECL_FUNCTION_CODE (callee)); + break; + + case BUILT_IN_STRCPY_CHK: + case BUILT_IN_STPCPY_CHK: + if (val[1] && is_gimple_val (val[1]) && nargs == 3) + result = fold_builtin_stxcpy_chk (loc, callee, + gimple_call_arg (stmt, 0), + gimple_call_arg (stmt, 1), + gimple_call_arg (stmt, 2), + val[1], ignore, + DECL_FUNCTION_CODE (callee)); + break; + + case BUILT_IN_STRNCPY_CHK: + case BUILT_IN_STPNCPY_CHK: + if (val[2] && is_gimple_val (val[2]) && nargs == 4) + result = fold_builtin_stxncpy_chk (loc, gimple_call_arg (stmt, 0), + gimple_call_arg (stmt, 1), + gimple_call_arg (stmt, 2), + gimple_call_arg (stmt, 3), + val[2], ignore, + DECL_FUNCTION_CODE (callee)); + break; + + case BUILT_IN_SNPRINTF_CHK: + case BUILT_IN_VSNPRINTF_CHK: + if (val[1] && is_gimple_val (val[1])) + result = gimple_fold_builtin_snprintf_chk (stmt, val[1], + DECL_FUNCTION_CODE (callee)); + break; + + default: + gcc_unreachable (); + } + + if (result && ignore) + result = fold_ignored_result (result); + return result; +} + + +/* Return a binfo to be used for devirtualization of calls based on an object + represented by a declaration (i.e. a global or automatically allocated one) + or NULL if it cannot be found or is not safe. CST is expected to be an + ADDR_EXPR of such object or the function will return NULL. Currently it is + safe to use such binfo only if it has no base binfo (i.e. no ancestors). */ + +tree +gimple_extract_devirt_binfo_from_cst (tree cst) +{ + HOST_WIDE_INT offset, size, max_size; + tree base, type, expected_type, binfo; + bool last_artificial = false; + + if (!flag_devirtualize + || TREE_CODE (cst) != ADDR_EXPR + || TREE_CODE (TREE_TYPE (TREE_TYPE (cst))) != RECORD_TYPE) + return NULL_TREE; + + cst = TREE_OPERAND (cst, 0); + expected_type = TREE_TYPE (cst); + base = get_ref_base_and_extent (cst, &offset, &size, &max_size); + type = TREE_TYPE (base); + if (!DECL_P (base) + || max_size == -1 + || max_size != size + || TREE_CODE (type) != RECORD_TYPE) + return NULL_TREE; + + /* Find the sub-object the constant actually refers to and mark whether it is + an artificial one (as opposed to a user-defined one). */ + while (true) + { + HOST_WIDE_INT pos, size; + tree fld; + + if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (expected_type)) + break; + if (offset < 0) + return NULL_TREE; + + for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld)) + { + if (TREE_CODE (fld) != FIELD_DECL) + continue; + + pos = int_bit_position (fld); + size = tree_low_cst (DECL_SIZE (fld), 1); + if (pos <= offset && (pos + size) > offset) + break; + } + if (!fld || TREE_CODE (TREE_TYPE (fld)) != RECORD_TYPE) + return NULL_TREE; + + last_artificial = DECL_ARTIFICIAL (fld); + type = TREE_TYPE (fld); + offset -= pos; + } + /* Artificial sub-objects are ancestors, we do not want to use them for + devirtualization, at least not here. */ + if (last_artificial) + return NULL_TREE; + binfo = TYPE_BINFO (type); + if (!binfo || BINFO_N_BASE_BINFOS (binfo) > 0) + return NULL_TREE; + else + return binfo; +} + +/* Attempt to fold a call statement referenced by the statement iterator GSI. + The statement may be replaced by another statement, e.g., if the call + simplifies to a constant value. Return true if any changes were made. + It is assumed that the operands have been previously folded. */ + +static bool +gimple_fold_call (gimple_stmt_iterator *gsi, bool inplace) +{ + gimple stmt = gsi_stmt (*gsi); + tree callee; + bool changed = false; + unsigned i; + + /* Fold *& in call arguments. */ + for (i = 0; i < gimple_call_num_args (stmt); ++i) + if (REFERENCE_CLASS_P (gimple_call_arg (stmt, i))) + { + tree tmp = maybe_fold_reference (gimple_call_arg (stmt, i), false); + if (tmp) + { + gimple_call_set_arg (stmt, i, tmp); + changed = true; + } + } + + /* Check for virtual calls that became direct calls. */ + callee = gimple_call_fn (stmt); + if (callee && TREE_CODE (callee) == OBJ_TYPE_REF) + { + if (gimple_call_addr_fndecl (OBJ_TYPE_REF_EXPR (callee)) != NULL_TREE) + { + gimple_call_set_fn (stmt, OBJ_TYPE_REF_EXPR (callee)); + changed = true; + } + else + { + tree obj = OBJ_TYPE_REF_OBJECT (callee); + tree binfo = gimple_extract_devirt_binfo_from_cst (obj); + if (binfo) + { + HOST_WIDE_INT token + = TREE_INT_CST_LOW (OBJ_TYPE_REF_TOKEN (callee)); + tree fndecl = gimple_get_virt_method_for_binfo (token, binfo); + if (fndecl) + { + gimple_call_set_fndecl (stmt, fndecl); + changed = true; + } + } + } + } + + if (inplace) + return changed; + + /* Check for builtins that CCP can handle using information not + available in the generic fold routines. */ + callee = gimple_call_fndecl (stmt); + if (callee && DECL_BUILT_IN (callee)) + { + tree result = gimple_fold_builtin (stmt); + if (result) + { + if (!update_call_from_tree (gsi, result)) + gimplify_and_update_call_from_tree (gsi, result); + changed = true; + } + } + + return changed; +} + +/* Worker for both fold_stmt and fold_stmt_inplace. The INPLACE argument + distinguishes both cases. */ + +static bool +fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace) +{ + bool changed = false; + gimple stmt = gsi_stmt (*gsi); + unsigned i; + + /* Fold the main computation performed by the statement. */ + switch (gimple_code (stmt)) + { + case GIMPLE_ASSIGN: + { + unsigned old_num_ops = gimple_num_ops (stmt); + enum tree_code subcode = gimple_assign_rhs_code (stmt); + tree lhs = gimple_assign_lhs (stmt); + tree new_rhs; + /* First canonicalize operand order. This avoids building new + trees if this is the only thing fold would later do. */ + if ((commutative_tree_code (subcode) + || commutative_ternary_tree_code (subcode)) + && tree_swap_operands_p (gimple_assign_rhs1 (stmt), + gimple_assign_rhs2 (stmt), false)) + { + tree tem = gimple_assign_rhs1 (stmt); + gimple_assign_set_rhs1 (stmt, gimple_assign_rhs2 (stmt)); + gimple_assign_set_rhs2 (stmt, tem); + changed = true; + } + new_rhs = fold_gimple_assign (gsi); + if (new_rhs + && !useless_type_conversion_p (TREE_TYPE (lhs), + TREE_TYPE (new_rhs))) + new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); + if (new_rhs + && (!inplace + || get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops)) + { + gimple_assign_set_rhs_from_tree (gsi, new_rhs); + changed = true; + } + break; + } + + case GIMPLE_COND: + changed |= fold_gimple_cond (stmt); + break; + + case GIMPLE_CALL: + changed |= gimple_fold_call (gsi, inplace); + break; + + case GIMPLE_ASM: + /* Fold *& in asm operands. */ + { + size_t noutputs; + const char **oconstraints; + const char *constraint; + bool allows_mem, allows_reg; + + noutputs = gimple_asm_noutputs (stmt); + oconstraints = XALLOCAVEC (const char *, noutputs); + + for (i = 0; i < gimple_asm_noutputs (stmt); ++i) + { + tree link = gimple_asm_output_op (stmt, i); + tree op = TREE_VALUE (link); + oconstraints[i] + = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link))); + if (REFERENCE_CLASS_P (op) + && (op = maybe_fold_reference (op, true)) != NULL_TREE) + { + TREE_VALUE (link) = op; + changed = true; + } + } + for (i = 0; i < gimple_asm_ninputs (stmt); ++i) + { + tree link = gimple_asm_input_op (stmt, i); + tree op = TREE_VALUE (link); + constraint + = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link))); + parse_input_constraint (&constraint, 0, 0, noutputs, 0, + oconstraints, &allows_mem, &allows_reg); + if (REFERENCE_CLASS_P (op) + && (op = maybe_fold_reference (op, !allows_reg && allows_mem)) + != NULL_TREE) + { + TREE_VALUE (link) = op; + changed = true; + } + } + } + break; + + case GIMPLE_DEBUG: + if (gimple_debug_bind_p (stmt)) + { + tree val = gimple_debug_bind_get_value (stmt); + if (val + && REFERENCE_CLASS_P (val)) + { + tree tem = maybe_fold_reference (val, false); + if (tem) + { + gimple_debug_bind_set_value (stmt, tem); + changed = true; + } + } + else if (val + && TREE_CODE (val) == ADDR_EXPR) + { + tree ref = TREE_OPERAND (val, 0); + tree tem = maybe_fold_reference (ref, false); + if (tem) + { + tem = build_fold_addr_expr_with_type (tem, TREE_TYPE (val)); + gimple_debug_bind_set_value (stmt, tem); + changed = true; + } + } + } + break; + + default:; + } + + stmt = gsi_stmt (*gsi); + + /* Fold *& on the lhs. */ + if (gimple_has_lhs (stmt)) + { + tree lhs = gimple_get_lhs (stmt); + if (lhs && REFERENCE_CLASS_P (lhs)) + { + tree new_lhs = maybe_fold_reference (lhs, true); + if (new_lhs) + { + gimple_set_lhs (stmt, new_lhs); + changed = true; + } + } + } + + return changed; +} + +/* Fold the statement pointed to by GSI. In some cases, this function may + replace the whole statement with a new one. Returns true iff folding + makes any changes. + The statement pointed to by GSI should be in valid gimple form but may + be in unfolded state as resulting from for example constant propagation + which can produce *&x = 0. */ + +bool +fold_stmt (gimple_stmt_iterator *gsi) +{ + return fold_stmt_1 (gsi, false); +} + +/* Perform the minimal folding on statement *GSI. Only operations like + *&x created by constant propagation are handled. The statement cannot + be replaced with a new one. Return true if the statement was + changed, false otherwise. + The statement *GSI should be in valid gimple form but may + be in unfolded state as resulting from for example constant propagation + which can produce *&x = 0. */ + +bool +fold_stmt_inplace (gimple_stmt_iterator *gsi) +{ + gimple stmt = gsi_stmt (*gsi); + bool changed = fold_stmt_1 (gsi, true); + gcc_assert (gsi_stmt (*gsi) == stmt); + return changed; +} + +/* Canonicalize and possibly invert the boolean EXPR; return NULL_TREE + if EXPR is null or we don't know how. + If non-null, the result always has boolean type. */ + +static tree +canonicalize_bool (tree expr, bool invert) +{ + if (!expr) + return NULL_TREE; + else if (invert) + { + if (integer_nonzerop (expr)) + return boolean_false_node; + else if (integer_zerop (expr)) + return boolean_true_node; + else if (TREE_CODE (expr) == SSA_NAME) + return fold_build2 (EQ_EXPR, boolean_type_node, expr, + build_int_cst (TREE_TYPE (expr), 0)); + else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison) + return fold_build2 (invert_tree_comparison (TREE_CODE (expr), false), + boolean_type_node, + TREE_OPERAND (expr, 0), + TREE_OPERAND (expr, 1)); + else + return NULL_TREE; + } + else + { + if (TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE) + return expr; + if (integer_nonzerop (expr)) + return boolean_true_node; + else if (integer_zerop (expr)) + return boolean_false_node; + else if (TREE_CODE (expr) == SSA_NAME) + return fold_build2 (NE_EXPR, boolean_type_node, expr, + build_int_cst (TREE_TYPE (expr), 0)); + else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison) + return fold_build2 (TREE_CODE (expr), + boolean_type_node, + TREE_OPERAND (expr, 0), + TREE_OPERAND (expr, 1)); + else + return NULL_TREE; + } +} + +/* Check to see if a boolean expression EXPR is logically equivalent to the + comparison (OP1 CODE OP2). Check for various identities involving + SSA_NAMEs. */ + +static bool +same_bool_comparison_p (const_tree expr, enum tree_code code, + const_tree op1, const_tree op2) +{ + gimple s; + + /* The obvious case. */ + if (TREE_CODE (expr) == code + && operand_equal_p (TREE_OPERAND (expr, 0), op1, 0) + && operand_equal_p (TREE_OPERAND (expr, 1), op2, 0)) + return true; + + /* Check for comparing (name, name != 0) and the case where expr + is an SSA_NAME with a definition matching the comparison. */ + if (TREE_CODE (expr) == SSA_NAME + && TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE) + { + if (operand_equal_p (expr, op1, 0)) + return ((code == NE_EXPR && integer_zerop (op2)) + || (code == EQ_EXPR && integer_nonzerop (op2))); + s = SSA_NAME_DEF_STMT (expr); + if (is_gimple_assign (s) + && gimple_assign_rhs_code (s) == code + && operand_equal_p (gimple_assign_rhs1 (s), op1, 0) + && operand_equal_p (gimple_assign_rhs2 (s), op2, 0)) + return true; + } + + /* If op1 is of the form (name != 0) or (name == 0), and the definition + of name is a comparison, recurse. */ + if (TREE_CODE (op1) == SSA_NAME + && TREE_CODE (TREE_TYPE (op1)) == BOOLEAN_TYPE) + { + s = SSA_NAME_DEF_STMT (op1); + if (is_gimple_assign (s) + && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison) + { + enum tree_code c = gimple_assign_rhs_code (s); + if ((c == NE_EXPR && integer_zerop (op2)) + || (c == EQ_EXPR && integer_nonzerop (op2))) + return same_bool_comparison_p (expr, c, + gimple_assign_rhs1 (s), + gimple_assign_rhs2 (s)); + if ((c == EQ_EXPR && integer_zerop (op2)) + || (c == NE_EXPR && integer_nonzerop (op2))) + return same_bool_comparison_p (expr, + invert_tree_comparison (c, false), + gimple_assign_rhs1 (s), + gimple_assign_rhs2 (s)); + } + } + return false; +} + +/* Check to see if two boolean expressions OP1 and OP2 are logically + equivalent. */ + +static bool +same_bool_result_p (const_tree op1, const_tree op2) +{ + /* Simple cases first. */ + if (operand_equal_p (op1, op2, 0)) + return true; + + /* Check the cases where at least one of the operands is a comparison. + These are a bit smarter than operand_equal_p in that they apply some + identifies on SSA_NAMEs. */ + if (TREE_CODE_CLASS (TREE_CODE (op2)) == tcc_comparison + && same_bool_comparison_p (op1, TREE_CODE (op2), + TREE_OPERAND (op2, 0), + TREE_OPERAND (op2, 1))) + return true; + if (TREE_CODE_CLASS (TREE_CODE (op1)) == tcc_comparison + && same_bool_comparison_p (op2, TREE_CODE (op1), + TREE_OPERAND (op1, 0), + TREE_OPERAND (op1, 1))) + return true; + + /* Default case. */ + return false; +} + +/* Forward declarations for some mutually recursive functions. */ + +static tree +and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b, + enum tree_code code2, tree op2a, tree op2b); +static tree +and_var_with_comparison (tree var, bool invert, + enum tree_code code2, tree op2a, tree op2b); +static tree +and_var_with_comparison_1 (gimple stmt, + enum tree_code code2, tree op2a, tree op2b); +static tree +or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b, + enum tree_code code2, tree op2a, tree op2b); +static tree +or_var_with_comparison (tree var, bool invert, + enum tree_code code2, tree op2a, tree op2b); +static tree +or_var_with_comparison_1 (gimple stmt, + enum tree_code code2, tree op2a, tree op2b); + +/* Helper function for and_comparisons_1: try to simplify the AND of the + ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B). + If INVERT is true, invert the value of the VAR before doing the AND. + Return NULL_EXPR if we can't simplify this to a single expression. */ + +static tree +and_var_with_comparison (tree var, bool invert, + enum tree_code code2, tree op2a, tree op2b) +{ + tree t; + gimple stmt = SSA_NAME_DEF_STMT (var); + + /* We can only deal with variables whose definitions are assignments. */ + if (!is_gimple_assign (stmt)) + return NULL_TREE; + + /* If we have an inverted comparison, apply DeMorgan's law and rewrite + !var AND (op2a code2 op2b) => !(var OR !(op2a code2 op2b)) + Then we only have to consider the simpler non-inverted cases. */ + if (invert) + t = or_var_with_comparison_1 (stmt, + invert_tree_comparison (code2, false), + op2a, op2b); + else + t = and_var_with_comparison_1 (stmt, code2, op2a, op2b); + return canonicalize_bool (t, invert); +} + +/* Try to simplify the AND of the ssa variable defined by the assignment + STMT with the comparison specified by (OP2A CODE2 OP2B). + Return NULL_EXPR if we can't simplify this to a single expression. */ + +static tree +and_var_with_comparison_1 (gimple stmt, + enum tree_code code2, tree op2a, tree op2b) +{ + tree var = gimple_assign_lhs (stmt); + tree true_test_var = NULL_TREE; + tree false_test_var = NULL_TREE; + enum tree_code innercode = gimple_assign_rhs_code (stmt); + + /* Check for identities like (var AND (var == 0)) => false. */ + if (TREE_CODE (op2a) == SSA_NAME + && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE) + { + if ((code2 == NE_EXPR && integer_zerop (op2b)) + || (code2 == EQ_EXPR && integer_nonzerop (op2b))) + { + true_test_var = op2a; + if (var == true_test_var) + return var; + } + else if ((code2 == EQ_EXPR && integer_zerop (op2b)) + || (code2 == NE_EXPR && integer_nonzerop (op2b))) + { + false_test_var = op2a; + if (var == false_test_var) + return boolean_false_node; + } + } + + /* If the definition is a comparison, recurse on it. */ + if (TREE_CODE_CLASS (innercode) == tcc_comparison) + { + tree t = and_comparisons_1 (innercode, + gimple_assign_rhs1 (stmt), + gimple_assign_rhs2 (stmt), + code2, + op2a, + op2b); + if (t) + return t; + } + + /* If the definition is an AND or OR expression, we may be able to + simplify by reassociating. */ + if (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE + && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)) + { + tree inner1 = gimple_assign_rhs1 (stmt); + tree inner2 = gimple_assign_rhs2 (stmt); + gimple s; + tree t; + tree partial = NULL_TREE; + bool is_and = (innercode == BIT_AND_EXPR); + + /* Check for boolean identities that don't require recursive examination + of inner1/inner2: + inner1 AND (inner1 AND inner2) => inner1 AND inner2 => var + inner1 AND (inner1 OR inner2) => inner1 + !inner1 AND (inner1 AND inner2) => false + !inner1 AND (inner1 OR inner2) => !inner1 AND inner2 + Likewise for similar cases involving inner2. */ + if (inner1 == true_test_var) + return (is_and ? var : inner1); + else if (inner2 == true_test_var) + return (is_and ? var : inner2); + else if (inner1 == false_test_var) + return (is_and + ? boolean_false_node + : and_var_with_comparison (inner2, false, code2, op2a, op2b)); + else if (inner2 == false_test_var) + return (is_and + ? boolean_false_node + : and_var_with_comparison (inner1, false, code2, op2a, op2b)); + + /* Next, redistribute/reassociate the AND across the inner tests. + Compute the first partial result, (inner1 AND (op2a code op2b)) */ + if (TREE_CODE (inner1) == SSA_NAME + && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1)) + && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison + && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s), + gimple_assign_rhs1 (s), + gimple_assign_rhs2 (s), + code2, op2a, op2b))) + { + /* Handle the AND case, where we are reassociating: + (inner1 AND inner2) AND (op2a code2 op2b) + => (t AND inner2) + If the partial result t is a constant, we win. Otherwise + continue on to try reassociating with the other inner test. */ + if (is_and) + { + if (integer_onep (t)) + return inner2; + else if (integer_zerop (t)) + return boolean_false_node; + } + + /* Handle the OR case, where we are redistributing: + (inner1 OR inner2) AND (op2a code2 op2b) + => (t OR (inner2 AND (op2a code2 op2b))) */ + else if (integer_onep (t)) + return boolean_true_node; + + /* Save partial result for later. */ + partial = t; + } + + /* Compute the second partial result, (inner2 AND (op2a code op2b)) */ + if (TREE_CODE (inner2) == SSA_NAME + && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2)) + && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison + && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s), + gimple_assign_rhs1 (s), + gimple_assign_rhs2 (s), + code2, op2a, op2b))) + { + /* Handle the AND case, where we are reassociating: + (inner1 AND inner2) AND (op2a code2 op2b) + => (inner1 AND t) */ + if (is_and) + { + if (integer_onep (t)) + return inner1; + else if (integer_zerop (t)) + return boolean_false_node; + /* If both are the same, we can apply the identity + (x AND x) == x. */ + else if (partial && same_bool_result_p (t, partial)) + return t; + } + + /* Handle the OR case. where we are redistributing: + (inner1 OR inner2) AND (op2a code2 op2b) + => (t OR (inner1 AND (op2a code2 op2b))) + => (t OR partial) */ + else + { + if (integer_onep (t)) + return boolean_true_node; + else if (partial) + { + /* We already got a simplification for the other + operand to the redistributed OR expression. The + interesting case is when at least one is false. + Or, if both are the same, we can apply the identity + (x OR x) == x. */ + if (integer_zerop (partial)) + return t; + else if (integer_zerop (t)) + return partial; + else if (same_bool_result_p (t, partial)) + return t; + } + } + } + } + return NULL_TREE; +} + +/* Try to simplify the AND of two comparisons defined by + (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively. + If this can be done without constructing an intermediate value, + return the resulting tree; otherwise NULL_TREE is returned. + This function is deliberately asymmetric as it recurses on SSA_DEFs + in the first comparison but not the second. */ + +static tree +and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b, + enum tree_code code2, tree op2a, tree op2b) +{ + tree truth_type = truth_type_for (TREE_TYPE (op1a)); + + /* First check for ((x CODE1 y) AND (x CODE2 y)). */ + if (operand_equal_p (op1a, op2a, 0) + && operand_equal_p (op1b, op2b, 0)) + { + /* Result will be either NULL_TREE, or a combined comparison. */ + tree t = combine_comparisons (UNKNOWN_LOCATION, + TRUTH_ANDIF_EXPR, code1, code2, + truth_type, op1a, op1b); + if (t) + return t; + } + + /* Likewise the swapped case of the above. */ + if (operand_equal_p (op1a, op2b, 0) + && operand_equal_p (op1b, op2a, 0)) + { + /* Result will be either NULL_TREE, or a combined comparison. */ + tree t = combine_comparisons (UNKNOWN_LOCATION, + TRUTH_ANDIF_EXPR, code1, + swap_tree_comparison (code2), + truth_type, op1a, op1b); + if (t) + return t; + } + + /* If both comparisons are of the same value against constants, we might + be able to merge them. */ + if (operand_equal_p (op1a, op2a, 0) + && TREE_CODE (op1b) == INTEGER_CST + && TREE_CODE (op2b) == INTEGER_CST) + { + int cmp = tree_int_cst_compare (op1b, op2b); + + /* If we have (op1a == op1b), we should either be able to + return that or FALSE, depending on whether the constant op1b + also satisfies the other comparison against op2b. */ + if (code1 == EQ_EXPR) + { + bool done = true; + bool val; + switch (code2) + { + case EQ_EXPR: val = (cmp == 0); break; + case NE_EXPR: val = (cmp != 0); break; + case LT_EXPR: val = (cmp < 0); break; + case GT_EXPR: val = (cmp > 0); break; + case LE_EXPR: val = (cmp <= 0); break; + case GE_EXPR: val = (cmp >= 0); break; + default: done = false; + } + if (done) + { + if (val) + return fold_build2 (code1, boolean_type_node, op1a, op1b); + else + return boolean_false_node; + } + } + /* Likewise if the second comparison is an == comparison. */ + else if (code2 == EQ_EXPR) + { + bool done = true; + bool val; + switch (code1) + { + case EQ_EXPR: val = (cmp == 0); break; + case NE_EXPR: val = (cmp != 0); break; + case LT_EXPR: val = (cmp > 0); break; + case GT_EXPR: val = (cmp < 0); break; + case LE_EXPR: val = (cmp >= 0); break; + case GE_EXPR: val = (cmp <= 0); break; + default: done = false; + } + if (done) + { + if (val) + return fold_build2 (code2, boolean_type_node, op2a, op2b); + else + return boolean_false_node; + } + } + + /* Same business with inequality tests. */ + else if (code1 == NE_EXPR) + { + bool val; + switch (code2) + { + case EQ_EXPR: val = (cmp != 0); break; + case NE_EXPR: val = (cmp == 0); break; + case LT_EXPR: val = (cmp >= 0); break; + case GT_EXPR: val = (cmp <= 0); break; + case LE_EXPR: val = (cmp > 0); break; + case GE_EXPR: val = (cmp < 0); break; + default: + val = false; + } + if (val) + return fold_build2 (code2, boolean_type_node, op2a, op2b); + } + else if (code2 == NE_EXPR) + { + bool val; + switch (code1) + { + case EQ_EXPR: val = (cmp == 0); break; + case NE_EXPR: val = (cmp != 0); break; + case LT_EXPR: val = (cmp <= 0); break; + case GT_EXPR: val = (cmp >= 0); break; + case LE_EXPR: val = (cmp < 0); break; + case GE_EXPR: val = (cmp > 0); break; + default: + val = false; + } + if (val) + return fold_build2 (code1, boolean_type_node, op1a, op1b); + } + + /* Chose the more restrictive of two < or <= comparisons. */ + else if ((code1 == LT_EXPR || code1 == LE_EXPR) + && (code2 == LT_EXPR || code2 == LE_EXPR)) + { + if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR)) + return fold_build2 (code1, boolean_type_node, op1a, op1b); + else + return fold_build2 (code2, boolean_type_node, op2a, op2b); + } + + /* Likewise chose the more restrictive of two > or >= comparisons. */ + else if ((code1 == GT_EXPR || code1 == GE_EXPR) + && (code2 == GT_EXPR || code2 == GE_EXPR)) + { + if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR)) + return fold_build2 (code1, boolean_type_node, op1a, op1b); + else + return fold_build2 (code2, boolean_type_node, op2a, op2b); + } + + /* Check for singleton ranges. */ + else if (cmp == 0 + && ((code1 == LE_EXPR && code2 == GE_EXPR) + || (code1 == GE_EXPR && code2 == LE_EXPR))) + return fold_build2 (EQ_EXPR, boolean_type_node, op1a, op2b); + + /* Check for disjoint ranges. */ + else if (cmp <= 0 + && (code1 == LT_EXPR || code1 == LE_EXPR) + && (code2 == GT_EXPR || code2 == GE_EXPR)) + return boolean_false_node; + else if (cmp >= 0 + && (code1 == GT_EXPR || code1 == GE_EXPR) + && (code2 == LT_EXPR || code2 == LE_EXPR)) + return boolean_false_node; + } + + /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where + NAME's definition is a truth value. See if there are any simplifications + that can be done against the NAME's definition. */ + if (TREE_CODE (op1a) == SSA_NAME + && (code1 == NE_EXPR || code1 == EQ_EXPR) + && (integer_zerop (op1b) || integer_onep (op1b))) + { + bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b)) + || (code1 == NE_EXPR && integer_onep (op1b))); + gimple stmt = SSA_NAME_DEF_STMT (op1a); + switch (gimple_code (stmt)) + { + case GIMPLE_ASSIGN: + /* Try to simplify by copy-propagating the definition. */ + return and_var_with_comparison (op1a, invert, code2, op2a, op2b); + + case GIMPLE_PHI: + /* If every argument to the PHI produces the same result when + ANDed with the second comparison, we win. + Do not do this unless the type is bool since we need a bool + result here anyway. */ + if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE) + { + tree result = NULL_TREE; + unsigned i; + for (i = 0; i < gimple_phi_num_args (stmt); i++) + { + tree arg = gimple_phi_arg_def (stmt, i); + + /* If this PHI has itself as an argument, ignore it. + If all the other args produce the same result, + we're still OK. */ + if (arg == gimple_phi_result (stmt)) + continue; + else if (TREE_CODE (arg) == INTEGER_CST) + { + if (invert ? integer_nonzerop (arg) : integer_zerop (arg)) + { + if (!result) + result = boolean_false_node; + else if (!integer_zerop (result)) + return NULL_TREE; + } + else if (!result) + result = fold_build2 (code2, boolean_type_node, + op2a, op2b); + else if (!same_bool_comparison_p (result, + code2, op2a, op2b)) + return NULL_TREE; + } + else if (TREE_CODE (arg) == SSA_NAME + && !SSA_NAME_IS_DEFAULT_DEF (arg)) + { + tree temp; + gimple def_stmt = SSA_NAME_DEF_STMT (arg); + /* In simple cases we can look through PHI nodes, + but we have to be careful with loops. + See PR49073. */ + if (! dom_info_available_p (CDI_DOMINATORS) + || gimple_bb (def_stmt) == gimple_bb (stmt) + || dominated_by_p (CDI_DOMINATORS, + gimple_bb (def_stmt), + gimple_bb (stmt))) + return NULL_TREE; + temp = and_var_with_comparison (arg, invert, code2, + op2a, op2b); + if (!temp) + return NULL_TREE; + else if (!result) + result = temp; + else if (!same_bool_result_p (result, temp)) + return NULL_TREE; + } + else + return NULL_TREE; + } + return result; + } + + default: + break; + } + } + return NULL_TREE; +} + +/* Try to simplify the AND of two comparisons, specified by + (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively. + If this can be simplified to a single expression (without requiring + introducing more SSA variables to hold intermediate values), + return the resulting tree. Otherwise return NULL_TREE. + If the result expression is non-null, it has boolean type. */ + +tree +maybe_fold_and_comparisons (enum tree_code code1, tree op1a, tree op1b, + enum tree_code code2, tree op2a, tree op2b) +{ + tree t = and_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b); + if (t) + return t; + else + return and_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b); +} + +/* Helper function for or_comparisons_1: try to simplify the OR of the + ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B). + If INVERT is true, invert the value of VAR before doing the OR. + Return NULL_EXPR if we can't simplify this to a single expression. */ + +static tree +or_var_with_comparison (tree var, bool invert, + enum tree_code code2, tree op2a, tree op2b) +{ + tree t; + gimple stmt = SSA_NAME_DEF_STMT (var); + + /* We can only deal with variables whose definitions are assignments. */ + if (!is_gimple_assign (stmt)) + return NULL_TREE; + + /* If we have an inverted comparison, apply DeMorgan's law and rewrite + !var OR (op2a code2 op2b) => !(var AND !(op2a code2 op2b)) + Then we only have to consider the simpler non-inverted cases. */ + if (invert) + t = and_var_with_comparison_1 (stmt, + invert_tree_comparison (code2, false), + op2a, op2b); + else + t = or_var_with_comparison_1 (stmt, code2, op2a, op2b); + return canonicalize_bool (t, invert); +} + +/* Try to simplify the OR of the ssa variable defined by the assignment + STMT with the comparison specified by (OP2A CODE2 OP2B). + Return NULL_EXPR if we can't simplify this to a single expression. */ + +static tree +or_var_with_comparison_1 (gimple stmt, + enum tree_code code2, tree op2a, tree op2b) +{ + tree var = gimple_assign_lhs (stmt); + tree true_test_var = NULL_TREE; + tree false_test_var = NULL_TREE; + enum tree_code innercode = gimple_assign_rhs_code (stmt); + + /* Check for identities like (var OR (var != 0)) => true . */ + if (TREE_CODE (op2a) == SSA_NAME + && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE) + { + if ((code2 == NE_EXPR && integer_zerop (op2b)) + || (code2 == EQ_EXPR && integer_nonzerop (op2b))) + { + true_test_var = op2a; + if (var == true_test_var) + return var; + } + else if ((code2 == EQ_EXPR && integer_zerop (op2b)) + || (code2 == NE_EXPR && integer_nonzerop (op2b))) + { + false_test_var = op2a; + if (var == false_test_var) + return boolean_true_node; + } + } + + /* If the definition is a comparison, recurse on it. */ + if (TREE_CODE_CLASS (innercode) == tcc_comparison) + { + tree t = or_comparisons_1 (innercode, + gimple_assign_rhs1 (stmt), + gimple_assign_rhs2 (stmt), + code2, + op2a, + op2b); + if (t) + return t; + } + + /* If the definition is an AND or OR expression, we may be able to + simplify by reassociating. */ + if (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE + && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)) + { + tree inner1 = gimple_assign_rhs1 (stmt); + tree inner2 = gimple_assign_rhs2 (stmt); + gimple s; + tree t; + tree partial = NULL_TREE; + bool is_or = (innercode == BIT_IOR_EXPR); + + /* Check for boolean identities that don't require recursive examination + of inner1/inner2: + inner1 OR (inner1 OR inner2) => inner1 OR inner2 => var + inner1 OR (inner1 AND inner2) => inner1 + !inner1 OR (inner1 OR inner2) => true + !inner1 OR (inner1 AND inner2) => !inner1 OR inner2 + */ + if (inner1 == true_test_var) + return (is_or ? var : inner1); + else if (inner2 == true_test_var) + return (is_or ? var : inner2); + else if (inner1 == false_test_var) + return (is_or + ? boolean_true_node + : or_var_with_comparison (inner2, false, code2, op2a, op2b)); + else if (inner2 == false_test_var) + return (is_or + ? boolean_true_node + : or_var_with_comparison (inner1, false, code2, op2a, op2b)); + + /* Next, redistribute/reassociate the OR across the inner tests. + Compute the first partial result, (inner1 OR (op2a code op2b)) */ + if (TREE_CODE (inner1) == SSA_NAME + && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1)) + && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison + && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s), + gimple_assign_rhs1 (s), + gimple_assign_rhs2 (s), + code2, op2a, op2b))) + { + /* Handle the OR case, where we are reassociating: + (inner1 OR inner2) OR (op2a code2 op2b) + => (t OR inner2) + If the partial result t is a constant, we win. Otherwise + continue on to try reassociating with the other inner test. */ + if (is_or) + { + if (integer_onep (t)) + return boolean_true_node; + else if (integer_zerop (t)) + return inner2; + } + + /* Handle the AND case, where we are redistributing: + (inner1 AND inner2) OR (op2a code2 op2b) + => (t AND (inner2 OR (op2a code op2b))) */ + else if (integer_zerop (t)) + return boolean_false_node; + + /* Save partial result for later. */ + partial = t; + } + + /* Compute the second partial result, (inner2 OR (op2a code op2b)) */ + if (TREE_CODE (inner2) == SSA_NAME + && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2)) + && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison + && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s), + gimple_assign_rhs1 (s), + gimple_assign_rhs2 (s), + code2, op2a, op2b))) + { + /* Handle the OR case, where we are reassociating: + (inner1 OR inner2) OR (op2a code2 op2b) + => (inner1 OR t) + => (t OR partial) */ + if (is_or) + { + if (integer_zerop (t)) + return inner1; + else if (integer_onep (t)) + return boolean_true_node; + /* If both are the same, we can apply the identity + (x OR x) == x. */ + else if (partial && same_bool_result_p (t, partial)) + return t; + } + + /* Handle the AND case, where we are redistributing: + (inner1 AND inner2) OR (op2a code2 op2b) + => (t AND (inner1 OR (op2a code2 op2b))) + => (t AND partial) */ + else + { + if (integer_zerop (t)) + return boolean_false_node; + else if (partial) + { + /* We already got a simplification for the other + operand to the redistributed AND expression. The + interesting case is when at least one is true. + Or, if both are the same, we can apply the identity + (x AND x) == x. */ + if (integer_onep (partial)) + return t; + else if (integer_onep (t)) + return partial; + else if (same_bool_result_p (t, partial)) + return t; + } + } + } + } + return NULL_TREE; +} + +/* Try to simplify the OR of two comparisons defined by + (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively. + If this can be done without constructing an intermediate value, + return the resulting tree; otherwise NULL_TREE is returned. + This function is deliberately asymmetric as it recurses on SSA_DEFs + in the first comparison but not the second. */ + +static tree +or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b, + enum tree_code code2, tree op2a, tree op2b) +{ + tree truth_type = truth_type_for (TREE_TYPE (op1a)); + + /* First check for ((x CODE1 y) OR (x CODE2 y)). */ + if (operand_equal_p (op1a, op2a, 0) + && operand_equal_p (op1b, op2b, 0)) + { + /* Result will be either NULL_TREE, or a combined comparison. */ + tree t = combine_comparisons (UNKNOWN_LOCATION, + TRUTH_ORIF_EXPR, code1, code2, + truth_type, op1a, op1b); + if (t) + return t; + } + + /* Likewise the swapped case of the above. */ + if (operand_equal_p (op1a, op2b, 0) + && operand_equal_p (op1b, op2a, 0)) + { + /* Result will be either NULL_TREE, or a combined comparison. */ + tree t = combine_comparisons (UNKNOWN_LOCATION, + TRUTH_ORIF_EXPR, code1, + swap_tree_comparison (code2), + truth_type, op1a, op1b); + if (t) + return t; + } + + /* If both comparisons are of the same value against constants, we might + be able to merge them. */ + if (operand_equal_p (op1a, op2a, 0) + && TREE_CODE (op1b) == INTEGER_CST + && TREE_CODE (op2b) == INTEGER_CST) + { + int cmp = tree_int_cst_compare (op1b, op2b); + + /* If we have (op1a != op1b), we should either be able to + return that or TRUE, depending on whether the constant op1b + also satisfies the other comparison against op2b. */ + if (code1 == NE_EXPR) + { + bool done = true; + bool val; + switch (code2) + { + case EQ_EXPR: val = (cmp == 0); break; + case NE_EXPR: val = (cmp != 0); break; + case LT_EXPR: val = (cmp < 0); break; + case GT_EXPR: val = (cmp > 0); break; + case LE_EXPR: val = (cmp <= 0); break; + case GE_EXPR: val = (cmp >= 0); break; + default: done = false; + } + if (done) + { + if (val) + return boolean_true_node; + else + return fold_build2 (code1, boolean_type_node, op1a, op1b); + } + } + /* Likewise if the second comparison is a != comparison. */ + else if (code2 == NE_EXPR) + { + bool done = true; + bool val; + switch (code1) + { + case EQ_EXPR: val = (cmp == 0); break; + case NE_EXPR: val = (cmp != 0); break; + case LT_EXPR: val = (cmp > 0); break; + case GT_EXPR: val = (cmp < 0); break; + case LE_EXPR: val = (cmp >= 0); break; + case GE_EXPR: val = (cmp <= 0); break; + default: done = false; + } + if (done) + { + if (val) + return boolean_true_node; + else + return fold_build2 (code2, boolean_type_node, op2a, op2b); + } + } + + /* See if an equality test is redundant with the other comparison. */ + else if (code1 == EQ_EXPR) + { + bool val; + switch (code2) + { + case EQ_EXPR: val = (cmp == 0); break; + case NE_EXPR: val = (cmp != 0); break; + case LT_EXPR: val = (cmp < 0); break; + case GT_EXPR: val = (cmp > 0); break; + case LE_EXPR: val = (cmp <= 0); break; + case GE_EXPR: val = (cmp >= 0); break; + default: + val = false; + } + if (val) + return fold_build2 (code2, boolean_type_node, op2a, op2b); + } + else if (code2 == EQ_EXPR) + { + bool val; + switch (code1) + { + case EQ_EXPR: val = (cmp == 0); break; + case NE_EXPR: val = (cmp != 0); break; + case LT_EXPR: val = (cmp > 0); break; + case GT_EXPR: val = (cmp < 0); break; + case LE_EXPR: val = (cmp >= 0); break; + case GE_EXPR: val = (cmp <= 0); break; + default: + val = false; + } + if (val) + return fold_build2 (code1, boolean_type_node, op1a, op1b); + } + + /* Chose the less restrictive of two < or <= comparisons. */ + else if ((code1 == LT_EXPR || code1 == LE_EXPR) + && (code2 == LT_EXPR || code2 == LE_EXPR)) + { + if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR)) + return fold_build2 (code2, boolean_type_node, op2a, op2b); + else + return fold_build2 (code1, boolean_type_node, op1a, op1b); + } + + /* Likewise chose the less restrictive of two > or >= comparisons. */ + else if ((code1 == GT_EXPR || code1 == GE_EXPR) + && (code2 == GT_EXPR || code2 == GE_EXPR)) + { + if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR)) + return fold_build2 (code2, boolean_type_node, op2a, op2b); + else + return fold_build2 (code1, boolean_type_node, op1a, op1b); + } + + /* Check for singleton ranges. */ + else if (cmp == 0 + && ((code1 == LT_EXPR && code2 == GT_EXPR) + || (code1 == GT_EXPR && code2 == LT_EXPR))) + return fold_build2 (NE_EXPR, boolean_type_node, op1a, op2b); + + /* Check for less/greater pairs that don't restrict the range at all. */ + else if (cmp >= 0 + && (code1 == LT_EXPR || code1 == LE_EXPR) + && (code2 == GT_EXPR || code2 == GE_EXPR)) + return boolean_true_node; + else if (cmp <= 0 + && (code1 == GT_EXPR || code1 == GE_EXPR) + && (code2 == LT_EXPR || code2 == LE_EXPR)) + return boolean_true_node; + } + + /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where + NAME's definition is a truth value. See if there are any simplifications + that can be done against the NAME's definition. */ + if (TREE_CODE (op1a) == SSA_NAME + && (code1 == NE_EXPR || code1 == EQ_EXPR) + && (integer_zerop (op1b) || integer_onep (op1b))) + { + bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b)) + || (code1 == NE_EXPR && integer_onep (op1b))); + gimple stmt = SSA_NAME_DEF_STMT (op1a); + switch (gimple_code (stmt)) + { + case GIMPLE_ASSIGN: + /* Try to simplify by copy-propagating the definition. */ + return or_var_with_comparison (op1a, invert, code2, op2a, op2b); + + case GIMPLE_PHI: + /* If every argument to the PHI produces the same result when + ORed with the second comparison, we win. + Do not do this unless the type is bool since we need a bool + result here anyway. */ + if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE) + { + tree result = NULL_TREE; + unsigned i; + for (i = 0; i < gimple_phi_num_args (stmt); i++) + { + tree arg = gimple_phi_arg_def (stmt, i); + + /* If this PHI has itself as an argument, ignore it. + If all the other args produce the same result, + we're still OK. */ + if (arg == gimple_phi_result (stmt)) + continue; + else if (TREE_CODE (arg) == INTEGER_CST) + { + if (invert ? integer_zerop (arg) : integer_nonzerop (arg)) + { + if (!result) + result = boolean_true_node; + else if (!integer_onep (result)) + return NULL_TREE; + } + else if (!result) + result = fold_build2 (code2, boolean_type_node, + op2a, op2b); + else if (!same_bool_comparison_p (result, + code2, op2a, op2b)) + return NULL_TREE; + } + else if (TREE_CODE (arg) == SSA_NAME + && !SSA_NAME_IS_DEFAULT_DEF (arg)) + { + tree temp; + gimple def_stmt = SSA_NAME_DEF_STMT (arg); + /* In simple cases we can look through PHI nodes, + but we have to be careful with loops. + See PR49073. */ + if (! dom_info_available_p (CDI_DOMINATORS) + || gimple_bb (def_stmt) == gimple_bb (stmt) + || dominated_by_p (CDI_DOMINATORS, + gimple_bb (def_stmt), + gimple_bb (stmt))) + return NULL_TREE; + temp = or_var_with_comparison (arg, invert, code2, + op2a, op2b); + if (!temp) + return NULL_TREE; + else if (!result) + result = temp; + else if (!same_bool_result_p (result, temp)) + return NULL_TREE; + } + else + return NULL_TREE; + } + return result; + } + + default: + break; + } + } + return NULL_TREE; +} + +/* Try to simplify the OR of two comparisons, specified by + (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively. + If this can be simplified to a single expression (without requiring + introducing more SSA variables to hold intermediate values), + return the resulting tree. Otherwise return NULL_TREE. + If the result expression is non-null, it has boolean type. */ + +tree +maybe_fold_or_comparisons (enum tree_code code1, tree op1a, tree op1b, + enum tree_code code2, tree op2a, tree op2b) +{ + tree t = or_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b); + if (t) + return t; + else + return or_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b); +} + + +/* Fold STMT to a constant using VALUEIZE to valueize SSA names. + + Either NULL_TREE, a simplified but non-constant or a constant + is returned. + + ??? This should go into a gimple-fold-inline.h file to be eventually + privatized with the single valueize function used in the various TUs + to avoid the indirect function call overhead. */ + +tree +gimple_fold_stmt_to_constant_1 (gimple stmt, tree (*valueize) (tree)) +{ + location_t loc = gimple_location (stmt); + switch (gimple_code (stmt)) + { + case GIMPLE_ASSIGN: + { + enum tree_code subcode = gimple_assign_rhs_code (stmt); + + switch (get_gimple_rhs_class (subcode)) + { + case GIMPLE_SINGLE_RHS: + { + tree rhs = gimple_assign_rhs1 (stmt); + enum tree_code_class kind = TREE_CODE_CLASS (subcode); + + if (TREE_CODE (rhs) == SSA_NAME) + { + /* If the RHS is an SSA_NAME, return its known constant value, + if any. */ + return (*valueize) (rhs); + } + /* Handle propagating invariant addresses into address + operations. */ + else if (TREE_CODE (rhs) == ADDR_EXPR + && !is_gimple_min_invariant (rhs)) + { + HOST_WIDE_INT offset = 0; + tree base; + base = get_addr_base_and_unit_offset_1 (TREE_OPERAND (rhs, 0), + &offset, + valueize); + if (base + && (CONSTANT_CLASS_P (base) + || decl_address_invariant_p (base))) + return build_invariant_address (TREE_TYPE (rhs), + base, offset); + } + else if (TREE_CODE (rhs) == CONSTRUCTOR + && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE + && (CONSTRUCTOR_NELTS (rhs) + == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs)))) + { + unsigned i; + tree val, *vec; + + vec = XALLOCAVEC (tree, + TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))); + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val) + { + val = (*valueize) (val); + if (TREE_CODE (val) == INTEGER_CST + || TREE_CODE (val) == REAL_CST + || TREE_CODE (val) == FIXED_CST) + vec[i] = val; + else + return NULL_TREE; + } + + return build_vector (TREE_TYPE (rhs), vec); + } + + if (kind == tcc_reference) + { + if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR + || TREE_CODE (rhs) == REALPART_EXPR + || TREE_CODE (rhs) == IMAGPART_EXPR) + && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) + { + tree val = (*valueize) (TREE_OPERAND (rhs, 0)); + return fold_unary_loc (EXPR_LOCATION (rhs), + TREE_CODE (rhs), + TREE_TYPE (rhs), val); + } + else if (TREE_CODE (rhs) == BIT_FIELD_REF + && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) + { + tree val = (*valueize) (TREE_OPERAND (rhs, 0)); + return fold_ternary_loc (EXPR_LOCATION (rhs), + TREE_CODE (rhs), + TREE_TYPE (rhs), val, + TREE_OPERAND (rhs, 1), + TREE_OPERAND (rhs, 2)); + } + else if (TREE_CODE (rhs) == MEM_REF + && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) + { + tree val = (*valueize) (TREE_OPERAND (rhs, 0)); + if (TREE_CODE (val) == ADDR_EXPR + && is_gimple_min_invariant (val)) + { + tree tem = fold_build2 (MEM_REF, TREE_TYPE (rhs), + unshare_expr (val), + TREE_OPERAND (rhs, 1)); + if (tem) + rhs = tem; + } + } + return fold_const_aggregate_ref_1 (rhs, valueize); + } + else if (kind == tcc_declaration) + return get_symbol_constant_value (rhs); + return rhs; + } + + case GIMPLE_UNARY_RHS: + { + /* Handle unary operators that can appear in GIMPLE form. + Note that we know the single operand must be a constant, + so this should almost always return a simplified RHS. */ + tree lhs = gimple_assign_lhs (stmt); + tree op0 = (*valueize) (gimple_assign_rhs1 (stmt)); + + /* Conversions are useless for CCP purposes if they are + value-preserving. Thus the restrictions that + useless_type_conversion_p places for restrict qualification + of pointer types should not apply here. + Substitution later will only substitute to allowed places. */ + if (CONVERT_EXPR_CODE_P (subcode) + && POINTER_TYPE_P (TREE_TYPE (lhs)) + && POINTER_TYPE_P (TREE_TYPE (op0)) + && TYPE_ADDR_SPACE (TREE_TYPE (lhs)) + == TYPE_ADDR_SPACE (TREE_TYPE (op0)) + && TYPE_MODE (TREE_TYPE (lhs)) + == TYPE_MODE (TREE_TYPE (op0))) + return op0; + + return + fold_unary_ignore_overflow_loc (loc, subcode, + gimple_expr_type (stmt), op0); + } + + case GIMPLE_BINARY_RHS: + { + /* Handle binary operators that can appear in GIMPLE form. */ + tree op0 = (*valueize) (gimple_assign_rhs1 (stmt)); + tree op1 = (*valueize) (gimple_assign_rhs2 (stmt)); + + /* Translate &x + CST into an invariant form suitable for + further propagation. */ + if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR + && TREE_CODE (op0) == ADDR_EXPR + && TREE_CODE (op1) == INTEGER_CST) + { + tree off = fold_convert (ptr_type_node, op1); + return build_fold_addr_expr_loc + (loc, + fold_build2 (MEM_REF, + TREE_TYPE (TREE_TYPE (op0)), + unshare_expr (op0), off)); + } + + return fold_binary_loc (loc, subcode, + gimple_expr_type (stmt), op0, op1); + } + + case GIMPLE_TERNARY_RHS: + { + /* Handle ternary operators that can appear in GIMPLE form. */ + tree op0 = (*valueize) (gimple_assign_rhs1 (stmt)); + tree op1 = (*valueize) (gimple_assign_rhs2 (stmt)); + tree op2 = (*valueize) (gimple_assign_rhs3 (stmt)); + + /* Fold embedded expressions in ternary codes. */ + if ((subcode == COND_EXPR + || subcode == VEC_COND_EXPR) + && COMPARISON_CLASS_P (op0)) + { + tree op00 = (*valueize) (TREE_OPERAND (op0, 0)); + tree op01 = (*valueize) (TREE_OPERAND (op0, 1)); + tree tem = fold_binary_loc (loc, TREE_CODE (op0), + TREE_TYPE (op0), op00, op01); + if (tem) + op0 = tem; + } + + return fold_ternary_loc (loc, subcode, + gimple_expr_type (stmt), op0, op1, op2); + } + + default: + gcc_unreachable (); + } + } + + case GIMPLE_CALL: + { + tree fn; + + if (gimple_call_internal_p (stmt)) + /* No folding yet for these functions. */ + return NULL_TREE; + + fn = (*valueize) (gimple_call_fn (stmt)); + if (TREE_CODE (fn) == ADDR_EXPR + && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL + && DECL_BUILT_IN (TREE_OPERAND (fn, 0))) + { + tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt)); + tree call, retval; + unsigned i; + for (i = 0; i < gimple_call_num_args (stmt); ++i) + args[i] = (*valueize) (gimple_call_arg (stmt, i)); + call = build_call_array_loc (loc, + gimple_call_return_type (stmt), + fn, gimple_call_num_args (stmt), args); + retval = fold_call_expr (EXPR_LOCATION (call), call, false); + if (retval) + /* fold_call_expr wraps the result inside a NOP_EXPR. */ + STRIP_NOPS (retval); + return retval; + } + return NULL_TREE; + } + + default: + return NULL_TREE; + } +} + +/* Fold STMT to a constant using VALUEIZE to valueize SSA names. + Returns NULL_TREE if folding to a constant is not possible, otherwise + returns a constant according to is_gimple_min_invariant. */ + +tree +gimple_fold_stmt_to_constant (gimple stmt, tree (*valueize) (tree)) +{ + tree res = gimple_fold_stmt_to_constant_1 (stmt, valueize); + if (res && is_gimple_min_invariant (res)) + return res; + return NULL_TREE; +} + + +/* The following set of functions are supposed to fold references using + their constant initializers. */ + +static tree fold_ctor_reference (tree type, tree ctor, + unsigned HOST_WIDE_INT offset, + unsigned HOST_WIDE_INT size, tree); + +/* See if we can find constructor defining value of BASE. + When we know the consructor with constant offset (such as + base is array[40] and we do know constructor of array), then + BIT_OFFSET is adjusted accordingly. + + As a special case, return error_mark_node when constructor + is not explicitly available, but it is known to be zero + such as 'static const int a;'. */ +static tree +get_base_constructor (tree base, HOST_WIDE_INT *bit_offset, + tree (*valueize)(tree)) +{ + HOST_WIDE_INT bit_offset2, size, max_size; + if (TREE_CODE (base) == MEM_REF) + { + if (!integer_zerop (TREE_OPERAND (base, 1))) + { + if (!host_integerp (TREE_OPERAND (base, 1), 0)) + return NULL_TREE; + *bit_offset += (mem_ref_offset (base).low + * BITS_PER_UNIT); + } + + if (valueize + && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) + base = valueize (TREE_OPERAND (base, 0)); + if (!base || TREE_CODE (base) != ADDR_EXPR) + return NULL_TREE; + base = TREE_OPERAND (base, 0); + } + + /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its + DECL_INITIAL. If BASE is a nested reference into another + ARRAY_REF or COMPONENT_REF, make a recursive call to resolve + the inner reference. */ + switch (TREE_CODE (base)) + { + case VAR_DECL: + if (!const_value_known_p (base)) + return NULL_TREE; + + /* Fallthru. */ + case CONST_DECL: + if (!DECL_INITIAL (base) + && (TREE_STATIC (base) || DECL_EXTERNAL (base))) + return error_mark_node; + /* Do not return an error_mark_node DECL_INITIAL. LTO uses this + as special marker (_not_ zero ...) for its own purposes. */ + if (DECL_INITIAL (base) == error_mark_node) + return NULL_TREE; + return DECL_INITIAL (base); + + case ARRAY_REF: + case COMPONENT_REF: + base = get_ref_base_and_extent (base, &bit_offset2, &size, &max_size); + if (max_size == -1 || size != max_size) + return NULL_TREE; + *bit_offset += bit_offset2; + return get_base_constructor (base, bit_offset, valueize); + + case STRING_CST: + case CONSTRUCTOR: + return base; + + default: + return NULL_TREE; + } +} + +/* CTOR is STRING_CST. Fold reference of type TYPE and size SIZE + to the memory at bit OFFSET. + + We do only simple job of folding byte accesses. */ + +static tree +fold_string_cst_ctor_reference (tree type, tree ctor, + unsigned HOST_WIDE_INT offset, + unsigned HOST_WIDE_INT size) +{ + if (INTEGRAL_TYPE_P (type) + && (TYPE_MODE (type) + == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) + && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) + == MODE_INT) + && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 + && size == BITS_PER_UNIT + && !(offset % BITS_PER_UNIT)) + { + offset /= BITS_PER_UNIT; + if (offset < (unsigned HOST_WIDE_INT) TREE_STRING_LENGTH (ctor)) + return build_int_cst_type (type, (TREE_STRING_POINTER (ctor) + [offset])); + /* Folding + const char a[20]="hello"; + return a[10]; + + might lead to offset greater than string length. In this case we + know value is either initialized to 0 or out of bounds. Return 0 + in both cases. */ + return build_zero_cst (type); + } + return NULL_TREE; +} + +/* CTOR is CONSTRUCTOR of an array type. Fold reference of type TYPE and size + SIZE to the memory at bit OFFSET. */ + +static tree +fold_array_ctor_reference (tree type, tree ctor, + unsigned HOST_WIDE_INT offset, + unsigned HOST_WIDE_INT size, + tree from_decl) +{ + unsigned HOST_WIDE_INT cnt; + tree cfield, cval; + double_int low_bound, elt_size; + double_int index, max_index; + double_int access_index; + tree domain_type = NULL_TREE, index_type = NULL_TREE; + HOST_WIDE_INT inner_offset; + + /* Compute low bound and elt size. */ + if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE) + domain_type = TYPE_DOMAIN (TREE_TYPE (ctor)); + if (domain_type && TYPE_MIN_VALUE (domain_type)) + { + /* Static constructors for variably sized objects makes no sense. */ + gcc_assert (TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST); + index_type = TREE_TYPE (TYPE_MIN_VALUE (domain_type)); + low_bound = tree_to_double_int (TYPE_MIN_VALUE (domain_type)); + } + else + low_bound = double_int_zero; + /* Static constructors for variably sized objects makes no sense. */ + gcc_assert (TREE_CODE(TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor)))) + == INTEGER_CST); + elt_size = + tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (ctor)))); + + + /* We can handle only constantly sized accesses that are known to not + be larger than size of array element. */ + if (!TYPE_SIZE_UNIT (type) + || TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST + || elt_size.slt (tree_to_double_int (TYPE_SIZE_UNIT (type)))) + return NULL_TREE; + + /* Compute the array index we look for. */ + access_index = double_int::from_uhwi (offset / BITS_PER_UNIT) + .udiv (elt_size, TRUNC_DIV_EXPR); + access_index += low_bound; + if (index_type) + access_index = access_index.ext (TYPE_PRECISION (index_type), + TYPE_UNSIGNED (index_type)); + + /* And offset within the access. */ + inner_offset = offset % (elt_size.to_uhwi () * BITS_PER_UNIT); + + /* See if the array field is large enough to span whole access. We do not + care to fold accesses spanning multiple array indexes. */ + if (inner_offset + size > elt_size.to_uhwi () * BITS_PER_UNIT) + return NULL_TREE; + + index = low_bound - double_int_one; + if (index_type) + index = index.ext (TYPE_PRECISION (index_type), TYPE_UNSIGNED (index_type)); + + FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) + { + /* Array constructor might explicitely set index, or specify range + or leave index NULL meaning that it is next index after previous + one. */ + if (cfield) + { + if (TREE_CODE (cfield) == INTEGER_CST) + max_index = index = tree_to_double_int (cfield); + else + { + gcc_assert (TREE_CODE (cfield) == RANGE_EXPR); + index = tree_to_double_int (TREE_OPERAND (cfield, 0)); + max_index = tree_to_double_int (TREE_OPERAND (cfield, 1)); + } + } + else + { + index += double_int_one; + if (index_type) + index = index.ext (TYPE_PRECISION (index_type), + TYPE_UNSIGNED (index_type)); + max_index = index; + } + + /* Do we have match? */ + if (access_index.cmp (index, 1) >= 0 + && access_index.cmp (max_index, 1) <= 0) + return fold_ctor_reference (type, cval, inner_offset, size, + from_decl); + } + /* When memory is not explicitely mentioned in constructor, + it is 0 (or out of range). */ + return build_zero_cst (type); +} + +/* CTOR is CONSTRUCTOR of an aggregate or vector. + Fold reference of type TYPE and size SIZE to the memory at bit OFFSET. */ + +static tree +fold_nonarray_ctor_reference (tree type, tree ctor, + unsigned HOST_WIDE_INT offset, + unsigned HOST_WIDE_INT size, + tree from_decl) +{ + unsigned HOST_WIDE_INT cnt; + tree cfield, cval; + + FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, + cval) + { + tree byte_offset = DECL_FIELD_OFFSET (cfield); + tree field_offset = DECL_FIELD_BIT_OFFSET (cfield); + tree field_size = DECL_SIZE (cfield); + double_int bitoffset; + double_int byte_offset_cst = tree_to_double_int (byte_offset); + double_int bits_per_unit_cst = double_int::from_uhwi (BITS_PER_UNIT); + double_int bitoffset_end, access_end; + + /* Variable sized objects in static constructors makes no sense, + but field_size can be NULL for flexible array members. */ + gcc_assert (TREE_CODE (field_offset) == INTEGER_CST + && TREE_CODE (byte_offset) == INTEGER_CST + && (field_size != NULL_TREE + ? TREE_CODE (field_size) == INTEGER_CST + : TREE_CODE (TREE_TYPE (cfield)) == ARRAY_TYPE)); + + /* Compute bit offset of the field. */ + bitoffset = tree_to_double_int (field_offset) + + byte_offset_cst * bits_per_unit_cst; + /* Compute bit offset where the field ends. */ + if (field_size != NULL_TREE) + bitoffset_end = bitoffset + tree_to_double_int (field_size); + else + bitoffset_end = double_int_zero; + + access_end = double_int::from_uhwi (offset) + + double_int::from_uhwi (size); + + /* Is there any overlap between [OFFSET, OFFSET+SIZE) and + [BITOFFSET, BITOFFSET_END)? */ + if (access_end.cmp (bitoffset, 0) > 0 + && (field_size == NULL_TREE + || double_int::from_uhwi (offset).slt (bitoffset_end))) + { + double_int inner_offset = double_int::from_uhwi (offset) - bitoffset; + /* We do have overlap. Now see if field is large enough to + cover the access. Give up for accesses spanning multiple + fields. */ + if (access_end.cmp (bitoffset_end, 0) > 0) + return NULL_TREE; + if (double_int::from_uhwi (offset).slt (bitoffset)) + return NULL_TREE; + return fold_ctor_reference (type, cval, + inner_offset.to_uhwi (), size, + from_decl); + } + } + /* When memory is not explicitely mentioned in constructor, it is 0. */ + return build_zero_cst (type); +} + +/* CTOR is value initializing memory, fold reference of type TYPE and size SIZE + to the memory at bit OFFSET. */ + +static tree +fold_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset, + unsigned HOST_WIDE_INT size, tree from_decl) +{ + tree ret; + + /* We found the field with exact match. */ + if (useless_type_conversion_p (type, TREE_TYPE (ctor)) + && !offset) + return canonicalize_constructor_val (unshare_expr (ctor), from_decl); + + /* We are at the end of walk, see if we can view convert the + result. */ + if (!AGGREGATE_TYPE_P (TREE_TYPE (ctor)) && !offset + /* VIEW_CONVERT_EXPR is defined only for matching sizes. */ + && operand_equal_p (TYPE_SIZE (type), + TYPE_SIZE (TREE_TYPE (ctor)), 0)) + { + ret = canonicalize_constructor_val (unshare_expr (ctor), from_decl); + ret = fold_unary (VIEW_CONVERT_EXPR, type, ret); + if (ret) + STRIP_NOPS (ret); + return ret; + } + if (TREE_CODE (ctor) == STRING_CST) + return fold_string_cst_ctor_reference (type, ctor, offset, size); + if (TREE_CODE (ctor) == CONSTRUCTOR) + { + + if (TREE_CODE (TREE_TYPE (ctor)) == ARRAY_TYPE + || TREE_CODE (TREE_TYPE (ctor)) == VECTOR_TYPE) + return fold_array_ctor_reference (type, ctor, offset, size, + from_decl); + else + return fold_nonarray_ctor_reference (type, ctor, offset, size, + from_decl); + } + + return NULL_TREE; +} + +/* Return the tree representing the element referenced by T if T is an + ARRAY_REF or COMPONENT_REF into constant aggregates valuezing SSA + names using VALUEIZE. Return NULL_TREE otherwise. */ + +tree +fold_const_aggregate_ref_1 (tree t, tree (*valueize) (tree)) +{ + tree ctor, idx, base; + HOST_WIDE_INT offset, size, max_size; + tree tem; + + if (TREE_THIS_VOLATILE (t)) + return NULL_TREE; + + if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration) + return get_symbol_constant_value (t); + + tem = fold_read_from_constant_string (t); + if (tem) + return tem; + + switch (TREE_CODE (t)) + { + case ARRAY_REF: + case ARRAY_RANGE_REF: + /* Constant indexes are handled well by get_base_constructor. + Only special case variable offsets. + FIXME: This code can't handle nested references with variable indexes + (they will be handled only by iteration of ccp). Perhaps we can bring + get_ref_base_and_extent here and make it use a valueize callback. */ + if (TREE_CODE (TREE_OPERAND (t, 1)) == SSA_NAME + && valueize + && (idx = (*valueize) (TREE_OPERAND (t, 1))) + && TREE_CODE (idx) == INTEGER_CST) + { + tree low_bound, unit_size; + double_int doffset; + + /* If the resulting bit-offset is constant, track it. */ + if ((low_bound = array_ref_low_bound (t), + TREE_CODE (low_bound) == INTEGER_CST) + && (unit_size = array_ref_element_size (t), + host_integerp (unit_size, 1)) + && (doffset = (TREE_INT_CST (idx) - TREE_INT_CST (low_bound)) + .sext (TYPE_PRECISION (TREE_TYPE (idx))), + doffset.fits_shwi ())) + { + offset = doffset.to_shwi (); + offset *= TREE_INT_CST_LOW (unit_size); + offset *= BITS_PER_UNIT; + + base = TREE_OPERAND (t, 0); + ctor = get_base_constructor (base, &offset, valueize); + /* Empty constructor. Always fold to 0. */ + if (ctor == error_mark_node) + return build_zero_cst (TREE_TYPE (t)); + /* Out of bound array access. Value is undefined, + but don't fold. */ + if (offset < 0) + return NULL_TREE; + /* We can not determine ctor. */ + if (!ctor) + return NULL_TREE; + return fold_ctor_reference (TREE_TYPE (t), ctor, offset, + TREE_INT_CST_LOW (unit_size) + * BITS_PER_UNIT, + base); + } + } + /* Fallthru. */ + + case COMPONENT_REF: + case BIT_FIELD_REF: + case TARGET_MEM_REF: + case MEM_REF: + base = get_ref_base_and_extent (t, &offset, &size, &max_size); + ctor = get_base_constructor (base, &offset, valueize); + + /* Empty constructor. Always fold to 0. */ + if (ctor == error_mark_node) + return build_zero_cst (TREE_TYPE (t)); + /* We do not know precise address. */ + if (max_size == -1 || max_size != size) + return NULL_TREE; + /* We can not determine ctor. */ + if (!ctor) + return NULL_TREE; + + /* Out of bound array access. Value is undefined, but don't fold. */ + if (offset < 0) + return NULL_TREE; + + return fold_ctor_reference (TREE_TYPE (t), ctor, offset, size, + base); + + case REALPART_EXPR: + case IMAGPART_EXPR: + { + tree c = fold_const_aggregate_ref_1 (TREE_OPERAND (t, 0), valueize); + if (c && TREE_CODE (c) == COMPLEX_CST) + return fold_build1_loc (EXPR_LOCATION (t), + TREE_CODE (t), TREE_TYPE (t), c); + break; + } + + default: + break; + } + + return NULL_TREE; +} + +tree +fold_const_aggregate_ref (tree t) +{ + return fold_const_aggregate_ref_1 (t, NULL); +} + +/* Return a declaration of a function which an OBJ_TYPE_REF references. TOKEN + is integer form of OBJ_TYPE_REF_TOKEN of the reference expression. + KNOWN_BINFO carries the binfo describing the true type of + OBJ_TYPE_REF_OBJECT(REF). */ + +tree +gimple_get_virt_method_for_binfo (HOST_WIDE_INT token, tree known_binfo) +{ + unsigned HOST_WIDE_INT offset, size; + tree v, fn, vtable; + + vtable = v = BINFO_VTABLE (known_binfo); + /* If there is no virtual methods table, leave the OBJ_TYPE_REF alone. */ + if (!v) + return NULL_TREE; + + if (TREE_CODE (v) == POINTER_PLUS_EXPR) + { + offset = tree_low_cst (TREE_OPERAND (v, 1), 1) * BITS_PER_UNIT; + v = TREE_OPERAND (v, 0); + } + else + offset = 0; + + if (TREE_CODE (v) != ADDR_EXPR) + return NULL_TREE; + v = TREE_OPERAND (v, 0); + + if (TREE_CODE (v) != VAR_DECL + || !DECL_VIRTUAL_P (v) + || !DECL_INITIAL (v) + || DECL_INITIAL (v) == error_mark_node) + return NULL_TREE; + gcc_checking_assert (TREE_CODE (TREE_TYPE (v)) == ARRAY_TYPE); + size = tree_low_cst (TYPE_SIZE (TREE_TYPE (TREE_TYPE (v))), 1); + offset += token * size; + fn = fold_ctor_reference (TREE_TYPE (TREE_TYPE (v)), DECL_INITIAL (v), + offset, size, vtable); + if (!fn || integer_zerop (fn)) + return NULL_TREE; + gcc_assert (TREE_CODE (fn) == ADDR_EXPR + || TREE_CODE (fn) == FDESC_EXPR); + fn = TREE_OPERAND (fn, 0); + gcc_assert (TREE_CODE (fn) == FUNCTION_DECL); + + /* When cgraph node is missing and function is not public, we cannot + devirtualize. This can happen in WHOPR when the actual method + ends up in other partition, because we found devirtualization + possibility too late. */ + if (!can_refer_decl_in_current_unit_p (fn, vtable)) + return NULL_TREE; + + /* Make sure we create a cgraph node for functions we'll reference. + They can be non-existent if the reference comes from an entry + of an external vtable for example. */ + cgraph_get_create_node (fn); + + return fn; +} + +/* Return true iff VAL is a gimple expression that is known to be + non-negative. Restricted to floating-point inputs. */ + +bool +gimple_val_nonnegative_real_p (tree val) +{ + gimple def_stmt; + + gcc_assert (val && SCALAR_FLOAT_TYPE_P (TREE_TYPE (val))); + + /* Use existing logic for non-gimple trees. */ + if (tree_expr_nonnegative_p (val)) + return true; + + if (TREE_CODE (val) != SSA_NAME) + return false; + + /* Currently we look only at the immediately defining statement + to make this determination, since recursion on defining + statements of operands can lead to quadratic behavior in the + worst case. This is expected to catch almost all occurrences + in practice. It would be possible to implement limited-depth + recursion if important cases are lost. Alternatively, passes + that need this information (such as the pow/powi lowering code + in the cse_sincos pass) could be revised to provide it through + dataflow propagation. */ + + def_stmt = SSA_NAME_DEF_STMT (val); + + if (is_gimple_assign (def_stmt)) + { + tree op0, op1; + + /* See fold-const.c:tree_expr_nonnegative_p for additional + cases that could be handled with recursion. */ + + switch (gimple_assign_rhs_code (def_stmt)) + { + case ABS_EXPR: + /* Always true for floating-point operands. */ + return true; + + case MULT_EXPR: + /* True if the two operands are identical (since we are + restricted to floating-point inputs). */ + op0 = gimple_assign_rhs1 (def_stmt); + op1 = gimple_assign_rhs2 (def_stmt); + + if (op0 == op1 + || operand_equal_p (op0, op1, 0)) + return true; + + default: + return false; + } + } + else if (is_gimple_call (def_stmt)) + { + tree fndecl = gimple_call_fndecl (def_stmt); + if (fndecl + && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) + { + tree arg1; + + switch (DECL_FUNCTION_CODE (fndecl)) + { + CASE_FLT_FN (BUILT_IN_ACOS): + CASE_FLT_FN (BUILT_IN_ACOSH): + CASE_FLT_FN (BUILT_IN_CABS): + CASE_FLT_FN (BUILT_IN_COSH): + CASE_FLT_FN (BUILT_IN_ERFC): + CASE_FLT_FN (BUILT_IN_EXP): + CASE_FLT_FN (BUILT_IN_EXP10): + CASE_FLT_FN (BUILT_IN_EXP2): + CASE_FLT_FN (BUILT_IN_FABS): + CASE_FLT_FN (BUILT_IN_FDIM): + CASE_FLT_FN (BUILT_IN_HYPOT): + CASE_FLT_FN (BUILT_IN_POW10): + return true; + + CASE_FLT_FN (BUILT_IN_SQRT): + /* sqrt(-0.0) is -0.0, and sqrt is not defined over other + nonnegative inputs. */ + if (!HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (val)))) + return true; + + break; + + CASE_FLT_FN (BUILT_IN_POWI): + /* True if the second argument is an even integer. */ + arg1 = gimple_call_arg (def_stmt, 1); + + if (TREE_CODE (arg1) == INTEGER_CST + && (TREE_INT_CST_LOW (arg1) & 1) == 0) + return true; + + break; + + CASE_FLT_FN (BUILT_IN_POW): + /* True if the second argument is an even integer-valued + real. */ + arg1 = gimple_call_arg (def_stmt, 1); + + if (TREE_CODE (arg1) == REAL_CST) + { + REAL_VALUE_TYPE c; + HOST_WIDE_INT n; + + c = TREE_REAL_CST (arg1); + n = real_to_integer (&c); + + if ((n & 1) == 0) + { + REAL_VALUE_TYPE cint; + real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0); + if (real_identical (&c, &cint)) + return true; + } + } + + break; + + default: + return false; + } + } + } + + return false; +} |