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Diffstat (limited to 'gcc-4.8.1/gcc/tree-ssa-loop-im.c')
| -rw-r--r-- | gcc-4.8.1/gcc/tree-ssa-loop-im.c | 2644 |
1 files changed, 0 insertions, 2644 deletions
diff --git a/gcc-4.8.1/gcc/tree-ssa-loop-im.c b/gcc-4.8.1/gcc/tree-ssa-loop-im.c deleted file mode 100644 index 78ad07330..000000000 --- a/gcc-4.8.1/gcc/tree-ssa-loop-im.c +++ /dev/null @@ -1,2644 +0,0 @@ -/* Loop invariant motion. - Copyright (C) 2003-2013 Free Software Foundation, Inc. - -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 "tm_p.h" -#include "basic-block.h" -#include "gimple-pretty-print.h" -#include "tree-flow.h" -#include "cfgloop.h" -#include "domwalk.h" -#include "params.h" -#include "tree-pass.h" -#include "flags.h" -#include "hashtab.h" -#include "tree-affine.h" -#include "pointer-set.h" -#include "tree-ssa-propagate.h" - -/* TODO: Support for predicated code motion. I.e. - - while (1) - { - if (cond) - { - a = inv; - something; - } - } - - Where COND and INV are invariants, but evaluating INV may trap or be - invalid from some other reason if !COND. This may be transformed to - - if (cond) - a = inv; - while (1) - { - if (cond) - something; - } */ - -/* A type for the list of statements that have to be moved in order to be able - to hoist an invariant computation. */ - -struct depend -{ - gimple stmt; - struct depend *next; -}; - -/* The auxiliary data kept for each statement. */ - -struct lim_aux_data -{ - struct loop *max_loop; /* The outermost loop in that the statement - is invariant. */ - - struct loop *tgt_loop; /* The loop out of that we want to move the - invariant. */ - - struct loop *always_executed_in; - /* The outermost loop for that we are sure - the statement is executed if the loop - is entered. */ - - unsigned cost; /* Cost of the computation performed by the - statement. */ - - struct depend *depends; /* List of statements that must be also hoisted - out of the loop when this statement is - hoisted; i.e. those that define the operands - of the statement and are inside of the - MAX_LOOP loop. */ -}; - -/* Maps statements to their lim_aux_data. */ - -static struct pointer_map_t *lim_aux_data_map; - -/* Description of a memory reference location. */ - -typedef struct mem_ref_loc -{ - tree *ref; /* The reference itself. */ - gimple stmt; /* The statement in that it occurs. */ -} *mem_ref_loc_p; - - -/* The list of memory reference locations in a loop. */ - -typedef struct mem_ref_locs -{ - vec<mem_ref_loc_p> locs; -} *mem_ref_locs_p; - - -/* Description of a memory reference. */ - -typedef struct mem_ref -{ - tree mem; /* The memory itself. */ - unsigned id; /* ID assigned to the memory reference - (its index in memory_accesses.refs_list) */ - hashval_t hash; /* Its hash value. */ - bitmap stored; /* The set of loops in that this memory location - is stored to. */ - vec<mem_ref_locs_p> accesses_in_loop; - /* The locations of the accesses. Vector - indexed by the loop number. */ - - /* The following sets are computed on demand. We keep both set and - its complement, so that we know whether the information was - already computed or not. */ - bitmap indep_loop; /* The set of loops in that the memory - reference is independent, meaning: - If it is stored in the loop, this store - is independent on all other loads and - stores. - If it is only loaded, then it is independent - on all stores in the loop. */ - bitmap dep_loop; /* The complement of INDEP_LOOP. */ - - bitmap indep_ref; /* The set of memory references on that - this reference is independent. */ - bitmap dep_ref; /* The complement of INDEP_REF. */ -} *mem_ref_p; - - - - -/* Description of memory accesses in loops. */ - -static struct -{ - /* The hash table of memory references accessed in loops. */ - htab_t refs; - - /* The list of memory references. */ - vec<mem_ref_p> refs_list; - - /* The set of memory references accessed in each loop. */ - vec<bitmap> refs_in_loop; - - /* The set of memory references accessed in each loop, including - subloops. */ - vec<bitmap> all_refs_in_loop; - - /* The set of memory references stored in each loop, including - subloops. */ - vec<bitmap> all_refs_stored_in_loop; - - /* Cache for expanding memory addresses. */ - struct pointer_map_t *ttae_cache; -} memory_accesses; - -/* Obstack for the bitmaps in the above data structures. */ -static bitmap_obstack lim_bitmap_obstack; - -static bool ref_indep_loop_p (struct loop *, mem_ref_p); - -/* Minimum cost of an expensive expression. */ -#define LIM_EXPENSIVE ((unsigned) PARAM_VALUE (PARAM_LIM_EXPENSIVE)) - -/* The outermost loop for which execution of the header guarantees that the - block will be executed. */ -#define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux) -#define SET_ALWAYS_EXECUTED_IN(BB, VAL) ((BB)->aux = (void *) (VAL)) - -/* Whether the reference was analyzable. */ -#define MEM_ANALYZABLE(REF) ((REF)->mem != error_mark_node) - -static struct lim_aux_data * -init_lim_data (gimple stmt) -{ - void **p = pointer_map_insert (lim_aux_data_map, stmt); - - *p = XCNEW (struct lim_aux_data); - return (struct lim_aux_data *) *p; -} - -static struct lim_aux_data * -get_lim_data (gimple stmt) -{ - void **p = pointer_map_contains (lim_aux_data_map, stmt); - if (!p) - return NULL; - - return (struct lim_aux_data *) *p; -} - -/* Releases the memory occupied by DATA. */ - -static void -free_lim_aux_data (struct lim_aux_data *data) -{ - struct depend *dep, *next; - - for (dep = data->depends; dep; dep = next) - { - next = dep->next; - free (dep); - } - free (data); -} - -static void -clear_lim_data (gimple stmt) -{ - void **p = pointer_map_contains (lim_aux_data_map, stmt); - if (!p) - return; - - free_lim_aux_data ((struct lim_aux_data *) *p); - *p = NULL; -} - -/* Calls CBCK for each index in memory reference ADDR_P. There are two - kinds situations handled; in each of these cases, the memory reference - and DATA are passed to the callback: - - Access to an array: ARRAY_{RANGE_}REF (base, index). In this case we also - pass the pointer to the index to the callback. - - Pointer dereference: INDIRECT_REF (addr). In this case we also pass the - pointer to addr to the callback. - - If the callback returns false, the whole search stops and false is returned. - Otherwise the function returns true after traversing through the whole - reference *ADDR_P. */ - -bool -for_each_index (tree *addr_p, bool (*cbck) (tree, tree *, void *), void *data) -{ - tree *nxt, *idx; - - for (; ; addr_p = nxt) - { - switch (TREE_CODE (*addr_p)) - { - case SSA_NAME: - return cbck (*addr_p, addr_p, data); - - case MEM_REF: - nxt = &TREE_OPERAND (*addr_p, 0); - return cbck (*addr_p, nxt, data); - - case BIT_FIELD_REF: - case VIEW_CONVERT_EXPR: - case REALPART_EXPR: - case IMAGPART_EXPR: - nxt = &TREE_OPERAND (*addr_p, 0); - break; - - case COMPONENT_REF: - /* If the component has varying offset, it behaves like index - as well. */ - idx = &TREE_OPERAND (*addr_p, 2); - if (*idx - && !cbck (*addr_p, idx, data)) - return false; - - nxt = &TREE_OPERAND (*addr_p, 0); - break; - - case ARRAY_REF: - case ARRAY_RANGE_REF: - nxt = &TREE_OPERAND (*addr_p, 0); - if (!cbck (*addr_p, &TREE_OPERAND (*addr_p, 1), data)) - return false; - break; - - case VAR_DECL: - case PARM_DECL: - case CONST_DECL: - case STRING_CST: - case RESULT_DECL: - case VECTOR_CST: - case COMPLEX_CST: - case INTEGER_CST: - case REAL_CST: - case FIXED_CST: - case CONSTRUCTOR: - return true; - - case ADDR_EXPR: - gcc_assert (is_gimple_min_invariant (*addr_p)); - return true; - - case TARGET_MEM_REF: - idx = &TMR_BASE (*addr_p); - if (*idx - && !cbck (*addr_p, idx, data)) - return false; - idx = &TMR_INDEX (*addr_p); - if (*idx - && !cbck (*addr_p, idx, data)) - return false; - idx = &TMR_INDEX2 (*addr_p); - if (*idx - && !cbck (*addr_p, idx, data)) - return false; - return true; - - default: - gcc_unreachable (); - } - } -} - -/* If it is possible to hoist the statement STMT unconditionally, - returns MOVE_POSSIBLE. - If it is possible to hoist the statement STMT, but we must avoid making - it executed if it would not be executed in the original program (e.g. - because it may trap), return MOVE_PRESERVE_EXECUTION. - Otherwise return MOVE_IMPOSSIBLE. */ - -enum move_pos -movement_possibility (gimple stmt) -{ - tree lhs; - enum move_pos ret = MOVE_POSSIBLE; - - if (flag_unswitch_loops - && gimple_code (stmt) == GIMPLE_COND) - { - /* If we perform unswitching, force the operands of the invariant - condition to be moved out of the loop. */ - return MOVE_POSSIBLE; - } - - if (gimple_code (stmt) == GIMPLE_PHI - && gimple_phi_num_args (stmt) <= 2 - && !virtual_operand_p (gimple_phi_result (stmt)) - && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_phi_result (stmt))) - return MOVE_POSSIBLE; - - if (gimple_get_lhs (stmt) == NULL_TREE) - return MOVE_IMPOSSIBLE; - - if (gimple_vdef (stmt)) - return MOVE_IMPOSSIBLE; - - if (stmt_ends_bb_p (stmt) - || gimple_has_volatile_ops (stmt) - || gimple_has_side_effects (stmt) - || stmt_could_throw_p (stmt)) - return MOVE_IMPOSSIBLE; - - if (is_gimple_call (stmt)) - { - /* While pure or const call is guaranteed to have no side effects, we - cannot move it arbitrarily. Consider code like - - char *s = something (); - - while (1) - { - if (s) - t = strlen (s); - else - t = 0; - } - - Here the strlen call cannot be moved out of the loop, even though - s is invariant. In addition to possibly creating a call with - invalid arguments, moving out a function call that is not executed - may cause performance regressions in case the call is costly and - not executed at all. */ - ret = MOVE_PRESERVE_EXECUTION; - lhs = gimple_call_lhs (stmt); - } - else if (is_gimple_assign (stmt)) - lhs = gimple_assign_lhs (stmt); - else - return MOVE_IMPOSSIBLE; - - if (TREE_CODE (lhs) == SSA_NAME - && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) - return MOVE_IMPOSSIBLE; - - if (TREE_CODE (lhs) != SSA_NAME - || gimple_could_trap_p (stmt)) - return MOVE_PRESERVE_EXECUTION; - - /* Non local loads in a transaction cannot be hoisted out. Well, - unless the load happens on every path out of the loop, but we - don't take this into account yet. */ - if (flag_tm - && gimple_in_transaction (stmt) - && gimple_assign_single_p (stmt)) - { - tree rhs = gimple_assign_rhs1 (stmt); - if (DECL_P (rhs) && is_global_var (rhs)) - { - if (dump_file) - { - fprintf (dump_file, "Cannot hoist conditional load of "); - print_generic_expr (dump_file, rhs, TDF_SLIM); - fprintf (dump_file, " because it is in a transaction.\n"); - } - return MOVE_IMPOSSIBLE; - } - } - - return ret; -} - -/* Suppose that operand DEF is used inside the LOOP. Returns the outermost - loop to that we could move the expression using DEF if it did not have - other operands, i.e. the outermost loop enclosing LOOP in that the value - of DEF is invariant. */ - -static struct loop * -outermost_invariant_loop (tree def, struct loop *loop) -{ - gimple def_stmt; - basic_block def_bb; - struct loop *max_loop; - struct lim_aux_data *lim_data; - - if (!def) - return superloop_at_depth (loop, 1); - - if (TREE_CODE (def) != SSA_NAME) - { - gcc_assert (is_gimple_min_invariant (def)); - return superloop_at_depth (loop, 1); - } - - def_stmt = SSA_NAME_DEF_STMT (def); - def_bb = gimple_bb (def_stmt); - if (!def_bb) - return superloop_at_depth (loop, 1); - - max_loop = find_common_loop (loop, def_bb->loop_father); - - lim_data = get_lim_data (def_stmt); - if (lim_data != NULL && lim_data->max_loop != NULL) - max_loop = find_common_loop (max_loop, - loop_outer (lim_data->max_loop)); - if (max_loop == loop) - return NULL; - max_loop = superloop_at_depth (loop, loop_depth (max_loop) + 1); - - return max_loop; -} - -/* DATA is a structure containing information associated with a statement - inside LOOP. DEF is one of the operands of this statement. - - Find the outermost loop enclosing LOOP in that value of DEF is invariant - and record this in DATA->max_loop field. If DEF itself is defined inside - this loop as well (i.e. we need to hoist it out of the loop if we want - to hoist the statement represented by DATA), record the statement in that - DEF is defined to the DATA->depends list. Additionally if ADD_COST is true, - add the cost of the computation of DEF to the DATA->cost. - - If DEF is not invariant in LOOP, return false. Otherwise return TRUE. */ - -static bool -add_dependency (tree def, struct lim_aux_data *data, struct loop *loop, - bool add_cost) -{ - gimple def_stmt = SSA_NAME_DEF_STMT (def); - basic_block def_bb = gimple_bb (def_stmt); - struct loop *max_loop; - struct depend *dep; - struct lim_aux_data *def_data; - - if (!def_bb) - return true; - - max_loop = outermost_invariant_loop (def, loop); - if (!max_loop) - return false; - - if (flow_loop_nested_p (data->max_loop, max_loop)) - data->max_loop = max_loop; - - def_data = get_lim_data (def_stmt); - if (!def_data) - return true; - - if (add_cost - /* Only add the cost if the statement defining DEF is inside LOOP, - i.e. if it is likely that by moving the invariants dependent - on it, we will be able to avoid creating a new register for - it (since it will be only used in these dependent invariants). */ - && def_bb->loop_father == loop) - data->cost += def_data->cost; - - dep = XNEW (struct depend); - dep->stmt = def_stmt; - dep->next = data->depends; - data->depends = dep; - - return true; -} - -/* Returns an estimate for a cost of statement STMT. The values here - are just ad-hoc constants, similar to costs for inlining. */ - -static unsigned -stmt_cost (gimple stmt) -{ - /* Always try to create possibilities for unswitching. */ - if (gimple_code (stmt) == GIMPLE_COND - || gimple_code (stmt) == GIMPLE_PHI) - return LIM_EXPENSIVE; - - /* We should be hoisting calls if possible. */ - if (is_gimple_call (stmt)) - { - tree fndecl; - - /* Unless the call is a builtin_constant_p; this always folds to a - constant, so moving it is useless. */ - fndecl = gimple_call_fndecl (stmt); - if (fndecl - && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL - && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P) - return 0; - - return LIM_EXPENSIVE; - } - - /* Hoisting memory references out should almost surely be a win. */ - if (gimple_references_memory_p (stmt)) - return LIM_EXPENSIVE; - - if (gimple_code (stmt) != GIMPLE_ASSIGN) - return 1; - - switch (gimple_assign_rhs_code (stmt)) - { - case MULT_EXPR: - case WIDEN_MULT_EXPR: - case WIDEN_MULT_PLUS_EXPR: - case WIDEN_MULT_MINUS_EXPR: - case DOT_PROD_EXPR: - case FMA_EXPR: - case TRUNC_DIV_EXPR: - case CEIL_DIV_EXPR: - case FLOOR_DIV_EXPR: - case ROUND_DIV_EXPR: - case EXACT_DIV_EXPR: - case CEIL_MOD_EXPR: - case FLOOR_MOD_EXPR: - case ROUND_MOD_EXPR: - case TRUNC_MOD_EXPR: - case RDIV_EXPR: - /* Division and multiplication are usually expensive. */ - return LIM_EXPENSIVE; - - case LSHIFT_EXPR: - case RSHIFT_EXPR: - case WIDEN_LSHIFT_EXPR: - case LROTATE_EXPR: - case RROTATE_EXPR: - /* Shifts and rotates are usually expensive. */ - return LIM_EXPENSIVE; - - case CONSTRUCTOR: - /* Make vector construction cost proportional to the number - of elements. */ - return CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt)); - - case SSA_NAME: - case PAREN_EXPR: - /* Whether or not something is wrapped inside a PAREN_EXPR - should not change move cost. Nor should an intermediate - unpropagated SSA name copy. */ - return 0; - - default: - return 1; - } -} - -/* Finds the outermost loop between OUTER and LOOP in that the memory reference - REF is independent. If REF is not independent in LOOP, NULL is returned - instead. */ - -static struct loop * -outermost_indep_loop (struct loop *outer, struct loop *loop, mem_ref_p ref) -{ - struct loop *aloop; - - if (bitmap_bit_p (ref->stored, loop->num)) - return NULL; - - for (aloop = outer; - aloop != loop; - aloop = superloop_at_depth (loop, loop_depth (aloop) + 1)) - if (!bitmap_bit_p (ref->stored, aloop->num) - && ref_indep_loop_p (aloop, ref)) - return aloop; - - if (ref_indep_loop_p (loop, ref)) - return loop; - else - return NULL; -} - -/* If there is a simple load or store to a memory reference in STMT, returns - the location of the memory reference, and sets IS_STORE according to whether - it is a store or load. Otherwise, returns NULL. */ - -static tree * -simple_mem_ref_in_stmt (gimple stmt, bool *is_store) -{ - tree *lhs, *rhs; - - /* Recognize SSA_NAME = MEM and MEM = (SSA_NAME | invariant) patterns. */ - if (!gimple_assign_single_p (stmt)) - return NULL; - - lhs = gimple_assign_lhs_ptr (stmt); - rhs = gimple_assign_rhs1_ptr (stmt); - - if (TREE_CODE (*lhs) == SSA_NAME && gimple_vuse (stmt)) - { - *is_store = false; - return rhs; - } - else if (gimple_vdef (stmt) - && (TREE_CODE (*rhs) == SSA_NAME || is_gimple_min_invariant (*rhs))) - { - *is_store = true; - return lhs; - } - else - return NULL; -} - -/* Returns the memory reference contained in STMT. */ - -static mem_ref_p -mem_ref_in_stmt (gimple stmt) -{ - bool store; - tree *mem = simple_mem_ref_in_stmt (stmt, &store); - hashval_t hash; - mem_ref_p ref; - - if (!mem) - return NULL; - gcc_assert (!store); - - hash = iterative_hash_expr (*mem, 0); - ref = (mem_ref_p) htab_find_with_hash (memory_accesses.refs, *mem, hash); - - gcc_assert (ref != NULL); - return ref; -} - -/* From a controlling predicate in DOM determine the arguments from - the PHI node PHI that are chosen if the predicate evaluates to - true and false and store them to *TRUE_ARG_P and *FALSE_ARG_P if - they are non-NULL. Returns true if the arguments can be determined, - else return false. */ - -static bool -extract_true_false_args_from_phi (basic_block dom, gimple phi, - tree *true_arg_p, tree *false_arg_p) -{ - basic_block bb = gimple_bb (phi); - edge true_edge, false_edge, tem; - tree arg0 = NULL_TREE, arg1 = NULL_TREE; - - /* We have to verify that one edge into the PHI node is dominated - by the true edge of the predicate block and the other edge - dominated by the false edge. This ensures that the PHI argument - we are going to take is completely determined by the path we - take from the predicate block. - We can only use BB dominance checks below if the destination of - the true/false edges are dominated by their edge, thus only - have a single predecessor. */ - extract_true_false_edges_from_block (dom, &true_edge, &false_edge); - tem = EDGE_PRED (bb, 0); - if (tem == true_edge - || (single_pred_p (true_edge->dest) - && (tem->src == true_edge->dest - || dominated_by_p (CDI_DOMINATORS, - tem->src, true_edge->dest)))) - arg0 = PHI_ARG_DEF (phi, tem->dest_idx); - else if (tem == false_edge - || (single_pred_p (false_edge->dest) - && (tem->src == false_edge->dest - || dominated_by_p (CDI_DOMINATORS, - tem->src, false_edge->dest)))) - arg1 = PHI_ARG_DEF (phi, tem->dest_idx); - else - return false; - tem = EDGE_PRED (bb, 1); - if (tem == true_edge - || (single_pred_p (true_edge->dest) - && (tem->src == true_edge->dest - || dominated_by_p (CDI_DOMINATORS, - tem->src, true_edge->dest)))) - arg0 = PHI_ARG_DEF (phi, tem->dest_idx); - else if (tem == false_edge - || (single_pred_p (false_edge->dest) - && (tem->src == false_edge->dest - || dominated_by_p (CDI_DOMINATORS, - tem->src, false_edge->dest)))) - arg1 = PHI_ARG_DEF (phi, tem->dest_idx); - else - return false; - if (!arg0 || !arg1) - return false; - - if (true_arg_p) - *true_arg_p = arg0; - if (false_arg_p) - *false_arg_p = arg1; - - return true; -} - -/* Determine the outermost loop to that it is possible to hoist a statement - STMT and store it to LIM_DATA (STMT)->max_loop. To do this we determine - the outermost loop in that the value computed by STMT is invariant. - If MUST_PRESERVE_EXEC is true, additionally choose such a loop that - we preserve the fact whether STMT is executed. It also fills other related - information to LIM_DATA (STMT). - - The function returns false if STMT cannot be hoisted outside of the loop it - is defined in, and true otherwise. */ - -static bool -determine_max_movement (gimple stmt, bool must_preserve_exec) -{ - basic_block bb = gimple_bb (stmt); - struct loop *loop = bb->loop_father; - struct loop *level; - struct lim_aux_data *lim_data = get_lim_data (stmt); - tree val; - ssa_op_iter iter; - - if (must_preserve_exec) - level = ALWAYS_EXECUTED_IN (bb); - else - level = superloop_at_depth (loop, 1); - lim_data->max_loop = level; - - if (gimple_code (stmt) == GIMPLE_PHI) - { - use_operand_p use_p; - unsigned min_cost = UINT_MAX; - unsigned total_cost = 0; - struct lim_aux_data *def_data; - - /* We will end up promoting dependencies to be unconditionally - evaluated. For this reason the PHI cost (and thus the - cost we remove from the loop by doing the invariant motion) - is that of the cheapest PHI argument dependency chain. */ - FOR_EACH_PHI_ARG (use_p, stmt, iter, SSA_OP_USE) - { - val = USE_FROM_PTR (use_p); - if (TREE_CODE (val) != SSA_NAME) - continue; - if (!add_dependency (val, lim_data, loop, false)) - return false; - def_data = get_lim_data (SSA_NAME_DEF_STMT (val)); - if (def_data) - { - min_cost = MIN (min_cost, def_data->cost); - total_cost += def_data->cost; - } - } - - lim_data->cost += min_cost; - - if (gimple_phi_num_args (stmt) > 1) - { - basic_block dom = get_immediate_dominator (CDI_DOMINATORS, bb); - gimple cond; - if (gsi_end_p (gsi_last_bb (dom))) - return false; - cond = gsi_stmt (gsi_last_bb (dom)); - if (gimple_code (cond) != GIMPLE_COND) - return false; - /* Verify that this is an extended form of a diamond and - the PHI arguments are completely controlled by the - predicate in DOM. */ - if (!extract_true_false_args_from_phi (dom, stmt, NULL, NULL)) - return false; - - /* Fold in dependencies and cost of the condition. */ - FOR_EACH_SSA_TREE_OPERAND (val, cond, iter, SSA_OP_USE) - { - if (!add_dependency (val, lim_data, loop, false)) - return false; - def_data = get_lim_data (SSA_NAME_DEF_STMT (val)); - if (def_data) - total_cost += def_data->cost; - } - - /* We want to avoid unconditionally executing very expensive - operations. As costs for our dependencies cannot be - negative just claim we are not invariand for this case. - We also are not sure whether the control-flow inside the - loop will vanish. */ - if (total_cost - min_cost >= 2 * LIM_EXPENSIVE - && !(min_cost != 0 - && total_cost / min_cost <= 2)) - return false; - - /* Assume that the control-flow in the loop will vanish. - ??? We should verify this and not artificially increase - the cost if that is not the case. */ - lim_data->cost += stmt_cost (stmt); - } - - return true; - } - else - FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_USE) - if (!add_dependency (val, lim_data, loop, true)) - return false; - - if (gimple_vuse (stmt)) - { - mem_ref_p ref = mem_ref_in_stmt (stmt); - - if (ref) - { - lim_data->max_loop - = outermost_indep_loop (lim_data->max_loop, loop, ref); - if (!lim_data->max_loop) - return false; - } - else - { - if ((val = gimple_vuse (stmt)) != NULL_TREE) - { - if (!add_dependency (val, lim_data, loop, false)) - return false; - } - } - } - - lim_data->cost += stmt_cost (stmt); - - return true; -} - -/* Suppose that some statement in ORIG_LOOP is hoisted to the loop LEVEL, - and that one of the operands of this statement is computed by STMT. - Ensure that STMT (together with all the statements that define its - operands) is hoisted at least out of the loop LEVEL. */ - -static void -set_level (gimple stmt, struct loop *orig_loop, struct loop *level) -{ - struct loop *stmt_loop = gimple_bb (stmt)->loop_father; - struct depend *dep; - struct lim_aux_data *lim_data; - - stmt_loop = find_common_loop (orig_loop, stmt_loop); - lim_data = get_lim_data (stmt); - if (lim_data != NULL && lim_data->tgt_loop != NULL) - stmt_loop = find_common_loop (stmt_loop, - loop_outer (lim_data->tgt_loop)); - if (flow_loop_nested_p (stmt_loop, level)) - return; - - gcc_assert (level == lim_data->max_loop - || flow_loop_nested_p (lim_data->max_loop, level)); - - lim_data->tgt_loop = level; - for (dep = lim_data->depends; dep; dep = dep->next) - set_level (dep->stmt, orig_loop, level); -} - -/* Determines an outermost loop from that we want to hoist the statement STMT. - For now we chose the outermost possible loop. TODO -- use profiling - information to set it more sanely. */ - -static void -set_profitable_level (gimple stmt) -{ - set_level (stmt, gimple_bb (stmt)->loop_father, get_lim_data (stmt)->max_loop); -} - -/* Returns true if STMT is a call that has side effects. */ - -static bool -nonpure_call_p (gimple stmt) -{ - if (gimple_code (stmt) != GIMPLE_CALL) - return false; - - return gimple_has_side_effects (stmt); -} - -/* Rewrite a/b to a*(1/b). Return the invariant stmt to process. */ - -static gimple -rewrite_reciprocal (gimple_stmt_iterator *bsi) -{ - gimple stmt, stmt1, stmt2; - tree name, lhs, type; - tree real_one; - gimple_stmt_iterator gsi; - - stmt = gsi_stmt (*bsi); - lhs = gimple_assign_lhs (stmt); - type = TREE_TYPE (lhs); - - real_one = build_one_cst (type); - - name = make_temp_ssa_name (type, NULL, "reciptmp"); - stmt1 = gimple_build_assign_with_ops (RDIV_EXPR, name, real_one, - gimple_assign_rhs2 (stmt)); - - stmt2 = gimple_build_assign_with_ops (MULT_EXPR, lhs, name, - gimple_assign_rhs1 (stmt)); - - /* Replace division stmt with reciprocal and multiply stmts. - The multiply stmt is not invariant, so update iterator - and avoid rescanning. */ - gsi = *bsi; - gsi_insert_before (bsi, stmt1, GSI_NEW_STMT); - gsi_replace (&gsi, stmt2, true); - - /* Continue processing with invariant reciprocal statement. */ - return stmt1; -} - -/* Check if the pattern at *BSI is a bittest of the form - (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0. */ - -static gimple -rewrite_bittest (gimple_stmt_iterator *bsi) -{ - gimple stmt, use_stmt, stmt1, stmt2; - tree lhs, name, t, a, b; - use_operand_p use; - - stmt = gsi_stmt (*bsi); - lhs = gimple_assign_lhs (stmt); - - /* Verify that the single use of lhs is a comparison against zero. */ - if (TREE_CODE (lhs) != SSA_NAME - || !single_imm_use (lhs, &use, &use_stmt) - || gimple_code (use_stmt) != GIMPLE_COND) - return stmt; - if (gimple_cond_lhs (use_stmt) != lhs - || (gimple_cond_code (use_stmt) != NE_EXPR - && gimple_cond_code (use_stmt) != EQ_EXPR) - || !integer_zerop (gimple_cond_rhs (use_stmt))) - return stmt; - - /* Get at the operands of the shift. The rhs is TMP1 & 1. */ - stmt1 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); - if (gimple_code (stmt1) != GIMPLE_ASSIGN) - return stmt; - - /* There is a conversion in between possibly inserted by fold. */ - if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt1))) - { - t = gimple_assign_rhs1 (stmt1); - if (TREE_CODE (t) != SSA_NAME - || !has_single_use (t)) - return stmt; - stmt1 = SSA_NAME_DEF_STMT (t); - if (gimple_code (stmt1) != GIMPLE_ASSIGN) - return stmt; - } - - /* Verify that B is loop invariant but A is not. Verify that with - all the stmt walking we are still in the same loop. */ - if (gimple_assign_rhs_code (stmt1) != RSHIFT_EXPR - || loop_containing_stmt (stmt1) != loop_containing_stmt (stmt)) - return stmt; - - a = gimple_assign_rhs1 (stmt1); - b = gimple_assign_rhs2 (stmt1); - - if (outermost_invariant_loop (b, loop_containing_stmt (stmt1)) != NULL - && outermost_invariant_loop (a, loop_containing_stmt (stmt1)) == NULL) - { - gimple_stmt_iterator rsi; - - /* 1 << B */ - t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (a), - build_int_cst (TREE_TYPE (a), 1), b); - name = make_temp_ssa_name (TREE_TYPE (a), NULL, "shifttmp"); - stmt1 = gimple_build_assign (name, t); - - /* A & (1 << B) */ - t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (a), a, name); - name = make_temp_ssa_name (TREE_TYPE (a), NULL, "shifttmp"); - stmt2 = gimple_build_assign (name, t); - - /* Replace the SSA_NAME we compare against zero. Adjust - the type of zero accordingly. */ - SET_USE (use, name); - gimple_cond_set_rhs (use_stmt, build_int_cst_type (TREE_TYPE (name), 0)); - - /* Don't use gsi_replace here, none of the new assignments sets - the variable originally set in stmt. Move bsi to stmt1, and - then remove the original stmt, so that we get a chance to - retain debug info for it. */ - rsi = *bsi; - gsi_insert_before (bsi, stmt1, GSI_NEW_STMT); - gsi_insert_before (&rsi, stmt2, GSI_SAME_STMT); - gsi_remove (&rsi, true); - - return stmt1; - } - - return stmt; -} - - -/* Determine the outermost loops in that statements in basic block BB are - invariant, and record them to the LIM_DATA associated with the statements. - Callback for walk_dominator_tree. */ - -static void -determine_invariantness_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED, - basic_block bb) -{ - enum move_pos pos; - gimple_stmt_iterator bsi; - gimple stmt; - bool maybe_never = ALWAYS_EXECUTED_IN (bb) == NULL; - struct loop *outermost = ALWAYS_EXECUTED_IN (bb); - struct lim_aux_data *lim_data; - - if (!loop_outer (bb->loop_father)) - return; - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "Basic block %d (loop %d -- depth %d):\n\n", - bb->index, bb->loop_father->num, loop_depth (bb->loop_father)); - - /* Look at PHI nodes, but only if there is at most two. - ??? We could relax this further by post-processing the inserted - code and transforming adjacent cond-exprs with the same predicate - to control flow again. */ - bsi = gsi_start_phis (bb); - if (!gsi_end_p (bsi) - && ((gsi_next (&bsi), gsi_end_p (bsi)) - || (gsi_next (&bsi), gsi_end_p (bsi)))) - for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi)) - { - stmt = gsi_stmt (bsi); - - pos = movement_possibility (stmt); - if (pos == MOVE_IMPOSSIBLE) - continue; - - lim_data = init_lim_data (stmt); - lim_data->always_executed_in = outermost; - - if (!determine_max_movement (stmt, false)) - { - lim_data->max_loop = NULL; - continue; - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - print_gimple_stmt (dump_file, stmt, 2, 0); - fprintf (dump_file, " invariant up to level %d, cost %d.\n\n", - loop_depth (lim_data->max_loop), - lim_data->cost); - } - - if (lim_data->cost >= LIM_EXPENSIVE) - set_profitable_level (stmt); - } - - for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) - { - stmt = gsi_stmt (bsi); - - pos = movement_possibility (stmt); - if (pos == MOVE_IMPOSSIBLE) - { - if (nonpure_call_p (stmt)) - { - maybe_never = true; - outermost = NULL; - } - /* Make sure to note always_executed_in for stores to make - store-motion work. */ - else if (stmt_makes_single_store (stmt)) - { - struct lim_aux_data *lim_data = init_lim_data (stmt); - lim_data->always_executed_in = outermost; - } - continue; - } - - if (is_gimple_assign (stmt) - && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) - == GIMPLE_BINARY_RHS)) - { - tree op0 = gimple_assign_rhs1 (stmt); - tree op1 = gimple_assign_rhs2 (stmt); - struct loop *ol1 = outermost_invariant_loop (op1, - loop_containing_stmt (stmt)); - - /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal - to be hoisted out of loop, saving expensive divide. */ - if (pos == MOVE_POSSIBLE - && gimple_assign_rhs_code (stmt) == RDIV_EXPR - && flag_unsafe_math_optimizations - && !flag_trapping_math - && ol1 != NULL - && outermost_invariant_loop (op0, ol1) == NULL) - stmt = rewrite_reciprocal (&bsi); - - /* If the shift count is invariant, convert (A >> B) & 1 to - A & (1 << B) allowing the bit mask to be hoisted out of the loop - saving an expensive shift. */ - if (pos == MOVE_POSSIBLE - && gimple_assign_rhs_code (stmt) == BIT_AND_EXPR - && integer_onep (op1) - && TREE_CODE (op0) == SSA_NAME - && has_single_use (op0)) - stmt = rewrite_bittest (&bsi); - } - - lim_data = init_lim_data (stmt); - lim_data->always_executed_in = outermost; - - if (maybe_never && pos == MOVE_PRESERVE_EXECUTION) - continue; - - if (!determine_max_movement (stmt, pos == MOVE_PRESERVE_EXECUTION)) - { - lim_data->max_loop = NULL; - continue; - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - print_gimple_stmt (dump_file, stmt, 2, 0); - fprintf (dump_file, " invariant up to level %d, cost %d.\n\n", - loop_depth (lim_data->max_loop), - lim_data->cost); - } - - if (lim_data->cost >= LIM_EXPENSIVE) - set_profitable_level (stmt); - } -} - -/* For each statement determines the outermost loop in that it is invariant, - statements on whose motion it depends and the cost of the computation. - This information is stored to the LIM_DATA structure associated with - each statement. */ - -static void -determine_invariantness (void) -{ - struct dom_walk_data walk_data; - - memset (&walk_data, 0, sizeof (struct dom_walk_data)); - walk_data.dom_direction = CDI_DOMINATORS; - walk_data.before_dom_children = determine_invariantness_stmt; - - init_walk_dominator_tree (&walk_data); - walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); - fini_walk_dominator_tree (&walk_data); -} - -/* Hoist the statements in basic block BB out of the loops prescribed by - data stored in LIM_DATA structures associated with each statement. Callback - for walk_dominator_tree. */ - -static void -move_computations_stmt (struct dom_walk_data *dw_data, - basic_block bb) -{ - struct loop *level; - gimple_stmt_iterator bsi; - gimple stmt; - unsigned cost = 0; - struct lim_aux_data *lim_data; - - if (!loop_outer (bb->loop_father)) - return; - - for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); ) - { - gimple new_stmt; - stmt = gsi_stmt (bsi); - - lim_data = get_lim_data (stmt); - if (lim_data == NULL) - { - gsi_next (&bsi); - continue; - } - - cost = lim_data->cost; - level = lim_data->tgt_loop; - clear_lim_data (stmt); - - if (!level) - { - gsi_next (&bsi); - continue; - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Moving PHI node\n"); - print_gimple_stmt (dump_file, stmt, 0, 0); - fprintf (dump_file, "(cost %u) out of loop %d.\n\n", - cost, level->num); - } - - if (gimple_phi_num_args (stmt) == 1) - { - tree arg = PHI_ARG_DEF (stmt, 0); - new_stmt = gimple_build_assign_with_ops (TREE_CODE (arg), - gimple_phi_result (stmt), - arg, NULL_TREE); - SSA_NAME_DEF_STMT (gimple_phi_result (stmt)) = new_stmt; - } - else - { - basic_block dom = get_immediate_dominator (CDI_DOMINATORS, bb); - gimple cond = gsi_stmt (gsi_last_bb (dom)); - tree arg0 = NULL_TREE, arg1 = NULL_TREE, t; - /* Get the PHI arguments corresponding to the true and false - edges of COND. */ - extract_true_false_args_from_phi (dom, stmt, &arg0, &arg1); - gcc_assert (arg0 && arg1); - t = build2 (gimple_cond_code (cond), boolean_type_node, - gimple_cond_lhs (cond), gimple_cond_rhs (cond)); - new_stmt = gimple_build_assign_with_ops (COND_EXPR, - gimple_phi_result (stmt), - t, arg0, arg1); - SSA_NAME_DEF_STMT (gimple_phi_result (stmt)) = new_stmt; - *((unsigned int *)(dw_data->global_data)) |= TODO_cleanup_cfg; - } - gsi_insert_on_edge (loop_preheader_edge (level), new_stmt); - remove_phi_node (&bsi, false); - } - - for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); ) - { - edge e; - - stmt = gsi_stmt (bsi); - - lim_data = get_lim_data (stmt); - if (lim_data == NULL) - { - gsi_next (&bsi); - continue; - } - - cost = lim_data->cost; - level = lim_data->tgt_loop; - clear_lim_data (stmt); - - if (!level) - { - gsi_next (&bsi); - continue; - } - - /* We do not really want to move conditionals out of the loop; we just - placed it here to force its operands to be moved if necessary. */ - if (gimple_code (stmt) == GIMPLE_COND) - continue; - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Moving statement\n"); - print_gimple_stmt (dump_file, stmt, 0, 0); - fprintf (dump_file, "(cost %u) out of loop %d.\n\n", - cost, level->num); - } - - e = loop_preheader_edge (level); - gcc_assert (!gimple_vdef (stmt)); - if (gimple_vuse (stmt)) - { - /* The new VUSE is the one from the virtual PHI in the loop - header or the one already present. */ - gimple_stmt_iterator gsi2; - for (gsi2 = gsi_start_phis (e->dest); - !gsi_end_p (gsi2); gsi_next (&gsi2)) - { - gimple phi = gsi_stmt (gsi2); - if (virtual_operand_p (gimple_phi_result (phi))) - { - gimple_set_vuse (stmt, PHI_ARG_DEF_FROM_EDGE (phi, e)); - break; - } - } - } - gsi_remove (&bsi, false); - gsi_insert_on_edge (e, stmt); - } -} - -/* Hoist the statements out of the loops prescribed by data stored in - LIM_DATA structures associated with each statement.*/ - -static unsigned int -move_computations (void) -{ - struct dom_walk_data walk_data; - unsigned int todo = 0; - - memset (&walk_data, 0, sizeof (struct dom_walk_data)); - walk_data.global_data = &todo; - walk_data.dom_direction = CDI_DOMINATORS; - walk_data.before_dom_children = move_computations_stmt; - - init_walk_dominator_tree (&walk_data); - walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); - fini_walk_dominator_tree (&walk_data); - - gsi_commit_edge_inserts (); - if (need_ssa_update_p (cfun)) - rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); - - return todo; -} - -/* Checks whether the statement defining variable *INDEX can be hoisted - out of the loop passed in DATA. Callback for for_each_index. */ - -static bool -may_move_till (tree ref, tree *index, void *data) -{ - struct loop *loop = (struct loop *) data, *max_loop; - - /* If REF is an array reference, check also that the step and the lower - bound is invariant in LOOP. */ - if (TREE_CODE (ref) == ARRAY_REF) - { - tree step = TREE_OPERAND (ref, 3); - tree lbound = TREE_OPERAND (ref, 2); - - max_loop = outermost_invariant_loop (step, loop); - if (!max_loop) - return false; - - max_loop = outermost_invariant_loop (lbound, loop); - if (!max_loop) - return false; - } - - max_loop = outermost_invariant_loop (*index, loop); - if (!max_loop) - return false; - - return true; -} - -/* If OP is SSA NAME, force the statement that defines it to be - moved out of the LOOP. ORIG_LOOP is the loop in that EXPR is used. */ - -static void -force_move_till_op (tree op, struct loop *orig_loop, struct loop *loop) -{ - gimple stmt; - - if (!op - || is_gimple_min_invariant (op)) - return; - - gcc_assert (TREE_CODE (op) == SSA_NAME); - - stmt = SSA_NAME_DEF_STMT (op); - if (gimple_nop_p (stmt)) - return; - - set_level (stmt, orig_loop, loop); -} - -/* Forces statement defining invariants in REF (and *INDEX) to be moved out of - the LOOP. The reference REF is used in the loop ORIG_LOOP. Callback for - for_each_index. */ - -struct fmt_data -{ - struct loop *loop; - struct loop *orig_loop; -}; - -static bool -force_move_till (tree ref, tree *index, void *data) -{ - struct fmt_data *fmt_data = (struct fmt_data *) data; - - if (TREE_CODE (ref) == ARRAY_REF) - { - tree step = TREE_OPERAND (ref, 3); - tree lbound = TREE_OPERAND (ref, 2); - - force_move_till_op (step, fmt_data->orig_loop, fmt_data->loop); - force_move_till_op (lbound, fmt_data->orig_loop, fmt_data->loop); - } - - force_move_till_op (*index, fmt_data->orig_loop, fmt_data->loop); - - return true; -} - -/* A hash function for struct mem_ref object OBJ. */ - -static hashval_t -memref_hash (const void *obj) -{ - const struct mem_ref *const mem = (const struct mem_ref *) obj; - - return mem->hash; -} - -/* An equality function for struct mem_ref object OBJ1 with - memory reference OBJ2. */ - -static int -memref_eq (const void *obj1, const void *obj2) -{ - const struct mem_ref *const mem1 = (const struct mem_ref *) obj1; - - return operand_equal_p (mem1->mem, (const_tree) obj2, 0); -} - -/* Releases list of memory reference locations ACCS. */ - -static void -free_mem_ref_locs (mem_ref_locs_p accs) -{ - unsigned i; - mem_ref_loc_p loc; - - if (!accs) - return; - - FOR_EACH_VEC_ELT (accs->locs, i, loc) - free (loc); - accs->locs.release (); - free (accs); -} - -/* A function to free the mem_ref object OBJ. */ - -static void -memref_free (struct mem_ref *mem) -{ - unsigned i; - mem_ref_locs_p accs; - - FOR_EACH_VEC_ELT (mem->accesses_in_loop, i, accs) - free_mem_ref_locs (accs); - mem->accesses_in_loop.release (); - - free (mem); -} - -/* Allocates and returns a memory reference description for MEM whose hash - value is HASH and id is ID. */ - -static mem_ref_p -mem_ref_alloc (tree mem, unsigned hash, unsigned id) -{ - mem_ref_p ref = XNEW (struct mem_ref); - ref->mem = mem; - ref->id = id; - ref->hash = hash; - ref->stored = BITMAP_ALLOC (&lim_bitmap_obstack); - ref->indep_loop = BITMAP_ALLOC (&lim_bitmap_obstack); - ref->dep_loop = BITMAP_ALLOC (&lim_bitmap_obstack); - ref->indep_ref = BITMAP_ALLOC (&lim_bitmap_obstack); - ref->dep_ref = BITMAP_ALLOC (&lim_bitmap_obstack); - ref->accesses_in_loop.create (0); - - return ref; -} - -/* Allocates and returns the new list of locations. */ - -static mem_ref_locs_p -mem_ref_locs_alloc (void) -{ - mem_ref_locs_p accs = XNEW (struct mem_ref_locs); - accs->locs.create (0); - return accs; -} - -/* Records memory reference location *LOC in LOOP to the memory reference - description REF. The reference occurs in statement STMT. */ - -static void -record_mem_ref_loc (mem_ref_p ref, struct loop *loop, gimple stmt, tree *loc) -{ - mem_ref_loc_p aref = XNEW (struct mem_ref_loc); - mem_ref_locs_p accs; - bitmap ril = memory_accesses.refs_in_loop[loop->num]; - - if (ref->accesses_in_loop.length () - <= (unsigned) loop->num) - ref->accesses_in_loop.safe_grow_cleared (loop->num + 1); - accs = ref->accesses_in_loop[loop->num]; - if (!accs) - { - accs = mem_ref_locs_alloc (); - ref->accesses_in_loop[loop->num] = accs; - } - - aref->stmt = stmt; - aref->ref = loc; - - accs->locs.safe_push (aref); - bitmap_set_bit (ril, ref->id); -} - -/* Marks reference REF as stored in LOOP. */ - -static void -mark_ref_stored (mem_ref_p ref, struct loop *loop) -{ - for (; - loop != current_loops->tree_root - && !bitmap_bit_p (ref->stored, loop->num); - loop = loop_outer (loop)) - bitmap_set_bit (ref->stored, loop->num); -} - -/* Gathers memory references in statement STMT in LOOP, storing the - information about them in the memory_accesses structure. Marks - the vops accessed through unrecognized statements there as - well. */ - -static void -gather_mem_refs_stmt (struct loop *loop, gimple stmt) -{ - tree *mem = NULL; - hashval_t hash; - PTR *slot; - mem_ref_p ref; - bool is_stored; - unsigned id; - - if (!gimple_vuse (stmt)) - return; - - mem = simple_mem_ref_in_stmt (stmt, &is_stored); - if (!mem) - { - id = memory_accesses.refs_list.length (); - ref = mem_ref_alloc (error_mark_node, 0, id); - memory_accesses.refs_list.safe_push (ref); - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Unanalyzed memory reference %u: ", id); - print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); - } - if (gimple_vdef (stmt)) - mark_ref_stored (ref, loop); - record_mem_ref_loc (ref, loop, stmt, mem); - return; - } - - hash = iterative_hash_expr (*mem, 0); - slot = htab_find_slot_with_hash (memory_accesses.refs, *mem, hash, INSERT); - - if (*slot) - { - ref = (mem_ref_p) *slot; - id = ref->id; - } - else - { - id = memory_accesses.refs_list.length (); - ref = mem_ref_alloc (*mem, hash, id); - memory_accesses.refs_list.safe_push (ref); - *slot = ref; - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Memory reference %u: ", id); - print_generic_expr (dump_file, ref->mem, TDF_SLIM); - fprintf (dump_file, "\n"); - } - } - - if (is_stored) - mark_ref_stored (ref, loop); - - record_mem_ref_loc (ref, loop, stmt, mem); - return; -} - -/* Gathers memory references in loops. */ - -static void -gather_mem_refs_in_loops (void) -{ - gimple_stmt_iterator bsi; - basic_block bb; - struct loop *loop; - loop_iterator li; - bitmap lrefs, alrefs, alrefso; - - FOR_EACH_BB (bb) - { - loop = bb->loop_father; - if (loop == current_loops->tree_root) - continue; - - for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) - gather_mem_refs_stmt (loop, gsi_stmt (bsi)); - } - - /* Propagate the information about accessed memory references up - the loop hierarchy. */ - FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST) - { - lrefs = memory_accesses.refs_in_loop[loop->num]; - alrefs = memory_accesses.all_refs_in_loop[loop->num]; - bitmap_ior_into (alrefs, lrefs); - - if (loop_outer (loop) == current_loops->tree_root) - continue; - - alrefso = memory_accesses.all_refs_in_loop[loop_outer (loop)->num]; - bitmap_ior_into (alrefso, alrefs); - } -} - -/* Create a mapping from virtual operands to references that touch them - in LOOP. */ - -static void -create_vop_ref_mapping_loop (struct loop *loop) -{ - bitmap refs = memory_accesses.refs_in_loop[loop->num]; - struct loop *sloop; - bitmap_iterator bi; - unsigned i; - mem_ref_p ref; - - EXECUTE_IF_SET_IN_BITMAP (refs, 0, i, bi) - { - ref = memory_accesses.refs_list[i]; - for (sloop = loop; sloop != current_loops->tree_root; - sloop = loop_outer (sloop)) - if (bitmap_bit_p (ref->stored, loop->num)) - { - bitmap refs_stored - = memory_accesses.all_refs_stored_in_loop[sloop->num]; - bitmap_set_bit (refs_stored, ref->id); - } - } -} - -/* For each non-clobbered virtual operand and each loop, record the memory - references in this loop that touch the operand. */ - -static void -create_vop_ref_mapping (void) -{ - loop_iterator li; - struct loop *loop; - - FOR_EACH_LOOP (li, loop, 0) - { - create_vop_ref_mapping_loop (loop); - } -} - -/* Gathers information about memory accesses in the loops. */ - -static void -analyze_memory_references (void) -{ - unsigned i; - bitmap empty; - - memory_accesses.refs = htab_create (100, memref_hash, memref_eq, NULL); - memory_accesses.refs_list.create (0); - memory_accesses.refs_in_loop.create (number_of_loops ()); - memory_accesses.all_refs_in_loop.create (number_of_loops ()); - memory_accesses.all_refs_stored_in_loop.create (number_of_loops ()); - - for (i = 0; i < number_of_loops (); i++) - { - empty = BITMAP_ALLOC (&lim_bitmap_obstack); - memory_accesses.refs_in_loop.quick_push (empty); - empty = BITMAP_ALLOC (&lim_bitmap_obstack); - memory_accesses.all_refs_in_loop.quick_push (empty); - empty = BITMAP_ALLOC (&lim_bitmap_obstack); - memory_accesses.all_refs_stored_in_loop.quick_push (empty); - } - - memory_accesses.ttae_cache = NULL; - - gather_mem_refs_in_loops (); - create_vop_ref_mapping (); -} - -/* Returns true if MEM1 and MEM2 may alias. TTAE_CACHE is used as a cache in - tree_to_aff_combination_expand. */ - -static bool -mem_refs_may_alias_p (tree mem1, tree mem2, struct pointer_map_t **ttae_cache) -{ - /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the same - object and their offset differ in such a way that the locations cannot - overlap, then they cannot alias. */ - double_int size1, size2; - aff_tree off1, off2; - - /* Perform basic offset and type-based disambiguation. */ - if (!refs_may_alias_p (mem1, mem2)) - return false; - - /* The expansion of addresses may be a bit expensive, thus we only do - the check at -O2 and higher optimization levels. */ - if (optimize < 2) - return true; - - get_inner_reference_aff (mem1, &off1, &size1); - get_inner_reference_aff (mem2, &off2, &size2); - aff_combination_expand (&off1, ttae_cache); - aff_combination_expand (&off2, ttae_cache); - aff_combination_scale (&off1, double_int_minus_one); - aff_combination_add (&off2, &off1); - - if (aff_comb_cannot_overlap_p (&off2, size1, size2)) - return false; - - return true; -} - -/* Rewrites location LOC by TMP_VAR. */ - -static void -rewrite_mem_ref_loc (mem_ref_loc_p loc, tree tmp_var) -{ - *loc->ref = tmp_var; - update_stmt (loc->stmt); -} - -/* Adds all locations of REF in LOOP and its subloops to LOCS. */ - -static void -get_all_locs_in_loop (struct loop *loop, mem_ref_p ref, - vec<mem_ref_loc_p> *locs) -{ - mem_ref_locs_p accs; - unsigned i; - mem_ref_loc_p loc; - bitmap refs = memory_accesses.all_refs_in_loop[loop->num]; - struct loop *subloop; - - if (!bitmap_bit_p (refs, ref->id)) - return; - - if (ref->accesses_in_loop.length () - > (unsigned) loop->num) - { - accs = ref->accesses_in_loop[loop->num]; - if (accs) - { - FOR_EACH_VEC_ELT (accs->locs, i, loc) - locs->safe_push (loc); - } - } - - for (subloop = loop->inner; subloop != NULL; subloop = subloop->next) - get_all_locs_in_loop (subloop, ref, locs); -} - -/* Rewrites all references to REF in LOOP by variable TMP_VAR. */ - -static void -rewrite_mem_refs (struct loop *loop, mem_ref_p ref, tree tmp_var) -{ - unsigned i; - mem_ref_loc_p loc; - vec<mem_ref_loc_p> locs = vNULL; - - get_all_locs_in_loop (loop, ref, &locs); - FOR_EACH_VEC_ELT (locs, i, loc) - rewrite_mem_ref_loc (loc, tmp_var); - locs.release (); -} - -/* The name and the length of the currently generated variable - for lsm. */ -#define MAX_LSM_NAME_LENGTH 40 -static char lsm_tmp_name[MAX_LSM_NAME_LENGTH + 1]; -static int lsm_tmp_name_length; - -/* Adds S to lsm_tmp_name. */ - -static void -lsm_tmp_name_add (const char *s) -{ - int l = strlen (s) + lsm_tmp_name_length; - if (l > MAX_LSM_NAME_LENGTH) - return; - - strcpy (lsm_tmp_name + lsm_tmp_name_length, s); - lsm_tmp_name_length = l; -} - -/* Stores the name for temporary variable that replaces REF to - lsm_tmp_name. */ - -static void -gen_lsm_tmp_name (tree ref) -{ - const char *name; - - switch (TREE_CODE (ref)) - { - case MEM_REF: - case TARGET_MEM_REF: - gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); - lsm_tmp_name_add ("_"); - break; - - case ADDR_EXPR: - gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); - break; - - case BIT_FIELD_REF: - case VIEW_CONVERT_EXPR: - case ARRAY_RANGE_REF: - gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); - break; - - case REALPART_EXPR: - gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); - lsm_tmp_name_add ("_RE"); - break; - - case IMAGPART_EXPR: - gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); - lsm_tmp_name_add ("_IM"); - break; - - case COMPONENT_REF: - gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); - lsm_tmp_name_add ("_"); - name = get_name (TREE_OPERAND (ref, 1)); - if (!name) - name = "F"; - lsm_tmp_name_add (name); - break; - - case ARRAY_REF: - gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); - lsm_tmp_name_add ("_I"); - break; - - case SSA_NAME: - case VAR_DECL: - case PARM_DECL: - name = get_name (ref); - if (!name) - name = "D"; - lsm_tmp_name_add (name); - break; - - case STRING_CST: - lsm_tmp_name_add ("S"); - break; - - case RESULT_DECL: - lsm_tmp_name_add ("R"); - break; - - case INTEGER_CST: - /* Nothing. */ - break; - - default: - gcc_unreachable (); - } -} - -/* Determines name for temporary variable that replaces REF. - The name is accumulated into the lsm_tmp_name variable. - N is added to the name of the temporary. */ - -char * -get_lsm_tmp_name (tree ref, unsigned n) -{ - char ns[2]; - - lsm_tmp_name_length = 0; - gen_lsm_tmp_name (ref); - lsm_tmp_name_add ("_lsm"); - if (n < 10) - { - ns[0] = '0' + n; - ns[1] = 0; - lsm_tmp_name_add (ns); - } - return lsm_tmp_name; -} - -struct prev_flag_edges { - /* Edge to insert new flag comparison code. */ - edge append_cond_position; - - /* Edge for fall through from previous flag comparison. */ - edge last_cond_fallthru; -}; - -/* Helper function for execute_sm. Emit code to store TMP_VAR into - MEM along edge EX. - - The store is only done if MEM has changed. We do this so no - changes to MEM occur on code paths that did not originally store - into it. - - The common case for execute_sm will transform: - - for (...) { - if (foo) - stuff; - else - MEM = TMP_VAR; - } - - into: - - lsm = MEM; - for (...) { - if (foo) - stuff; - else - lsm = TMP_VAR; - } - MEM = lsm; - - This function will generate: - - lsm = MEM; - - lsm_flag = false; - ... - for (...) { - if (foo) - stuff; - else { - lsm = TMP_VAR; - lsm_flag = true; - } - } - if (lsm_flag) <-- - MEM = lsm; <-- -*/ - -static void -execute_sm_if_changed (edge ex, tree mem, tree tmp_var, tree flag) -{ - basic_block new_bb, then_bb, old_dest; - bool loop_has_only_one_exit; - edge then_old_edge, orig_ex = ex; - gimple_stmt_iterator gsi; - gimple stmt; - struct prev_flag_edges *prev_edges = (struct prev_flag_edges *) ex->aux; - - /* ?? Insert store after previous store if applicable. See note - below. */ - if (prev_edges) - ex = prev_edges->append_cond_position; - - loop_has_only_one_exit = single_pred_p (ex->dest); - - if (loop_has_only_one_exit) - ex = split_block_after_labels (ex->dest); - - old_dest = ex->dest; - new_bb = split_edge (ex); - then_bb = create_empty_bb (new_bb); - if (current_loops && new_bb->loop_father) - add_bb_to_loop (then_bb, new_bb->loop_father); - - gsi = gsi_start_bb (new_bb); - stmt = gimple_build_cond (NE_EXPR, flag, boolean_false_node, - NULL_TREE, NULL_TREE); - gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING); - - gsi = gsi_start_bb (then_bb); - /* Insert actual store. */ - stmt = gimple_build_assign (unshare_expr (mem), tmp_var); - gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING); - - make_edge (new_bb, then_bb, EDGE_TRUE_VALUE); - make_edge (new_bb, old_dest, EDGE_FALSE_VALUE); - then_old_edge = make_edge (then_bb, old_dest, EDGE_FALLTHRU); - - set_immediate_dominator (CDI_DOMINATORS, then_bb, new_bb); - - if (prev_edges) - { - basic_block prevbb = prev_edges->last_cond_fallthru->src; - redirect_edge_succ (prev_edges->last_cond_fallthru, new_bb); - set_immediate_dominator (CDI_DOMINATORS, new_bb, prevbb); - set_immediate_dominator (CDI_DOMINATORS, old_dest, - recompute_dominator (CDI_DOMINATORS, old_dest)); - } - - /* ?? Because stores may alias, they must happen in the exact - sequence they originally happened. Save the position right after - the (_lsm) store we just created so we can continue appending after - it and maintain the original order. */ - { - struct prev_flag_edges *p; - - if (orig_ex->aux) - orig_ex->aux = NULL; - alloc_aux_for_edge (orig_ex, sizeof (struct prev_flag_edges)); - p = (struct prev_flag_edges *) orig_ex->aux; - p->append_cond_position = then_old_edge; - p->last_cond_fallthru = find_edge (new_bb, old_dest); - orig_ex->aux = (void *) p; - } - - if (!loop_has_only_one_exit) - for (gsi = gsi_start_phis (old_dest); !gsi_end_p (gsi); gsi_next (&gsi)) - { - gimple phi = gsi_stmt (gsi); - unsigned i; - - for (i = 0; i < gimple_phi_num_args (phi); i++) - if (gimple_phi_arg_edge (phi, i)->src == new_bb) - { - tree arg = gimple_phi_arg_def (phi, i); - add_phi_arg (phi, arg, then_old_edge, UNKNOWN_LOCATION); - update_stmt (phi); - } - } - /* Remove the original fall through edge. This was the - single_succ_edge (new_bb). */ - EDGE_SUCC (new_bb, 0)->flags &= ~EDGE_FALLTHRU; -} - -/* Helper function for execute_sm. On every location where REF is - set, set an appropriate flag indicating the store. */ - -static tree -execute_sm_if_changed_flag_set (struct loop *loop, mem_ref_p ref) -{ - unsigned i; - mem_ref_loc_p loc; - tree flag; - vec<mem_ref_loc_p> locs = vNULL; - char *str = get_lsm_tmp_name (ref->mem, ~0); - - lsm_tmp_name_add ("_flag"); - flag = create_tmp_reg (boolean_type_node, str); - get_all_locs_in_loop (loop, ref, &locs); - FOR_EACH_VEC_ELT (locs, i, loc) - { - gimple_stmt_iterator gsi; - gimple stmt; - - /* Only set the flag for writes. */ - if (is_gimple_assign (loc->stmt) - && gimple_assign_lhs_ptr (loc->stmt) == loc->ref) - { - gsi = gsi_for_stmt (loc->stmt); - stmt = gimple_build_assign (flag, boolean_true_node); - gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING); - } - } - locs.release (); - return flag; -} - -/* Executes store motion of memory reference REF from LOOP. - Exits from the LOOP are stored in EXITS. The initialization of the - temporary variable is put to the preheader of the loop, and assignments - to the reference from the temporary variable are emitted to exits. */ - -static void -execute_sm (struct loop *loop, vec<edge> exits, mem_ref_p ref) -{ - tree tmp_var, store_flag; - unsigned i; - gimple load; - struct fmt_data fmt_data; - edge ex, latch_edge; - struct lim_aux_data *lim_data; - bool multi_threaded_model_p = false; - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Executing store motion of "); - print_generic_expr (dump_file, ref->mem, 0); - fprintf (dump_file, " from loop %d\n", loop->num); - } - - tmp_var = create_tmp_reg (TREE_TYPE (ref->mem), - get_lsm_tmp_name (ref->mem, ~0)); - - fmt_data.loop = loop; - fmt_data.orig_loop = loop; - for_each_index (&ref->mem, force_move_till, &fmt_data); - - if (block_in_transaction (loop_preheader_edge (loop)->src) - || !PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES)) - multi_threaded_model_p = true; - - if (multi_threaded_model_p) - store_flag = execute_sm_if_changed_flag_set (loop, ref); - - rewrite_mem_refs (loop, ref, tmp_var); - - /* Emit the load code into the latch, so that we are sure it will - be processed after all dependencies. */ - latch_edge = loop_latch_edge (loop); - - /* FIXME/TODO: For the multi-threaded variant, we could avoid this - load altogether, since the store is predicated by a flag. We - could, do the load only if it was originally in the loop. */ - load = gimple_build_assign (tmp_var, unshare_expr (ref->mem)); - lim_data = init_lim_data (load); - lim_data->max_loop = loop; - lim_data->tgt_loop = loop; - gsi_insert_on_edge (latch_edge, load); - - if (multi_threaded_model_p) - { - load = gimple_build_assign (store_flag, boolean_false_node); - lim_data = init_lim_data (load); - lim_data->max_loop = loop; - lim_data->tgt_loop = loop; - gsi_insert_on_edge (latch_edge, load); - } - - /* Sink the store to every exit from the loop. */ - FOR_EACH_VEC_ELT (exits, i, ex) - if (!multi_threaded_model_p) - { - gimple store; - store = gimple_build_assign (unshare_expr (ref->mem), tmp_var); - gsi_insert_on_edge (ex, store); - } - else - execute_sm_if_changed (ex, ref->mem, tmp_var, store_flag); -} - -/* Hoists memory references MEM_REFS out of LOOP. EXITS is the list of exit - edges of the LOOP. */ - -static void -hoist_memory_references (struct loop *loop, bitmap mem_refs, - vec<edge> exits) -{ - mem_ref_p ref; - unsigned i; - bitmap_iterator bi; - - EXECUTE_IF_SET_IN_BITMAP (mem_refs, 0, i, bi) - { - ref = memory_accesses.refs_list[i]; - execute_sm (loop, exits, ref); - } -} - -/* Returns true if REF is always accessed in LOOP. If STORED_P is true - make sure REF is always stored to in LOOP. */ - -static bool -ref_always_accessed_p (struct loop *loop, mem_ref_p ref, bool stored_p) -{ - vec<mem_ref_loc_p> locs = vNULL; - unsigned i; - mem_ref_loc_p loc; - bool ret = false; - struct loop *must_exec; - tree base; - - base = get_base_address (ref->mem); - if (INDIRECT_REF_P (base) - || TREE_CODE (base) == MEM_REF) - base = TREE_OPERAND (base, 0); - - get_all_locs_in_loop (loop, ref, &locs); - FOR_EACH_VEC_ELT (locs, i, loc) - { - if (!get_lim_data (loc->stmt)) - continue; - - /* If we require an always executed store make sure the statement - stores to the reference. */ - if (stored_p) - { - tree lhs; - if (!gimple_get_lhs (loc->stmt)) - continue; - lhs = get_base_address (gimple_get_lhs (loc->stmt)); - if (!lhs) - continue; - if (INDIRECT_REF_P (lhs) - || TREE_CODE (lhs) == MEM_REF) - lhs = TREE_OPERAND (lhs, 0); - if (lhs != base) - continue; - } - - must_exec = get_lim_data (loc->stmt)->always_executed_in; - if (!must_exec) - continue; - - if (must_exec == loop - || flow_loop_nested_p (must_exec, loop)) - { - ret = true; - break; - } - } - locs.release (); - - return ret; -} - -/* Returns true if REF1 and REF2 are independent. */ - -static bool -refs_independent_p (mem_ref_p ref1, mem_ref_p ref2) -{ - if (ref1 == ref2 - || bitmap_bit_p (ref1->indep_ref, ref2->id)) - return true; - if (bitmap_bit_p (ref1->dep_ref, ref2->id)) - return false; - if (!MEM_ANALYZABLE (ref1) - || !MEM_ANALYZABLE (ref2)) - return false; - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "Querying dependency of refs %u and %u: ", - ref1->id, ref2->id); - - if (mem_refs_may_alias_p (ref1->mem, ref2->mem, - &memory_accesses.ttae_cache)) - { - bitmap_set_bit (ref1->dep_ref, ref2->id); - bitmap_set_bit (ref2->dep_ref, ref1->id); - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "dependent.\n"); - return false; - } - else - { - bitmap_set_bit (ref1->indep_ref, ref2->id); - bitmap_set_bit (ref2->indep_ref, ref1->id); - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "independent.\n"); - return true; - } -} - -/* Records the information whether REF is independent in LOOP (according - to INDEP). */ - -static void -record_indep_loop (struct loop *loop, mem_ref_p ref, bool indep) -{ - if (indep) - bitmap_set_bit (ref->indep_loop, loop->num); - else - bitmap_set_bit (ref->dep_loop, loop->num); -} - -/* Returns true if REF is independent on all other memory references in - LOOP. */ - -static bool -ref_indep_loop_p_1 (struct loop *loop, mem_ref_p ref) -{ - bitmap refs_to_check; - unsigned i; - bitmap_iterator bi; - bool ret = true, stored = bitmap_bit_p (ref->stored, loop->num); - mem_ref_p aref; - - if (stored) - refs_to_check = memory_accesses.all_refs_in_loop[loop->num]; - else - refs_to_check = memory_accesses.all_refs_stored_in_loop[loop->num]; - - EXECUTE_IF_SET_IN_BITMAP (refs_to_check, 0, i, bi) - { - aref = memory_accesses.refs_list[i]; - if (!MEM_ANALYZABLE (aref) - || !refs_independent_p (ref, aref)) - { - ret = false; - record_indep_loop (loop, aref, false); - break; - } - } - - return ret; -} - -/* Returns true if REF is independent on all other memory references in - LOOP. Wrapper over ref_indep_loop_p_1, caching its results. */ - -static bool -ref_indep_loop_p (struct loop *loop, mem_ref_p ref) -{ - bool ret; - - if (bitmap_bit_p (ref->indep_loop, loop->num)) - return true; - if (bitmap_bit_p (ref->dep_loop, loop->num)) - return false; - - ret = ref_indep_loop_p_1 (loop, ref); - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "Querying dependencies of ref %u in loop %d: %s\n", - ref->id, loop->num, ret ? "independent" : "dependent"); - - record_indep_loop (loop, ref, ret); - - return ret; -} - -/* Returns true if we can perform store motion of REF from LOOP. */ - -static bool -can_sm_ref_p (struct loop *loop, mem_ref_p ref) -{ - tree base; - - /* Can't hoist unanalyzable refs. */ - if (!MEM_ANALYZABLE (ref)) - return false; - - /* Unless the reference is stored in the loop, there is nothing to do. */ - if (!bitmap_bit_p (ref->stored, loop->num)) - return false; - - /* It should be movable. */ - if (!is_gimple_reg_type (TREE_TYPE (ref->mem)) - || TREE_THIS_VOLATILE (ref->mem) - || !for_each_index (&ref->mem, may_move_till, loop)) - return false; - - /* If it can throw fail, we do not properly update EH info. */ - if (tree_could_throw_p (ref->mem)) - return false; - - /* If it can trap, it must be always executed in LOOP. - Readonly memory locations may trap when storing to them, but - tree_could_trap_p is a predicate for rvalues, so check that - explicitly. */ - base = get_base_address (ref->mem); - if ((tree_could_trap_p (ref->mem) - || (DECL_P (base) && TREE_READONLY (base))) - && !ref_always_accessed_p (loop, ref, true)) - return false; - - /* And it must be independent on all other memory references - in LOOP. */ - if (!ref_indep_loop_p (loop, ref)) - return false; - - return true; -} - -/* Marks the references in LOOP for that store motion should be performed - in REFS_TO_SM. SM_EXECUTED is the set of references for that store - motion was performed in one of the outer loops. */ - -static void -find_refs_for_sm (struct loop *loop, bitmap sm_executed, bitmap refs_to_sm) -{ - bitmap refs = memory_accesses.all_refs_in_loop[loop->num]; - unsigned i; - bitmap_iterator bi; - mem_ref_p ref; - - EXECUTE_IF_AND_COMPL_IN_BITMAP (refs, sm_executed, 0, i, bi) - { - ref = memory_accesses.refs_list[i]; - if (can_sm_ref_p (loop, ref)) - bitmap_set_bit (refs_to_sm, i); - } -} - -/* Checks whether LOOP (with exits stored in EXITS array) is suitable - for a store motion optimization (i.e. whether we can insert statement - on its exits). */ - -static bool -loop_suitable_for_sm (struct loop *loop ATTRIBUTE_UNUSED, - vec<edge> exits) -{ - unsigned i; - edge ex; - - FOR_EACH_VEC_ELT (exits, i, ex) - if (ex->flags & (EDGE_ABNORMAL | EDGE_EH)) - return false; - - return true; -} - -/* Try to perform store motion for all memory references modified inside - LOOP. SM_EXECUTED is the bitmap of the memory references for that - store motion was executed in one of the outer loops. */ - -static void -store_motion_loop (struct loop *loop, bitmap sm_executed) -{ - vec<edge> exits = get_loop_exit_edges (loop); - struct loop *subloop; - bitmap sm_in_loop = BITMAP_ALLOC (NULL); - - if (loop_suitable_for_sm (loop, exits)) - { - find_refs_for_sm (loop, sm_executed, sm_in_loop); - hoist_memory_references (loop, sm_in_loop, exits); - } - exits.release (); - - bitmap_ior_into (sm_executed, sm_in_loop); - for (subloop = loop->inner; subloop != NULL; subloop = subloop->next) - store_motion_loop (subloop, sm_executed); - bitmap_and_compl_into (sm_executed, sm_in_loop); - BITMAP_FREE (sm_in_loop); -} - -/* Try to perform store motion for all memory references modified inside - loops. */ - -static void -store_motion (void) -{ - struct loop *loop; - bitmap sm_executed = BITMAP_ALLOC (NULL); - - for (loop = current_loops->tree_root->inner; loop != NULL; loop = loop->next) - store_motion_loop (loop, sm_executed); - - BITMAP_FREE (sm_executed); - gsi_commit_edge_inserts (); -} - -/* Fills ALWAYS_EXECUTED_IN information for basic blocks of LOOP, i.e. - for each such basic block bb records the outermost loop for that execution - of its header implies execution of bb. CONTAINS_CALL is the bitmap of - blocks that contain a nonpure call. */ - -static void -fill_always_executed_in (struct loop *loop, sbitmap contains_call) -{ - basic_block bb = NULL, *bbs, last = NULL; - unsigned i; - edge e; - struct loop *inn_loop = loop; - - if (ALWAYS_EXECUTED_IN (loop->header) == NULL) - { - bbs = get_loop_body_in_dom_order (loop); - - for (i = 0; i < loop->num_nodes; i++) - { - edge_iterator ei; - bb = bbs[i]; - - if (dominated_by_p (CDI_DOMINATORS, loop->latch, bb)) - last = bb; - - if (bitmap_bit_p (contains_call, bb->index)) - break; - - FOR_EACH_EDGE (e, ei, bb->succs) - if (!flow_bb_inside_loop_p (loop, e->dest)) - break; - if (e) - break; - - /* A loop might be infinite (TODO use simple loop analysis - to disprove this if possible). */ - if (bb->flags & BB_IRREDUCIBLE_LOOP) - break; - - if (!flow_bb_inside_loop_p (inn_loop, bb)) - break; - - if (bb->loop_father->header == bb) - { - if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb)) - break; - - /* In a loop that is always entered we may proceed anyway. - But record that we entered it and stop once we leave it. */ - inn_loop = bb->loop_father; - } - } - - while (1) - { - SET_ALWAYS_EXECUTED_IN (last, loop); - if (last == loop->header) - break; - last = get_immediate_dominator (CDI_DOMINATORS, last); - } - - free (bbs); - } - - for (loop = loop->inner; loop; loop = loop->next) - fill_always_executed_in (loop, contains_call); -} - -/* Compute the global information needed by the loop invariant motion pass. */ - -static void -tree_ssa_lim_initialize (void) -{ - sbitmap contains_call = sbitmap_alloc (last_basic_block); - gimple_stmt_iterator bsi; - struct loop *loop; - basic_block bb; - - bitmap_obstack_initialize (&lim_bitmap_obstack); - - bitmap_clear (contains_call); - FOR_EACH_BB (bb) - { - for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) - { - if (nonpure_call_p (gsi_stmt (bsi))) - break; - } - - if (!gsi_end_p (bsi)) - bitmap_set_bit (contains_call, bb->index); - } - - for (loop = current_loops->tree_root->inner; loop; loop = loop->next) - fill_always_executed_in (loop, contains_call); - - sbitmap_free (contains_call); - - lim_aux_data_map = pointer_map_create (); - - if (flag_tm) - compute_transaction_bits (); - - alloc_aux_for_edges (0); -} - -/* Cleans up after the invariant motion pass. */ - -static void -tree_ssa_lim_finalize (void) -{ - basic_block bb; - unsigned i; - mem_ref_p ref; - - free_aux_for_edges (); - - FOR_EACH_BB (bb) - SET_ALWAYS_EXECUTED_IN (bb, NULL); - - bitmap_obstack_release (&lim_bitmap_obstack); - pointer_map_destroy (lim_aux_data_map); - - htab_delete (memory_accesses.refs); - - FOR_EACH_VEC_ELT (memory_accesses.refs_list, i, ref) - memref_free (ref); - memory_accesses.refs_list.release (); - - memory_accesses.refs_in_loop.release (); - memory_accesses.all_refs_in_loop.release (); - memory_accesses.all_refs_stored_in_loop.release (); - - if (memory_accesses.ttae_cache) - free_affine_expand_cache (&memory_accesses.ttae_cache); -} - -/* Moves invariants from loops. Only "expensive" invariants are moved out -- - i.e. those that are likely to be win regardless of the register pressure. */ - -unsigned int -tree_ssa_lim (void) -{ - unsigned int todo; - - tree_ssa_lim_initialize (); - - /* Gathers information about memory accesses in the loops. */ - analyze_memory_references (); - - /* For each statement determine the outermost loop in that it is - invariant and cost for computing the invariant. */ - determine_invariantness (); - - /* Execute store motion. Force the necessary invariants to be moved - out of the loops as well. */ - store_motion (); - - /* Move the expressions that are expensive enough. */ - todo = move_computations (); - - tree_ssa_lim_finalize (); - - return todo; -} |