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Diffstat (limited to 'gcc/tree-ssa-loop-im.c')
| -rw-r--r-- | gcc/tree-ssa-loop-im.c | 2596 |
1 files changed, 2596 insertions, 0 deletions
diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c new file mode 100644 index 000000000..4ec67cf11 --- /dev/null +++ b/gcc/tree-ssa-loop-im.c @@ -0,0 +1,2596 @@ +/* Loop invariant motion. + Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2010 + 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 "output.h" +#include "tree-pretty-print.h" +#include "gimple-pretty-print.h" +#include "tree-flow.h" +#include "tree-dump.h" +#include "timevar.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 is 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; + +DEF_VEC_P(mem_ref_loc_p); +DEF_VEC_ALLOC_P(mem_ref_loc_p, heap); + +/* The list of memory reference locations in a loop. */ + +typedef struct mem_ref_locs +{ + VEC (mem_ref_loc_p, heap) *locs; +} *mem_ref_locs_p; + +DEF_VEC_P(mem_ref_locs_p); +DEF_VEC_ALLOC_P(mem_ref_locs_p, heap); + +/* 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, heap) *accesses_in_loop; + /* The locations of the accesses. Vector + indexed by the loop number. */ + bitmap vops; /* Vops corresponding to this memory + location. */ + + /* 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 DEP_REF. */ +} *mem_ref_p; + +DEF_VEC_P(mem_ref_p); +DEF_VEC_ALLOC_P(mem_ref_p, heap); + +DEF_VEC_P(bitmap); +DEF_VEC_ALLOC_P(bitmap, heap); + +DEF_VEC_P(htab_t); +DEF_VEC_ALLOC_P(htab_t, heap); + +/* 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, heap) *refs_list; + + /* The set of memory references accessed in each loop. */ + VEC (bitmap, heap) *refs_in_loop; + + /* The set of memory references accessed in each loop, including + subloops. */ + VEC (bitmap, heap) *all_refs_in_loop; + + /* The set of virtual operands clobbered in a given loop. */ + VEC (bitmap, heap) *clobbered_vops; + + /* Map from the pair (loop, virtual operand) to the set of refs that + touch the virtual operand in the loop. */ + VEC (htab_t, heap) *vop_ref_map; + + /* Cache for expanding memory addresses. */ + struct pointer_map_t *ttae_cache; +} memory_accesses; + +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 that execution of the header guarantees that the + block will be executed. */ +#define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux) + +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 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 + && is_gimple_reg (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; + + 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. TODO -- the values here + are just ad-hoc constants. The estimates should be based on target-specific + values. */ + +static unsigned +stmt_cost (gimple stmt) +{ + tree fndecl; + unsigned cost = 1; + + /* Always try to create possibilities for unswitching. */ + if (gimple_code (stmt) == GIMPLE_COND + || gimple_code (stmt) == GIMPLE_PHI) + return LIM_EXPENSIVE; + + /* Hoisting memory references out should almost surely be a win. */ + if (gimple_references_memory_p (stmt)) + cost += 20; + + if (is_gimple_call (stmt)) + { + /* We should be hoisting calls if possible. */ + + /* 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 cost + 20; + } + + if (gimple_code (stmt) != GIMPLE_ASSIGN) + return cost; + + switch (gimple_assign_rhs_code (stmt)) + { + case MULT_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. */ + cost += 20; + break; + + case LSHIFT_EXPR: + case RSHIFT_EXPR: + cost += 20; + break; + + default: + break; + } + + return cost; +} + +/* 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; + enum tree_code code; + + /* Recognize MEM = (SSA_NAME | invariant) and SSA_NAME = MEM patterns. */ + if (gimple_code (stmt) != GIMPLE_ASSIGN) + return NULL; + + code = gimple_assign_rhs_code (stmt); + + lhs = gimple_assign_lhs_ptr (stmt); + + if (TREE_CODE (*lhs) == SSA_NAME) + { + if (get_gimple_rhs_class (code) != GIMPLE_SINGLE_RHS + || !is_gimple_addressable (gimple_assign_rhs1 (stmt))) + return NULL; + + *is_store = false; + return gimple_assign_rhs1_ptr (stmt); + } + else if (code == SSA_NAME + || (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS + && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))) + { + *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 var, name, lhs, type; + tree real_one; + gimple_stmt_iterator gsi; + + stmt = gsi_stmt (*bsi); + lhs = gimple_assign_lhs (stmt); + type = TREE_TYPE (lhs); + + var = create_tmp_var (type, "reciptmp"); + add_referenced_var (var); + DECL_GIMPLE_REG_P (var) = 1; + + real_one = build_one_cst (type); + + stmt1 = gimple_build_assign_with_ops (RDIV_EXPR, + var, real_one, gimple_assign_rhs2 (stmt)); + name = make_ssa_name (var, stmt1); + gimple_assign_set_lhs (stmt1, name); + + 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, var, 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 */ + var = create_tmp_var (TREE_TYPE (a), "shifttmp"); + add_referenced_var (var); + t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (a), + build_int_cst (TREE_TYPE (a), 1), b); + stmt1 = gimple_build_assign (var, t); + name = make_ssa_name (var, stmt1); + gimple_assign_set_lhs (stmt1, name); + + /* A & (1 << B) */ + t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (a), a, name); + stmt2 = gimple_build_assign (var, t); + name = make_ssa_name (var, stmt2); + gimple_assign_set_lhs (stmt2, name); + + /* 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)); + t = build3 (COND_EXPR, TREE_TYPE (gimple_phi_result (stmt)), + t, arg0, arg1); + new_stmt = gimple_build_assign_with_ops (COND_EXPR, + gimple_phi_result (stmt), + t, NULL_TREE); + 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); ) + { + 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); + } + + mark_virtual_ops_for_renaming (stmt); + gsi_insert_on_edge (loop_preheader_edge (level), stmt); + gsi_remove (&bsi, false); + } +} + +/* 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 (mem_ref_loc_p, accs->locs, i, loc) + free (loc); + VEC_free (mem_ref_loc_p, heap, accs->locs); + free (accs); +} + +/* A function to free the mem_ref object OBJ. */ + +static void +memref_free (void *obj) +{ + struct mem_ref *const mem = (struct mem_ref *) obj; + unsigned i; + mem_ref_locs_p accs; + + BITMAP_FREE (mem->stored); + BITMAP_FREE (mem->indep_loop); + BITMAP_FREE (mem->dep_loop); + BITMAP_FREE (mem->indep_ref); + BITMAP_FREE (mem->dep_ref); + + FOR_EACH_VEC_ELT (mem_ref_locs_p, mem->accesses_in_loop, i, accs) + free_mem_ref_locs (accs); + VEC_free (mem_ref_locs_p, heap, mem->accesses_in_loop); + + BITMAP_FREE (mem->vops); + 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 (NULL); + ref->indep_loop = BITMAP_ALLOC (NULL); + ref->dep_loop = BITMAP_ALLOC (NULL); + ref->indep_ref = BITMAP_ALLOC (NULL); + ref->dep_ref = BITMAP_ALLOC (NULL); + ref->accesses_in_loop = NULL; + ref->vops = BITMAP_ALLOC (NULL); + + 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 = NULL; + 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 = VEC_index (bitmap, memory_accesses.refs_in_loop, loop->num); + + if (VEC_length (mem_ref_locs_p, ref->accesses_in_loop) + <= (unsigned) loop->num) + VEC_safe_grow_cleared (mem_ref_locs_p, heap, ref->accesses_in_loop, + loop->num + 1); + accs = VEC_index (mem_ref_locs_p, ref->accesses_in_loop, loop->num); + if (!accs) + { + accs = mem_ref_locs_alloc (); + VEC_replace (mem_ref_locs_p, ref->accesses_in_loop, loop->num, accs); + } + + aref->stmt = stmt; + aref->ref = loc; + + VEC_safe_push (mem_ref_loc_p, heap, accs->locs, 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; + tree vname; + bool is_stored; + bitmap clvops; + unsigned id; + + if (!gimple_vuse (stmt)) + return; + + mem = simple_mem_ref_in_stmt (stmt, &is_stored); + if (!mem) + goto fail; + + 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 = VEC_length (mem_ref_p, memory_accesses.refs_list); + ref = mem_ref_alloc (*mem, hash, id); + VEC_safe_push (mem_ref_p, heap, memory_accesses.refs_list, 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); + + if ((vname = gimple_vuse (stmt)) != NULL_TREE) + bitmap_set_bit (ref->vops, DECL_UID (SSA_NAME_VAR (vname))); + record_mem_ref_loc (ref, loop, stmt, mem); + return; + +fail: + clvops = VEC_index (bitmap, memory_accesses.clobbered_vops, loop->num); + if ((vname = gimple_vuse (stmt)) != NULL_TREE) + bitmap_set_bit (clvops, DECL_UID (SSA_NAME_VAR (vname))); +} + +/* 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 clvo, clvi; + 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 clobbered vops and accessed memory + references up the loop hierarchy. */ + FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST) + { + lrefs = VEC_index (bitmap, memory_accesses.refs_in_loop, loop->num); + alrefs = VEC_index (bitmap, memory_accesses.all_refs_in_loop, loop->num); + bitmap_ior_into (alrefs, lrefs); + + if (loop_outer (loop) == current_loops->tree_root) + continue; + + clvi = VEC_index (bitmap, memory_accesses.clobbered_vops, loop->num); + clvo = VEC_index (bitmap, memory_accesses.clobbered_vops, + loop_outer (loop)->num); + bitmap_ior_into (clvo, clvi); + + alrefso = VEC_index (bitmap, memory_accesses.all_refs_in_loop, + loop_outer (loop)->num); + bitmap_ior_into (alrefso, alrefs); + } +} + +/* Element of the hash table that maps vops to memory references. */ + +struct vop_to_refs_elt +{ + /* DECL_UID of the vop. */ + unsigned uid; + + /* List of the all references. */ + bitmap refs_all; + + /* List of stored references. */ + bitmap refs_stored; +}; + +/* A hash function for struct vop_to_refs_elt object OBJ. */ + +static hashval_t +vtoe_hash (const void *obj) +{ + const struct vop_to_refs_elt *const vtoe = + (const struct vop_to_refs_elt *) obj; + + return vtoe->uid; +} + +/* An equality function for struct vop_to_refs_elt object OBJ1 with + uid of a vop OBJ2. */ + +static int +vtoe_eq (const void *obj1, const void *obj2) +{ + const struct vop_to_refs_elt *const vtoe = + (const struct vop_to_refs_elt *) obj1; + const unsigned *const uid = (const unsigned *) obj2; + + return vtoe->uid == *uid; +} + +/* A function to free the struct vop_to_refs_elt object. */ + +static void +vtoe_free (void *obj) +{ + struct vop_to_refs_elt *const vtoe = + (struct vop_to_refs_elt *) obj; + + BITMAP_FREE (vtoe->refs_all); + BITMAP_FREE (vtoe->refs_stored); + free (vtoe); +} + +/* Records REF to hashtable VOP_TO_REFS for the index VOP. STORED is true + if the reference REF is stored. */ + +static void +record_vop_access (htab_t vop_to_refs, unsigned vop, unsigned ref, bool stored) +{ + void **slot = htab_find_slot_with_hash (vop_to_refs, &vop, vop, INSERT); + struct vop_to_refs_elt *vtoe; + + if (!*slot) + { + vtoe = XNEW (struct vop_to_refs_elt); + vtoe->uid = vop; + vtoe->refs_all = BITMAP_ALLOC (NULL); + vtoe->refs_stored = BITMAP_ALLOC (NULL); + *slot = vtoe; + } + else + vtoe = (struct vop_to_refs_elt *) *slot; + + bitmap_set_bit (vtoe->refs_all, ref); + if (stored) + bitmap_set_bit (vtoe->refs_stored, ref); +} + +/* Returns the set of references that access VOP according to the table + VOP_TO_REFS. */ + +static bitmap +get_vop_accesses (htab_t vop_to_refs, unsigned vop) +{ + struct vop_to_refs_elt *const vtoe = + (struct vop_to_refs_elt *) htab_find_with_hash (vop_to_refs, &vop, vop); + return vtoe->refs_all; +} + +/* Returns the set of stores that access VOP according to the table + VOP_TO_REFS. */ + +static bitmap +get_vop_stores (htab_t vop_to_refs, unsigned vop) +{ + struct vop_to_refs_elt *const vtoe = + (struct vop_to_refs_elt *) htab_find_with_hash (vop_to_refs, &vop, vop); + return vtoe->refs_stored; +} + +/* Adds REF to mapping from virtual operands to references in LOOP. */ + +static void +add_vop_ref_mapping (struct loop *loop, mem_ref_p ref) +{ + htab_t map = VEC_index (htab_t, memory_accesses.vop_ref_map, loop->num); + bool stored = bitmap_bit_p (ref->stored, loop->num); + bitmap clobbers = VEC_index (bitmap, memory_accesses.clobbered_vops, + loop->num); + bitmap_iterator bi; + unsigned vop; + + EXECUTE_IF_AND_COMPL_IN_BITMAP (ref->vops, clobbers, 0, vop, bi) + { + record_vop_access (map, vop, ref->id, stored); + } +} + +/* 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 = VEC_index (bitmap, 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 = VEC_index (mem_ref_p, memory_accesses.refs_list, i); + for (sloop = loop; sloop != current_loops->tree_root; sloop = loop_outer (sloop)) + add_vop_ref_mapping (sloop, ref); + } +} + +/* 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; + htab_t hempty; + + memory_accesses.refs + = htab_create (100, memref_hash, memref_eq, memref_free); + memory_accesses.refs_list = NULL; + memory_accesses.refs_in_loop = VEC_alloc (bitmap, heap, + number_of_loops ()); + memory_accesses.all_refs_in_loop = VEC_alloc (bitmap, heap, + number_of_loops ()); + memory_accesses.clobbered_vops = VEC_alloc (bitmap, heap, + number_of_loops ()); + memory_accesses.vop_ref_map = VEC_alloc (htab_t, heap, + number_of_loops ()); + + for (i = 0; i < number_of_loops (); i++) + { + empty = BITMAP_ALLOC (NULL); + VEC_quick_push (bitmap, memory_accesses.refs_in_loop, empty); + empty = BITMAP_ALLOC (NULL); + VEC_quick_push (bitmap, memory_accesses.all_refs_in_loop, empty); + empty = BITMAP_ALLOC (NULL); + VEC_quick_push (bitmap, memory_accesses.clobbered_vops, empty); + hempty = htab_create (10, vtoe_hash, vtoe_eq, vtoe_free); + VEC_quick_push (htab_t, memory_accesses.vop_ref_map, hempty); + } + + memory_accesses.ttae_cache = NULL; + + gather_mem_refs_in_loops (); + create_vop_ref_mapping (); +} + +/* Returns true if a region of size SIZE1 at position 0 and a region of + size SIZE2 at position DIFF cannot overlap. */ + +static bool +cannot_overlap_p (aff_tree *diff, double_int size1, double_int size2) +{ + double_int d, bound; + + /* Unless the difference is a constant, we fail. */ + if (diff->n != 0) + return false; + + d = diff->offset; + if (double_int_negative_p (d)) + { + /* The second object is before the first one, we succeed if the last + element of the second object is before the start of the first one. */ + bound = double_int_add (d, double_int_add (size2, double_int_minus_one)); + return double_int_negative_p (bound); + } + else + { + /* We succeed if the second object starts after the first one ends. */ + return double_int_scmp (size1, d) <= 0; + } +} + +/* 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 (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) +{ + mark_virtual_ops_for_renaming (loc->stmt); + *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, heap) **locs) +{ + mem_ref_locs_p accs; + unsigned i; + mem_ref_loc_p loc; + bitmap refs = VEC_index (bitmap, memory_accesses.all_refs_in_loop, + loop->num); + struct loop *subloop; + + if (!bitmap_bit_p (refs, ref->id)) + return; + + if (VEC_length (mem_ref_locs_p, ref->accesses_in_loop) + > (unsigned) loop->num) + { + accs = VEC_index (mem_ref_locs_p, ref->accesses_in_loop, loop->num); + if (accs) + { + FOR_EACH_VEC_ELT (mem_ref_loc_p, accs->locs, i, loc) + VEC_safe_push (mem_ref_loc_p, heap, *locs, 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, heap) *locs = NULL; + + get_all_locs_in_loop (loop, ref, &locs); + FOR_EACH_VEC_ELT (mem_ref_loc_p, locs, i, loc) + rewrite_mem_ref_loc (loc, tmp_var); + VEC_free (mem_ref_loc_p, heap, locs); +} + +/* 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: + 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: + ref = SSA_NAME_VAR (ref); + /* Fallthru. */ + + 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; +} + +/* 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, heap) *exits, mem_ref_p ref) +{ + tree tmp_var; + unsigned i; + gimple load, store; + struct fmt_data fmt_data; + edge ex; + struct lim_aux_data *lim_data; + + 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 = make_rename_temp (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); + + rewrite_mem_refs (loop, ref, tmp_var); + + /* Emit the load & stores. */ + 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; + + /* Put this into the latch, so that we are sure it will be processed after + all dependencies. */ + gsi_insert_on_edge (loop_latch_edge (loop), load); + + FOR_EACH_VEC_ELT (edge, exits, i, ex) + { + store = gimple_build_assign (unshare_expr (ref->mem), tmp_var); + gsi_insert_on_edge (ex, store); + } +} + +/* 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, heap) *exits) +{ + mem_ref_p ref; + unsigned i; + bitmap_iterator bi; + + EXECUTE_IF_SET_IN_BITMAP (mem_refs, 0, i, bi) + { + ref = VEC_index (mem_ref_p, 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, heap) *locs = NULL; + 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 (mem_ref_loc_p, 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; + } + } + VEC_free (mem_ref_loc_p, heap, locs); + + 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 (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 clobbers, refs_to_check, refs; + unsigned i; + bitmap_iterator bi; + bool ret = true, stored = bitmap_bit_p (ref->stored, loop->num); + htab_t map; + mem_ref_p aref; + + /* If the reference is clobbered, it is not independent. */ + clobbers = VEC_index (bitmap, memory_accesses.clobbered_vops, loop->num); + if (bitmap_intersect_p (ref->vops, clobbers)) + return false; + + refs_to_check = BITMAP_ALLOC (NULL); + + map = VEC_index (htab_t, memory_accesses.vop_ref_map, loop->num); + EXECUTE_IF_AND_COMPL_IN_BITMAP (ref->vops, clobbers, 0, i, bi) + { + if (stored) + refs = get_vop_accesses (map, i); + else + refs = get_vop_stores (map, i); + + bitmap_ior_into (refs_to_check, refs); + } + + EXECUTE_IF_SET_IN_BITMAP (refs_to_check, 0, i, bi) + { + aref = VEC_index (mem_ref_p, memory_accesses.refs_list, i); + if (!refs_independent_p (ref, aref)) + { + ret = false; + record_indep_loop (loop, aref, false); + break; + } + } + + BITMAP_FREE (refs_to_check); + 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; + + /* 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 = VEC_index (bitmap, 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 = VEC_index (mem_ref_p, 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, heap) *exits) +{ + unsigned i; + edge ex; + + FOR_EACH_VEC_ELT (edge, 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, heap) *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); + } + VEC_free (edge, heap, exits); + + 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 (!loop->header->aux) + { + 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 (TEST_BIT (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) + { + last->aux = 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; + + sbitmap_zero (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)) + 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 (); +} + +/* Cleans up after the invariant motion pass. */ + +static void +tree_ssa_lim_finalize (void) +{ + basic_block bb; + unsigned i; + bitmap b; + htab_t h; + + FOR_EACH_BB (bb) + { + bb->aux = NULL; + } + + pointer_map_destroy (lim_aux_data_map); + + VEC_free (mem_ref_p, heap, memory_accesses.refs_list); + htab_delete (memory_accesses.refs); + + FOR_EACH_VEC_ELT (bitmap, memory_accesses.refs_in_loop, i, b) + BITMAP_FREE (b); + VEC_free (bitmap, heap, memory_accesses.refs_in_loop); + + FOR_EACH_VEC_ELT (bitmap, memory_accesses.all_refs_in_loop, i, b) + BITMAP_FREE (b); + VEC_free (bitmap, heap, memory_accesses.all_refs_in_loop); + + FOR_EACH_VEC_ELT (bitmap, memory_accesses.clobbered_vops, i, b) + BITMAP_FREE (b); + VEC_free (bitmap, heap, memory_accesses.clobbered_vops); + + FOR_EACH_VEC_ELT (htab_t, memory_accesses.vop_ref_map, i, h) + htab_delete (h); + VEC_free (htab_t, heap, memory_accesses.vop_ref_map); + + if (memory_accesses.ttae_cache) + pointer_map_destroy (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; +} |