| /* Loop invariant motion. |
| Copyright (C) 2003-2017 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 "backend.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "cfghooks.h" |
| #include "tree-pass.h" |
| #include "ssa.h" |
| #include "gimple-pretty-print.h" |
| #include "fold-const.h" |
| #include "cfganal.h" |
| #include "tree-eh.h" |
| #include "gimplify.h" |
| #include "gimple-iterator.h" |
| #include "tree-cfg.h" |
| #include "tree-ssa-loop-manip.h" |
| #include "tree-ssa-loop.h" |
| #include "tree-into-ssa.h" |
| #include "cfgloop.h" |
| #include "domwalk.h" |
| #include "params.h" |
| #include "tree-affine.h" |
| #include "tree-ssa-propagate.h" |
| #include "trans-mem.h" |
| #include "gimple-fold.h" |
| #include "tree-scalar-evolution.h" |
| #include "tree-ssa-loop-niter.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; |
| } */ |
| |
| /* 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. */ |
| |
| vec<gimple *> depends; /* Vector 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 hash_map<gimple *, lim_aux_data *> *lim_aux_data_map; |
| |
| /* Description of a memory reference location. */ |
| |
| struct mem_ref_loc |
| { |
| tree *ref; /* The reference itself. */ |
| gimple *stmt; /* The statement in that it occurs. */ |
| }; |
| |
| |
| /* Description of a memory reference. */ |
| |
| struct im_mem_ref |
| { |
| unsigned id; /* ID assigned to the memory reference |
| (its index in memory_accesses.refs_list) */ |
| hashval_t hash; /* Its hash value. */ |
| |
| /* The memory access itself and associated caching of alias-oracle |
| query meta-data. */ |
| ao_ref mem; |
| |
| bitmap stored; /* The set of loops in that this memory location |
| is stored to. */ |
| vec<mem_ref_loc> 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_head 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_head dep_loop; /* The complement of INDEP_LOOP. */ |
| }; |
| |
| /* We use two bits per loop in the ref->{in,}dep_loop bitmaps, the first |
| to record (in)dependence against stores in the loop and its subloops, the |
| second to record (in)dependence against all references in the loop |
| and its subloops. */ |
| #define LOOP_DEP_BIT(loopnum, storedp) (2 * (loopnum) + (storedp ? 1 : 0)) |
| |
| /* Mem_ref hashtable helpers. */ |
| |
| struct mem_ref_hasher : nofree_ptr_hash <im_mem_ref> |
| { |
| typedef tree_node *compare_type; |
| static inline hashval_t hash (const im_mem_ref *); |
| static inline bool equal (const im_mem_ref *, const tree_node *); |
| }; |
| |
| /* A hash function for struct im_mem_ref object OBJ. */ |
| |
| inline hashval_t |
| mem_ref_hasher::hash (const im_mem_ref *mem) |
| { |
| return mem->hash; |
| } |
| |
| /* An equality function for struct im_mem_ref object MEM1 with |
| memory reference OBJ2. */ |
| |
| inline bool |
| mem_ref_hasher::equal (const im_mem_ref *mem1, const tree_node *obj2) |
| { |
| return operand_equal_p (mem1->mem.ref, (const_tree) obj2, 0); |
| } |
| |
| |
| /* Description of memory accesses in loops. */ |
| |
| static struct |
| { |
| /* The hash table of memory references accessed in loops. */ |
| hash_table<mem_ref_hasher> *refs; |
| |
| /* The list of memory references. */ |
| vec<im_mem_ref *> refs_list; |
| |
| /* The set of memory references accessed in each loop. */ |
| vec<bitmap_head> refs_in_loop; |
| |
| /* The set of memory references stored in each loop. */ |
| vec<bitmap_head> refs_stored_in_loop; |
| |
| /* The set of memory references stored in each loop, including subloops . */ |
| vec<bitmap_head> all_refs_stored_in_loop; |
| |
| /* Cache for expanding memory addresses. */ |
| hash_map<tree, name_expansion *> *ttae_cache; |
| } memory_accesses; |
| |
| /* Obstack for the bitmaps in the above data structures. */ |
| static bitmap_obstack lim_bitmap_obstack; |
| static obstack mem_ref_obstack; |
| |
| static bool ref_indep_loop_p (struct loop *, im_mem_ref *); |
| |
| /* 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)) |
| |
| /* ID of the shared unanalyzable mem. */ |
| #define UNANALYZABLE_MEM_ID 0 |
| |
| /* Whether the reference was analyzable. */ |
| #define MEM_ANALYZABLE(REF) ((REF)->id != UNANALYZABLE_MEM_ID) |
| |
| static struct lim_aux_data * |
| init_lim_data (gimple *stmt) |
| { |
| lim_aux_data *p = XCNEW (struct lim_aux_data); |
| lim_aux_data_map->put (stmt, p); |
| |
| return p; |
| } |
| |
| static struct lim_aux_data * |
| get_lim_data (gimple *stmt) |
| { |
| lim_aux_data **p = lim_aux_data_map->get (stmt); |
| if (!p) |
| return NULL; |
| |
| return *p; |
| } |
| |
| /* Releases the memory occupied by DATA. */ |
| |
| static void |
| free_lim_aux_data (struct lim_aux_data *data) |
| { |
| data->depends.release (); |
| free (data); |
| } |
| |
| static void |
| clear_lim_data (gimple *stmt) |
| { |
| lim_aux_data **p = lim_aux_data_map->get (stmt); |
| if (!p) |
| return; |
| |
| free_lim_aux_data (*p); |
| *p = NULL; |
| } |
| |
| |
| /* The possibilities of statement movement. */ |
| enum move_pos |
| { |
| MOVE_IMPOSSIBLE, /* No movement -- side effect expression. */ |
| MOVE_PRESERVE_EXECUTION, /* Must not cause the non-executed statement |
| become executed -- memory accesses, ... */ |
| MOVE_POSSIBLE /* Unlimited movement. */ |
| }; |
| |
| |
| /* 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 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; |
| |
| data->depends.safe_push (def_stmt); |
| |
| 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, im_mem_ref *ref) |
| { |
| struct loop *aloop; |
| |
| if (ref->stored && bitmap_bit_p (ref->stored, loop->num)) |
| return NULL; |
| |
| for (aloop = outer; |
| aloop != loop; |
| aloop = superloop_at_depth (loop, loop_depth (aloop) + 1)) |
| if ((!ref->stored || !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 im_mem_ref * |
| mem_ref_in_stmt (gimple *stmt) |
| { |
| bool store; |
| tree *mem = simple_mem_ref_in_stmt (stmt, &store); |
| hashval_t hash; |
| im_mem_ref *ref; |
| |
| if (!mem) |
| return NULL; |
| gcc_assert (!store); |
| |
| hash = iterative_hash_expr (*mem, 0); |
| ref = memory_accesses.refs->find_with_hash (*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, gphi *phi, |
| tree *true_arg_p, tree *false_arg_p) |
| { |
| edge te, fe; |
| if (! extract_true_false_controlled_edges (dom, gimple_bb (phi), |
| &te, &fe)) |
| return false; |
| |
| if (true_arg_p) |
| *true_arg_p = PHI_ARG_DEF (phi, te->dest_idx); |
| if (false_arg_p) |
| *false_arg_p = PHI_ARG_DEF (phi, fe->dest_idx); |
| |
| 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 (gphi *phi = dyn_cast <gphi *> (stmt)) |
| { |
| 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, phi, iter, SSA_OP_USE) |
| { |
| val = USE_FROM_PTR (use_p); |
| |
| if (TREE_CODE (val) != SSA_NAME) |
| { |
| /* Assign const 1 to constants. */ |
| min_cost = MIN (min_cost, 1); |
| total_cost += 1; |
| continue; |
| } |
| if (!add_dependency (val, lim_data, loop, false)) |
| return false; |
| |
| gimple *def_stmt = SSA_NAME_DEF_STMT (val); |
| if (gimple_bb (def_stmt) |
| && gimple_bb (def_stmt)->loop_father == loop) |
| { |
| def_data = get_lim_data (def_stmt); |
| if (def_data) |
| { |
| min_cost = MIN (min_cost, def_data->cost); |
| total_cost += def_data->cost; |
| } |
| } |
| } |
| |
| min_cost = MIN (min_cost, total_cost); |
| lim_data->cost += min_cost; |
| |
| if (gimple_phi_num_args (phi) > 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, phi, 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) |
| lim_data->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)) |
| { |
| im_mem_ref *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 lim_aux_data *lim_data; |
| gimple *dep_stmt; |
| unsigned i; |
| |
| 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_EACH_VEC_ELT (lim_data->depends, i, dep_stmt) |
| 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) |
| { |
| gassign *stmt, *stmt1, *stmt2; |
| tree name, lhs, type; |
| tree real_one; |
| gimple_stmt_iterator gsi; |
| |
| stmt = as_a <gassign *> (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 (name, RDIV_EXPR, real_one, |
| gimple_assign_rhs2 (stmt)); |
| stmt2 = gimple_build_assign (lhs, MULT_EXPR, 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) |
| { |
| gassign *stmt; |
| gimple *stmt1; |
| gassign *stmt2; |
| gimple *use_stmt; |
| gcond *cond_stmt; |
| tree lhs, name, t, a, b; |
| use_operand_p use; |
| |
| stmt = as_a <gassign *> (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)) |
| return stmt; |
| cond_stmt = dyn_cast <gcond *> (use_stmt); |
| if (!cond_stmt) |
| return stmt; |
| if (gimple_cond_lhs (cond_stmt) != lhs |
| || (gimple_cond_code (cond_stmt) != NE_EXPR |
| && gimple_cond_code (cond_stmt) != EQ_EXPR) |
| || !integer_zerop (gimple_cond_rhs (cond_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 (cond_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); |
| gimple *to_release = gsi_stmt (rsi); |
| gsi_remove (&rsi, true); |
| release_defs (to_release); |
| |
| return stmt1; |
| } |
| |
| return 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. */ |
| class invariantness_dom_walker : public dom_walker |
| { |
| public: |
| invariantness_dom_walker (cdi_direction direction) |
| : dom_walker (direction) {} |
| |
| virtual edge before_dom_children (basic_block); |
| }; |
| |
| /* 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 dom_walker. */ |
| |
| edge |
| invariantness_dom_walker::before_dom_children (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 NULL; |
| |
| 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); |
| } |
| return NULL; |
| } |
| |
| class move_computations_dom_walker : public dom_walker |
| { |
| public: |
| move_computations_dom_walker (cdi_direction direction) |
| : dom_walker (direction), todo_ (0) {} |
| |
| virtual edge before_dom_children (basic_block); |
| |
| unsigned int todo_; |
| }; |
| |
| /* 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. */ |
| |
| unsigned int |
| move_computations_worker (basic_block bb) |
| { |
| struct loop *level; |
| unsigned cost = 0; |
| struct lim_aux_data *lim_data; |
| unsigned int todo = 0; |
| |
| if (!loop_outer (bb->loop_father)) |
| return todo; |
| |
| for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi); ) |
| { |
| gassign *new_stmt; |
| gphi *stmt = bsi.phi (); |
| |
| 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 (gimple_phi_result (stmt), |
| TREE_CODE (arg), arg); |
| } |
| 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 (gimple_phi_result (stmt), |
| COND_EXPR, t, arg0, arg1); |
| todo |= TODO_cleanup_cfg; |
| } |
| if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (new_stmt))) |
| && (!ALWAYS_EXECUTED_IN (bb) |
| || (ALWAYS_EXECUTED_IN (bb) != level |
| && !flow_loop_nested_p (ALWAYS_EXECUTED_IN (bb), level)))) |
| { |
| tree lhs = gimple_assign_lhs (new_stmt); |
| SSA_NAME_RANGE_INFO (lhs) = NULL; |
| } |
| gsi_insert_on_edge (loop_preheader_edge (level), new_stmt); |
| remove_phi_node (&bsi, false); |
| } |
| |
| for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi); ) |
| { |
| edge e; |
| |
| gimple *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. */ |
| gphi_iterator gsi2; |
| for (gsi2 = gsi_start_phis (e->dest); |
| !gsi_end_p (gsi2); gsi_next (&gsi2)) |
| { |
| gphi *phi = gsi2.phi (); |
| if (virtual_operand_p (gimple_phi_result (phi))) |
| { |
| gimple_set_vuse (stmt, PHI_ARG_DEF_FROM_EDGE (phi, e)); |
| break; |
| } |
| } |
| } |
| gsi_remove (&bsi, false); |
| if (gimple_has_lhs (stmt) |
| && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME |
| && INTEGRAL_TYPE_P (TREE_TYPE (gimple_get_lhs (stmt))) |
| && (!ALWAYS_EXECUTED_IN (bb) |
| || !(ALWAYS_EXECUTED_IN (bb) == level |
| || flow_loop_nested_p (ALWAYS_EXECUTED_IN (bb), level)))) |
| { |
| tree lhs = gimple_get_lhs (stmt); |
| SSA_NAME_RANGE_INFO (lhs) = NULL; |
| } |
| /* In case this is a stmt that is not unconditionally executed |
| when the target loop header is executed and the stmt may |
| invoke undefined integer or pointer overflow rewrite it to |
| unsigned arithmetic. */ |
| if (is_gimple_assign (stmt) |
| && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (stmt))) |
| && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (gimple_assign_lhs (stmt))) |
| && arith_code_with_undefined_signed_overflow |
| (gimple_assign_rhs_code (stmt)) |
| && (!ALWAYS_EXECUTED_IN (bb) |
| || !(ALWAYS_EXECUTED_IN (bb) == level |
| || flow_loop_nested_p (ALWAYS_EXECUTED_IN (bb), level)))) |
| gsi_insert_seq_on_edge (e, rewrite_to_defined_overflow (stmt)); |
| else |
| gsi_insert_on_edge (e, stmt); |
| } |
| |
| return todo; |
| } |
| |
| /* 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) |
| { |
| int *rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); |
| int n = pre_and_rev_post_order_compute_fn (cfun, NULL, rpo, false); |
| unsigned todo = 0; |
| |
| for (int i = 0; i < n; ++i) |
| todo |= move_computations_worker (BASIC_BLOCK_FOR_FN (cfun, rpo[i])); |
| |
| free (rpo); |
| |
| 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 function to free the mem_ref object OBJ. */ |
| |
| static void |
| memref_free (struct im_mem_ref *mem) |
| { |
| mem->accesses_in_loop.release (); |
| } |
| |
| /* Allocates and returns a memory reference description for MEM whose hash |
| value is HASH and id is ID. */ |
| |
| static im_mem_ref * |
| mem_ref_alloc (tree mem, unsigned hash, unsigned id) |
| { |
| im_mem_ref *ref = XOBNEW (&mem_ref_obstack, struct im_mem_ref); |
| ao_ref_init (&ref->mem, mem); |
| ref->id = id; |
| ref->hash = hash; |
| ref->stored = NULL; |
| bitmap_initialize (&ref->indep_loop, &lim_bitmap_obstack); |
| bitmap_initialize (&ref->dep_loop, &lim_bitmap_obstack); |
| ref->accesses_in_loop.create (1); |
| |
| return ref; |
| } |
| |
| /* 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 (im_mem_ref *ref, gimple *stmt, tree *loc) |
| { |
| mem_ref_loc aref; |
| aref.stmt = stmt; |
| aref.ref = loc; |
| ref->accesses_in_loop.safe_push (aref); |
| } |
| |
| /* Set the LOOP bit in REF stored bitmap and allocate that if |
| necessary. Return whether a bit was changed. */ |
| |
| static bool |
| set_ref_stored_in_loop (im_mem_ref *ref, struct loop *loop) |
| { |
| if (!ref->stored) |
| ref->stored = BITMAP_ALLOC (&lim_bitmap_obstack); |
| return bitmap_set_bit (ref->stored, loop->num); |
| } |
| |
| /* Marks reference REF as stored in LOOP. */ |
| |
| static void |
| mark_ref_stored (im_mem_ref *ref, struct loop *loop) |
| { |
| while (loop != current_loops->tree_root |
| && set_ref_stored_in_loop (ref, loop)) |
| loop = loop_outer (loop); |
| } |
| |
| /* 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; |
| im_mem_ref **slot; |
| im_mem_ref *ref; |
| bool is_stored; |
| unsigned id; |
| |
| if (!gimple_vuse (stmt)) |
| return; |
| |
| mem = simple_mem_ref_in_stmt (stmt, &is_stored); |
| if (!mem) |
| { |
| /* We use the shared mem_ref for all unanalyzable refs. */ |
| id = UNANALYZABLE_MEM_ID; |
| ref = memory_accesses.refs_list[id]; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Unanalyzed memory reference %u: ", id); |
| print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
| } |
| is_stored = gimple_vdef (stmt); |
| } |
| else |
| { |
| hash = iterative_hash_expr (*mem, 0); |
| slot = memory_accesses.refs->find_slot_with_hash (*mem, hash, INSERT); |
| if (*slot) |
| { |
| ref = *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.ref, TDF_SLIM); |
| fprintf (dump_file, "\n"); |
| } |
| } |
| |
| record_mem_ref_loc (ref, stmt, mem); |
| } |
| bitmap_set_bit (&memory_accesses.refs_in_loop[loop->num], ref->id); |
| if (is_stored) |
| { |
| bitmap_set_bit (&memory_accesses.refs_stored_in_loop[loop->num], ref->id); |
| mark_ref_stored (ref, loop); |
| } |
| return; |
| } |
| |
| static unsigned *bb_loop_postorder; |
| |
| /* qsort sort function to sort blocks after their loop fathers postorder. */ |
| |
| static int |
| sort_bbs_in_loop_postorder_cmp (const void *bb1_, const void *bb2_) |
| { |
| basic_block bb1 = *(basic_block *)const_cast<void *>(bb1_); |
| basic_block bb2 = *(basic_block *)const_cast<void *>(bb2_); |
| struct loop *loop1 = bb1->loop_father; |
| struct loop *loop2 = bb2->loop_father; |
| if (loop1->num == loop2->num) |
| return 0; |
| return bb_loop_postorder[loop1->num] < bb_loop_postorder[loop2->num] ? -1 : 1; |
| } |
| |
| /* qsort sort function to sort ref locs after their loop fathers postorder. */ |
| |
| static int |
| sort_locs_in_loop_postorder_cmp (const void *loc1_, const void *loc2_) |
| { |
| mem_ref_loc *loc1 = (mem_ref_loc *)const_cast<void *>(loc1_); |
| mem_ref_loc *loc2 = (mem_ref_loc *)const_cast<void *>(loc2_); |
| struct loop *loop1 = gimple_bb (loc1->stmt)->loop_father; |
| struct loop *loop2 = gimple_bb (loc2->stmt)->loop_father; |
| if (loop1->num == loop2->num) |
| return 0; |
| return bb_loop_postorder[loop1->num] < bb_loop_postorder[loop2->num] ? -1 : 1; |
| } |
| |
| /* Gathers memory references in loops. */ |
| |
| static void |
| analyze_memory_references (void) |
| { |
| gimple_stmt_iterator bsi; |
| basic_block bb, *bbs; |
| struct loop *loop, *outer; |
| unsigned i, n; |
| |
| /* Collect all basic-blocks in loops and sort them after their |
| loops postorder. */ |
| i = 0; |
| bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS); |
| FOR_EACH_BB_FN (bb, cfun) |
| if (bb->loop_father != current_loops->tree_root) |
| bbs[i++] = bb; |
| n = i; |
| qsort (bbs, n, sizeof (basic_block), sort_bbs_in_loop_postorder_cmp); |
| |
| /* Visit blocks in loop postorder and assign mem-ref IDs in that order. |
| That results in better locality for all the bitmaps. */ |
| for (i = 0; i < n; ++i) |
| { |
| basic_block bb = bbs[i]; |
| for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) |
| gather_mem_refs_stmt (bb->loop_father, gsi_stmt (bsi)); |
| } |
| |
| /* Sort the location list of gathered memory references after their |
| loop postorder number. */ |
| im_mem_ref *ref; |
| FOR_EACH_VEC_ELT (memory_accesses.refs_list, i, ref) |
| ref->accesses_in_loop.qsort (sort_locs_in_loop_postorder_cmp); |
| |
| free (bbs); |
| // free (bb_loop_postorder); |
| |
| /* Propagate the information about accessed memory references up |
| the loop hierarchy. */ |
| FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
| { |
| /* Finalize the overall touched references (including subloops). */ |
| bitmap_ior_into (&memory_accesses.all_refs_stored_in_loop[loop->num], |
| &memory_accesses.refs_stored_in_loop[loop->num]); |
| |
| /* Propagate the information about accessed memory references up |
| the loop hierarchy. */ |
| outer = loop_outer (loop); |
| if (outer == current_loops->tree_root) |
| continue; |
| |
| bitmap_ior_into (&memory_accesses.all_refs_stored_in_loop[outer->num], |
| &memory_accesses.all_refs_stored_in_loop[loop->num]); |
| } |
| } |
| |
| /* 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 (im_mem_ref *mem1, im_mem_ref *mem2, |
| hash_map<tree, name_expansion *> **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. */ |
| widest_int size1, size2; |
| aff_tree off1, off2; |
| |
| /* Perform basic offset and type-based disambiguation. */ |
| if (!refs_may_alias_p_1 (&mem1->mem, &mem2->mem, true)) |
| 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->mem.ref, &off1, &size1); |
| get_inner_reference_aff (mem2->mem.ref, &off2, &size2); |
| aff_combination_expand (&off1, ttae_cache); |
| aff_combination_expand (&off2, ttae_cache); |
| aff_combination_scale (&off1, -1); |
| aff_combination_add (&off2, &off1); |
| |
| if (aff_comb_cannot_overlap_p (&off2, size1, size2)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Compare function for bsearch searching for reference locations |
| in a loop. */ |
| |
| static int |
| find_ref_loc_in_loop_cmp (const void *loop_, const void *loc_) |
| { |
| struct loop *loop = (struct loop *)const_cast<void *>(loop_); |
| mem_ref_loc *loc = (mem_ref_loc *)const_cast<void *>(loc_); |
| struct loop *loc_loop = gimple_bb (loc->stmt)->loop_father; |
| if (loop->num == loc_loop->num |
| || flow_loop_nested_p (loop, loc_loop)) |
| return 0; |
| return (bb_loop_postorder[loop->num] < bb_loop_postorder[loc_loop->num] |
| ? -1 : 1); |
| } |
| |
| /* Iterates over all locations of REF in LOOP and its subloops calling |
| fn.operator() with the location as argument. When that operator |
| returns true the iteration is stopped and true is returned. |
| Otherwise false is returned. */ |
| |
| template <typename FN> |
| static bool |
| for_all_locs_in_loop (struct loop *loop, im_mem_ref *ref, FN fn) |
| { |
| unsigned i; |
| mem_ref_loc *loc; |
| |
| /* Search for the cluster of locs in the accesses_in_loop vector |
| which is sorted after postorder index of the loop father. */ |
| loc = ref->accesses_in_loop.bsearch (loop, find_ref_loc_in_loop_cmp); |
| if (!loc) |
| return false; |
| |
| /* We have found one location inside loop or its sub-loops. Iterate |
| both forward and backward to cover the whole cluster. */ |
| i = loc - ref->accesses_in_loop.address (); |
| while (i > 0) |
| { |
| --i; |
| mem_ref_loc *l = &ref->accesses_in_loop[i]; |
| if (!flow_bb_inside_loop_p (loop, gimple_bb (l->stmt))) |
| break; |
| if (fn (l)) |
| return true; |
| } |
| for (i = loc - ref->accesses_in_loop.address (); |
| i < ref->accesses_in_loop.length (); ++i) |
| { |
| mem_ref_loc *l = &ref->accesses_in_loop[i]; |
| if (!flow_bb_inside_loop_p (loop, gimple_bb (l->stmt))) |
| break; |
| if (fn (l)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Rewrites location LOC by TMP_VAR. */ |
| |
| struct rewrite_mem_ref_loc |
| { |
| rewrite_mem_ref_loc (tree tmp_var_) : tmp_var (tmp_var_) {} |
| bool operator () (mem_ref_loc *loc); |
| tree tmp_var; |
| }; |
| |
| bool |
| rewrite_mem_ref_loc::operator () (mem_ref_loc *loc) |
| { |
| *loc->ref = tmp_var; |
| update_stmt (loc->stmt); |
| return false; |
| } |
| |
| /* Rewrites all references to REF in LOOP by variable TMP_VAR. */ |
| |
| static void |
| rewrite_mem_refs (struct loop *loop, im_mem_ref *ref, tree tmp_var) |
| { |
| for_all_locs_in_loop (loop, ref, rewrite_mem_ref_loc (tmp_var)); |
| } |
| |
| /* Stores the first reference location in LOCP. */ |
| |
| struct first_mem_ref_loc_1 |
| { |
| first_mem_ref_loc_1 (mem_ref_loc **locp_) : locp (locp_) {} |
| bool operator () (mem_ref_loc *loc); |
| mem_ref_loc **locp; |
| }; |
| |
| bool |
| first_mem_ref_loc_1::operator () (mem_ref_loc *loc) |
| { |
| *locp = loc; |
| return true; |
| } |
| |
| /* Returns the first reference location to REF in LOOP. */ |
| |
| static mem_ref_loc * |
| first_mem_ref_loc (struct loop *loop, im_mem_ref *ref) |
| { |
| mem_ref_loc *locp = NULL; |
| for_all_locs_in_loop (loop, ref, first_mem_ref_loc_1 (&locp)); |
| return locp; |
| } |
| |
| 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; |
| bool irr = ex->flags & EDGE_IRREDUCIBLE_LOOP; |
| |
| /* ?? 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); |
| else |
| { |
| for (gphi_iterator gpi = gsi_start_phis (ex->dest); |
| !gsi_end_p (gpi); gsi_next (&gpi)) |
| { |
| gphi *phi = gpi.phi (); |
| if (virtual_operand_p (gimple_phi_result (phi))) |
| continue; |
| |
| /* When the destination has a non-virtual PHI node with multiple |
| predecessors make sure we preserve the PHI structure by |
| forcing a forwarder block so that hoisting of that PHI will |
| still work. */ |
| split_edge (ex); |
| break; |
| } |
| } |
| |
| old_dest = ex->dest; |
| new_bb = split_edge (ex); |
| then_bb = create_empty_bb (new_bb); |
| if (irr) |
| then_bb->flags = BB_IRREDUCIBLE_LOOP; |
| 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 | (irr ? EDGE_IRREDUCIBLE_LOOP : 0)); |
| make_edge (new_bb, old_dest, |
| EDGE_FALSE_VALUE | (irr ? EDGE_IRREDUCIBLE_LOOP : 0)); |
| then_old_edge = make_edge (then_bb, old_dest, |
| EDGE_FALLTHRU | (irr ? EDGE_IRREDUCIBLE_LOOP : 0)); |
| |
| 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 (gphi_iterator gpi = gsi_start_phis (old_dest); |
| !gsi_end_p (gpi); gsi_next (&gpi)) |
| { |
| gphi *phi = gpi.phi (); |
| 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; |
| } |
| |
| /* When REF is set on the location, set flag indicating the store. */ |
| |
| struct sm_set_flag_if_changed |
| { |
| sm_set_flag_if_changed (tree flag_) : flag (flag_) {} |
| bool operator () (mem_ref_loc *loc); |
| tree flag; |
| }; |
| |
| bool |
| sm_set_flag_if_changed::operator () (mem_ref_loc *loc) |
| { |
| /* Only set the flag for writes. */ |
| if (is_gimple_assign (loc->stmt) |
| && gimple_assign_lhs_ptr (loc->stmt) == loc->ref) |
| { |
| gimple_stmt_iterator gsi = gsi_for_stmt (loc->stmt); |
| gimple *stmt = gimple_build_assign (flag, boolean_true_node); |
| gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING); |
| } |
| return false; |
| } |
| |
| /* 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, im_mem_ref *ref) |
| { |
| tree flag; |
| char *str = get_lsm_tmp_name (ref->mem.ref, ~0, "_flag"); |
| flag = create_tmp_reg (boolean_type_node, str); |
| for_all_locs_in_loop (loop, ref, sm_set_flag_if_changed (flag)); |
| 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, im_mem_ref *ref) |
| { |
| tree tmp_var, store_flag = NULL_TREE; |
| unsigned i; |
| gassign *load; |
| struct fmt_data fmt_data; |
| edge ex; |
| struct lim_aux_data *lim_data; |
| bool multi_threaded_model_p = false; |
| gimple_stmt_iterator gsi; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Executing store motion of "); |
| print_generic_expr (dump_file, ref->mem.ref, 0); |
| fprintf (dump_file, " from loop %d\n", loop->num); |
| } |
| |
| tmp_var = create_tmp_reg (TREE_TYPE (ref->mem.ref), |
| get_lsm_tmp_name (ref->mem.ref, ~0)); |
| |
| fmt_data.loop = loop; |
| fmt_data.orig_loop = loop; |
| for_each_index (&ref->mem.ref, force_move_till, &fmt_data); |
| |
| if (bb_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 on a random exit edge or into the latch if |
| the loop does not exit, so that we are sure it will be processed |
| by move_computations after all dependencies. */ |
| gsi = gsi_for_stmt (first_mem_ref_loc (loop, ref)->stmt); |
| |
| /* 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.ref)); |
| lim_data = init_lim_data (load); |
| lim_data->max_loop = loop; |
| lim_data->tgt_loop = loop; |
| gsi_insert_before (&gsi, load, GSI_SAME_STMT); |
| |
| 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_before (&gsi, load, GSI_SAME_STMT); |
| } |
| |
| /* Sink the store to every exit from the loop. */ |
| FOR_EACH_VEC_ELT (exits, i, ex) |
| if (!multi_threaded_model_p) |
| { |
| gassign *store; |
| store = gimple_build_assign (unshare_expr (ref->mem.ref), tmp_var); |
| gsi_insert_on_edge (ex, store); |
| } |
| else |
| execute_sm_if_changed (ex, ref->mem.ref, 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) |
| { |
| im_mem_ref *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); |
| } |
| } |
| |
| struct ref_always_accessed |
| { |
| ref_always_accessed (struct loop *loop_, bool stored_p_) |
| : loop (loop_), stored_p (stored_p_) {} |
| bool operator () (mem_ref_loc *loc); |
| struct loop *loop; |
| bool stored_p; |
| }; |
| |
| bool |
| ref_always_accessed::operator () (mem_ref_loc *loc) |
| { |
| struct loop *must_exec; |
| |
| if (!get_lim_data (loc->stmt)) |
| return false; |
| |
| /* If we require an always executed store make sure the statement |
| stores to the reference. */ |
| if (stored_p) |
| { |
| tree lhs = gimple_get_lhs (loc->stmt); |
| if (!lhs |
| || lhs != *loc->ref) |
| return false; |
| } |
| |
| must_exec = get_lim_data (loc->stmt)->always_executed_in; |
| if (!must_exec) |
| return false; |
| |
| if (must_exec == loop |
| || flow_loop_nested_p (must_exec, loop)) |
| return true; |
| |
| return false; |
| } |
| |
| /* 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, im_mem_ref *ref, bool stored_p) |
| { |
| return for_all_locs_in_loop (loop, ref, |
| ref_always_accessed (loop, stored_p)); |
| } |
| |
| /* Returns true if REF1 and REF2 are independent. */ |
| |
| static bool |
| refs_independent_p (im_mem_ref *ref1, im_mem_ref *ref2) |
| { |
| if (ref1 == ref2) |
| return true; |
| |
| 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, ref2, &memory_accesses.ttae_cache)) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "dependent.\n"); |
| return false; |
| } |
| else |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "independent.\n"); |
| return true; |
| } |
| } |
| |
| /* Mark REF dependent on stores or loads (according to STORED_P) in LOOP |
| and its super-loops. */ |
| |
| static void |
| record_dep_loop (struct loop *loop, im_mem_ref *ref, bool stored_p) |
| { |
| /* We can propagate dependent-in-loop bits up the loop |
| hierarchy to all outer loops. */ |
| while (loop != current_loops->tree_root |
| && bitmap_set_bit (&ref->dep_loop, LOOP_DEP_BIT (loop->num, stored_p))) |
| loop = loop_outer (loop); |
| } |
| |
| /* Returns true if REF is independent on all other memory |
| references in LOOP. */ |
| |
| static bool |
| ref_indep_loop_p_1 (struct loop *loop, im_mem_ref *ref, bool stored_p) |
| { |
| stored_p |= (ref->stored && bitmap_bit_p (ref->stored, loop->num)); |
| |
| bool indep_p = true; |
| bitmap refs_to_check; |
| |
| if (stored_p) |
| refs_to_check = &memory_accesses.refs_in_loop[loop->num]; |
| else |
| refs_to_check = &memory_accesses.refs_stored_in_loop[loop->num]; |
| |
| if (bitmap_bit_p (refs_to_check, UNANALYZABLE_MEM_ID)) |
| indep_p = false; |
| else |
| { |
| if (bitmap_bit_p (&ref->indep_loop, LOOP_DEP_BIT (loop->num, stored_p))) |
| return true; |
| if (bitmap_bit_p (&ref->dep_loop, LOOP_DEP_BIT (loop->num, stored_p))) |
| return false; |
| |
| struct loop *inner = loop->inner; |
| while (inner) |
| { |
| if (!ref_indep_loop_p_1 (inner, ref, stored_p)) |
| { |
| indep_p = false; |
| break; |
| } |
| inner = inner->next; |
| } |
| |
| if (indep_p) |
| { |
| unsigned i; |
| bitmap_iterator bi; |
| EXECUTE_IF_SET_IN_BITMAP (refs_to_check, 0, i, bi) |
| { |
| im_mem_ref *aref = memory_accesses.refs_list[i]; |
| if (!refs_independent_p (ref, aref)) |
| { |
| indep_p = false; |
| break; |
| } |
| } |
| } |
| } |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Querying dependencies of ref %u in loop %d: %s\n", |
| ref->id, loop->num, indep_p ? "independent" : "dependent"); |
| |
| /* Record the computed result in the cache. */ |
| if (indep_p) |
| { |
| if (bitmap_set_bit (&ref->indep_loop, LOOP_DEP_BIT (loop->num, stored_p)) |
| && stored_p) |
| { |
| /* If it's independend against all refs then it's independent |
| against stores, too. */ |
| bitmap_set_bit (&ref->indep_loop, LOOP_DEP_BIT (loop->num, false)); |
| } |
| } |
| else |
| { |
| record_dep_loop (loop, ref, stored_p); |
| if (!stored_p) |
| { |
| /* If it's dependent against stores it's dependent against |
| all refs, too. */ |
| record_dep_loop (loop, ref, true); |
| } |
| } |
| |
| return indep_p; |
| } |
| |
| /* Returns true if REF is independent on all other memory references in |
| LOOP. */ |
| |
| static bool |
| ref_indep_loop_p (struct loop *loop, im_mem_ref *ref) |
| { |
| gcc_checking_assert (MEM_ANALYZABLE (ref)); |
| |
| return ref_indep_loop_p_1 (loop, ref, false); |
| } |
| |
| /* Returns true if we can perform store motion of REF from LOOP. */ |
| |
| static bool |
| can_sm_ref_p (struct loop *loop, im_mem_ref *ref) |
| { |
| tree base; |
| |
| /* Can't hoist unanalyzable refs. */ |
| if (!MEM_ANALYZABLE (ref)) |
| return false; |
| |
| /* It should be movable. */ |
| if (!is_gimple_reg_type (TREE_TYPE (ref->mem.ref)) |
| || TREE_THIS_VOLATILE (ref->mem.ref) |
| || !for_each_index (&ref->mem.ref, 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.ref)) |
| 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.ref); |
| if ((tree_could_trap_p (ref->mem.ref) |
| || (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_stored_in_loop[loop->num]; |
| unsigned i; |
| bitmap_iterator bi; |
| im_mem_ref *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 (&lim_bitmap_obstack); |
| |
| 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 (&lim_bitmap_obstack); |
| |
| 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_1 (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 there is an exit from this BB. */ |
| if (!flow_bb_inside_loop_p (loop, e->dest)) |
| break; |
| /* Or we enter a possibly non-finite loop. */ |
| if (flow_loop_nested_p (bb->loop_father, |
| e->dest->loop_father) |
| && ! finite_loop_p (e->dest->loop_father)) |
| 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_1 (loop, contains_call); |
| } |
| |
| /* Fills ALWAYS_EXECUTED_IN information for basic blocks, i.e. |
| for each such basic block bb records the outermost loop for that execution |
| of its header implies execution of bb. */ |
| |
| static void |
| fill_always_executed_in (void) |
| { |
| basic_block bb; |
| struct loop *loop; |
| |
| auto_sbitmap contains_call (last_basic_block_for_fn (cfun)); |
| bitmap_clear (contains_call); |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| gimple_stmt_iterator gsi; |
| for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| { |
| if (nonpure_call_p (gsi_stmt (gsi))) |
| break; |
| } |
| |
| if (!gsi_end_p (gsi)) |
| bitmap_set_bit (contains_call, bb->index); |
| } |
| |
| for (loop = current_loops->tree_root->inner; loop; loop = loop->next) |
| fill_always_executed_in_1 (loop, contains_call); |
| } |
| |
| |
| /* Compute the global information needed by the loop invariant motion pass. */ |
| |
| static void |
| tree_ssa_lim_initialize (void) |
| { |
| struct loop *loop; |
| unsigned i; |
| |
| bitmap_obstack_initialize (&lim_bitmap_obstack); |
| gcc_obstack_init (&mem_ref_obstack); |
| lim_aux_data_map = new hash_map<gimple *, lim_aux_data *>; |
| |
| if (flag_tm) |
| compute_transaction_bits (); |
| |
| alloc_aux_for_edges (0); |
| |
| memory_accesses.refs = new hash_table<mem_ref_hasher> (100); |
| memory_accesses.refs_list.create (100); |
| /* Allocate a special, unanalyzable mem-ref with ID zero. */ |
| memory_accesses.refs_list.quick_push |
| (mem_ref_alloc (error_mark_node, 0, UNANALYZABLE_MEM_ID)); |
| |
| memory_accesses.refs_in_loop.create (number_of_loops (cfun)); |
| memory_accesses.refs_in_loop.quick_grow (number_of_loops (cfun)); |
| memory_accesses.refs_stored_in_loop.create (number_of_loops (cfun)); |
| memory_accesses.refs_stored_in_loop.quick_grow (number_of_loops (cfun)); |
| memory_accesses.all_refs_stored_in_loop.create (number_of_loops (cfun)); |
| memory_accesses.all_refs_stored_in_loop.quick_grow (number_of_loops (cfun)); |
| |
| for (i = 0; i < number_of_loops (cfun); i++) |
| { |
| bitmap_initialize (&memory_accesses.refs_in_loop[i], |
| &lim_bitmap_obstack); |
| bitmap_initialize (&memory_accesses.refs_stored_in_loop[i], |
| &lim_bitmap_obstack); |
| bitmap_initialize (&memory_accesses.all_refs_stored_in_loop[i], |
| &lim_bitmap_obstack); |
| } |
| |
| memory_accesses.ttae_cache = NULL; |
| |
| /* Initialize bb_loop_postorder with a mapping from loop->num to |
| its postorder index. */ |
| i = 0; |
| bb_loop_postorder = XNEWVEC (unsigned, number_of_loops (cfun)); |
| FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
| bb_loop_postorder[loop->num] = i++; |
| } |
| |
| /* Cleans up after the invariant motion pass. */ |
| |
| static void |
| tree_ssa_lim_finalize (void) |
| { |
| basic_block bb; |
| unsigned i; |
| im_mem_ref *ref; |
| |
| free_aux_for_edges (); |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| SET_ALWAYS_EXECUTED_IN (bb, NULL); |
| |
| bitmap_obstack_release (&lim_bitmap_obstack); |
| delete lim_aux_data_map; |
| |
| delete memory_accesses.refs; |
| memory_accesses.refs = NULL; |
| |
| FOR_EACH_VEC_ELT (memory_accesses.refs_list, i, ref) |
| memref_free (ref); |
| memory_accesses.refs_list.release (); |
| obstack_free (&mem_ref_obstack, NULL); |
| |
| memory_accesses.refs_in_loop.release (); |
| memory_accesses.refs_stored_in_loop.release (); |
| memory_accesses.all_refs_stored_in_loop.release (); |
| |
| if (memory_accesses.ttae_cache) |
| free_affine_expand_cache (&memory_accesses.ttae_cache); |
| |
| free (bb_loop_postorder); |
| } |
| |
| /* Moves invariants from loops. Only "expensive" invariants are moved out -- |
| i.e. those that are likely to be win regardless of the register pressure. */ |
| |
| static unsigned int |
| tree_ssa_lim (void) |
| { |
| unsigned int todo; |
| |
| tree_ssa_lim_initialize (); |
| |
| /* Gathers information about memory accesses in the loops. */ |
| analyze_memory_references (); |
| |
| /* Fills ALWAYS_EXECUTED_IN information for basic blocks. */ |
| fill_always_executed_in (); |
| |
| /* For each statement determine the outermost loop in that it is |
| invariant and cost for computing the invariant. */ |
| invariantness_dom_walker (CDI_DOMINATORS) |
| .walk (cfun->cfg->x_entry_block_ptr); |
| |
| /* 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; |
| } |
| |
| /* Loop invariant motion pass. */ |
| |
| namespace { |
| |
| const pass_data pass_data_lim = |
| { |
| GIMPLE_PASS, /* type */ |
| "lim", /* name */ |
| OPTGROUP_LOOP, /* optinfo_flags */ |
| TV_LIM, /* tv_id */ |
| PROP_cfg, /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| 0, /* todo_flags_finish */ |
| }; |
| |
| class pass_lim : public gimple_opt_pass |
| { |
| public: |
| pass_lim (gcc::context *ctxt) |
| : gimple_opt_pass (pass_data_lim, ctxt) |
| {} |
| |
| /* opt_pass methods: */ |
| opt_pass * clone () { return new pass_lim (m_ctxt); } |
| virtual bool gate (function *) { return flag_tree_loop_im != 0; } |
| virtual unsigned int execute (function *); |
| |
| }; // class pass_lim |
| |
| unsigned int |
| pass_lim::execute (function *fun) |
| { |
| bool in_loop_pipeline = scev_initialized_p (); |
| if (!in_loop_pipeline) |
| loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS); |
| |
| if (number_of_loops (fun) <= 1) |
| return 0; |
| unsigned int todo = tree_ssa_lim (); |
| |
| if (!in_loop_pipeline) |
| loop_optimizer_finalize (); |
| return todo; |
| } |
| |
| } // anon namespace |
| |
| gimple_opt_pass * |
| make_pass_lim (gcc::context *ctxt) |
| { |
| return new pass_lim (ctxt); |
| } |
| |
| |