1 /* Loop invariant motion.
2 Copyright (C) 2003-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 3, or (at your option) any
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
26 #include "basic-block.h"
27 #include "gimple-pretty-print.h"
29 #include "hash-table.h"
30 #include "tree-ssa-alias.h"
31 #include "internal-fn.h"
33 #include "gimple-expr.h"
37 #include "gimple-iterator.h"
38 #include "gimple-ssa.h"
40 #include "tree-phinodes.h"
41 #include "ssa-iterators.h"
42 #include "stringpool.h"
43 #include "tree-ssanames.h"
44 #include "tree-ssa-loop-manip.h"
45 #include "tree-ssa-loop.h"
46 #include "tree-into-ssa.h"
50 #include "tree-pass.h"
52 #include "tree-affine.h"
53 #include "tree-ssa-propagate.h"
54 #include "trans-mem.h"
55 #include "gimple-fold.h"
57 /* TODO: Support for predicated code motion. I.e.
68 Where COND and INV are invariants, but evaluating INV may trap or be
69 invalid from some other reason if !COND. This may be transformed to
79 /* The auxiliary data kept for each statement. */
83 struct loop
*max_loop
; /* The outermost loop in that the statement
86 struct loop
*tgt_loop
; /* The loop out of that we want to move the
89 struct loop
*always_executed_in
;
90 /* The outermost loop for that we are sure
91 the statement is executed if the loop
94 unsigned cost
; /* Cost of the computation performed by the
97 vec
<gimple
> depends
; /* Vector of statements that must be also
98 hoisted out of the loop when this statement
99 is hoisted; i.e. those that define the
100 operands of the statement and are inside of
101 the MAX_LOOP loop. */
104 /* Maps statements to their lim_aux_data. */
106 static hash_map
<gimple
, lim_aux_data
*> *lim_aux_data_map
;
108 /* Description of a memory reference location. */
110 typedef struct mem_ref_loc
112 tree
*ref
; /* The reference itself. */
113 gimple stmt
; /* The statement in that it occurs. */
117 /* Description of a memory reference. */
119 typedef struct im_mem_ref
121 unsigned id
; /* ID assigned to the memory reference
122 (its index in memory_accesses.refs_list) */
123 hashval_t hash
; /* Its hash value. */
125 /* The memory access itself and associated caching of alias-oracle
129 bitmap stored
; /* The set of loops in that this memory location
131 vec
<mem_ref_loc
> accesses_in_loop
;
132 /* The locations of the accesses. Vector
133 indexed by the loop number. */
135 /* The following sets are computed on demand. We keep both set and
136 its complement, so that we know whether the information was
137 already computed or not. */
138 bitmap_head indep_loop
; /* The set of loops in that the memory
139 reference is independent, meaning:
140 If it is stored in the loop, this store
141 is independent on all other loads and
143 If it is only loaded, then it is independent
144 on all stores in the loop. */
145 bitmap_head dep_loop
; /* The complement of INDEP_LOOP. */
148 /* We use two bits per loop in the ref->{in,}dep_loop bitmaps, the first
149 to record (in)dependence against stores in the loop and its subloops, the
150 second to record (in)dependence against all references in the loop
152 #define LOOP_DEP_BIT(loopnum, storedp) (2 * (loopnum) + (storedp ? 1 : 0))
154 /* Mem_ref hashtable helpers. */
156 struct mem_ref_hasher
: typed_noop_remove
<im_mem_ref
>
158 typedef im_mem_ref value_type
;
159 typedef tree_node compare_type
;
160 static inline hashval_t
hash (const value_type
*);
161 static inline bool equal (const value_type
*, const compare_type
*);
164 /* A hash function for struct im_mem_ref object OBJ. */
167 mem_ref_hasher::hash (const value_type
*mem
)
172 /* An equality function for struct im_mem_ref object MEM1 with
173 memory reference OBJ2. */
176 mem_ref_hasher::equal (const value_type
*mem1
, const compare_type
*obj2
)
178 return operand_equal_p (mem1
->mem
.ref
, (const_tree
) obj2
, 0);
182 /* Description of memory accesses in loops. */
186 /* The hash table of memory references accessed in loops. */
187 hash_table
<mem_ref_hasher
> *refs
;
189 /* The list of memory references. */
190 vec
<mem_ref_p
> refs_list
;
192 /* The set of memory references accessed in each loop. */
193 vec
<bitmap_head
> refs_in_loop
;
195 /* The set of memory references stored in each loop. */
196 vec
<bitmap_head
> refs_stored_in_loop
;
198 /* The set of memory references stored in each loop, including subloops . */
199 vec
<bitmap_head
> all_refs_stored_in_loop
;
201 /* Cache for expanding memory addresses. */
202 hash_map
<tree
, name_expansion
*> *ttae_cache
;
205 /* Obstack for the bitmaps in the above data structures. */
206 static bitmap_obstack lim_bitmap_obstack
;
207 static obstack mem_ref_obstack
;
209 static bool ref_indep_loop_p (struct loop
*, mem_ref_p
);
211 /* Minimum cost of an expensive expression. */
212 #define LIM_EXPENSIVE ((unsigned) PARAM_VALUE (PARAM_LIM_EXPENSIVE))
214 /* The outermost loop for which execution of the header guarantees that the
215 block will be executed. */
216 #define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux)
217 #define SET_ALWAYS_EXECUTED_IN(BB, VAL) ((BB)->aux = (void *) (VAL))
219 /* ID of the shared unanalyzable mem. */
220 #define UNANALYZABLE_MEM_ID 0
222 /* Whether the reference was analyzable. */
223 #define MEM_ANALYZABLE(REF) ((REF)->id != UNANALYZABLE_MEM_ID)
225 static struct lim_aux_data
*
226 init_lim_data (gimple stmt
)
228 lim_aux_data
*p
= XCNEW (struct lim_aux_data
);
229 lim_aux_data_map
->put (stmt
, p
);
234 static struct lim_aux_data
*
235 get_lim_data (gimple stmt
)
237 lim_aux_data
**p
= lim_aux_data_map
->get (stmt
);
244 /* Releases the memory occupied by DATA. */
247 free_lim_aux_data (struct lim_aux_data
*data
)
249 data
->depends
.release ();
254 clear_lim_data (gimple stmt
)
256 lim_aux_data
**p
= lim_aux_data_map
->get (stmt
);
260 free_lim_aux_data (*p
);
265 /* The possibilities of statement movement. */
268 MOVE_IMPOSSIBLE
, /* No movement -- side effect expression. */
269 MOVE_PRESERVE_EXECUTION
, /* Must not cause the non-executed statement
270 become executed -- memory accesses, ... */
271 MOVE_POSSIBLE
/* Unlimited movement. */
275 /* If it is possible to hoist the statement STMT unconditionally,
276 returns MOVE_POSSIBLE.
277 If it is possible to hoist the statement STMT, but we must avoid making
278 it executed if it would not be executed in the original program (e.g.
279 because it may trap), return MOVE_PRESERVE_EXECUTION.
280 Otherwise return MOVE_IMPOSSIBLE. */
283 movement_possibility (gimple stmt
)
286 enum move_pos ret
= MOVE_POSSIBLE
;
288 if (flag_unswitch_loops
289 && gimple_code (stmt
) == GIMPLE_COND
)
291 /* If we perform unswitching, force the operands of the invariant
292 condition to be moved out of the loop. */
293 return MOVE_POSSIBLE
;
296 if (gimple_code (stmt
) == GIMPLE_PHI
297 && gimple_phi_num_args (stmt
) <= 2
298 && !virtual_operand_p (gimple_phi_result (stmt
))
299 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_phi_result (stmt
)))
300 return MOVE_POSSIBLE
;
302 if (gimple_get_lhs (stmt
) == NULL_TREE
)
303 return MOVE_IMPOSSIBLE
;
305 if (gimple_vdef (stmt
))
306 return MOVE_IMPOSSIBLE
;
308 if (stmt_ends_bb_p (stmt
)
309 || gimple_has_volatile_ops (stmt
)
310 || gimple_has_side_effects (stmt
)
311 || stmt_could_throw_p (stmt
))
312 return MOVE_IMPOSSIBLE
;
314 if (is_gimple_call (stmt
))
316 /* While pure or const call is guaranteed to have no side effects, we
317 cannot move it arbitrarily. Consider code like
319 char *s = something ();
329 Here the strlen call cannot be moved out of the loop, even though
330 s is invariant. In addition to possibly creating a call with
331 invalid arguments, moving out a function call that is not executed
332 may cause performance regressions in case the call is costly and
333 not executed at all. */
334 ret
= MOVE_PRESERVE_EXECUTION
;
335 lhs
= gimple_call_lhs (stmt
);
337 else if (is_gimple_assign (stmt
))
338 lhs
= gimple_assign_lhs (stmt
);
340 return MOVE_IMPOSSIBLE
;
342 if (TREE_CODE (lhs
) == SSA_NAME
343 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
344 return MOVE_IMPOSSIBLE
;
346 if (TREE_CODE (lhs
) != SSA_NAME
347 || gimple_could_trap_p (stmt
))
348 return MOVE_PRESERVE_EXECUTION
;
350 /* Non local loads in a transaction cannot be hoisted out. Well,
351 unless the load happens on every path out of the loop, but we
352 don't take this into account yet. */
354 && gimple_in_transaction (stmt
)
355 && gimple_assign_single_p (stmt
))
357 tree rhs
= gimple_assign_rhs1 (stmt
);
358 if (DECL_P (rhs
) && is_global_var (rhs
))
362 fprintf (dump_file
, "Cannot hoist conditional load of ");
363 print_generic_expr (dump_file
, rhs
, TDF_SLIM
);
364 fprintf (dump_file
, " because it is in a transaction.\n");
366 return MOVE_IMPOSSIBLE
;
373 /* Suppose that operand DEF is used inside the LOOP. Returns the outermost
374 loop to that we could move the expression using DEF if it did not have
375 other operands, i.e. the outermost loop enclosing LOOP in that the value
376 of DEF is invariant. */
379 outermost_invariant_loop (tree def
, struct loop
*loop
)
383 struct loop
*max_loop
;
384 struct lim_aux_data
*lim_data
;
387 return superloop_at_depth (loop
, 1);
389 if (TREE_CODE (def
) != SSA_NAME
)
391 gcc_assert (is_gimple_min_invariant (def
));
392 return superloop_at_depth (loop
, 1);
395 def_stmt
= SSA_NAME_DEF_STMT (def
);
396 def_bb
= gimple_bb (def_stmt
);
398 return superloop_at_depth (loop
, 1);
400 max_loop
= find_common_loop (loop
, def_bb
->loop_father
);
402 lim_data
= get_lim_data (def_stmt
);
403 if (lim_data
!= NULL
&& lim_data
->max_loop
!= NULL
)
404 max_loop
= find_common_loop (max_loop
,
405 loop_outer (lim_data
->max_loop
));
406 if (max_loop
== loop
)
408 max_loop
= superloop_at_depth (loop
, loop_depth (max_loop
) + 1);
413 /* DATA is a structure containing information associated with a statement
414 inside LOOP. DEF is one of the operands of this statement.
416 Find the outermost loop enclosing LOOP in that value of DEF is invariant
417 and record this in DATA->max_loop field. If DEF itself is defined inside
418 this loop as well (i.e. we need to hoist it out of the loop if we want
419 to hoist the statement represented by DATA), record the statement in that
420 DEF is defined to the DATA->depends list. Additionally if ADD_COST is true,
421 add the cost of the computation of DEF to the DATA->cost.
423 If DEF is not invariant in LOOP, return false. Otherwise return TRUE. */
426 add_dependency (tree def
, struct lim_aux_data
*data
, struct loop
*loop
,
429 gimple def_stmt
= SSA_NAME_DEF_STMT (def
);
430 basic_block def_bb
= gimple_bb (def_stmt
);
431 struct loop
*max_loop
;
432 struct lim_aux_data
*def_data
;
437 max_loop
= outermost_invariant_loop (def
, loop
);
441 if (flow_loop_nested_p (data
->max_loop
, max_loop
))
442 data
->max_loop
= max_loop
;
444 def_data
= get_lim_data (def_stmt
);
449 /* Only add the cost if the statement defining DEF is inside LOOP,
450 i.e. if it is likely that by moving the invariants dependent
451 on it, we will be able to avoid creating a new register for
452 it (since it will be only used in these dependent invariants). */
453 && def_bb
->loop_father
== loop
)
454 data
->cost
+= def_data
->cost
;
456 data
->depends
.safe_push (def_stmt
);
461 /* Returns an estimate for a cost of statement STMT. The values here
462 are just ad-hoc constants, similar to costs for inlining. */
465 stmt_cost (gimple stmt
)
467 /* Always try to create possibilities for unswitching. */
468 if (gimple_code (stmt
) == GIMPLE_COND
469 || gimple_code (stmt
) == GIMPLE_PHI
)
470 return LIM_EXPENSIVE
;
472 /* We should be hoisting calls if possible. */
473 if (is_gimple_call (stmt
))
477 /* Unless the call is a builtin_constant_p; this always folds to a
478 constant, so moving it is useless. */
479 fndecl
= gimple_call_fndecl (stmt
);
481 && DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
482 && DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_CONSTANT_P
)
485 return LIM_EXPENSIVE
;
488 /* Hoisting memory references out should almost surely be a win. */
489 if (gimple_references_memory_p (stmt
))
490 return LIM_EXPENSIVE
;
492 if (gimple_code (stmt
) != GIMPLE_ASSIGN
)
495 switch (gimple_assign_rhs_code (stmt
))
498 case WIDEN_MULT_EXPR
:
499 case WIDEN_MULT_PLUS_EXPR
:
500 case WIDEN_MULT_MINUS_EXPR
:
513 /* Division and multiplication are usually expensive. */
514 return LIM_EXPENSIVE
;
518 case WIDEN_LSHIFT_EXPR
:
521 /* Shifts and rotates are usually expensive. */
522 return LIM_EXPENSIVE
;
525 /* Make vector construction cost proportional to the number
527 return CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt
));
531 /* Whether or not something is wrapped inside a PAREN_EXPR
532 should not change move cost. Nor should an intermediate
533 unpropagated SSA name copy. */
541 /* Finds the outermost loop between OUTER and LOOP in that the memory reference
542 REF is independent. If REF is not independent in LOOP, NULL is returned
546 outermost_indep_loop (struct loop
*outer
, struct loop
*loop
, mem_ref_p ref
)
550 if (ref
->stored
&& bitmap_bit_p (ref
->stored
, loop
->num
))
555 aloop
= superloop_at_depth (loop
, loop_depth (aloop
) + 1))
556 if ((!ref
->stored
|| !bitmap_bit_p (ref
->stored
, aloop
->num
))
557 && ref_indep_loop_p (aloop
, ref
))
560 if (ref_indep_loop_p (loop
, ref
))
566 /* If there is a simple load or store to a memory reference in STMT, returns
567 the location of the memory reference, and sets IS_STORE according to whether
568 it is a store or load. Otherwise, returns NULL. */
571 simple_mem_ref_in_stmt (gimple stmt
, bool *is_store
)
575 /* Recognize SSA_NAME = MEM and MEM = (SSA_NAME | invariant) patterns. */
576 if (!gimple_assign_single_p (stmt
))
579 lhs
= gimple_assign_lhs_ptr (stmt
);
580 rhs
= gimple_assign_rhs1_ptr (stmt
);
582 if (TREE_CODE (*lhs
) == SSA_NAME
&& gimple_vuse (stmt
))
587 else if (gimple_vdef (stmt
)
588 && (TREE_CODE (*rhs
) == SSA_NAME
|| is_gimple_min_invariant (*rhs
)))
597 /* Returns the memory reference contained in STMT. */
600 mem_ref_in_stmt (gimple stmt
)
603 tree
*mem
= simple_mem_ref_in_stmt (stmt
, &store
);
611 hash
= iterative_hash_expr (*mem
, 0);
612 ref
= memory_accesses
.refs
->find_with_hash (*mem
, hash
);
614 gcc_assert (ref
!= NULL
);
618 /* From a controlling predicate in DOM determine the arguments from
619 the PHI node PHI that are chosen if the predicate evaluates to
620 true and false and store them to *TRUE_ARG_P and *FALSE_ARG_P if
621 they are non-NULL. Returns true if the arguments can be determined,
622 else return false. */
625 extract_true_false_args_from_phi (basic_block dom
, gimple phi
,
626 tree
*true_arg_p
, tree
*false_arg_p
)
628 basic_block bb
= gimple_bb (phi
);
629 edge true_edge
, false_edge
, tem
;
630 tree arg0
= NULL_TREE
, arg1
= NULL_TREE
;
632 /* We have to verify that one edge into the PHI node is dominated
633 by the true edge of the predicate block and the other edge
634 dominated by the false edge. This ensures that the PHI argument
635 we are going to take is completely determined by the path we
636 take from the predicate block.
637 We can only use BB dominance checks below if the destination of
638 the true/false edges are dominated by their edge, thus only
639 have a single predecessor. */
640 extract_true_false_edges_from_block (dom
, &true_edge
, &false_edge
);
641 tem
= EDGE_PRED (bb
, 0);
643 || (single_pred_p (true_edge
->dest
)
644 && (tem
->src
== true_edge
->dest
645 || dominated_by_p (CDI_DOMINATORS
,
646 tem
->src
, true_edge
->dest
))))
647 arg0
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
648 else if (tem
== false_edge
649 || (single_pred_p (false_edge
->dest
)
650 && (tem
->src
== false_edge
->dest
651 || dominated_by_p (CDI_DOMINATORS
,
652 tem
->src
, false_edge
->dest
))))
653 arg1
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
656 tem
= EDGE_PRED (bb
, 1);
658 || (single_pred_p (true_edge
->dest
)
659 && (tem
->src
== true_edge
->dest
660 || dominated_by_p (CDI_DOMINATORS
,
661 tem
->src
, true_edge
->dest
))))
662 arg0
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
663 else if (tem
== false_edge
664 || (single_pred_p (false_edge
->dest
)
665 && (tem
->src
== false_edge
->dest
666 || dominated_by_p (CDI_DOMINATORS
,
667 tem
->src
, false_edge
->dest
))))
668 arg1
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
682 /* Determine the outermost loop to that it is possible to hoist a statement
683 STMT and store it to LIM_DATA (STMT)->max_loop. To do this we determine
684 the outermost loop in that the value computed by STMT is invariant.
685 If MUST_PRESERVE_EXEC is true, additionally choose such a loop that
686 we preserve the fact whether STMT is executed. It also fills other related
687 information to LIM_DATA (STMT).
689 The function returns false if STMT cannot be hoisted outside of the loop it
690 is defined in, and true otherwise. */
693 determine_max_movement (gimple stmt
, bool must_preserve_exec
)
695 basic_block bb
= gimple_bb (stmt
);
696 struct loop
*loop
= bb
->loop_father
;
698 struct lim_aux_data
*lim_data
= get_lim_data (stmt
);
702 if (must_preserve_exec
)
703 level
= ALWAYS_EXECUTED_IN (bb
);
705 level
= superloop_at_depth (loop
, 1);
706 lim_data
->max_loop
= level
;
708 if (gimple_code (stmt
) == GIMPLE_PHI
)
711 unsigned min_cost
= UINT_MAX
;
712 unsigned total_cost
= 0;
713 struct lim_aux_data
*def_data
;
715 /* We will end up promoting dependencies to be unconditionally
716 evaluated. For this reason the PHI cost (and thus the
717 cost we remove from the loop by doing the invariant motion)
718 is that of the cheapest PHI argument dependency chain. */
719 FOR_EACH_PHI_ARG (use_p
, stmt
, iter
, SSA_OP_USE
)
721 val
= USE_FROM_PTR (use_p
);
723 if (TREE_CODE (val
) != SSA_NAME
)
725 /* Assign const 1 to constants. */
726 min_cost
= MIN (min_cost
, 1);
730 if (!add_dependency (val
, lim_data
, loop
, false))
733 gimple def_stmt
= SSA_NAME_DEF_STMT (val
);
734 if (gimple_bb (def_stmt
)
735 && gimple_bb (def_stmt
)->loop_father
== loop
)
737 def_data
= get_lim_data (def_stmt
);
740 min_cost
= MIN (min_cost
, def_data
->cost
);
741 total_cost
+= def_data
->cost
;
746 min_cost
= MIN (min_cost
, total_cost
);
747 lim_data
->cost
+= min_cost
;
749 if (gimple_phi_num_args (stmt
) > 1)
751 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
753 if (gsi_end_p (gsi_last_bb (dom
)))
755 cond
= gsi_stmt (gsi_last_bb (dom
));
756 if (gimple_code (cond
) != GIMPLE_COND
)
758 /* Verify that this is an extended form of a diamond and
759 the PHI arguments are completely controlled by the
761 if (!extract_true_false_args_from_phi (dom
, stmt
, NULL
, NULL
))
764 /* Fold in dependencies and cost of the condition. */
765 FOR_EACH_SSA_TREE_OPERAND (val
, cond
, iter
, SSA_OP_USE
)
767 if (!add_dependency (val
, lim_data
, loop
, false))
769 def_data
= get_lim_data (SSA_NAME_DEF_STMT (val
));
771 total_cost
+= def_data
->cost
;
774 /* We want to avoid unconditionally executing very expensive
775 operations. As costs for our dependencies cannot be
776 negative just claim we are not invariand for this case.
777 We also are not sure whether the control-flow inside the
779 if (total_cost
- min_cost
>= 2 * LIM_EXPENSIVE
781 && total_cost
/ min_cost
<= 2))
784 /* Assume that the control-flow in the loop will vanish.
785 ??? We should verify this and not artificially increase
786 the cost if that is not the case. */
787 lim_data
->cost
+= stmt_cost (stmt
);
793 FOR_EACH_SSA_TREE_OPERAND (val
, stmt
, iter
, SSA_OP_USE
)
794 if (!add_dependency (val
, lim_data
, loop
, true))
797 if (gimple_vuse (stmt
))
799 mem_ref_p ref
= mem_ref_in_stmt (stmt
);
804 = outermost_indep_loop (lim_data
->max_loop
, loop
, ref
);
805 if (!lim_data
->max_loop
)
810 if ((val
= gimple_vuse (stmt
)) != NULL_TREE
)
812 if (!add_dependency (val
, lim_data
, loop
, false))
818 lim_data
->cost
+= stmt_cost (stmt
);
823 /* Suppose that some statement in ORIG_LOOP is hoisted to the loop LEVEL,
824 and that one of the operands of this statement is computed by STMT.
825 Ensure that STMT (together with all the statements that define its
826 operands) is hoisted at least out of the loop LEVEL. */
829 set_level (gimple stmt
, struct loop
*orig_loop
, struct loop
*level
)
831 struct loop
*stmt_loop
= gimple_bb (stmt
)->loop_father
;
832 struct lim_aux_data
*lim_data
;
836 stmt_loop
= find_common_loop (orig_loop
, stmt_loop
);
837 lim_data
= get_lim_data (stmt
);
838 if (lim_data
!= NULL
&& lim_data
->tgt_loop
!= NULL
)
839 stmt_loop
= find_common_loop (stmt_loop
,
840 loop_outer (lim_data
->tgt_loop
));
841 if (flow_loop_nested_p (stmt_loop
, level
))
844 gcc_assert (level
== lim_data
->max_loop
845 || flow_loop_nested_p (lim_data
->max_loop
, level
));
847 lim_data
->tgt_loop
= level
;
848 FOR_EACH_VEC_ELT (lim_data
->depends
, i
, dep_stmt
)
849 set_level (dep_stmt
, orig_loop
, level
);
852 /* Determines an outermost loop from that we want to hoist the statement STMT.
853 For now we chose the outermost possible loop. TODO -- use profiling
854 information to set it more sanely. */
857 set_profitable_level (gimple stmt
)
859 set_level (stmt
, gimple_bb (stmt
)->loop_father
, get_lim_data (stmt
)->max_loop
);
862 /* Returns true if STMT is a call that has side effects. */
865 nonpure_call_p (gimple stmt
)
867 if (gimple_code (stmt
) != GIMPLE_CALL
)
870 return gimple_has_side_effects (stmt
);
873 /* Rewrite a/b to a*(1/b). Return the invariant stmt to process. */
876 rewrite_reciprocal (gimple_stmt_iterator
*bsi
)
878 gimple_assign stmt
, stmt1
, stmt2
;
879 tree name
, lhs
, type
;
881 gimple_stmt_iterator gsi
;
883 stmt
= as_a
<gimple_assign
> (gsi_stmt (*bsi
));
884 lhs
= gimple_assign_lhs (stmt
);
885 type
= TREE_TYPE (lhs
);
887 real_one
= build_one_cst (type
);
889 name
= make_temp_ssa_name (type
, NULL
, "reciptmp");
890 stmt1
= gimple_build_assign_with_ops (RDIV_EXPR
, name
, real_one
,
891 gimple_assign_rhs2 (stmt
));
893 stmt2
= gimple_build_assign_with_ops (MULT_EXPR
, lhs
, name
,
894 gimple_assign_rhs1 (stmt
));
896 /* Replace division stmt with reciprocal and multiply stmts.
897 The multiply stmt is not invariant, so update iterator
898 and avoid rescanning. */
900 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
901 gsi_replace (&gsi
, stmt2
, true);
903 /* Continue processing with invariant reciprocal statement. */
907 /* Check if the pattern at *BSI is a bittest of the form
908 (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0. */
911 rewrite_bittest (gimple_stmt_iterator
*bsi
)
917 tree lhs
, name
, t
, a
, b
;
920 stmt
= as_a
<gimple_assign
> (gsi_stmt (*bsi
));
921 lhs
= gimple_assign_lhs (stmt
);
923 /* Verify that the single use of lhs is a comparison against zero. */
924 if (TREE_CODE (lhs
) != SSA_NAME
925 || !single_imm_use (lhs
, &use
, &use_stmt
)
926 || gimple_code (use_stmt
) != GIMPLE_COND
)
928 if (gimple_cond_lhs (use_stmt
) != lhs
929 || (gimple_cond_code (use_stmt
) != NE_EXPR
930 && gimple_cond_code (use_stmt
) != EQ_EXPR
)
931 || !integer_zerop (gimple_cond_rhs (use_stmt
)))
934 /* Get at the operands of the shift. The rhs is TMP1 & 1. */
935 stmt1
= SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt
));
936 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
939 /* There is a conversion in between possibly inserted by fold. */
940 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt1
)))
942 t
= gimple_assign_rhs1 (stmt1
);
943 if (TREE_CODE (t
) != SSA_NAME
944 || !has_single_use (t
))
946 stmt1
= SSA_NAME_DEF_STMT (t
);
947 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
951 /* Verify that B is loop invariant but A is not. Verify that with
952 all the stmt walking we are still in the same loop. */
953 if (gimple_assign_rhs_code (stmt1
) != RSHIFT_EXPR
954 || loop_containing_stmt (stmt1
) != loop_containing_stmt (stmt
))
957 a
= gimple_assign_rhs1 (stmt1
);
958 b
= gimple_assign_rhs2 (stmt1
);
960 if (outermost_invariant_loop (b
, loop_containing_stmt (stmt1
)) != NULL
961 && outermost_invariant_loop (a
, loop_containing_stmt (stmt1
)) == NULL
)
963 gimple_stmt_iterator rsi
;
966 t
= fold_build2 (LSHIFT_EXPR
, TREE_TYPE (a
),
967 build_int_cst (TREE_TYPE (a
), 1), b
);
968 name
= make_temp_ssa_name (TREE_TYPE (a
), NULL
, "shifttmp");
969 stmt1
= gimple_build_assign (name
, t
);
972 t
= fold_build2 (BIT_AND_EXPR
, TREE_TYPE (a
), a
, name
);
973 name
= make_temp_ssa_name (TREE_TYPE (a
), NULL
, "shifttmp");
974 stmt2
= gimple_build_assign (name
, t
);
976 /* Replace the SSA_NAME we compare against zero. Adjust
977 the type of zero accordingly. */
979 gimple_cond_set_rhs (use_stmt
, build_int_cst_type (TREE_TYPE (name
), 0));
981 /* Don't use gsi_replace here, none of the new assignments sets
982 the variable originally set in stmt. Move bsi to stmt1, and
983 then remove the original stmt, so that we get a chance to
984 retain debug info for it. */
986 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
987 gsi_insert_before (&rsi
, stmt2
, GSI_SAME_STMT
);
988 gsi_remove (&rsi
, true);
996 /* For each statement determines the outermost loop in that it is invariant,
997 - statements on whose motion it depends and the cost of the computation.
998 - This information is stored to the LIM_DATA structure associated with
1000 class invariantness_dom_walker
: public dom_walker
1003 invariantness_dom_walker (cdi_direction direction
)
1004 : dom_walker (direction
) {}
1006 virtual void before_dom_children (basic_block
);
1009 /* Determine the outermost loops in that statements in basic block BB are
1010 invariant, and record them to the LIM_DATA associated with the statements.
1011 Callback for dom_walker. */
1014 invariantness_dom_walker::before_dom_children (basic_block bb
)
1017 gimple_stmt_iterator bsi
;
1019 bool maybe_never
= ALWAYS_EXECUTED_IN (bb
) == NULL
;
1020 struct loop
*outermost
= ALWAYS_EXECUTED_IN (bb
);
1021 struct lim_aux_data
*lim_data
;
1023 if (!loop_outer (bb
->loop_father
))
1026 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1027 fprintf (dump_file
, "Basic block %d (loop %d -- depth %d):\n\n",
1028 bb
->index
, bb
->loop_father
->num
, loop_depth (bb
->loop_father
));
1030 /* Look at PHI nodes, but only if there is at most two.
1031 ??? We could relax this further by post-processing the inserted
1032 code and transforming adjacent cond-exprs with the same predicate
1033 to control flow again. */
1034 bsi
= gsi_start_phis (bb
);
1035 if (!gsi_end_p (bsi
)
1036 && ((gsi_next (&bsi
), gsi_end_p (bsi
))
1037 || (gsi_next (&bsi
), gsi_end_p (bsi
))))
1038 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1040 stmt
= gsi_stmt (bsi
);
1042 pos
= movement_possibility (stmt
);
1043 if (pos
== MOVE_IMPOSSIBLE
)
1046 lim_data
= init_lim_data (stmt
);
1047 lim_data
->always_executed_in
= outermost
;
1049 if (!determine_max_movement (stmt
, false))
1051 lim_data
->max_loop
= NULL
;
1055 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1057 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1058 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1059 loop_depth (lim_data
->max_loop
),
1063 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1064 set_profitable_level (stmt
);
1067 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1069 stmt
= gsi_stmt (bsi
);
1071 pos
= movement_possibility (stmt
);
1072 if (pos
== MOVE_IMPOSSIBLE
)
1074 if (nonpure_call_p (stmt
))
1079 /* Make sure to note always_executed_in for stores to make
1080 store-motion work. */
1081 else if (stmt_makes_single_store (stmt
))
1083 struct lim_aux_data
*lim_data
= init_lim_data (stmt
);
1084 lim_data
->always_executed_in
= outermost
;
1089 if (is_gimple_assign (stmt
)
1090 && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt
))
1091 == GIMPLE_BINARY_RHS
))
1093 tree op0
= gimple_assign_rhs1 (stmt
);
1094 tree op1
= gimple_assign_rhs2 (stmt
);
1095 struct loop
*ol1
= outermost_invariant_loop (op1
,
1096 loop_containing_stmt (stmt
));
1098 /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal
1099 to be hoisted out of loop, saving expensive divide. */
1100 if (pos
== MOVE_POSSIBLE
1101 && gimple_assign_rhs_code (stmt
) == RDIV_EXPR
1102 && flag_unsafe_math_optimizations
1103 && !flag_trapping_math
1105 && outermost_invariant_loop (op0
, ol1
) == NULL
)
1106 stmt
= rewrite_reciprocal (&bsi
);
1108 /* If the shift count is invariant, convert (A >> B) & 1 to
1109 A & (1 << B) allowing the bit mask to be hoisted out of the loop
1110 saving an expensive shift. */
1111 if (pos
== MOVE_POSSIBLE
1112 && gimple_assign_rhs_code (stmt
) == BIT_AND_EXPR
1113 && integer_onep (op1
)
1114 && TREE_CODE (op0
) == SSA_NAME
1115 && has_single_use (op0
))
1116 stmt
= rewrite_bittest (&bsi
);
1119 lim_data
= init_lim_data (stmt
);
1120 lim_data
->always_executed_in
= outermost
;
1122 if (maybe_never
&& pos
== MOVE_PRESERVE_EXECUTION
)
1125 if (!determine_max_movement (stmt
, pos
== MOVE_PRESERVE_EXECUTION
))
1127 lim_data
->max_loop
= NULL
;
1131 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1133 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1134 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1135 loop_depth (lim_data
->max_loop
),
1139 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1140 set_profitable_level (stmt
);
1144 class move_computations_dom_walker
: public dom_walker
1147 move_computations_dom_walker (cdi_direction direction
)
1148 : dom_walker (direction
), todo_ (0) {}
1150 virtual void before_dom_children (basic_block
);
1155 /* Hoist the statements in basic block BB out of the loops prescribed by
1156 data stored in LIM_DATA structures associated with each statement. Callback
1157 for walk_dominator_tree. */
1160 move_computations_dom_walker::before_dom_children (basic_block bb
)
1163 gimple_stmt_iterator bsi
;
1166 struct lim_aux_data
*lim_data
;
1168 if (!loop_outer (bb
->loop_father
))
1171 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); )
1173 gimple_assign new_stmt
;
1174 stmt
= gsi_stmt (bsi
);
1176 lim_data
= get_lim_data (stmt
);
1177 if (lim_data
== NULL
)
1183 cost
= lim_data
->cost
;
1184 level
= lim_data
->tgt_loop
;
1185 clear_lim_data (stmt
);
1193 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1195 fprintf (dump_file
, "Moving PHI node\n");
1196 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1197 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1201 if (gimple_phi_num_args (stmt
) == 1)
1203 tree arg
= PHI_ARG_DEF (stmt
, 0);
1204 new_stmt
= gimple_build_assign_with_ops (TREE_CODE (arg
),
1205 gimple_phi_result (stmt
),
1210 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
1211 gimple cond
= gsi_stmt (gsi_last_bb (dom
));
1212 tree arg0
= NULL_TREE
, arg1
= NULL_TREE
, t
;
1213 /* Get the PHI arguments corresponding to the true and false
1215 extract_true_false_args_from_phi (dom
, stmt
, &arg0
, &arg1
);
1216 gcc_assert (arg0
&& arg1
);
1217 t
= build2 (gimple_cond_code (cond
), boolean_type_node
,
1218 gimple_cond_lhs (cond
), gimple_cond_rhs (cond
));
1219 new_stmt
= gimple_build_assign_with_ops (COND_EXPR
,
1220 gimple_phi_result (stmt
),
1222 todo_
|= TODO_cleanup_cfg
;
1224 gsi_insert_on_edge (loop_preheader_edge (level
), new_stmt
);
1225 remove_phi_node (&bsi
, false);
1228 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); )
1232 stmt
= gsi_stmt (bsi
);
1234 lim_data
= get_lim_data (stmt
);
1235 if (lim_data
== NULL
)
1241 cost
= lim_data
->cost
;
1242 level
= lim_data
->tgt_loop
;
1243 clear_lim_data (stmt
);
1251 /* We do not really want to move conditionals out of the loop; we just
1252 placed it here to force its operands to be moved if necessary. */
1253 if (gimple_code (stmt
) == GIMPLE_COND
)
1256 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1258 fprintf (dump_file
, "Moving statement\n");
1259 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1260 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1264 e
= loop_preheader_edge (level
);
1265 gcc_assert (!gimple_vdef (stmt
));
1266 if (gimple_vuse (stmt
))
1268 /* The new VUSE is the one from the virtual PHI in the loop
1269 header or the one already present. */
1270 gimple_phi_iterator gsi2
;
1271 for (gsi2
= gsi_start_phis (e
->dest
);
1272 !gsi_end_p (gsi2
); gsi_next (&gsi2
))
1274 gimple_phi phi
= gsi2
.phi ();
1275 if (virtual_operand_p (gimple_phi_result (phi
)))
1277 gimple_set_vuse (stmt
, PHI_ARG_DEF_FROM_EDGE (phi
, e
));
1282 gsi_remove (&bsi
, false);
1283 /* In case this is a stmt that is not unconditionally executed
1284 when the target loop header is executed and the stmt may
1285 invoke undefined integer or pointer overflow rewrite it to
1286 unsigned arithmetic. */
1287 if (is_gimple_assign (stmt
)
1288 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (stmt
)))
1289 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (gimple_assign_lhs (stmt
)))
1290 && arith_code_with_undefined_signed_overflow
1291 (gimple_assign_rhs_code (stmt
))
1292 && (!ALWAYS_EXECUTED_IN (bb
)
1293 || !(ALWAYS_EXECUTED_IN (bb
) == level
1294 || flow_loop_nested_p (ALWAYS_EXECUTED_IN (bb
), level
))))
1295 gsi_insert_seq_on_edge (e
, rewrite_to_defined_overflow (stmt
));
1297 gsi_insert_on_edge (e
, stmt
);
1301 /* Hoist the statements out of the loops prescribed by data stored in
1302 LIM_DATA structures associated with each statement.*/
1305 move_computations (void)
1307 move_computations_dom_walker
walker (CDI_DOMINATORS
);
1308 walker
.walk (cfun
->cfg
->x_entry_block_ptr
);
1310 gsi_commit_edge_inserts ();
1311 if (need_ssa_update_p (cfun
))
1312 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
1314 return walker
.todo_
;
1317 /* Checks whether the statement defining variable *INDEX can be hoisted
1318 out of the loop passed in DATA. Callback for for_each_index. */
1321 may_move_till (tree ref
, tree
*index
, void *data
)
1323 struct loop
*loop
= (struct loop
*) data
, *max_loop
;
1325 /* If REF is an array reference, check also that the step and the lower
1326 bound is invariant in LOOP. */
1327 if (TREE_CODE (ref
) == ARRAY_REF
)
1329 tree step
= TREE_OPERAND (ref
, 3);
1330 tree lbound
= TREE_OPERAND (ref
, 2);
1332 max_loop
= outermost_invariant_loop (step
, loop
);
1336 max_loop
= outermost_invariant_loop (lbound
, loop
);
1341 max_loop
= outermost_invariant_loop (*index
, loop
);
1348 /* If OP is SSA NAME, force the statement that defines it to be
1349 moved out of the LOOP. ORIG_LOOP is the loop in that EXPR is used. */
1352 force_move_till_op (tree op
, struct loop
*orig_loop
, struct loop
*loop
)
1357 || is_gimple_min_invariant (op
))
1360 gcc_assert (TREE_CODE (op
) == SSA_NAME
);
1362 stmt
= SSA_NAME_DEF_STMT (op
);
1363 if (gimple_nop_p (stmt
))
1366 set_level (stmt
, orig_loop
, loop
);
1369 /* Forces statement defining invariants in REF (and *INDEX) to be moved out of
1370 the LOOP. The reference REF is used in the loop ORIG_LOOP. Callback for
1376 struct loop
*orig_loop
;
1380 force_move_till (tree ref
, tree
*index
, void *data
)
1382 struct fmt_data
*fmt_data
= (struct fmt_data
*) data
;
1384 if (TREE_CODE (ref
) == ARRAY_REF
)
1386 tree step
= TREE_OPERAND (ref
, 3);
1387 tree lbound
= TREE_OPERAND (ref
, 2);
1389 force_move_till_op (step
, fmt_data
->orig_loop
, fmt_data
->loop
);
1390 force_move_till_op (lbound
, fmt_data
->orig_loop
, fmt_data
->loop
);
1393 force_move_till_op (*index
, fmt_data
->orig_loop
, fmt_data
->loop
);
1398 /* A function to free the mem_ref object OBJ. */
1401 memref_free (struct im_mem_ref
*mem
)
1403 mem
->accesses_in_loop
.release ();
1406 /* Allocates and returns a memory reference description for MEM whose hash
1407 value is HASH and id is ID. */
1410 mem_ref_alloc (tree mem
, unsigned hash
, unsigned id
)
1412 mem_ref_p ref
= XOBNEW (&mem_ref_obstack
, struct im_mem_ref
);
1413 ao_ref_init (&ref
->mem
, mem
);
1417 bitmap_initialize (&ref
->indep_loop
, &lim_bitmap_obstack
);
1418 bitmap_initialize (&ref
->dep_loop
, &lim_bitmap_obstack
);
1419 ref
->accesses_in_loop
.create (1);
1424 /* Records memory reference location *LOC in LOOP to the memory reference
1425 description REF. The reference occurs in statement STMT. */
1428 record_mem_ref_loc (mem_ref_p ref
, gimple stmt
, tree
*loc
)
1433 ref
->accesses_in_loop
.safe_push (aref
);
1436 /* Set the LOOP bit in REF stored bitmap and allocate that if
1437 necessary. Return whether a bit was changed. */
1440 set_ref_stored_in_loop (mem_ref_p ref
, struct loop
*loop
)
1443 ref
->stored
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1444 return bitmap_set_bit (ref
->stored
, loop
->num
);
1447 /* Marks reference REF as stored in LOOP. */
1450 mark_ref_stored (mem_ref_p ref
, struct loop
*loop
)
1452 while (loop
!= current_loops
->tree_root
1453 && set_ref_stored_in_loop (ref
, loop
))
1454 loop
= loop_outer (loop
);
1457 /* Gathers memory references in statement STMT in LOOP, storing the
1458 information about them in the memory_accesses structure. Marks
1459 the vops accessed through unrecognized statements there as
1463 gather_mem_refs_stmt (struct loop
*loop
, gimple stmt
)
1472 if (!gimple_vuse (stmt
))
1475 mem
= simple_mem_ref_in_stmt (stmt
, &is_stored
);
1478 /* We use the shared mem_ref for all unanalyzable refs. */
1479 id
= UNANALYZABLE_MEM_ID
;
1480 ref
= memory_accesses
.refs_list
[id
];
1481 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1483 fprintf (dump_file
, "Unanalyzed memory reference %u: ", id
);
1484 print_gimple_stmt (dump_file
, stmt
, 0, TDF_SLIM
);
1486 is_stored
= gimple_vdef (stmt
);
1490 hash
= iterative_hash_expr (*mem
, 0);
1491 slot
= memory_accesses
.refs
->find_slot_with_hash (*mem
, hash
, INSERT
);
1494 ref
= (mem_ref_p
) *slot
;
1499 id
= memory_accesses
.refs_list
.length ();
1500 ref
= mem_ref_alloc (*mem
, hash
, id
);
1501 memory_accesses
.refs_list
.safe_push (ref
);
1504 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1506 fprintf (dump_file
, "Memory reference %u: ", id
);
1507 print_generic_expr (dump_file
, ref
->mem
.ref
, TDF_SLIM
);
1508 fprintf (dump_file
, "\n");
1512 record_mem_ref_loc (ref
, stmt
, mem
);
1514 bitmap_set_bit (&memory_accesses
.refs_in_loop
[loop
->num
], ref
->id
);
1517 bitmap_set_bit (&memory_accesses
.refs_stored_in_loop
[loop
->num
], ref
->id
);
1518 mark_ref_stored (ref
, loop
);
1523 static unsigned *bb_loop_postorder
;
1525 /* qsort sort function to sort blocks after their loop fathers postorder. */
1528 sort_bbs_in_loop_postorder_cmp (const void *bb1_
, const void *bb2_
)
1530 basic_block bb1
= *(basic_block
*)const_cast<void *>(bb1_
);
1531 basic_block bb2
= *(basic_block
*)const_cast<void *>(bb2_
);
1532 struct loop
*loop1
= bb1
->loop_father
;
1533 struct loop
*loop2
= bb2
->loop_father
;
1534 if (loop1
->num
== loop2
->num
)
1536 return bb_loop_postorder
[loop1
->num
] < bb_loop_postorder
[loop2
->num
] ? -1 : 1;
1539 /* qsort sort function to sort ref locs after their loop fathers postorder. */
1542 sort_locs_in_loop_postorder_cmp (const void *loc1_
, const void *loc2_
)
1544 mem_ref_loc
*loc1
= (mem_ref_loc
*)const_cast<void *>(loc1_
);
1545 mem_ref_loc
*loc2
= (mem_ref_loc
*)const_cast<void *>(loc2_
);
1546 struct loop
*loop1
= gimple_bb (loc1
->stmt
)->loop_father
;
1547 struct loop
*loop2
= gimple_bb (loc2
->stmt
)->loop_father
;
1548 if (loop1
->num
== loop2
->num
)
1550 return bb_loop_postorder
[loop1
->num
] < bb_loop_postorder
[loop2
->num
] ? -1 : 1;
1553 /* Gathers memory references in loops. */
1556 analyze_memory_references (void)
1558 gimple_stmt_iterator bsi
;
1559 basic_block bb
, *bbs
;
1560 struct loop
*loop
, *outer
;
1563 /* Collect all basic-blocks in loops and sort them after their
1566 bbs
= XNEWVEC (basic_block
, n_basic_blocks_for_fn (cfun
) - NUM_FIXED_BLOCKS
);
1567 FOR_EACH_BB_FN (bb
, cfun
)
1568 if (bb
->loop_father
!= current_loops
->tree_root
)
1571 qsort (bbs
, n
, sizeof (basic_block
), sort_bbs_in_loop_postorder_cmp
);
1573 /* Visit blocks in loop postorder and assign mem-ref IDs in that order.
1574 That results in better locality for all the bitmaps. */
1575 for (i
= 0; i
< n
; ++i
)
1577 basic_block bb
= bbs
[i
];
1578 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1579 gather_mem_refs_stmt (bb
->loop_father
, gsi_stmt (bsi
));
1582 /* Sort the location list of gathered memory references after their
1583 loop postorder number. */
1585 FOR_EACH_VEC_ELT (memory_accesses
.refs_list
, i
, ref
)
1586 ref
->accesses_in_loop
.qsort (sort_locs_in_loop_postorder_cmp
);
1589 // free (bb_loop_postorder);
1591 /* Propagate the information about accessed memory references up
1592 the loop hierarchy. */
1593 FOR_EACH_LOOP (loop
, LI_FROM_INNERMOST
)
1595 /* Finalize the overall touched references (including subloops). */
1596 bitmap_ior_into (&memory_accesses
.all_refs_stored_in_loop
[loop
->num
],
1597 &memory_accesses
.refs_stored_in_loop
[loop
->num
]);
1599 /* Propagate the information about accessed memory references up
1600 the loop hierarchy. */
1601 outer
= loop_outer (loop
);
1602 if (outer
== current_loops
->tree_root
)
1605 bitmap_ior_into (&memory_accesses
.all_refs_stored_in_loop
[outer
->num
],
1606 &memory_accesses
.all_refs_stored_in_loop
[loop
->num
]);
1610 /* Returns true if MEM1 and MEM2 may alias. TTAE_CACHE is used as a cache in
1611 tree_to_aff_combination_expand. */
1614 mem_refs_may_alias_p (mem_ref_p mem1
, mem_ref_p mem2
,
1615 hash_map
<tree
, name_expansion
*> **ttae_cache
)
1617 /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the same
1618 object and their offset differ in such a way that the locations cannot
1619 overlap, then they cannot alias. */
1620 widest_int size1
, size2
;
1621 aff_tree off1
, off2
;
1623 /* Perform basic offset and type-based disambiguation. */
1624 if (!refs_may_alias_p_1 (&mem1
->mem
, &mem2
->mem
, true))
1627 /* The expansion of addresses may be a bit expensive, thus we only do
1628 the check at -O2 and higher optimization levels. */
1632 get_inner_reference_aff (mem1
->mem
.ref
, &off1
, &size1
);
1633 get_inner_reference_aff (mem2
->mem
.ref
, &off2
, &size2
);
1634 aff_combination_expand (&off1
, ttae_cache
);
1635 aff_combination_expand (&off2
, ttae_cache
);
1636 aff_combination_scale (&off1
, -1);
1637 aff_combination_add (&off2
, &off1
);
1639 if (aff_comb_cannot_overlap_p (&off2
, size1
, size2
))
1645 /* Compare function for bsearch searching for reference locations
1649 find_ref_loc_in_loop_cmp (const void *loop_
, const void *loc_
)
1651 struct loop
*loop
= (struct loop
*)const_cast<void *>(loop_
);
1652 mem_ref_loc
*loc
= (mem_ref_loc
*)const_cast<void *>(loc_
);
1653 struct loop
*loc_loop
= gimple_bb (loc
->stmt
)->loop_father
;
1654 if (loop
->num
== loc_loop
->num
1655 || flow_loop_nested_p (loop
, loc_loop
))
1657 return (bb_loop_postorder
[loop
->num
] < bb_loop_postorder
[loc_loop
->num
]
1661 /* Iterates over all locations of REF in LOOP and its subloops calling
1662 fn.operator() with the location as argument. When that operator
1663 returns true the iteration is stopped and true is returned.
1664 Otherwise false is returned. */
1666 template <typename FN
>
1668 for_all_locs_in_loop (struct loop
*loop
, mem_ref_p ref
, FN fn
)
1673 /* Search for the cluster of locs in the accesses_in_loop vector
1674 which is sorted after postorder index of the loop father. */
1675 loc
= ref
->accesses_in_loop
.bsearch (loop
, find_ref_loc_in_loop_cmp
);
1679 /* We have found one location inside loop or its sub-loops. Iterate
1680 both forward and backward to cover the whole cluster. */
1681 i
= loc
- ref
->accesses_in_loop
.address ();
1685 mem_ref_loc_p l
= &ref
->accesses_in_loop
[i
];
1686 if (!flow_bb_inside_loop_p (loop
, gimple_bb (l
->stmt
)))
1691 for (i
= loc
- ref
->accesses_in_loop
.address ();
1692 i
< ref
->accesses_in_loop
.length (); ++i
)
1694 mem_ref_loc_p l
= &ref
->accesses_in_loop
[i
];
1695 if (!flow_bb_inside_loop_p (loop
, gimple_bb (l
->stmt
)))
1704 /* Rewrites location LOC by TMP_VAR. */
1706 struct rewrite_mem_ref_loc
1708 rewrite_mem_ref_loc (tree tmp_var_
) : tmp_var (tmp_var_
) {}
1709 bool operator () (mem_ref_loc_p loc
);
1714 rewrite_mem_ref_loc::operator () (mem_ref_loc_p loc
)
1716 *loc
->ref
= tmp_var
;
1717 update_stmt (loc
->stmt
);
1721 /* Rewrites all references to REF in LOOP by variable TMP_VAR. */
1724 rewrite_mem_refs (struct loop
*loop
, mem_ref_p ref
, tree tmp_var
)
1726 for_all_locs_in_loop (loop
, ref
, rewrite_mem_ref_loc (tmp_var
));
1729 /* Stores the first reference location in LOCP. */
1731 struct first_mem_ref_loc_1
1733 first_mem_ref_loc_1 (mem_ref_loc_p
*locp_
) : locp (locp_
) {}
1734 bool operator () (mem_ref_loc_p loc
);
1735 mem_ref_loc_p
*locp
;
1739 first_mem_ref_loc_1::operator () (mem_ref_loc_p loc
)
1745 /* Returns the first reference location to REF in LOOP. */
1747 static mem_ref_loc_p
1748 first_mem_ref_loc (struct loop
*loop
, mem_ref_p ref
)
1750 mem_ref_loc_p locp
= NULL
;
1751 for_all_locs_in_loop (loop
, ref
, first_mem_ref_loc_1 (&locp
));
1755 struct prev_flag_edges
{
1756 /* Edge to insert new flag comparison code. */
1757 edge append_cond_position
;
1759 /* Edge for fall through from previous flag comparison. */
1760 edge last_cond_fallthru
;
1763 /* Helper function for execute_sm. Emit code to store TMP_VAR into
1766 The store is only done if MEM has changed. We do this so no
1767 changes to MEM occur on code paths that did not originally store
1770 The common case for execute_sm will transform:
1790 This function will generate:
1809 execute_sm_if_changed (edge ex
, tree mem
, tree tmp_var
, tree flag
)
1811 basic_block new_bb
, then_bb
, old_dest
;
1812 bool loop_has_only_one_exit
;
1813 edge then_old_edge
, orig_ex
= ex
;
1814 gimple_stmt_iterator gsi
;
1816 struct prev_flag_edges
*prev_edges
= (struct prev_flag_edges
*) ex
->aux
;
1817 bool irr
= ex
->flags
& EDGE_IRREDUCIBLE_LOOP
;
1819 /* ?? Insert store after previous store if applicable. See note
1822 ex
= prev_edges
->append_cond_position
;
1824 loop_has_only_one_exit
= single_pred_p (ex
->dest
);
1826 if (loop_has_only_one_exit
)
1827 ex
= split_block_after_labels (ex
->dest
);
1829 old_dest
= ex
->dest
;
1830 new_bb
= split_edge (ex
);
1831 then_bb
= create_empty_bb (new_bb
);
1833 then_bb
->flags
= BB_IRREDUCIBLE_LOOP
;
1834 add_bb_to_loop (then_bb
, new_bb
->loop_father
);
1836 gsi
= gsi_start_bb (new_bb
);
1837 stmt
= gimple_build_cond (NE_EXPR
, flag
, boolean_false_node
,
1838 NULL_TREE
, NULL_TREE
);
1839 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
1841 gsi
= gsi_start_bb (then_bb
);
1842 /* Insert actual store. */
1843 stmt
= gimple_build_assign (unshare_expr (mem
), tmp_var
);
1844 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
1846 make_edge (new_bb
, then_bb
,
1847 EDGE_TRUE_VALUE
| (irr
? EDGE_IRREDUCIBLE_LOOP
: 0));
1848 make_edge (new_bb
, old_dest
,
1849 EDGE_FALSE_VALUE
| (irr
? EDGE_IRREDUCIBLE_LOOP
: 0));
1850 then_old_edge
= make_edge (then_bb
, old_dest
,
1851 EDGE_FALLTHRU
| (irr
? EDGE_IRREDUCIBLE_LOOP
: 0));
1853 set_immediate_dominator (CDI_DOMINATORS
, then_bb
, new_bb
);
1857 basic_block prevbb
= prev_edges
->last_cond_fallthru
->src
;
1858 redirect_edge_succ (prev_edges
->last_cond_fallthru
, new_bb
);
1859 set_immediate_dominator (CDI_DOMINATORS
, new_bb
, prevbb
);
1860 set_immediate_dominator (CDI_DOMINATORS
, old_dest
,
1861 recompute_dominator (CDI_DOMINATORS
, old_dest
));
1864 /* ?? Because stores may alias, they must happen in the exact
1865 sequence they originally happened. Save the position right after
1866 the (_lsm) store we just created so we can continue appending after
1867 it and maintain the original order. */
1869 struct prev_flag_edges
*p
;
1872 orig_ex
->aux
= NULL
;
1873 alloc_aux_for_edge (orig_ex
, sizeof (struct prev_flag_edges
));
1874 p
= (struct prev_flag_edges
*) orig_ex
->aux
;
1875 p
->append_cond_position
= then_old_edge
;
1876 p
->last_cond_fallthru
= find_edge (new_bb
, old_dest
);
1877 orig_ex
->aux
= (void *) p
;
1880 if (!loop_has_only_one_exit
)
1881 for (gimple_phi_iterator gpi
= gsi_start_phis (old_dest
);
1882 !gsi_end_p (gpi
); gsi_next (&gpi
))
1884 gimple_phi phi
= gpi
.phi ();
1887 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
1888 if (gimple_phi_arg_edge (phi
, i
)->src
== new_bb
)
1890 tree arg
= gimple_phi_arg_def (phi
, i
);
1891 add_phi_arg (phi
, arg
, then_old_edge
, UNKNOWN_LOCATION
);
1895 /* Remove the original fall through edge. This was the
1896 single_succ_edge (new_bb). */
1897 EDGE_SUCC (new_bb
, 0)->flags
&= ~EDGE_FALLTHRU
;
1900 /* When REF is set on the location, set flag indicating the store. */
1902 struct sm_set_flag_if_changed
1904 sm_set_flag_if_changed (tree flag_
) : flag (flag_
) {}
1905 bool operator () (mem_ref_loc_p loc
);
1910 sm_set_flag_if_changed::operator () (mem_ref_loc_p loc
)
1912 /* Only set the flag for writes. */
1913 if (is_gimple_assign (loc
->stmt
)
1914 && gimple_assign_lhs_ptr (loc
->stmt
) == loc
->ref
)
1916 gimple_stmt_iterator gsi
= gsi_for_stmt (loc
->stmt
);
1917 gimple stmt
= gimple_build_assign (flag
, boolean_true_node
);
1918 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
1923 /* Helper function for execute_sm. On every location where REF is
1924 set, set an appropriate flag indicating the store. */
1927 execute_sm_if_changed_flag_set (struct loop
*loop
, mem_ref_p ref
)
1930 char *str
= get_lsm_tmp_name (ref
->mem
.ref
, ~0, "_flag");
1931 flag
= create_tmp_reg (boolean_type_node
, str
);
1932 for_all_locs_in_loop (loop
, ref
, sm_set_flag_if_changed (flag
));
1936 /* Executes store motion of memory reference REF from LOOP.
1937 Exits from the LOOP are stored in EXITS. The initialization of the
1938 temporary variable is put to the preheader of the loop, and assignments
1939 to the reference from the temporary variable are emitted to exits. */
1942 execute_sm (struct loop
*loop
, vec
<edge
> exits
, mem_ref_p ref
)
1944 tree tmp_var
, store_flag
= NULL_TREE
;
1947 struct fmt_data fmt_data
;
1949 struct lim_aux_data
*lim_data
;
1950 bool multi_threaded_model_p
= false;
1951 gimple_stmt_iterator gsi
;
1953 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1955 fprintf (dump_file
, "Executing store motion of ");
1956 print_generic_expr (dump_file
, ref
->mem
.ref
, 0);
1957 fprintf (dump_file
, " from loop %d\n", loop
->num
);
1960 tmp_var
= create_tmp_reg (TREE_TYPE (ref
->mem
.ref
),
1961 get_lsm_tmp_name (ref
->mem
.ref
, ~0));
1963 fmt_data
.loop
= loop
;
1964 fmt_data
.orig_loop
= loop
;
1965 for_each_index (&ref
->mem
.ref
, force_move_till
, &fmt_data
);
1967 if (bb_in_transaction (loop_preheader_edge (loop
)->src
)
1968 || !PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES
))
1969 multi_threaded_model_p
= true;
1971 if (multi_threaded_model_p
)
1972 store_flag
= execute_sm_if_changed_flag_set (loop
, ref
);
1974 rewrite_mem_refs (loop
, ref
, tmp_var
);
1976 /* Emit the load code on a random exit edge or into the latch if
1977 the loop does not exit, so that we are sure it will be processed
1978 by move_computations after all dependencies. */
1979 gsi
= gsi_for_stmt (first_mem_ref_loc (loop
, ref
)->stmt
);
1981 /* FIXME/TODO: For the multi-threaded variant, we could avoid this
1982 load altogether, since the store is predicated by a flag. We
1983 could, do the load only if it was originally in the loop. */
1984 load
= gimple_build_assign (tmp_var
, unshare_expr (ref
->mem
.ref
));
1985 lim_data
= init_lim_data (load
);
1986 lim_data
->max_loop
= loop
;
1987 lim_data
->tgt_loop
= loop
;
1988 gsi_insert_before (&gsi
, load
, GSI_SAME_STMT
);
1990 if (multi_threaded_model_p
)
1992 load
= gimple_build_assign (store_flag
, boolean_false_node
);
1993 lim_data
= init_lim_data (load
);
1994 lim_data
->max_loop
= loop
;
1995 lim_data
->tgt_loop
= loop
;
1996 gsi_insert_before (&gsi
, load
, GSI_SAME_STMT
);
1999 /* Sink the store to every exit from the loop. */
2000 FOR_EACH_VEC_ELT (exits
, i
, ex
)
2001 if (!multi_threaded_model_p
)
2003 gimple_assign store
;
2004 store
= gimple_build_assign (unshare_expr (ref
->mem
.ref
), tmp_var
);
2005 gsi_insert_on_edge (ex
, store
);
2008 execute_sm_if_changed (ex
, ref
->mem
.ref
, tmp_var
, store_flag
);
2011 /* Hoists memory references MEM_REFS out of LOOP. EXITS is the list of exit
2012 edges of the LOOP. */
2015 hoist_memory_references (struct loop
*loop
, bitmap mem_refs
,
2022 EXECUTE_IF_SET_IN_BITMAP (mem_refs
, 0, i
, bi
)
2024 ref
= memory_accesses
.refs_list
[i
];
2025 execute_sm (loop
, exits
, ref
);
2029 struct ref_always_accessed
2031 ref_always_accessed (struct loop
*loop_
, bool stored_p_
)
2032 : loop (loop_
), stored_p (stored_p_
) {}
2033 bool operator () (mem_ref_loc_p loc
);
2039 ref_always_accessed::operator () (mem_ref_loc_p loc
)
2041 struct loop
*must_exec
;
2043 if (!get_lim_data (loc
->stmt
))
2046 /* If we require an always executed store make sure the statement
2047 stores to the reference. */
2050 tree lhs
= gimple_get_lhs (loc
->stmt
);
2052 || lhs
!= *loc
->ref
)
2056 must_exec
= get_lim_data (loc
->stmt
)->always_executed_in
;
2060 if (must_exec
== loop
2061 || flow_loop_nested_p (must_exec
, loop
))
2067 /* Returns true if REF is always accessed in LOOP. If STORED_P is true
2068 make sure REF is always stored to in LOOP. */
2071 ref_always_accessed_p (struct loop
*loop
, mem_ref_p ref
, bool stored_p
)
2073 return for_all_locs_in_loop (loop
, ref
,
2074 ref_always_accessed (loop
, stored_p
));
2077 /* Returns true if REF1 and REF2 are independent. */
2080 refs_independent_p (mem_ref_p ref1
, mem_ref_p ref2
)
2085 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2086 fprintf (dump_file
, "Querying dependency of refs %u and %u: ",
2087 ref1
->id
, ref2
->id
);
2089 if (mem_refs_may_alias_p (ref1
, ref2
, &memory_accesses
.ttae_cache
))
2091 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2092 fprintf (dump_file
, "dependent.\n");
2097 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2098 fprintf (dump_file
, "independent.\n");
2103 /* Mark REF dependent on stores or loads (according to STORED_P) in LOOP
2104 and its super-loops. */
2107 record_dep_loop (struct loop
*loop
, mem_ref_p ref
, bool stored_p
)
2109 /* We can propagate dependent-in-loop bits up the loop
2110 hierarchy to all outer loops. */
2111 while (loop
!= current_loops
->tree_root
2112 && bitmap_set_bit (&ref
->dep_loop
, LOOP_DEP_BIT (loop
->num
, stored_p
)))
2113 loop
= loop_outer (loop
);
2116 /* Returns true if REF is independent on all other memory references in
2120 ref_indep_loop_p_1 (struct loop
*loop
, mem_ref_p ref
, bool stored_p
)
2122 bitmap refs_to_check
;
2128 refs_to_check
= &memory_accesses
.refs_in_loop
[loop
->num
];
2130 refs_to_check
= &memory_accesses
.refs_stored_in_loop
[loop
->num
];
2132 if (bitmap_bit_p (refs_to_check
, UNANALYZABLE_MEM_ID
))
2135 EXECUTE_IF_SET_IN_BITMAP (refs_to_check
, 0, i
, bi
)
2137 aref
= memory_accesses
.refs_list
[i
];
2138 if (!refs_independent_p (ref
, aref
))
2145 /* Returns true if REF is independent on all other memory references in
2146 LOOP. Wrapper over ref_indep_loop_p_1, caching its results. */
2149 ref_indep_loop_p_2 (struct loop
*loop
, mem_ref_p ref
, bool stored_p
)
2151 stored_p
|= (ref
->stored
&& bitmap_bit_p (ref
->stored
, loop
->num
));
2153 if (bitmap_bit_p (&ref
->indep_loop
, LOOP_DEP_BIT (loop
->num
, stored_p
)))
2155 if (bitmap_bit_p (&ref
->dep_loop
, LOOP_DEP_BIT (loop
->num
, stored_p
)))
2158 struct loop
*inner
= loop
->inner
;
2161 if (!ref_indep_loop_p_2 (inner
, ref
, stored_p
))
2163 inner
= inner
->next
;
2166 bool indep_p
= ref_indep_loop_p_1 (loop
, ref
, stored_p
);
2168 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2169 fprintf (dump_file
, "Querying dependencies of ref %u in loop %d: %s\n",
2170 ref
->id
, loop
->num
, indep_p
? "independent" : "dependent");
2172 /* Record the computed result in the cache. */
2175 if (bitmap_set_bit (&ref
->indep_loop
, LOOP_DEP_BIT (loop
->num
, stored_p
))
2178 /* If it's independend against all refs then it's independent
2179 against stores, too. */
2180 bitmap_set_bit (&ref
->indep_loop
, LOOP_DEP_BIT (loop
->num
, false));
2185 record_dep_loop (loop
, ref
, stored_p
);
2188 /* If it's dependent against stores it's dependent against
2190 record_dep_loop (loop
, ref
, true);
2197 /* Returns true if REF is independent on all other memory references in
2201 ref_indep_loop_p (struct loop
*loop
, mem_ref_p ref
)
2203 gcc_checking_assert (MEM_ANALYZABLE (ref
));
2205 return ref_indep_loop_p_2 (loop
, ref
, false);
2208 /* Returns true if we can perform store motion of REF from LOOP. */
2211 can_sm_ref_p (struct loop
*loop
, mem_ref_p ref
)
2215 /* Can't hoist unanalyzable refs. */
2216 if (!MEM_ANALYZABLE (ref
))
2219 /* It should be movable. */
2220 if (!is_gimple_reg_type (TREE_TYPE (ref
->mem
.ref
))
2221 || TREE_THIS_VOLATILE (ref
->mem
.ref
)
2222 || !for_each_index (&ref
->mem
.ref
, may_move_till
, loop
))
2225 /* If it can throw fail, we do not properly update EH info. */
2226 if (tree_could_throw_p (ref
->mem
.ref
))
2229 /* If it can trap, it must be always executed in LOOP.
2230 Readonly memory locations may trap when storing to them, but
2231 tree_could_trap_p is a predicate for rvalues, so check that
2233 base
= get_base_address (ref
->mem
.ref
);
2234 if ((tree_could_trap_p (ref
->mem
.ref
)
2235 || (DECL_P (base
) && TREE_READONLY (base
)))
2236 && !ref_always_accessed_p (loop
, ref
, true))
2239 /* And it must be independent on all other memory references
2241 if (!ref_indep_loop_p (loop
, ref
))
2247 /* Marks the references in LOOP for that store motion should be performed
2248 in REFS_TO_SM. SM_EXECUTED is the set of references for that store
2249 motion was performed in one of the outer loops. */
2252 find_refs_for_sm (struct loop
*loop
, bitmap sm_executed
, bitmap refs_to_sm
)
2254 bitmap refs
= &memory_accesses
.all_refs_stored_in_loop
[loop
->num
];
2259 EXECUTE_IF_AND_COMPL_IN_BITMAP (refs
, sm_executed
, 0, i
, bi
)
2261 ref
= memory_accesses
.refs_list
[i
];
2262 if (can_sm_ref_p (loop
, ref
))
2263 bitmap_set_bit (refs_to_sm
, i
);
2267 /* Checks whether LOOP (with exits stored in EXITS array) is suitable
2268 for a store motion optimization (i.e. whether we can insert statement
2272 loop_suitable_for_sm (struct loop
*loop ATTRIBUTE_UNUSED
,
2278 FOR_EACH_VEC_ELT (exits
, i
, ex
)
2279 if (ex
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
2285 /* Try to perform store motion for all memory references modified inside
2286 LOOP. SM_EXECUTED is the bitmap of the memory references for that
2287 store motion was executed in one of the outer loops. */
2290 store_motion_loop (struct loop
*loop
, bitmap sm_executed
)
2292 vec
<edge
> exits
= get_loop_exit_edges (loop
);
2293 struct loop
*subloop
;
2294 bitmap sm_in_loop
= BITMAP_ALLOC (&lim_bitmap_obstack
);
2296 if (loop_suitable_for_sm (loop
, exits
))
2298 find_refs_for_sm (loop
, sm_executed
, sm_in_loop
);
2299 hoist_memory_references (loop
, sm_in_loop
, exits
);
2303 bitmap_ior_into (sm_executed
, sm_in_loop
);
2304 for (subloop
= loop
->inner
; subloop
!= NULL
; subloop
= subloop
->next
)
2305 store_motion_loop (subloop
, sm_executed
);
2306 bitmap_and_compl_into (sm_executed
, sm_in_loop
);
2307 BITMAP_FREE (sm_in_loop
);
2310 /* Try to perform store motion for all memory references modified inside
2317 bitmap sm_executed
= BITMAP_ALLOC (&lim_bitmap_obstack
);
2319 for (loop
= current_loops
->tree_root
->inner
; loop
!= NULL
; loop
= loop
->next
)
2320 store_motion_loop (loop
, sm_executed
);
2322 BITMAP_FREE (sm_executed
);
2323 gsi_commit_edge_inserts ();
2326 /* Fills ALWAYS_EXECUTED_IN information for basic blocks of LOOP, i.e.
2327 for each such basic block bb records the outermost loop for that execution
2328 of its header implies execution of bb. CONTAINS_CALL is the bitmap of
2329 blocks that contain a nonpure call. */
2332 fill_always_executed_in_1 (struct loop
*loop
, sbitmap contains_call
)
2334 basic_block bb
= NULL
, *bbs
, last
= NULL
;
2337 struct loop
*inn_loop
= loop
;
2339 if (ALWAYS_EXECUTED_IN (loop
->header
) == NULL
)
2341 bbs
= get_loop_body_in_dom_order (loop
);
2343 for (i
= 0; i
< loop
->num_nodes
; i
++)
2348 if (dominated_by_p (CDI_DOMINATORS
, loop
->latch
, bb
))
2351 if (bitmap_bit_p (contains_call
, bb
->index
))
2354 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2355 if (!flow_bb_inside_loop_p (loop
, e
->dest
))
2360 /* A loop might be infinite (TODO use simple loop analysis
2361 to disprove this if possible). */
2362 if (bb
->flags
& BB_IRREDUCIBLE_LOOP
)
2365 if (!flow_bb_inside_loop_p (inn_loop
, bb
))
2368 if (bb
->loop_father
->header
== bb
)
2370 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, bb
))
2373 /* In a loop that is always entered we may proceed anyway.
2374 But record that we entered it and stop once we leave it. */
2375 inn_loop
= bb
->loop_father
;
2381 SET_ALWAYS_EXECUTED_IN (last
, loop
);
2382 if (last
== loop
->header
)
2384 last
= get_immediate_dominator (CDI_DOMINATORS
, last
);
2390 for (loop
= loop
->inner
; loop
; loop
= loop
->next
)
2391 fill_always_executed_in_1 (loop
, contains_call
);
2394 /* Fills ALWAYS_EXECUTED_IN information for basic blocks, i.e.
2395 for each such basic block bb records the outermost loop for that execution
2396 of its header implies execution of bb. */
2399 fill_always_executed_in (void)
2401 sbitmap contains_call
= sbitmap_alloc (last_basic_block_for_fn (cfun
));
2405 bitmap_clear (contains_call
);
2406 FOR_EACH_BB_FN (bb
, cfun
)
2408 gimple_stmt_iterator gsi
;
2409 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2411 if (nonpure_call_p (gsi_stmt (gsi
)))
2415 if (!gsi_end_p (gsi
))
2416 bitmap_set_bit (contains_call
, bb
->index
);
2419 for (loop
= current_loops
->tree_root
->inner
; loop
; loop
= loop
->next
)
2420 fill_always_executed_in_1 (loop
, contains_call
);
2422 sbitmap_free (contains_call
);
2426 /* Compute the global information needed by the loop invariant motion pass. */
2429 tree_ssa_lim_initialize (void)
2434 bitmap_obstack_initialize (&lim_bitmap_obstack
);
2435 gcc_obstack_init (&mem_ref_obstack
);
2436 lim_aux_data_map
= new hash_map
<gimple
, lim_aux_data
*>;
2439 compute_transaction_bits ();
2441 alloc_aux_for_edges (0);
2443 memory_accesses
.refs
= new hash_table
<mem_ref_hasher
> (100);
2444 memory_accesses
.refs_list
.create (100);
2445 /* Allocate a special, unanalyzable mem-ref with ID zero. */
2446 memory_accesses
.refs_list
.quick_push
2447 (mem_ref_alloc (error_mark_node
, 0, UNANALYZABLE_MEM_ID
));
2449 memory_accesses
.refs_in_loop
.create (number_of_loops (cfun
));
2450 memory_accesses
.refs_in_loop
.quick_grow (number_of_loops (cfun
));
2451 memory_accesses
.refs_stored_in_loop
.create (number_of_loops (cfun
));
2452 memory_accesses
.refs_stored_in_loop
.quick_grow (number_of_loops (cfun
));
2453 memory_accesses
.all_refs_stored_in_loop
.create (number_of_loops (cfun
));
2454 memory_accesses
.all_refs_stored_in_loop
.quick_grow (number_of_loops (cfun
));
2456 for (i
= 0; i
< number_of_loops (cfun
); i
++)
2458 bitmap_initialize (&memory_accesses
.refs_in_loop
[i
],
2459 &lim_bitmap_obstack
);
2460 bitmap_initialize (&memory_accesses
.refs_stored_in_loop
[i
],
2461 &lim_bitmap_obstack
);
2462 bitmap_initialize (&memory_accesses
.all_refs_stored_in_loop
[i
],
2463 &lim_bitmap_obstack
);
2466 memory_accesses
.ttae_cache
= NULL
;
2468 /* Initialize bb_loop_postorder with a mapping from loop->num to
2469 its postorder index. */
2471 bb_loop_postorder
= XNEWVEC (unsigned, number_of_loops (cfun
));
2472 FOR_EACH_LOOP (loop
, LI_FROM_INNERMOST
)
2473 bb_loop_postorder
[loop
->num
] = i
++;
2476 /* Cleans up after the invariant motion pass. */
2479 tree_ssa_lim_finalize (void)
2485 free_aux_for_edges ();
2487 FOR_EACH_BB_FN (bb
, cfun
)
2488 SET_ALWAYS_EXECUTED_IN (bb
, NULL
);
2490 bitmap_obstack_release (&lim_bitmap_obstack
);
2491 delete lim_aux_data_map
;
2493 delete memory_accesses
.refs
;
2494 memory_accesses
.refs
= NULL
;
2496 FOR_EACH_VEC_ELT (memory_accesses
.refs_list
, i
, ref
)
2498 memory_accesses
.refs_list
.release ();
2499 obstack_free (&mem_ref_obstack
, NULL
);
2501 memory_accesses
.refs_in_loop
.release ();
2502 memory_accesses
.refs_stored_in_loop
.release ();
2503 memory_accesses
.all_refs_stored_in_loop
.release ();
2505 if (memory_accesses
.ttae_cache
)
2506 free_affine_expand_cache (&memory_accesses
.ttae_cache
);
2508 free (bb_loop_postorder
);
2511 /* Moves invariants from loops. Only "expensive" invariants are moved out --
2512 i.e. those that are likely to be win regardless of the register pressure. */
2519 tree_ssa_lim_initialize ();
2521 /* Gathers information about memory accesses in the loops. */
2522 analyze_memory_references ();
2524 /* Fills ALWAYS_EXECUTED_IN information for basic blocks. */
2525 fill_always_executed_in ();
2527 /* For each statement determine the outermost loop in that it is
2528 invariant and cost for computing the invariant. */
2529 invariantness_dom_walker (CDI_DOMINATORS
)
2530 .walk (cfun
->cfg
->x_entry_block_ptr
);
2532 /* Execute store motion. Force the necessary invariants to be moved
2533 out of the loops as well. */
2536 /* Move the expressions that are expensive enough. */
2537 todo
= move_computations ();
2539 tree_ssa_lim_finalize ();
2544 /* Loop invariant motion pass. */
2548 const pass_data pass_data_lim
=
2550 GIMPLE_PASS
, /* type */
2552 OPTGROUP_LOOP
, /* optinfo_flags */
2554 PROP_cfg
, /* properties_required */
2555 0, /* properties_provided */
2556 0, /* properties_destroyed */
2557 0, /* todo_flags_start */
2558 0, /* todo_flags_finish */
2561 class pass_lim
: public gimple_opt_pass
2564 pass_lim (gcc::context
*ctxt
)
2565 : gimple_opt_pass (pass_data_lim
, ctxt
)
2568 /* opt_pass methods: */
2569 opt_pass
* clone () { return new pass_lim (m_ctxt
); }
2570 virtual bool gate (function
*) { return flag_tree_loop_im
!= 0; }
2571 virtual unsigned int execute (function
*);
2573 }; // class pass_lim
2576 pass_lim::execute (function
*fun
)
2578 if (number_of_loops (fun
) <= 1)
2581 return tree_ssa_lim ();
2587 make_pass_lim (gcc::context
*ctxt
)
2589 return new pass_lim (ctxt
);