1 /* Loop invariant motion.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2010
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 3, or (at your option) any
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
27 #include "basic-block.h"
28 #include "gimple-pretty-print.h"
29 #include "tree-flow.h"
33 #include "tree-pass.h"
36 #include "tree-affine.h"
37 #include "pointer-set.h"
38 #include "tree-ssa-propagate.h"
40 /* TODO: Support for predicated code motion. I.e.
51 Where COND and INV are invariants, but evaluating INV may trap or be
52 invalid from some other reason if !COND. This may be transformed to
62 /* A type for the list of statements that have to be moved in order to be able
63 to hoist an invariant computation. */
71 /* The auxiliary data kept for each statement. */
75 struct loop
*max_loop
; /* The outermost loop in that the statement
78 struct loop
*tgt_loop
; /* The loop out of that we want to move the
81 struct loop
*always_executed_in
;
82 /* The outermost loop for that we are sure
83 the statement is executed if the loop
86 unsigned cost
; /* Cost of the computation performed by the
89 struct depend
*depends
; /* List of statements that must be also hoisted
90 out of the loop when this statement is
91 hoisted; i.e. those that define the operands
92 of the statement and are inside of the
96 /* Maps statements to their lim_aux_data. */
98 static struct pointer_map_t
*lim_aux_data_map
;
100 /* Description of a memory reference location. */
102 typedef struct mem_ref_loc
104 tree
*ref
; /* The reference itself. */
105 gimple stmt
; /* The statement in that it occurs. */
108 DEF_VEC_P(mem_ref_loc_p
);
109 DEF_VEC_ALLOC_P(mem_ref_loc_p
, heap
);
111 /* The list of memory reference locations in a loop. */
113 typedef struct mem_ref_locs
115 VEC (mem_ref_loc_p
, heap
) *locs
;
118 DEF_VEC_P(mem_ref_locs_p
);
119 DEF_VEC_ALLOC_P(mem_ref_locs_p
, heap
);
121 /* Description of a memory reference. */
123 typedef struct mem_ref
125 tree mem
; /* The memory itself. */
126 unsigned id
; /* ID assigned to the memory reference
127 (its index in memory_accesses.refs_list) */
128 hashval_t hash
; /* Its hash value. */
129 bitmap stored
; /* The set of loops in that this memory location
131 VEC (mem_ref_locs_p
, heap
) *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 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 dep_loop
; /* The complement of INDEP_LOOP. */
147 bitmap indep_ref
; /* The set of memory references on that
148 this reference is independent. */
149 bitmap dep_ref
; /* The complement of INDEP_REF. */
152 DEF_VEC_P(mem_ref_p
);
153 DEF_VEC_ALLOC_P(mem_ref_p
, heap
);
156 DEF_VEC_ALLOC_P(bitmap
, heap
);
159 DEF_VEC_ALLOC_P(htab_t
, heap
);
161 /* Description of memory accesses in loops. */
165 /* The hash table of memory references accessed in loops. */
168 /* The list of memory references. */
169 VEC (mem_ref_p
, heap
) *refs_list
;
171 /* The set of memory references accessed in each loop. */
172 VEC (bitmap
, heap
) *refs_in_loop
;
174 /* The set of memory references accessed in each loop, including
176 VEC (bitmap
, heap
) *all_refs_in_loop
;
178 /* The set of memory references stored in each loop, including
180 VEC (bitmap
, heap
) *all_refs_stored_in_loop
;
182 /* Cache for expanding memory addresses. */
183 struct pointer_map_t
*ttae_cache
;
186 /* Obstack for the bitmaps in the above data structures. */
187 static bitmap_obstack lim_bitmap_obstack
;
189 static bool ref_indep_loop_p (struct loop
*, mem_ref_p
);
191 /* Minimum cost of an expensive expression. */
192 #define LIM_EXPENSIVE ((unsigned) PARAM_VALUE (PARAM_LIM_EXPENSIVE))
194 /* The outermost loop for which execution of the header guarantees that the
195 block will be executed. */
196 #define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux)
197 #define SET_ALWAYS_EXECUTED_IN(BB, VAL) ((BB)->aux = (void *) (VAL))
199 /* Whether the reference was analyzable. */
200 #define MEM_ANALYZABLE(REF) ((REF)->mem != error_mark_node)
202 static struct lim_aux_data
*
203 init_lim_data (gimple stmt
)
205 void **p
= pointer_map_insert (lim_aux_data_map
, stmt
);
207 *p
= XCNEW (struct lim_aux_data
);
208 return (struct lim_aux_data
*) *p
;
211 static struct lim_aux_data
*
212 get_lim_data (gimple stmt
)
214 void **p
= pointer_map_contains (lim_aux_data_map
, stmt
);
218 return (struct lim_aux_data
*) *p
;
221 /* Releases the memory occupied by DATA. */
224 free_lim_aux_data (struct lim_aux_data
*data
)
226 struct depend
*dep
, *next
;
228 for (dep
= data
->depends
; dep
; dep
= next
)
237 clear_lim_data (gimple stmt
)
239 void **p
= pointer_map_contains (lim_aux_data_map
, stmt
);
243 free_lim_aux_data ((struct lim_aux_data
*) *p
);
247 /* Calls CBCK for each index in memory reference ADDR_P. There are two
248 kinds situations handled; in each of these cases, the memory reference
249 and DATA are passed to the callback:
251 Access to an array: ARRAY_{RANGE_}REF (base, index). In this case we also
252 pass the pointer to the index to the callback.
254 Pointer dereference: INDIRECT_REF (addr). In this case we also pass the
255 pointer to addr to the callback.
257 If the callback returns false, the whole search stops and false is returned.
258 Otherwise the function returns true after traversing through the whole
259 reference *ADDR_P. */
262 for_each_index (tree
*addr_p
, bool (*cbck
) (tree
, tree
*, void *), void *data
)
266 for (; ; addr_p
= nxt
)
268 switch (TREE_CODE (*addr_p
))
271 return cbck (*addr_p
, addr_p
, data
);
274 nxt
= &TREE_OPERAND (*addr_p
, 0);
275 return cbck (*addr_p
, nxt
, data
);
278 case VIEW_CONVERT_EXPR
:
281 nxt
= &TREE_OPERAND (*addr_p
, 0);
285 /* If the component has varying offset, it behaves like index
287 idx
= &TREE_OPERAND (*addr_p
, 2);
289 && !cbck (*addr_p
, idx
, data
))
292 nxt
= &TREE_OPERAND (*addr_p
, 0);
296 case ARRAY_RANGE_REF
:
297 nxt
= &TREE_OPERAND (*addr_p
, 0);
298 if (!cbck (*addr_p
, &TREE_OPERAND (*addr_p
, 1), data
))
315 gcc_assert (is_gimple_min_invariant (*addr_p
));
319 idx
= &TMR_BASE (*addr_p
);
321 && !cbck (*addr_p
, idx
, data
))
323 idx
= &TMR_INDEX (*addr_p
);
325 && !cbck (*addr_p
, idx
, data
))
327 idx
= &TMR_INDEX2 (*addr_p
);
329 && !cbck (*addr_p
, idx
, data
))
339 /* If it is possible to hoist the statement STMT unconditionally,
340 returns MOVE_POSSIBLE.
341 If it is possible to hoist the statement STMT, but we must avoid making
342 it executed if it would not be executed in the original program (e.g.
343 because it may trap), return MOVE_PRESERVE_EXECUTION.
344 Otherwise return MOVE_IMPOSSIBLE. */
347 movement_possibility (gimple stmt
)
350 enum move_pos ret
= MOVE_POSSIBLE
;
352 if (flag_unswitch_loops
353 && gimple_code (stmt
) == GIMPLE_COND
)
355 /* If we perform unswitching, force the operands of the invariant
356 condition to be moved out of the loop. */
357 return MOVE_POSSIBLE
;
360 if (gimple_code (stmt
) == GIMPLE_PHI
361 && gimple_phi_num_args (stmt
) <= 2
362 && !virtual_operand_p (gimple_phi_result (stmt
))
363 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_phi_result (stmt
)))
364 return MOVE_POSSIBLE
;
366 if (gimple_get_lhs (stmt
) == NULL_TREE
)
367 return MOVE_IMPOSSIBLE
;
369 if (gimple_vdef (stmt
))
370 return MOVE_IMPOSSIBLE
;
372 if (stmt_ends_bb_p (stmt
)
373 || gimple_has_volatile_ops (stmt
)
374 || gimple_has_side_effects (stmt
)
375 || stmt_could_throw_p (stmt
))
376 return MOVE_IMPOSSIBLE
;
378 if (is_gimple_call (stmt
))
380 /* While pure or const call is guaranteed to have no side effects, we
381 cannot move it arbitrarily. Consider code like
383 char *s = something ();
393 Here the strlen call cannot be moved out of the loop, even though
394 s is invariant. In addition to possibly creating a call with
395 invalid arguments, moving out a function call that is not executed
396 may cause performance regressions in case the call is costly and
397 not executed at all. */
398 ret
= MOVE_PRESERVE_EXECUTION
;
399 lhs
= gimple_call_lhs (stmt
);
401 else if (is_gimple_assign (stmt
))
402 lhs
= gimple_assign_lhs (stmt
);
404 return MOVE_IMPOSSIBLE
;
406 if (TREE_CODE (lhs
) == SSA_NAME
407 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
408 return MOVE_IMPOSSIBLE
;
410 if (TREE_CODE (lhs
) != SSA_NAME
411 || gimple_could_trap_p (stmt
))
412 return MOVE_PRESERVE_EXECUTION
;
414 /* Non local loads in a transaction cannot be hoisted out. Well,
415 unless the load happens on every path out of the loop, but we
416 don't take this into account yet. */
418 && gimple_in_transaction (stmt
)
419 && gimple_assign_single_p (stmt
))
421 tree rhs
= gimple_assign_rhs1 (stmt
);
422 if (DECL_P (rhs
) && is_global_var (rhs
))
426 fprintf (dump_file
, "Cannot hoist conditional load of ");
427 print_generic_expr (dump_file
, rhs
, TDF_SLIM
);
428 fprintf (dump_file
, " because it is in a transaction.\n");
430 return MOVE_IMPOSSIBLE
;
437 /* Suppose that operand DEF is used inside the LOOP. Returns the outermost
438 loop to that we could move the expression using DEF if it did not have
439 other operands, i.e. the outermost loop enclosing LOOP in that the value
440 of DEF is invariant. */
443 outermost_invariant_loop (tree def
, struct loop
*loop
)
447 struct loop
*max_loop
;
448 struct lim_aux_data
*lim_data
;
451 return superloop_at_depth (loop
, 1);
453 if (TREE_CODE (def
) != SSA_NAME
)
455 gcc_assert (is_gimple_min_invariant (def
));
456 return superloop_at_depth (loop
, 1);
459 def_stmt
= SSA_NAME_DEF_STMT (def
);
460 def_bb
= gimple_bb (def_stmt
);
462 return superloop_at_depth (loop
, 1);
464 max_loop
= find_common_loop (loop
, def_bb
->loop_father
);
466 lim_data
= get_lim_data (def_stmt
);
467 if (lim_data
!= NULL
&& lim_data
->max_loop
!= NULL
)
468 max_loop
= find_common_loop (max_loop
,
469 loop_outer (lim_data
->max_loop
));
470 if (max_loop
== loop
)
472 max_loop
= superloop_at_depth (loop
, loop_depth (max_loop
) + 1);
477 /* DATA is a structure containing information associated with a statement
478 inside LOOP. DEF is one of the operands of this statement.
480 Find the outermost loop enclosing LOOP in that value of DEF is invariant
481 and record this in DATA->max_loop field. If DEF itself is defined inside
482 this loop as well (i.e. we need to hoist it out of the loop if we want
483 to hoist the statement represented by DATA), record the statement in that
484 DEF is defined to the DATA->depends list. Additionally if ADD_COST is true,
485 add the cost of the computation of DEF to the DATA->cost.
487 If DEF is not invariant in LOOP, return false. Otherwise return TRUE. */
490 add_dependency (tree def
, struct lim_aux_data
*data
, struct loop
*loop
,
493 gimple def_stmt
= SSA_NAME_DEF_STMT (def
);
494 basic_block def_bb
= gimple_bb (def_stmt
);
495 struct loop
*max_loop
;
497 struct lim_aux_data
*def_data
;
502 max_loop
= outermost_invariant_loop (def
, loop
);
506 if (flow_loop_nested_p (data
->max_loop
, max_loop
))
507 data
->max_loop
= max_loop
;
509 def_data
= get_lim_data (def_stmt
);
514 /* Only add the cost if the statement defining DEF is inside LOOP,
515 i.e. if it is likely that by moving the invariants dependent
516 on it, we will be able to avoid creating a new register for
517 it (since it will be only used in these dependent invariants). */
518 && def_bb
->loop_father
== loop
)
519 data
->cost
+= def_data
->cost
;
521 dep
= XNEW (struct depend
);
522 dep
->stmt
= def_stmt
;
523 dep
->next
= data
->depends
;
529 /* Returns an estimate for a cost of statement STMT. The values here
530 are just ad-hoc constants, similar to costs for inlining. */
533 stmt_cost (gimple stmt
)
535 /* Always try to create possibilities for unswitching. */
536 if (gimple_code (stmt
) == GIMPLE_COND
537 || gimple_code (stmt
) == GIMPLE_PHI
)
538 return LIM_EXPENSIVE
;
540 /* We should be hoisting calls if possible. */
541 if (is_gimple_call (stmt
))
545 /* Unless the call is a builtin_constant_p; this always folds to a
546 constant, so moving it is useless. */
547 fndecl
= gimple_call_fndecl (stmt
);
549 && DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
550 && DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_CONSTANT_P
)
553 return LIM_EXPENSIVE
;
556 /* Hoisting memory references out should almost surely be a win. */
557 if (gimple_references_memory_p (stmt
))
558 return LIM_EXPENSIVE
;
560 if (gimple_code (stmt
) != GIMPLE_ASSIGN
)
563 switch (gimple_assign_rhs_code (stmt
))
566 case WIDEN_MULT_EXPR
:
567 case WIDEN_MULT_PLUS_EXPR
:
568 case WIDEN_MULT_MINUS_EXPR
:
581 /* Division and multiplication are usually expensive. */
582 return LIM_EXPENSIVE
;
586 case WIDEN_LSHIFT_EXPR
:
589 /* Shifts and rotates are usually expensive. */
590 return LIM_EXPENSIVE
;
593 /* Make vector construction cost proportional to the number
595 return CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt
));
599 /* Whether or not something is wrapped inside a PAREN_EXPR
600 should not change move cost. Nor should an intermediate
601 unpropagated SSA name copy. */
609 /* Finds the outermost loop between OUTER and LOOP in that the memory reference
610 REF is independent. If REF is not independent in LOOP, NULL is returned
614 outermost_indep_loop (struct loop
*outer
, struct loop
*loop
, mem_ref_p ref
)
618 if (bitmap_bit_p (ref
->stored
, loop
->num
))
623 aloop
= superloop_at_depth (loop
, loop_depth (aloop
) + 1))
624 if (!bitmap_bit_p (ref
->stored
, aloop
->num
)
625 && ref_indep_loop_p (aloop
, ref
))
628 if (ref_indep_loop_p (loop
, ref
))
634 /* If there is a simple load or store to a memory reference in STMT, returns
635 the location of the memory reference, and sets IS_STORE according to whether
636 it is a store or load. Otherwise, returns NULL. */
639 simple_mem_ref_in_stmt (gimple stmt
, bool *is_store
)
644 /* Recognize MEM = (SSA_NAME | invariant) and SSA_NAME = MEM patterns. */
645 if (gimple_code (stmt
) != GIMPLE_ASSIGN
)
648 code
= gimple_assign_rhs_code (stmt
);
650 lhs
= gimple_assign_lhs_ptr (stmt
);
652 if (TREE_CODE (*lhs
) == SSA_NAME
)
654 if (get_gimple_rhs_class (code
) != GIMPLE_SINGLE_RHS
655 || !is_gimple_addressable (gimple_assign_rhs1 (stmt
)))
659 return gimple_assign_rhs1_ptr (stmt
);
661 else if (code
== SSA_NAME
662 || (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
663 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
))))
672 /* Returns the memory reference contained in STMT. */
675 mem_ref_in_stmt (gimple stmt
)
678 tree
*mem
= simple_mem_ref_in_stmt (stmt
, &store
);
686 hash
= iterative_hash_expr (*mem
, 0);
687 ref
= (mem_ref_p
) htab_find_with_hash (memory_accesses
.refs
, *mem
, hash
);
689 gcc_assert (ref
!= NULL
);
693 /* From a controlling predicate in DOM determine the arguments from
694 the PHI node PHI that are chosen if the predicate evaluates to
695 true and false and store them to *TRUE_ARG_P and *FALSE_ARG_P if
696 they are non-NULL. Returns true if the arguments can be determined,
697 else return false. */
700 extract_true_false_args_from_phi (basic_block dom
, gimple phi
,
701 tree
*true_arg_p
, tree
*false_arg_p
)
703 basic_block bb
= gimple_bb (phi
);
704 edge true_edge
, false_edge
, tem
;
705 tree arg0
= NULL_TREE
, arg1
= NULL_TREE
;
707 /* We have to verify that one edge into the PHI node is dominated
708 by the true edge of the predicate block and the other edge
709 dominated by the false edge. This ensures that the PHI argument
710 we are going to take is completely determined by the path we
711 take from the predicate block.
712 We can only use BB dominance checks below if the destination of
713 the true/false edges are dominated by their edge, thus only
714 have a single predecessor. */
715 extract_true_false_edges_from_block (dom
, &true_edge
, &false_edge
);
716 tem
= EDGE_PRED (bb
, 0);
718 || (single_pred_p (true_edge
->dest
)
719 && (tem
->src
== true_edge
->dest
720 || dominated_by_p (CDI_DOMINATORS
,
721 tem
->src
, true_edge
->dest
))))
722 arg0
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
723 else if (tem
== false_edge
724 || (single_pred_p (false_edge
->dest
)
725 && (tem
->src
== false_edge
->dest
726 || dominated_by_p (CDI_DOMINATORS
,
727 tem
->src
, false_edge
->dest
))))
728 arg1
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
731 tem
= EDGE_PRED (bb
, 1);
733 || (single_pred_p (true_edge
->dest
)
734 && (tem
->src
== true_edge
->dest
735 || dominated_by_p (CDI_DOMINATORS
,
736 tem
->src
, true_edge
->dest
))))
737 arg0
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
738 else if (tem
== false_edge
739 || (single_pred_p (false_edge
->dest
)
740 && (tem
->src
== false_edge
->dest
741 || dominated_by_p (CDI_DOMINATORS
,
742 tem
->src
, false_edge
->dest
))))
743 arg1
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
757 /* Determine the outermost loop to that it is possible to hoist a statement
758 STMT and store it to LIM_DATA (STMT)->max_loop. To do this we determine
759 the outermost loop in that the value computed by STMT is invariant.
760 If MUST_PRESERVE_EXEC is true, additionally choose such a loop that
761 we preserve the fact whether STMT is executed. It also fills other related
762 information to LIM_DATA (STMT).
764 The function returns false if STMT cannot be hoisted outside of the loop it
765 is defined in, and true otherwise. */
768 determine_max_movement (gimple stmt
, bool must_preserve_exec
)
770 basic_block bb
= gimple_bb (stmt
);
771 struct loop
*loop
= bb
->loop_father
;
773 struct lim_aux_data
*lim_data
= get_lim_data (stmt
);
777 if (must_preserve_exec
)
778 level
= ALWAYS_EXECUTED_IN (bb
);
780 level
= superloop_at_depth (loop
, 1);
781 lim_data
->max_loop
= level
;
783 if (gimple_code (stmt
) == GIMPLE_PHI
)
786 unsigned min_cost
= UINT_MAX
;
787 unsigned total_cost
= 0;
788 struct lim_aux_data
*def_data
;
790 /* We will end up promoting dependencies to be unconditionally
791 evaluated. For this reason the PHI cost (and thus the
792 cost we remove from the loop by doing the invariant motion)
793 is that of the cheapest PHI argument dependency chain. */
794 FOR_EACH_PHI_ARG (use_p
, stmt
, iter
, SSA_OP_USE
)
796 val
= USE_FROM_PTR (use_p
);
797 if (TREE_CODE (val
) != SSA_NAME
)
799 if (!add_dependency (val
, lim_data
, loop
, false))
801 def_data
= get_lim_data (SSA_NAME_DEF_STMT (val
));
804 min_cost
= MIN (min_cost
, def_data
->cost
);
805 total_cost
+= def_data
->cost
;
809 lim_data
->cost
+= min_cost
;
811 if (gimple_phi_num_args (stmt
) > 1)
813 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
815 if (gsi_end_p (gsi_last_bb (dom
)))
817 cond
= gsi_stmt (gsi_last_bb (dom
));
818 if (gimple_code (cond
) != GIMPLE_COND
)
820 /* Verify that this is an extended form of a diamond and
821 the PHI arguments are completely controlled by the
823 if (!extract_true_false_args_from_phi (dom
, stmt
, NULL
, NULL
))
826 /* Fold in dependencies and cost of the condition. */
827 FOR_EACH_SSA_TREE_OPERAND (val
, cond
, iter
, SSA_OP_USE
)
829 if (!add_dependency (val
, lim_data
, loop
, false))
831 def_data
= get_lim_data (SSA_NAME_DEF_STMT (val
));
833 total_cost
+= def_data
->cost
;
836 /* We want to avoid unconditionally executing very expensive
837 operations. As costs for our dependencies cannot be
838 negative just claim we are not invariand for this case.
839 We also are not sure whether the control-flow inside the
841 if (total_cost
- min_cost
>= 2 * LIM_EXPENSIVE
843 && total_cost
/ min_cost
<= 2))
846 /* Assume that the control-flow in the loop will vanish.
847 ??? We should verify this and not artificially increase
848 the cost if that is not the case. */
849 lim_data
->cost
+= stmt_cost (stmt
);
855 FOR_EACH_SSA_TREE_OPERAND (val
, stmt
, iter
, SSA_OP_USE
)
856 if (!add_dependency (val
, lim_data
, loop
, true))
859 if (gimple_vuse (stmt
))
861 mem_ref_p ref
= mem_ref_in_stmt (stmt
);
866 = outermost_indep_loop (lim_data
->max_loop
, loop
, ref
);
867 if (!lim_data
->max_loop
)
872 if ((val
= gimple_vuse (stmt
)) != NULL_TREE
)
874 if (!add_dependency (val
, lim_data
, loop
, false))
880 lim_data
->cost
+= stmt_cost (stmt
);
885 /* Suppose that some statement in ORIG_LOOP is hoisted to the loop LEVEL,
886 and that one of the operands of this statement is computed by STMT.
887 Ensure that STMT (together with all the statements that define its
888 operands) is hoisted at least out of the loop LEVEL. */
891 set_level (gimple stmt
, struct loop
*orig_loop
, struct loop
*level
)
893 struct loop
*stmt_loop
= gimple_bb (stmt
)->loop_father
;
895 struct lim_aux_data
*lim_data
;
897 stmt_loop
= find_common_loop (orig_loop
, stmt_loop
);
898 lim_data
= get_lim_data (stmt
);
899 if (lim_data
!= NULL
&& lim_data
->tgt_loop
!= NULL
)
900 stmt_loop
= find_common_loop (stmt_loop
,
901 loop_outer (lim_data
->tgt_loop
));
902 if (flow_loop_nested_p (stmt_loop
, level
))
905 gcc_assert (level
== lim_data
->max_loop
906 || flow_loop_nested_p (lim_data
->max_loop
, level
));
908 lim_data
->tgt_loop
= level
;
909 for (dep
= lim_data
->depends
; dep
; dep
= dep
->next
)
910 set_level (dep
->stmt
, orig_loop
, level
);
913 /* Determines an outermost loop from that we want to hoist the statement STMT.
914 For now we chose the outermost possible loop. TODO -- use profiling
915 information to set it more sanely. */
918 set_profitable_level (gimple stmt
)
920 set_level (stmt
, gimple_bb (stmt
)->loop_father
, get_lim_data (stmt
)->max_loop
);
923 /* Returns true if STMT is a call that has side effects. */
926 nonpure_call_p (gimple stmt
)
928 if (gimple_code (stmt
) != GIMPLE_CALL
)
931 return gimple_has_side_effects (stmt
);
934 /* Rewrite a/b to a*(1/b). Return the invariant stmt to process. */
937 rewrite_reciprocal (gimple_stmt_iterator
*bsi
)
939 gimple stmt
, stmt1
, stmt2
;
940 tree name
, lhs
, type
;
942 gimple_stmt_iterator gsi
;
944 stmt
= gsi_stmt (*bsi
);
945 lhs
= gimple_assign_lhs (stmt
);
946 type
= TREE_TYPE (lhs
);
948 real_one
= build_one_cst (type
);
950 name
= make_temp_ssa_name (type
, NULL
, "reciptmp");
951 stmt1
= gimple_build_assign_with_ops (RDIV_EXPR
, name
, real_one
,
952 gimple_assign_rhs2 (stmt
));
954 stmt2
= gimple_build_assign_with_ops (MULT_EXPR
, lhs
, name
,
955 gimple_assign_rhs1 (stmt
));
957 /* Replace division stmt with reciprocal and multiply stmts.
958 The multiply stmt is not invariant, so update iterator
959 and avoid rescanning. */
961 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
962 gsi_replace (&gsi
, stmt2
, true);
964 /* Continue processing with invariant reciprocal statement. */
968 /* Check if the pattern at *BSI is a bittest of the form
969 (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0. */
972 rewrite_bittest (gimple_stmt_iterator
*bsi
)
974 gimple stmt
, use_stmt
, stmt1
, stmt2
;
975 tree lhs
, name
, t
, a
, b
;
978 stmt
= gsi_stmt (*bsi
);
979 lhs
= gimple_assign_lhs (stmt
);
981 /* Verify that the single use of lhs is a comparison against zero. */
982 if (TREE_CODE (lhs
) != SSA_NAME
983 || !single_imm_use (lhs
, &use
, &use_stmt
)
984 || gimple_code (use_stmt
) != GIMPLE_COND
)
986 if (gimple_cond_lhs (use_stmt
) != lhs
987 || (gimple_cond_code (use_stmt
) != NE_EXPR
988 && gimple_cond_code (use_stmt
) != EQ_EXPR
)
989 || !integer_zerop (gimple_cond_rhs (use_stmt
)))
992 /* Get at the operands of the shift. The rhs is TMP1 & 1. */
993 stmt1
= SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt
));
994 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
997 /* There is a conversion in between possibly inserted by fold. */
998 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt1
)))
1000 t
= gimple_assign_rhs1 (stmt1
);
1001 if (TREE_CODE (t
) != SSA_NAME
1002 || !has_single_use (t
))
1004 stmt1
= SSA_NAME_DEF_STMT (t
);
1005 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
1009 /* Verify that B is loop invariant but A is not. Verify that with
1010 all the stmt walking we are still in the same loop. */
1011 if (gimple_assign_rhs_code (stmt1
) != RSHIFT_EXPR
1012 || loop_containing_stmt (stmt1
) != loop_containing_stmt (stmt
))
1015 a
= gimple_assign_rhs1 (stmt1
);
1016 b
= gimple_assign_rhs2 (stmt1
);
1018 if (outermost_invariant_loop (b
, loop_containing_stmt (stmt1
)) != NULL
1019 && outermost_invariant_loop (a
, loop_containing_stmt (stmt1
)) == NULL
)
1021 gimple_stmt_iterator rsi
;
1024 t
= fold_build2 (LSHIFT_EXPR
, TREE_TYPE (a
),
1025 build_int_cst (TREE_TYPE (a
), 1), b
);
1026 name
= make_temp_ssa_name (TREE_TYPE (a
), NULL
, "shifttmp");
1027 stmt1
= gimple_build_assign (name
, t
);
1030 t
= fold_build2 (BIT_AND_EXPR
, TREE_TYPE (a
), a
, name
);
1031 name
= make_temp_ssa_name (TREE_TYPE (a
), NULL
, "shifttmp");
1032 stmt2
= gimple_build_assign (name
, t
);
1034 /* Replace the SSA_NAME we compare against zero. Adjust
1035 the type of zero accordingly. */
1036 SET_USE (use
, name
);
1037 gimple_cond_set_rhs (use_stmt
, build_int_cst_type (TREE_TYPE (name
), 0));
1039 /* Don't use gsi_replace here, none of the new assignments sets
1040 the variable originally set in stmt. Move bsi to stmt1, and
1041 then remove the original stmt, so that we get a chance to
1042 retain debug info for it. */
1044 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
1045 gsi_insert_before (&rsi
, stmt2
, GSI_SAME_STMT
);
1046 gsi_remove (&rsi
, true);
1055 /* Determine the outermost loops in that statements in basic block BB are
1056 invariant, and record them to the LIM_DATA associated with the statements.
1057 Callback for walk_dominator_tree. */
1060 determine_invariantness_stmt (struct dom_walk_data
*dw_data ATTRIBUTE_UNUSED
,
1064 gimple_stmt_iterator bsi
;
1066 bool maybe_never
= ALWAYS_EXECUTED_IN (bb
) == NULL
;
1067 struct loop
*outermost
= ALWAYS_EXECUTED_IN (bb
);
1068 struct lim_aux_data
*lim_data
;
1070 if (!loop_outer (bb
->loop_father
))
1073 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1074 fprintf (dump_file
, "Basic block %d (loop %d -- depth %d):\n\n",
1075 bb
->index
, bb
->loop_father
->num
, loop_depth (bb
->loop_father
));
1077 /* Look at PHI nodes, but only if there is at most two.
1078 ??? We could relax this further by post-processing the inserted
1079 code and transforming adjacent cond-exprs with the same predicate
1080 to control flow again. */
1081 bsi
= gsi_start_phis (bb
);
1082 if (!gsi_end_p (bsi
)
1083 && ((gsi_next (&bsi
), gsi_end_p (bsi
))
1084 || (gsi_next (&bsi
), gsi_end_p (bsi
))))
1085 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1087 stmt
= gsi_stmt (bsi
);
1089 pos
= movement_possibility (stmt
);
1090 if (pos
== MOVE_IMPOSSIBLE
)
1093 lim_data
= init_lim_data (stmt
);
1094 lim_data
->always_executed_in
= outermost
;
1096 if (!determine_max_movement (stmt
, false))
1098 lim_data
->max_loop
= NULL
;
1102 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1104 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1105 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1106 loop_depth (lim_data
->max_loop
),
1110 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1111 set_profitable_level (stmt
);
1114 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1116 stmt
= gsi_stmt (bsi
);
1118 pos
= movement_possibility (stmt
);
1119 if (pos
== MOVE_IMPOSSIBLE
)
1121 if (nonpure_call_p (stmt
))
1126 /* Make sure to note always_executed_in for stores to make
1127 store-motion work. */
1128 else if (stmt_makes_single_store (stmt
))
1130 struct lim_aux_data
*lim_data
= init_lim_data (stmt
);
1131 lim_data
->always_executed_in
= outermost
;
1136 if (is_gimple_assign (stmt
)
1137 && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt
))
1138 == GIMPLE_BINARY_RHS
))
1140 tree op0
= gimple_assign_rhs1 (stmt
);
1141 tree op1
= gimple_assign_rhs2 (stmt
);
1142 struct loop
*ol1
= outermost_invariant_loop (op1
,
1143 loop_containing_stmt (stmt
));
1145 /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal
1146 to be hoisted out of loop, saving expensive divide. */
1147 if (pos
== MOVE_POSSIBLE
1148 && gimple_assign_rhs_code (stmt
) == RDIV_EXPR
1149 && flag_unsafe_math_optimizations
1150 && !flag_trapping_math
1152 && outermost_invariant_loop (op0
, ol1
) == NULL
)
1153 stmt
= rewrite_reciprocal (&bsi
);
1155 /* If the shift count is invariant, convert (A >> B) & 1 to
1156 A & (1 << B) allowing the bit mask to be hoisted out of the loop
1157 saving an expensive shift. */
1158 if (pos
== MOVE_POSSIBLE
1159 && gimple_assign_rhs_code (stmt
) == BIT_AND_EXPR
1160 && integer_onep (op1
)
1161 && TREE_CODE (op0
) == SSA_NAME
1162 && has_single_use (op0
))
1163 stmt
= rewrite_bittest (&bsi
);
1166 lim_data
= init_lim_data (stmt
);
1167 lim_data
->always_executed_in
= outermost
;
1169 if (maybe_never
&& pos
== MOVE_PRESERVE_EXECUTION
)
1172 if (!determine_max_movement (stmt
, pos
== MOVE_PRESERVE_EXECUTION
))
1174 lim_data
->max_loop
= NULL
;
1178 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1180 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1181 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1182 loop_depth (lim_data
->max_loop
),
1186 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1187 set_profitable_level (stmt
);
1191 /* For each statement determines the outermost loop in that it is invariant,
1192 statements on whose motion it depends and the cost of the computation.
1193 This information is stored to the LIM_DATA structure associated with
1197 determine_invariantness (void)
1199 struct dom_walk_data walk_data
;
1201 memset (&walk_data
, 0, sizeof (struct dom_walk_data
));
1202 walk_data
.dom_direction
= CDI_DOMINATORS
;
1203 walk_data
.before_dom_children
= determine_invariantness_stmt
;
1205 init_walk_dominator_tree (&walk_data
);
1206 walk_dominator_tree (&walk_data
, ENTRY_BLOCK_PTR
);
1207 fini_walk_dominator_tree (&walk_data
);
1210 /* Hoist the statements in basic block BB out of the loops prescribed by
1211 data stored in LIM_DATA structures associated with each statement. Callback
1212 for walk_dominator_tree. */
1215 move_computations_stmt (struct dom_walk_data
*dw_data
,
1219 gimple_stmt_iterator bsi
;
1222 struct lim_aux_data
*lim_data
;
1224 if (!loop_outer (bb
->loop_father
))
1227 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); )
1230 stmt
= gsi_stmt (bsi
);
1232 lim_data
= get_lim_data (stmt
);
1233 if (lim_data
== NULL
)
1239 cost
= lim_data
->cost
;
1240 level
= lim_data
->tgt_loop
;
1241 clear_lim_data (stmt
);
1249 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1251 fprintf (dump_file
, "Moving PHI node\n");
1252 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1253 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1257 if (gimple_phi_num_args (stmt
) == 1)
1259 tree arg
= PHI_ARG_DEF (stmt
, 0);
1260 new_stmt
= gimple_build_assign_with_ops (TREE_CODE (arg
),
1261 gimple_phi_result (stmt
),
1263 SSA_NAME_DEF_STMT (gimple_phi_result (stmt
)) = new_stmt
;
1267 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
1268 gimple cond
= gsi_stmt (gsi_last_bb (dom
));
1269 tree arg0
= NULL_TREE
, arg1
= NULL_TREE
, t
;
1270 /* Get the PHI arguments corresponding to the true and false
1272 extract_true_false_args_from_phi (dom
, stmt
, &arg0
, &arg1
);
1273 gcc_assert (arg0
&& arg1
);
1274 t
= build2 (gimple_cond_code (cond
), boolean_type_node
,
1275 gimple_cond_lhs (cond
), gimple_cond_rhs (cond
));
1276 new_stmt
= gimple_build_assign_with_ops3 (COND_EXPR
,
1277 gimple_phi_result (stmt
),
1279 SSA_NAME_DEF_STMT (gimple_phi_result (stmt
)) = new_stmt
;
1280 *((unsigned int *)(dw_data
->global_data
)) |= TODO_cleanup_cfg
;
1282 gsi_insert_on_edge (loop_preheader_edge (level
), new_stmt
);
1283 remove_phi_node (&bsi
, false);
1286 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); )
1290 stmt
= gsi_stmt (bsi
);
1292 lim_data
= get_lim_data (stmt
);
1293 if (lim_data
== NULL
)
1299 cost
= lim_data
->cost
;
1300 level
= lim_data
->tgt_loop
;
1301 clear_lim_data (stmt
);
1309 /* We do not really want to move conditionals out of the loop; we just
1310 placed it here to force its operands to be moved if necessary. */
1311 if (gimple_code (stmt
) == GIMPLE_COND
)
1314 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1316 fprintf (dump_file
, "Moving statement\n");
1317 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1318 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1322 e
= loop_preheader_edge (level
);
1323 gcc_assert (!gimple_vdef (stmt
));
1324 if (gimple_vuse (stmt
))
1326 /* The new VUSE is the one from the virtual PHI in the loop
1327 header or the one already present. */
1328 gimple_stmt_iterator gsi2
;
1329 for (gsi2
= gsi_start_phis (e
->dest
);
1330 !gsi_end_p (gsi2
); gsi_next (&gsi2
))
1332 gimple phi
= gsi_stmt (gsi2
);
1333 if (virtual_operand_p (gimple_phi_result (phi
)))
1335 gimple_set_vuse (stmt
, PHI_ARG_DEF_FROM_EDGE (phi
, e
));
1340 gsi_remove (&bsi
, false);
1341 gsi_insert_on_edge (e
, stmt
);
1345 /* Hoist the statements out of the loops prescribed by data stored in
1346 LIM_DATA structures associated with each statement.*/
1349 move_computations (void)
1351 struct dom_walk_data walk_data
;
1352 unsigned int todo
= 0;
1354 memset (&walk_data
, 0, sizeof (struct dom_walk_data
));
1355 walk_data
.global_data
= &todo
;
1356 walk_data
.dom_direction
= CDI_DOMINATORS
;
1357 walk_data
.before_dom_children
= move_computations_stmt
;
1359 init_walk_dominator_tree (&walk_data
);
1360 walk_dominator_tree (&walk_data
, ENTRY_BLOCK_PTR
);
1361 fini_walk_dominator_tree (&walk_data
);
1363 gsi_commit_edge_inserts ();
1364 if (need_ssa_update_p (cfun
))
1365 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
1370 /* Checks whether the statement defining variable *INDEX can be hoisted
1371 out of the loop passed in DATA. Callback for for_each_index. */
1374 may_move_till (tree ref
, tree
*index
, void *data
)
1376 struct loop
*loop
= (struct loop
*) data
, *max_loop
;
1378 /* If REF is an array reference, check also that the step and the lower
1379 bound is invariant in LOOP. */
1380 if (TREE_CODE (ref
) == ARRAY_REF
)
1382 tree step
= TREE_OPERAND (ref
, 3);
1383 tree lbound
= TREE_OPERAND (ref
, 2);
1385 max_loop
= outermost_invariant_loop (step
, loop
);
1389 max_loop
= outermost_invariant_loop (lbound
, loop
);
1394 max_loop
= outermost_invariant_loop (*index
, loop
);
1401 /* If OP is SSA NAME, force the statement that defines it to be
1402 moved out of the LOOP. ORIG_LOOP is the loop in that EXPR is used. */
1405 force_move_till_op (tree op
, struct loop
*orig_loop
, struct loop
*loop
)
1410 || is_gimple_min_invariant (op
))
1413 gcc_assert (TREE_CODE (op
) == SSA_NAME
);
1415 stmt
= SSA_NAME_DEF_STMT (op
);
1416 if (gimple_nop_p (stmt
))
1419 set_level (stmt
, orig_loop
, loop
);
1422 /* Forces statement defining invariants in REF (and *INDEX) to be moved out of
1423 the LOOP. The reference REF is used in the loop ORIG_LOOP. Callback for
1429 struct loop
*orig_loop
;
1433 force_move_till (tree ref
, tree
*index
, void *data
)
1435 struct fmt_data
*fmt_data
= (struct fmt_data
*) data
;
1437 if (TREE_CODE (ref
) == ARRAY_REF
)
1439 tree step
= TREE_OPERAND (ref
, 3);
1440 tree lbound
= TREE_OPERAND (ref
, 2);
1442 force_move_till_op (step
, fmt_data
->orig_loop
, fmt_data
->loop
);
1443 force_move_till_op (lbound
, fmt_data
->orig_loop
, fmt_data
->loop
);
1446 force_move_till_op (*index
, fmt_data
->orig_loop
, fmt_data
->loop
);
1451 /* A hash function for struct mem_ref object OBJ. */
1454 memref_hash (const void *obj
)
1456 const struct mem_ref
*const mem
= (const struct mem_ref
*) obj
;
1461 /* An equality function for struct mem_ref object OBJ1 with
1462 memory reference OBJ2. */
1465 memref_eq (const void *obj1
, const void *obj2
)
1467 const struct mem_ref
*const mem1
= (const struct mem_ref
*) obj1
;
1469 return operand_equal_p (mem1
->mem
, (const_tree
) obj2
, 0);
1472 /* Releases list of memory reference locations ACCS. */
1475 free_mem_ref_locs (mem_ref_locs_p accs
)
1483 FOR_EACH_VEC_ELT (mem_ref_loc_p
, accs
->locs
, i
, loc
)
1485 VEC_free (mem_ref_loc_p
, heap
, accs
->locs
);
1489 /* A function to free the mem_ref object OBJ. */
1492 memref_free (struct mem_ref
*mem
)
1495 mem_ref_locs_p accs
;
1497 FOR_EACH_VEC_ELT (mem_ref_locs_p
, mem
->accesses_in_loop
, i
, accs
)
1498 free_mem_ref_locs (accs
);
1499 VEC_free (mem_ref_locs_p
, heap
, mem
->accesses_in_loop
);
1504 /* Allocates and returns a memory reference description for MEM whose hash
1505 value is HASH and id is ID. */
1508 mem_ref_alloc (tree mem
, unsigned hash
, unsigned id
)
1510 mem_ref_p ref
= XNEW (struct mem_ref
);
1514 ref
->stored
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1515 ref
->indep_loop
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1516 ref
->dep_loop
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1517 ref
->indep_ref
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1518 ref
->dep_ref
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1519 ref
->accesses_in_loop
= NULL
;
1524 /* Allocates and returns the new list of locations. */
1526 static mem_ref_locs_p
1527 mem_ref_locs_alloc (void)
1529 mem_ref_locs_p accs
= XNEW (struct mem_ref_locs
);
1534 /* Records memory reference location *LOC in LOOP to the memory reference
1535 description REF. The reference occurs in statement STMT. */
1538 record_mem_ref_loc (mem_ref_p ref
, struct loop
*loop
, gimple stmt
, tree
*loc
)
1540 mem_ref_loc_p aref
= XNEW (struct mem_ref_loc
);
1541 mem_ref_locs_p accs
;
1542 bitmap ril
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1544 if (VEC_length (mem_ref_locs_p
, ref
->accesses_in_loop
)
1545 <= (unsigned) loop
->num
)
1546 VEC_safe_grow_cleared (mem_ref_locs_p
, heap
, ref
->accesses_in_loop
,
1548 accs
= VEC_index (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
);
1551 accs
= mem_ref_locs_alloc ();
1552 VEC_replace (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
, accs
);
1558 VEC_safe_push (mem_ref_loc_p
, heap
, accs
->locs
, aref
);
1559 bitmap_set_bit (ril
, ref
->id
);
1562 /* Marks reference REF as stored in LOOP. */
1565 mark_ref_stored (mem_ref_p ref
, struct loop
*loop
)
1568 loop
!= current_loops
->tree_root
1569 && !bitmap_bit_p (ref
->stored
, loop
->num
);
1570 loop
= loop_outer (loop
))
1571 bitmap_set_bit (ref
->stored
, loop
->num
);
1574 /* Gathers memory references in statement STMT in LOOP, storing the
1575 information about them in the memory_accesses structure. Marks
1576 the vops accessed through unrecognized statements there as
1580 gather_mem_refs_stmt (struct loop
*loop
, gimple stmt
)
1589 if (!gimple_vuse (stmt
))
1592 mem
= simple_mem_ref_in_stmt (stmt
, &is_stored
);
1595 id
= VEC_length (mem_ref_p
, memory_accesses
.refs_list
);
1596 ref
= mem_ref_alloc (error_mark_node
, 0, id
);
1597 VEC_safe_push (mem_ref_p
, heap
, memory_accesses
.refs_list
, ref
);
1598 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1600 fprintf (dump_file
, "Unanalyzed memory reference %u: ", id
);
1601 print_gimple_stmt (dump_file
, stmt
, 0, TDF_SLIM
);
1603 if (gimple_vdef (stmt
))
1604 mark_ref_stored (ref
, loop
);
1605 record_mem_ref_loc (ref
, loop
, stmt
, mem
);
1609 hash
= iterative_hash_expr (*mem
, 0);
1610 slot
= htab_find_slot_with_hash (memory_accesses
.refs
, *mem
, hash
, INSERT
);
1614 ref
= (mem_ref_p
) *slot
;
1619 id
= VEC_length (mem_ref_p
, memory_accesses
.refs_list
);
1620 ref
= mem_ref_alloc (*mem
, hash
, id
);
1621 VEC_safe_push (mem_ref_p
, heap
, memory_accesses
.refs_list
, ref
);
1624 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1626 fprintf (dump_file
, "Memory reference %u: ", id
);
1627 print_generic_expr (dump_file
, ref
->mem
, TDF_SLIM
);
1628 fprintf (dump_file
, "\n");
1633 mark_ref_stored (ref
, loop
);
1635 record_mem_ref_loc (ref
, loop
, stmt
, mem
);
1639 /* Gathers memory references in loops. */
1642 gather_mem_refs_in_loops (void)
1644 gimple_stmt_iterator bsi
;
1648 bitmap lrefs
, alrefs
, alrefso
;
1652 loop
= bb
->loop_father
;
1653 if (loop
== current_loops
->tree_root
)
1656 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1657 gather_mem_refs_stmt (loop
, gsi_stmt (bsi
));
1660 /* Propagate the information about accessed memory references up
1661 the loop hierarchy. */
1662 FOR_EACH_LOOP (li
, loop
, LI_FROM_INNERMOST
)
1664 lrefs
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1665 alrefs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
, loop
->num
);
1666 bitmap_ior_into (alrefs
, lrefs
);
1668 if (loop_outer (loop
) == current_loops
->tree_root
)
1671 alrefso
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
1672 loop_outer (loop
)->num
);
1673 bitmap_ior_into (alrefso
, alrefs
);
1677 /* Create a mapping from virtual operands to references that touch them
1681 create_vop_ref_mapping_loop (struct loop
*loop
)
1683 bitmap refs
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1689 EXECUTE_IF_SET_IN_BITMAP (refs
, 0, i
, bi
)
1691 ref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
1692 for (sloop
= loop
; sloop
!= current_loops
->tree_root
;
1693 sloop
= loop_outer (sloop
))
1694 if (bitmap_bit_p (ref
->stored
, loop
->num
))
1697 = VEC_index (bitmap
, memory_accesses
.all_refs_stored_in_loop
,
1699 bitmap_set_bit (refs_stored
, ref
->id
);
1704 /* For each non-clobbered virtual operand and each loop, record the memory
1705 references in this loop that touch the operand. */
1708 create_vop_ref_mapping (void)
1713 FOR_EACH_LOOP (li
, loop
, 0)
1715 create_vop_ref_mapping_loop (loop
);
1719 /* Gathers information about memory accesses in the loops. */
1722 analyze_memory_references (void)
1727 memory_accesses
.refs
= htab_create (100, memref_hash
, memref_eq
, NULL
);
1728 memory_accesses
.refs_list
= NULL
;
1729 memory_accesses
.refs_in_loop
= VEC_alloc (bitmap
, heap
,
1730 number_of_loops ());
1731 memory_accesses
.all_refs_in_loop
= VEC_alloc (bitmap
, heap
,
1732 number_of_loops ());
1733 memory_accesses
.all_refs_stored_in_loop
= VEC_alloc (bitmap
, heap
,
1734 number_of_loops ());
1736 for (i
= 0; i
< number_of_loops (); i
++)
1738 empty
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1739 VEC_quick_push (bitmap
, memory_accesses
.refs_in_loop
, empty
);
1740 empty
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1741 VEC_quick_push (bitmap
, memory_accesses
.all_refs_in_loop
, empty
);
1742 empty
= BITMAP_ALLOC (&lim_bitmap_obstack
);
1743 VEC_quick_push (bitmap
, memory_accesses
.all_refs_stored_in_loop
, empty
);
1746 memory_accesses
.ttae_cache
= NULL
;
1748 gather_mem_refs_in_loops ();
1749 create_vop_ref_mapping ();
1752 /* Returns true if MEM1 and MEM2 may alias. TTAE_CACHE is used as a cache in
1753 tree_to_aff_combination_expand. */
1756 mem_refs_may_alias_p (tree mem1
, tree mem2
, struct pointer_map_t
**ttae_cache
)
1758 /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the same
1759 object and their offset differ in such a way that the locations cannot
1760 overlap, then they cannot alias. */
1761 double_int size1
, size2
;
1762 aff_tree off1
, off2
;
1764 /* Perform basic offset and type-based disambiguation. */
1765 if (!refs_may_alias_p (mem1
, mem2
))
1768 /* The expansion of addresses may be a bit expensive, thus we only do
1769 the check at -O2 and higher optimization levels. */
1773 get_inner_reference_aff (mem1
, &off1
, &size1
);
1774 get_inner_reference_aff (mem2
, &off2
, &size2
);
1775 aff_combination_expand (&off1
, ttae_cache
);
1776 aff_combination_expand (&off2
, ttae_cache
);
1777 aff_combination_scale (&off1
, double_int_minus_one
);
1778 aff_combination_add (&off2
, &off1
);
1780 if (aff_comb_cannot_overlap_p (&off2
, size1
, size2
))
1786 /* Rewrites location LOC by TMP_VAR. */
1789 rewrite_mem_ref_loc (mem_ref_loc_p loc
, tree tmp_var
)
1791 *loc
->ref
= tmp_var
;
1792 update_stmt (loc
->stmt
);
1795 /* Adds all locations of REF in LOOP and its subloops to LOCS. */
1798 get_all_locs_in_loop (struct loop
*loop
, mem_ref_p ref
,
1799 VEC (mem_ref_loc_p
, heap
) **locs
)
1801 mem_ref_locs_p accs
;
1804 bitmap refs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
1806 struct loop
*subloop
;
1808 if (!bitmap_bit_p (refs
, ref
->id
))
1811 if (VEC_length (mem_ref_locs_p
, ref
->accesses_in_loop
)
1812 > (unsigned) loop
->num
)
1814 accs
= VEC_index (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
);
1817 FOR_EACH_VEC_ELT (mem_ref_loc_p
, accs
->locs
, i
, loc
)
1818 VEC_safe_push (mem_ref_loc_p
, heap
, *locs
, loc
);
1822 for (subloop
= loop
->inner
; subloop
!= NULL
; subloop
= subloop
->next
)
1823 get_all_locs_in_loop (subloop
, ref
, locs
);
1826 /* Rewrites all references to REF in LOOP by variable TMP_VAR. */
1829 rewrite_mem_refs (struct loop
*loop
, mem_ref_p ref
, tree tmp_var
)
1833 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
1835 get_all_locs_in_loop (loop
, ref
, &locs
);
1836 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
1837 rewrite_mem_ref_loc (loc
, tmp_var
);
1838 VEC_free (mem_ref_loc_p
, heap
, locs
);
1841 /* The name and the length of the currently generated variable
1843 #define MAX_LSM_NAME_LENGTH 40
1844 static char lsm_tmp_name
[MAX_LSM_NAME_LENGTH
+ 1];
1845 static int lsm_tmp_name_length
;
1847 /* Adds S to lsm_tmp_name. */
1850 lsm_tmp_name_add (const char *s
)
1852 int l
= strlen (s
) + lsm_tmp_name_length
;
1853 if (l
> MAX_LSM_NAME_LENGTH
)
1856 strcpy (lsm_tmp_name
+ lsm_tmp_name_length
, s
);
1857 lsm_tmp_name_length
= l
;
1860 /* Stores the name for temporary variable that replaces REF to
1864 gen_lsm_tmp_name (tree ref
)
1868 switch (TREE_CODE (ref
))
1871 case TARGET_MEM_REF
:
1872 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1873 lsm_tmp_name_add ("_");
1877 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1881 case VIEW_CONVERT_EXPR
:
1882 case ARRAY_RANGE_REF
:
1883 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1887 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1888 lsm_tmp_name_add ("_RE");
1892 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1893 lsm_tmp_name_add ("_IM");
1897 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1898 lsm_tmp_name_add ("_");
1899 name
= get_name (TREE_OPERAND (ref
, 1));
1902 lsm_tmp_name_add (name
);
1906 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1907 lsm_tmp_name_add ("_I");
1913 name
= get_name (ref
);
1916 lsm_tmp_name_add (name
);
1920 lsm_tmp_name_add ("S");
1924 lsm_tmp_name_add ("R");
1936 /* Determines name for temporary variable that replaces REF.
1937 The name is accumulated into the lsm_tmp_name variable.
1938 N is added to the name of the temporary. */
1941 get_lsm_tmp_name (tree ref
, unsigned n
)
1945 lsm_tmp_name_length
= 0;
1946 gen_lsm_tmp_name (ref
);
1947 lsm_tmp_name_add ("_lsm");
1952 lsm_tmp_name_add (ns
);
1954 return lsm_tmp_name
;
1957 struct prev_flag_edges
{
1958 /* Edge to insert new flag comparison code. */
1959 edge append_cond_position
;
1961 /* Edge for fall through from previous flag comparison. */
1962 edge last_cond_fallthru
;
1965 /* Helper function for execute_sm. Emit code to store TMP_VAR into
1968 The store is only done if MEM has changed. We do this so no
1969 changes to MEM occur on code paths that did not originally store
1972 The common case for execute_sm will transform:
1992 This function will generate:
2011 execute_sm_if_changed (edge ex
, tree mem
, tree tmp_var
, tree flag
)
2013 basic_block new_bb
, then_bb
, old_dest
;
2014 bool loop_has_only_one_exit
;
2015 edge then_old_edge
, orig_ex
= ex
;
2016 gimple_stmt_iterator gsi
;
2018 struct prev_flag_edges
*prev_edges
= (struct prev_flag_edges
*) ex
->aux
;
2020 /* ?? Insert store after previous store if applicable. See note
2023 ex
= prev_edges
->append_cond_position
;
2025 loop_has_only_one_exit
= single_pred_p (ex
->dest
);
2027 if (loop_has_only_one_exit
)
2028 ex
= split_block_after_labels (ex
->dest
);
2030 old_dest
= ex
->dest
;
2031 new_bb
= split_edge (ex
);
2032 then_bb
= create_empty_bb (new_bb
);
2033 if (current_loops
&& new_bb
->loop_father
)
2034 add_bb_to_loop (then_bb
, new_bb
->loop_father
);
2036 gsi
= gsi_start_bb (new_bb
);
2037 stmt
= gimple_build_cond (NE_EXPR
, flag
, boolean_false_node
,
2038 NULL_TREE
, NULL_TREE
);
2039 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2041 gsi
= gsi_start_bb (then_bb
);
2042 /* Insert actual store. */
2043 stmt
= gimple_build_assign (unshare_expr (mem
), tmp_var
);
2044 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2046 make_edge (new_bb
, then_bb
, EDGE_TRUE_VALUE
);
2047 make_edge (new_bb
, old_dest
, EDGE_FALSE_VALUE
);
2048 then_old_edge
= make_edge (then_bb
, old_dest
, EDGE_FALLTHRU
);
2050 set_immediate_dominator (CDI_DOMINATORS
, then_bb
, new_bb
);
2054 basic_block prevbb
= prev_edges
->last_cond_fallthru
->src
;
2055 redirect_edge_succ (prev_edges
->last_cond_fallthru
, new_bb
);
2056 set_immediate_dominator (CDI_DOMINATORS
, new_bb
, prevbb
);
2057 set_immediate_dominator (CDI_DOMINATORS
, old_dest
,
2058 recompute_dominator (CDI_DOMINATORS
, old_dest
));
2061 /* ?? Because stores may alias, they must happen in the exact
2062 sequence they originally happened. Save the position right after
2063 the (_lsm) store we just created so we can continue appending after
2064 it and maintain the original order. */
2066 struct prev_flag_edges
*p
;
2069 orig_ex
->aux
= NULL
;
2070 alloc_aux_for_edge (orig_ex
, sizeof (struct prev_flag_edges
));
2071 p
= (struct prev_flag_edges
*) orig_ex
->aux
;
2072 p
->append_cond_position
= then_old_edge
;
2073 p
->last_cond_fallthru
= find_edge (new_bb
, old_dest
);
2074 orig_ex
->aux
= (void *) p
;
2077 if (!loop_has_only_one_exit
)
2078 for (gsi
= gsi_start_phis (old_dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2080 gimple phi
= gsi_stmt (gsi
);
2083 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
2084 if (gimple_phi_arg_edge (phi
, i
)->src
== new_bb
)
2086 tree arg
= gimple_phi_arg_def (phi
, i
);
2087 add_phi_arg (phi
, arg
, then_old_edge
, UNKNOWN_LOCATION
);
2091 /* Remove the original fall through edge. This was the
2092 single_succ_edge (new_bb). */
2093 EDGE_SUCC (new_bb
, 0)->flags
&= ~EDGE_FALLTHRU
;
2096 /* Helper function for execute_sm. On every location where REF is
2097 set, set an appropriate flag indicating the store. */
2100 execute_sm_if_changed_flag_set (struct loop
*loop
, mem_ref_p ref
)
2105 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
2106 char *str
= get_lsm_tmp_name (ref
->mem
, ~0);
2108 lsm_tmp_name_add ("_flag");
2109 flag
= create_tmp_reg (boolean_type_node
, str
);
2110 get_all_locs_in_loop (loop
, ref
, &locs
);
2111 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
2113 gimple_stmt_iterator gsi
;
2116 /* Only set the flag for writes. */
2117 if (is_gimple_assign (loc
->stmt
)
2118 && gimple_assign_lhs_ptr (loc
->stmt
) == loc
->ref
)
2120 gsi
= gsi_for_stmt (loc
->stmt
);
2121 stmt
= gimple_build_assign (flag
, boolean_true_node
);
2122 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2125 VEC_free (mem_ref_loc_p
, heap
, locs
);
2129 /* Executes store motion of memory reference REF from LOOP.
2130 Exits from the LOOP are stored in EXITS. The initialization of the
2131 temporary variable is put to the preheader of the loop, and assignments
2132 to the reference from the temporary variable are emitted to exits. */
2135 execute_sm (struct loop
*loop
, VEC (edge
, heap
) *exits
, mem_ref_p ref
)
2137 tree tmp_var
, store_flag
;
2140 struct fmt_data fmt_data
;
2141 edge ex
, latch_edge
;
2142 struct lim_aux_data
*lim_data
;
2143 bool multi_threaded_model_p
= false;
2145 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2147 fprintf (dump_file
, "Executing store motion of ");
2148 print_generic_expr (dump_file
, ref
->mem
, 0);
2149 fprintf (dump_file
, " from loop %d\n", loop
->num
);
2152 tmp_var
= create_tmp_reg (TREE_TYPE (ref
->mem
),
2153 get_lsm_tmp_name (ref
->mem
, ~0));
2155 fmt_data
.loop
= loop
;
2156 fmt_data
.orig_loop
= loop
;
2157 for_each_index (&ref
->mem
, force_move_till
, &fmt_data
);
2159 if (block_in_transaction (loop_preheader_edge (loop
)->src
)
2160 || !PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES
))
2161 multi_threaded_model_p
= true;
2163 if (multi_threaded_model_p
)
2164 store_flag
= execute_sm_if_changed_flag_set (loop
, ref
);
2166 rewrite_mem_refs (loop
, ref
, tmp_var
);
2168 /* Emit the load code into the latch, so that we are sure it will
2169 be processed after all dependencies. */
2170 latch_edge
= loop_latch_edge (loop
);
2172 /* FIXME/TODO: For the multi-threaded variant, we could avoid this
2173 load altogether, since the store is predicated by a flag. We
2174 could, do the load only if it was originally in the loop. */
2175 load
= gimple_build_assign (tmp_var
, unshare_expr (ref
->mem
));
2176 lim_data
= init_lim_data (load
);
2177 lim_data
->max_loop
= loop
;
2178 lim_data
->tgt_loop
= loop
;
2179 gsi_insert_on_edge (latch_edge
, load
);
2181 if (multi_threaded_model_p
)
2183 load
= gimple_build_assign (store_flag
, boolean_false_node
);
2184 lim_data
= init_lim_data (load
);
2185 lim_data
->max_loop
= loop
;
2186 lim_data
->tgt_loop
= loop
;
2187 gsi_insert_on_edge (latch_edge
, load
);
2190 /* Sink the store to every exit from the loop. */
2191 FOR_EACH_VEC_ELT (edge
, exits
, i
, ex
)
2192 if (!multi_threaded_model_p
)
2195 store
= gimple_build_assign (unshare_expr (ref
->mem
), tmp_var
);
2196 gsi_insert_on_edge (ex
, store
);
2199 execute_sm_if_changed (ex
, ref
->mem
, tmp_var
, store_flag
);
2202 /* Hoists memory references MEM_REFS out of LOOP. EXITS is the list of exit
2203 edges of the LOOP. */
2206 hoist_memory_references (struct loop
*loop
, bitmap mem_refs
,
2207 VEC (edge
, heap
) *exits
)
2213 EXECUTE_IF_SET_IN_BITMAP (mem_refs
, 0, i
, bi
)
2215 ref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
2216 execute_sm (loop
, exits
, ref
);
2220 /* Returns true if REF is always accessed in LOOP. If STORED_P is true
2221 make sure REF is always stored to in LOOP. */
2224 ref_always_accessed_p (struct loop
*loop
, mem_ref_p ref
, bool stored_p
)
2226 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
2230 struct loop
*must_exec
;
2233 base
= get_base_address (ref
->mem
);
2234 if (INDIRECT_REF_P (base
)
2235 || TREE_CODE (base
) == MEM_REF
)
2236 base
= TREE_OPERAND (base
, 0);
2238 get_all_locs_in_loop (loop
, ref
, &locs
);
2239 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
2241 if (!get_lim_data (loc
->stmt
))
2244 /* If we require an always executed store make sure the statement
2245 stores to the reference. */
2249 if (!gimple_get_lhs (loc
->stmt
))
2251 lhs
= get_base_address (gimple_get_lhs (loc
->stmt
));
2254 if (INDIRECT_REF_P (lhs
)
2255 || TREE_CODE (lhs
) == MEM_REF
)
2256 lhs
= TREE_OPERAND (lhs
, 0);
2261 must_exec
= get_lim_data (loc
->stmt
)->always_executed_in
;
2265 if (must_exec
== loop
2266 || flow_loop_nested_p (must_exec
, loop
))
2272 VEC_free (mem_ref_loc_p
, heap
, locs
);
2277 /* Returns true if REF1 and REF2 are independent. */
2280 refs_independent_p (mem_ref_p ref1
, mem_ref_p ref2
)
2283 || bitmap_bit_p (ref1
->indep_ref
, ref2
->id
))
2285 if (bitmap_bit_p (ref1
->dep_ref
, ref2
->id
))
2287 if (!MEM_ANALYZABLE (ref1
)
2288 || !MEM_ANALYZABLE (ref2
))
2291 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2292 fprintf (dump_file
, "Querying dependency of refs %u and %u: ",
2293 ref1
->id
, ref2
->id
);
2295 if (mem_refs_may_alias_p (ref1
->mem
, ref2
->mem
,
2296 &memory_accesses
.ttae_cache
))
2298 bitmap_set_bit (ref1
->dep_ref
, ref2
->id
);
2299 bitmap_set_bit (ref2
->dep_ref
, ref1
->id
);
2300 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2301 fprintf (dump_file
, "dependent.\n");
2306 bitmap_set_bit (ref1
->indep_ref
, ref2
->id
);
2307 bitmap_set_bit (ref2
->indep_ref
, ref1
->id
);
2308 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2309 fprintf (dump_file
, "independent.\n");
2314 /* Records the information whether REF is independent in LOOP (according
2318 record_indep_loop (struct loop
*loop
, mem_ref_p ref
, bool indep
)
2321 bitmap_set_bit (ref
->indep_loop
, loop
->num
);
2323 bitmap_set_bit (ref
->dep_loop
, loop
->num
);
2326 /* Returns true if REF is independent on all other memory references in
2330 ref_indep_loop_p_1 (struct loop
*loop
, mem_ref_p ref
)
2332 bitmap refs_to_check
;
2335 bool ret
= true, stored
= bitmap_bit_p (ref
->stored
, loop
->num
);
2339 refs_to_check
= VEC_index (bitmap
,
2340 memory_accesses
.all_refs_in_loop
, loop
->num
);
2342 refs_to_check
= VEC_index (bitmap
,
2343 memory_accesses
.all_refs_stored_in_loop
,
2346 EXECUTE_IF_SET_IN_BITMAP (refs_to_check
, 0, i
, bi
)
2348 aref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
2349 if (!MEM_ANALYZABLE (aref
)
2350 || !refs_independent_p (ref
, aref
))
2353 record_indep_loop (loop
, aref
, false);
2361 /* Returns true if REF is independent on all other memory references in
2362 LOOP. Wrapper over ref_indep_loop_p_1, caching its results. */
2365 ref_indep_loop_p (struct loop
*loop
, mem_ref_p ref
)
2369 if (bitmap_bit_p (ref
->indep_loop
, loop
->num
))
2371 if (bitmap_bit_p (ref
->dep_loop
, loop
->num
))
2374 ret
= ref_indep_loop_p_1 (loop
, ref
);
2376 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2377 fprintf (dump_file
, "Querying dependencies of ref %u in loop %d: %s\n",
2378 ref
->id
, loop
->num
, ret
? "independent" : "dependent");
2380 record_indep_loop (loop
, ref
, ret
);
2385 /* Returns true if we can perform store motion of REF from LOOP. */
2388 can_sm_ref_p (struct loop
*loop
, mem_ref_p ref
)
2392 /* Can't hoist unanalyzable refs. */
2393 if (!MEM_ANALYZABLE (ref
))
2396 /* Unless the reference is stored in the loop, there is nothing to do. */
2397 if (!bitmap_bit_p (ref
->stored
, loop
->num
))
2400 /* It should be movable. */
2401 if (!is_gimple_reg_type (TREE_TYPE (ref
->mem
))
2402 || TREE_THIS_VOLATILE (ref
->mem
)
2403 || !for_each_index (&ref
->mem
, may_move_till
, loop
))
2406 /* If it can throw fail, we do not properly update EH info. */
2407 if (tree_could_throw_p (ref
->mem
))
2410 /* If it can trap, it must be always executed in LOOP.
2411 Readonly memory locations may trap when storing to them, but
2412 tree_could_trap_p is a predicate for rvalues, so check that
2414 base
= get_base_address (ref
->mem
);
2415 if ((tree_could_trap_p (ref
->mem
)
2416 || (DECL_P (base
) && TREE_READONLY (base
)))
2417 && !ref_always_accessed_p (loop
, ref
, true))
2420 /* And it must be independent on all other memory references
2422 if (!ref_indep_loop_p (loop
, ref
))
2428 /* Marks the references in LOOP for that store motion should be performed
2429 in REFS_TO_SM. SM_EXECUTED is the set of references for that store
2430 motion was performed in one of the outer loops. */
2433 find_refs_for_sm (struct loop
*loop
, bitmap sm_executed
, bitmap refs_to_sm
)
2435 bitmap refs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
2441 EXECUTE_IF_AND_COMPL_IN_BITMAP (refs
, sm_executed
, 0, i
, bi
)
2443 ref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
2444 if (can_sm_ref_p (loop
, ref
))
2445 bitmap_set_bit (refs_to_sm
, i
);
2449 /* Checks whether LOOP (with exits stored in EXITS array) is suitable
2450 for a store motion optimization (i.e. whether we can insert statement
2454 loop_suitable_for_sm (struct loop
*loop ATTRIBUTE_UNUSED
,
2455 VEC (edge
, heap
) *exits
)
2460 FOR_EACH_VEC_ELT (edge
, exits
, i
, ex
)
2461 if (ex
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
2467 /* Try to perform store motion for all memory references modified inside
2468 LOOP. SM_EXECUTED is the bitmap of the memory references for that
2469 store motion was executed in one of the outer loops. */
2472 store_motion_loop (struct loop
*loop
, bitmap sm_executed
)
2474 VEC (edge
, heap
) *exits
= get_loop_exit_edges (loop
);
2475 struct loop
*subloop
;
2476 bitmap sm_in_loop
= BITMAP_ALLOC (NULL
);
2478 if (loop_suitable_for_sm (loop
, exits
))
2480 find_refs_for_sm (loop
, sm_executed
, sm_in_loop
);
2481 hoist_memory_references (loop
, sm_in_loop
, exits
);
2483 VEC_free (edge
, heap
, exits
);
2485 bitmap_ior_into (sm_executed
, sm_in_loop
);
2486 for (subloop
= loop
->inner
; subloop
!= NULL
; subloop
= subloop
->next
)
2487 store_motion_loop (subloop
, sm_executed
);
2488 bitmap_and_compl_into (sm_executed
, sm_in_loop
);
2489 BITMAP_FREE (sm_in_loop
);
2492 /* Try to perform store motion for all memory references modified inside
2499 bitmap sm_executed
= BITMAP_ALLOC (NULL
);
2501 for (loop
= current_loops
->tree_root
->inner
; loop
!= NULL
; loop
= loop
->next
)
2502 store_motion_loop (loop
, sm_executed
);
2504 BITMAP_FREE (sm_executed
);
2505 gsi_commit_edge_inserts ();
2508 /* Fills ALWAYS_EXECUTED_IN information for basic blocks of LOOP, i.e.
2509 for each such basic block bb records the outermost loop for that execution
2510 of its header implies execution of bb. CONTAINS_CALL is the bitmap of
2511 blocks that contain a nonpure call. */
2514 fill_always_executed_in (struct loop
*loop
, sbitmap contains_call
)
2516 basic_block bb
= NULL
, *bbs
, last
= NULL
;
2519 struct loop
*inn_loop
= loop
;
2521 if (ALWAYS_EXECUTED_IN (loop
->header
) == NULL
)
2523 bbs
= get_loop_body_in_dom_order (loop
);
2525 for (i
= 0; i
< loop
->num_nodes
; i
++)
2530 if (dominated_by_p (CDI_DOMINATORS
, loop
->latch
, bb
))
2533 if (TEST_BIT (contains_call
, bb
->index
))
2536 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2537 if (!flow_bb_inside_loop_p (loop
, e
->dest
))
2542 /* A loop might be infinite (TODO use simple loop analysis
2543 to disprove this if possible). */
2544 if (bb
->flags
& BB_IRREDUCIBLE_LOOP
)
2547 if (!flow_bb_inside_loop_p (inn_loop
, bb
))
2550 if (bb
->loop_father
->header
== bb
)
2552 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, bb
))
2555 /* In a loop that is always entered we may proceed anyway.
2556 But record that we entered it and stop once we leave it. */
2557 inn_loop
= bb
->loop_father
;
2563 SET_ALWAYS_EXECUTED_IN (last
, loop
);
2564 if (last
== loop
->header
)
2566 last
= get_immediate_dominator (CDI_DOMINATORS
, last
);
2572 for (loop
= loop
->inner
; loop
; loop
= loop
->next
)
2573 fill_always_executed_in (loop
, contains_call
);
2576 /* Compute the global information needed by the loop invariant motion pass. */
2579 tree_ssa_lim_initialize (void)
2581 sbitmap contains_call
= sbitmap_alloc (last_basic_block
);
2582 gimple_stmt_iterator bsi
;
2586 bitmap_obstack_initialize (&lim_bitmap_obstack
);
2588 sbitmap_zero (contains_call
);
2591 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
2593 if (nonpure_call_p (gsi_stmt (bsi
)))
2597 if (!gsi_end_p (bsi
))
2598 SET_BIT (contains_call
, bb
->index
);
2601 for (loop
= current_loops
->tree_root
->inner
; loop
; loop
= loop
->next
)
2602 fill_always_executed_in (loop
, contains_call
);
2604 sbitmap_free (contains_call
);
2606 lim_aux_data_map
= pointer_map_create ();
2609 compute_transaction_bits ();
2611 alloc_aux_for_edges (0);
2614 /* Cleans up after the invariant motion pass. */
2617 tree_ssa_lim_finalize (void)
2623 free_aux_for_edges ();
2626 SET_ALWAYS_EXECUTED_IN (bb
, NULL
);
2628 bitmap_obstack_release (&lim_bitmap_obstack
);
2629 pointer_map_destroy (lim_aux_data_map
);
2631 htab_delete (memory_accesses
.refs
);
2633 FOR_EACH_VEC_ELT (mem_ref_p
, memory_accesses
.refs_list
, i
, ref
)
2635 VEC_free (mem_ref_p
, heap
, memory_accesses
.refs_list
);
2637 VEC_free (bitmap
, heap
, memory_accesses
.refs_in_loop
);
2638 VEC_free (bitmap
, heap
, memory_accesses
.all_refs_in_loop
);
2639 VEC_free (bitmap
, heap
, memory_accesses
.all_refs_stored_in_loop
);
2641 if (memory_accesses
.ttae_cache
)
2642 free_affine_expand_cache (&memory_accesses
.ttae_cache
);
2645 /* Moves invariants from loops. Only "expensive" invariants are moved out --
2646 i.e. those that are likely to be win regardless of the register pressure. */
2653 tree_ssa_lim_initialize ();
2655 /* Gathers information about memory accesses in the loops. */
2656 analyze_memory_references ();
2658 /* For each statement determine the outermost loop in that it is
2659 invariant and cost for computing the invariant. */
2660 determine_invariantness ();
2662 /* Execute store motion. Force the necessary invariants to be moved
2663 out of the loops as well. */
2666 /* Move the expressions that are expensive enough. */
2667 todo
= move_computations ();
2669 tree_ssa_lim_finalize ();