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 static bool ref_indep_loop_p (struct loop
*, mem_ref_p
);
188 /* Minimum cost of an expensive expression. */
189 #define LIM_EXPENSIVE ((unsigned) PARAM_VALUE (PARAM_LIM_EXPENSIVE))
191 /* The outermost loop for which execution of the header guarantees that the
192 block will be executed. */
193 #define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux)
194 #define SET_ALWAYS_EXECUTED_IN(BB, VAL) ((BB)->aux = (void *) (VAL))
196 /* Whether the reference was analyzable. */
197 #define MEM_ANALYZABLE(REF) ((REF)->mem != error_mark_node)
199 static struct lim_aux_data
*
200 init_lim_data (gimple stmt
)
202 void **p
= pointer_map_insert (lim_aux_data_map
, stmt
);
204 *p
= XCNEW (struct lim_aux_data
);
205 return (struct lim_aux_data
*) *p
;
208 static struct lim_aux_data
*
209 get_lim_data (gimple stmt
)
211 void **p
= pointer_map_contains (lim_aux_data_map
, stmt
);
215 return (struct lim_aux_data
*) *p
;
218 /* Releases the memory occupied by DATA. */
221 free_lim_aux_data (struct lim_aux_data
*data
)
223 struct depend
*dep
, *next
;
225 for (dep
= data
->depends
; dep
; dep
= next
)
234 clear_lim_data (gimple stmt
)
236 void **p
= pointer_map_contains (lim_aux_data_map
, stmt
);
240 free_lim_aux_data ((struct lim_aux_data
*) *p
);
244 /* Calls CBCK for each index in memory reference ADDR_P. There are two
245 kinds situations handled; in each of these cases, the memory reference
246 and DATA are passed to the callback:
248 Access to an array: ARRAY_{RANGE_}REF (base, index). In this case we also
249 pass the pointer to the index to the callback.
251 Pointer dereference: INDIRECT_REF (addr). In this case we also pass the
252 pointer to addr to the callback.
254 If the callback returns false, the whole search stops and false is returned.
255 Otherwise the function returns true after traversing through the whole
256 reference *ADDR_P. */
259 for_each_index (tree
*addr_p
, bool (*cbck
) (tree
, tree
*, void *), void *data
)
263 for (; ; addr_p
= nxt
)
265 switch (TREE_CODE (*addr_p
))
268 return cbck (*addr_p
, addr_p
, data
);
271 nxt
= &TREE_OPERAND (*addr_p
, 0);
272 return cbck (*addr_p
, nxt
, data
);
275 case VIEW_CONVERT_EXPR
:
278 nxt
= &TREE_OPERAND (*addr_p
, 0);
282 /* If the component has varying offset, it behaves like index
284 idx
= &TREE_OPERAND (*addr_p
, 2);
286 && !cbck (*addr_p
, idx
, data
))
289 nxt
= &TREE_OPERAND (*addr_p
, 0);
293 case ARRAY_RANGE_REF
:
294 nxt
= &TREE_OPERAND (*addr_p
, 0);
295 if (!cbck (*addr_p
, &TREE_OPERAND (*addr_p
, 1), data
))
312 gcc_assert (is_gimple_min_invariant (*addr_p
));
316 idx
= &TMR_BASE (*addr_p
);
318 && !cbck (*addr_p
, idx
, data
))
320 idx
= &TMR_INDEX (*addr_p
);
322 && !cbck (*addr_p
, idx
, data
))
324 idx
= &TMR_INDEX2 (*addr_p
);
326 && !cbck (*addr_p
, idx
, data
))
336 /* If it is possible to hoist the statement STMT unconditionally,
337 returns MOVE_POSSIBLE.
338 If it is possible to hoist the statement STMT, but we must avoid making
339 it executed if it would not be executed in the original program (e.g.
340 because it may trap), return MOVE_PRESERVE_EXECUTION.
341 Otherwise return MOVE_IMPOSSIBLE. */
344 movement_possibility (gimple stmt
)
347 enum move_pos ret
= MOVE_POSSIBLE
;
349 if (flag_unswitch_loops
350 && gimple_code (stmt
) == GIMPLE_COND
)
352 /* If we perform unswitching, force the operands of the invariant
353 condition to be moved out of the loop. */
354 return MOVE_POSSIBLE
;
357 if (gimple_code (stmt
) == GIMPLE_PHI
358 && gimple_phi_num_args (stmt
) <= 2
359 && is_gimple_reg (gimple_phi_result (stmt
))
360 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_phi_result (stmt
)))
361 return MOVE_POSSIBLE
;
363 if (gimple_get_lhs (stmt
) == NULL_TREE
)
364 return MOVE_IMPOSSIBLE
;
366 if (gimple_vdef (stmt
))
367 return MOVE_IMPOSSIBLE
;
369 if (stmt_ends_bb_p (stmt
)
370 || gimple_has_volatile_ops (stmt
)
371 || gimple_has_side_effects (stmt
)
372 || stmt_could_throw_p (stmt
))
373 return MOVE_IMPOSSIBLE
;
375 if (is_gimple_call (stmt
))
377 /* While pure or const call is guaranteed to have no side effects, we
378 cannot move it arbitrarily. Consider code like
380 char *s = something ();
390 Here the strlen call cannot be moved out of the loop, even though
391 s is invariant. In addition to possibly creating a call with
392 invalid arguments, moving out a function call that is not executed
393 may cause performance regressions in case the call is costly and
394 not executed at all. */
395 ret
= MOVE_PRESERVE_EXECUTION
;
396 lhs
= gimple_call_lhs (stmt
);
398 else if (is_gimple_assign (stmt
))
399 lhs
= gimple_assign_lhs (stmt
);
401 return MOVE_IMPOSSIBLE
;
403 if (TREE_CODE (lhs
) == SSA_NAME
404 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
405 return MOVE_IMPOSSIBLE
;
407 if (TREE_CODE (lhs
) != SSA_NAME
408 || gimple_could_trap_p (stmt
))
409 return MOVE_PRESERVE_EXECUTION
;
411 /* Non local loads in a transaction cannot be hoisted out. Well,
412 unless the load happens on every path out of the loop, but we
413 don't take this into account yet. */
415 && gimple_in_transaction (stmt
)
416 && gimple_assign_single_p (stmt
))
418 tree rhs
= gimple_assign_rhs1 (stmt
);
419 if (DECL_P (rhs
) && is_global_var (rhs
))
423 fprintf (dump_file
, "Cannot hoist conditional load of ");
424 print_generic_expr (dump_file
, rhs
, TDF_SLIM
);
425 fprintf (dump_file
, " because it is in a transaction.\n");
427 return MOVE_IMPOSSIBLE
;
434 /* Suppose that operand DEF is used inside the LOOP. Returns the outermost
435 loop to that we could move the expression using DEF if it did not have
436 other operands, i.e. the outermost loop enclosing LOOP in that the value
437 of DEF is invariant. */
440 outermost_invariant_loop (tree def
, struct loop
*loop
)
444 struct loop
*max_loop
;
445 struct lim_aux_data
*lim_data
;
448 return superloop_at_depth (loop
, 1);
450 if (TREE_CODE (def
) != SSA_NAME
)
452 gcc_assert (is_gimple_min_invariant (def
));
453 return superloop_at_depth (loop
, 1);
456 def_stmt
= SSA_NAME_DEF_STMT (def
);
457 def_bb
= gimple_bb (def_stmt
);
459 return superloop_at_depth (loop
, 1);
461 max_loop
= find_common_loop (loop
, def_bb
->loop_father
);
463 lim_data
= get_lim_data (def_stmt
);
464 if (lim_data
!= NULL
&& lim_data
->max_loop
!= NULL
)
465 max_loop
= find_common_loop (max_loop
,
466 loop_outer (lim_data
->max_loop
));
467 if (max_loop
== loop
)
469 max_loop
= superloop_at_depth (loop
, loop_depth (max_loop
) + 1);
474 /* DATA is a structure containing information associated with a statement
475 inside LOOP. DEF is one of the operands of this statement.
477 Find the outermost loop enclosing LOOP in that value of DEF is invariant
478 and record this in DATA->max_loop field. If DEF itself is defined inside
479 this loop as well (i.e. we need to hoist it out of the loop if we want
480 to hoist the statement represented by DATA), record the statement in that
481 DEF is defined to the DATA->depends list. Additionally if ADD_COST is true,
482 add the cost of the computation of DEF to the DATA->cost.
484 If DEF is not invariant in LOOP, return false. Otherwise return TRUE. */
487 add_dependency (tree def
, struct lim_aux_data
*data
, struct loop
*loop
,
490 gimple def_stmt
= SSA_NAME_DEF_STMT (def
);
491 basic_block def_bb
= gimple_bb (def_stmt
);
492 struct loop
*max_loop
;
494 struct lim_aux_data
*def_data
;
499 max_loop
= outermost_invariant_loop (def
, loop
);
503 if (flow_loop_nested_p (data
->max_loop
, max_loop
))
504 data
->max_loop
= max_loop
;
506 def_data
= get_lim_data (def_stmt
);
511 /* Only add the cost if the statement defining DEF is inside LOOP,
512 i.e. if it is likely that by moving the invariants dependent
513 on it, we will be able to avoid creating a new register for
514 it (since it will be only used in these dependent invariants). */
515 && def_bb
->loop_father
== loop
)
516 data
->cost
+= def_data
->cost
;
518 dep
= XNEW (struct depend
);
519 dep
->stmt
= def_stmt
;
520 dep
->next
= data
->depends
;
526 /* Returns an estimate for a cost of statement STMT. The values here
527 are just ad-hoc constants, similar to costs for inlining. */
530 stmt_cost (gimple stmt
)
532 /* Always try to create possibilities for unswitching. */
533 if (gimple_code (stmt
) == GIMPLE_COND
534 || gimple_code (stmt
) == GIMPLE_PHI
)
535 return LIM_EXPENSIVE
;
537 /* We should be hoisting calls if possible. */
538 if (is_gimple_call (stmt
))
542 /* Unless the call is a builtin_constant_p; this always folds to a
543 constant, so moving it is useless. */
544 fndecl
= gimple_call_fndecl (stmt
);
546 && DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
547 && DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_CONSTANT_P
)
550 return LIM_EXPENSIVE
;
553 /* Hoisting memory references out should almost surely be a win. */
554 if (gimple_references_memory_p (stmt
))
555 return LIM_EXPENSIVE
;
557 if (gimple_code (stmt
) != GIMPLE_ASSIGN
)
560 switch (gimple_assign_rhs_code (stmt
))
563 case WIDEN_MULT_EXPR
:
564 case WIDEN_MULT_PLUS_EXPR
:
565 case WIDEN_MULT_MINUS_EXPR
:
578 /* Division and multiplication are usually expensive. */
579 return LIM_EXPENSIVE
;
583 case WIDEN_LSHIFT_EXPR
:
586 /* Shifts and rotates are usually expensive. */
587 return LIM_EXPENSIVE
;
590 /* Make vector construction cost proportional to the number
592 return CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt
));
596 /* Whether or not something is wrapped inside a PAREN_EXPR
597 should not change move cost. Nor should an intermediate
598 unpropagated SSA name copy. */
606 /* Finds the outermost loop between OUTER and LOOP in that the memory reference
607 REF is independent. If REF is not independent in LOOP, NULL is returned
611 outermost_indep_loop (struct loop
*outer
, struct loop
*loop
, mem_ref_p ref
)
615 if (bitmap_bit_p (ref
->stored
, loop
->num
))
620 aloop
= superloop_at_depth (loop
, loop_depth (aloop
) + 1))
621 if (!bitmap_bit_p (ref
->stored
, aloop
->num
)
622 && ref_indep_loop_p (aloop
, ref
))
625 if (ref_indep_loop_p (loop
, ref
))
631 /* If there is a simple load or store to a memory reference in STMT, returns
632 the location of the memory reference, and sets IS_STORE according to whether
633 it is a store or load. Otherwise, returns NULL. */
636 simple_mem_ref_in_stmt (gimple stmt
, bool *is_store
)
641 /* Recognize MEM = (SSA_NAME | invariant) and SSA_NAME = MEM patterns. */
642 if (gimple_code (stmt
) != GIMPLE_ASSIGN
)
645 code
= gimple_assign_rhs_code (stmt
);
647 lhs
= gimple_assign_lhs_ptr (stmt
);
649 if (TREE_CODE (*lhs
) == SSA_NAME
)
651 if (get_gimple_rhs_class (code
) != GIMPLE_SINGLE_RHS
652 || !is_gimple_addressable (gimple_assign_rhs1 (stmt
)))
656 return gimple_assign_rhs1_ptr (stmt
);
658 else if (code
== SSA_NAME
659 || (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
660 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
))))
669 /* Returns the memory reference contained in STMT. */
672 mem_ref_in_stmt (gimple stmt
)
675 tree
*mem
= simple_mem_ref_in_stmt (stmt
, &store
);
683 hash
= iterative_hash_expr (*mem
, 0);
684 ref
= (mem_ref_p
) htab_find_with_hash (memory_accesses
.refs
, *mem
, hash
);
686 gcc_assert (ref
!= NULL
);
690 /* From a controlling predicate in DOM determine the arguments from
691 the PHI node PHI that are chosen if the predicate evaluates to
692 true and false and store them to *TRUE_ARG_P and *FALSE_ARG_P if
693 they are non-NULL. Returns true if the arguments can be determined,
694 else return false. */
697 extract_true_false_args_from_phi (basic_block dom
, gimple phi
,
698 tree
*true_arg_p
, tree
*false_arg_p
)
700 basic_block bb
= gimple_bb (phi
);
701 edge true_edge
, false_edge
, tem
;
702 tree arg0
= NULL_TREE
, arg1
= NULL_TREE
;
704 /* We have to verify that one edge into the PHI node is dominated
705 by the true edge of the predicate block and the other edge
706 dominated by the false edge. This ensures that the PHI argument
707 we are going to take is completely determined by the path we
708 take from the predicate block.
709 We can only use BB dominance checks below if the destination of
710 the true/false edges are dominated by their edge, thus only
711 have a single predecessor. */
712 extract_true_false_edges_from_block (dom
, &true_edge
, &false_edge
);
713 tem
= EDGE_PRED (bb
, 0);
715 || (single_pred_p (true_edge
->dest
)
716 && (tem
->src
== true_edge
->dest
717 || dominated_by_p (CDI_DOMINATORS
,
718 tem
->src
, true_edge
->dest
))))
719 arg0
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
720 else if (tem
== false_edge
721 || (single_pred_p (false_edge
->dest
)
722 && (tem
->src
== false_edge
->dest
723 || dominated_by_p (CDI_DOMINATORS
,
724 tem
->src
, false_edge
->dest
))))
725 arg1
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
728 tem
= EDGE_PRED (bb
, 1);
730 || (single_pred_p (true_edge
->dest
)
731 && (tem
->src
== true_edge
->dest
732 || dominated_by_p (CDI_DOMINATORS
,
733 tem
->src
, true_edge
->dest
))))
734 arg0
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
735 else if (tem
== false_edge
736 || (single_pred_p (false_edge
->dest
)
737 && (tem
->src
== false_edge
->dest
738 || dominated_by_p (CDI_DOMINATORS
,
739 tem
->src
, false_edge
->dest
))))
740 arg1
= PHI_ARG_DEF (phi
, tem
->dest_idx
);
754 /* Determine the outermost loop to that it is possible to hoist a statement
755 STMT and store it to LIM_DATA (STMT)->max_loop. To do this we determine
756 the outermost loop in that the value computed by STMT is invariant.
757 If MUST_PRESERVE_EXEC is true, additionally choose such a loop that
758 we preserve the fact whether STMT is executed. It also fills other related
759 information to LIM_DATA (STMT).
761 The function returns false if STMT cannot be hoisted outside of the loop it
762 is defined in, and true otherwise. */
765 determine_max_movement (gimple stmt
, bool must_preserve_exec
)
767 basic_block bb
= gimple_bb (stmt
);
768 struct loop
*loop
= bb
->loop_father
;
770 struct lim_aux_data
*lim_data
= get_lim_data (stmt
);
774 if (must_preserve_exec
)
775 level
= ALWAYS_EXECUTED_IN (bb
);
777 level
= superloop_at_depth (loop
, 1);
778 lim_data
->max_loop
= level
;
780 if (gimple_code (stmt
) == GIMPLE_PHI
)
783 unsigned min_cost
= UINT_MAX
;
784 unsigned total_cost
= 0;
785 struct lim_aux_data
*def_data
;
787 /* We will end up promoting dependencies to be unconditionally
788 evaluated. For this reason the PHI cost (and thus the
789 cost we remove from the loop by doing the invariant motion)
790 is that of the cheapest PHI argument dependency chain. */
791 FOR_EACH_PHI_ARG (use_p
, stmt
, iter
, SSA_OP_USE
)
793 val
= USE_FROM_PTR (use_p
);
794 if (TREE_CODE (val
) != SSA_NAME
)
796 if (!add_dependency (val
, lim_data
, loop
, false))
798 def_data
= get_lim_data (SSA_NAME_DEF_STMT (val
));
801 min_cost
= MIN (min_cost
, def_data
->cost
);
802 total_cost
+= def_data
->cost
;
806 lim_data
->cost
+= min_cost
;
808 if (gimple_phi_num_args (stmt
) > 1)
810 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
812 if (gsi_end_p (gsi_last_bb (dom
)))
814 cond
= gsi_stmt (gsi_last_bb (dom
));
815 if (gimple_code (cond
) != GIMPLE_COND
)
817 /* Verify that this is an extended form of a diamond and
818 the PHI arguments are completely controlled by the
820 if (!extract_true_false_args_from_phi (dom
, stmt
, NULL
, NULL
))
823 /* Fold in dependencies and cost of the condition. */
824 FOR_EACH_SSA_TREE_OPERAND (val
, cond
, iter
, SSA_OP_USE
)
826 if (!add_dependency (val
, lim_data
, loop
, false))
828 def_data
= get_lim_data (SSA_NAME_DEF_STMT (val
));
830 total_cost
+= def_data
->cost
;
833 /* We want to avoid unconditionally executing very expensive
834 operations. As costs for our dependencies cannot be
835 negative just claim we are not invariand for this case.
836 We also are not sure whether the control-flow inside the
838 if (total_cost
- min_cost
>= 2 * LIM_EXPENSIVE
840 && total_cost
/ min_cost
<= 2))
843 /* Assume that the control-flow in the loop will vanish.
844 ??? We should verify this and not artificially increase
845 the cost if that is not the case. */
846 lim_data
->cost
+= stmt_cost (stmt
);
852 FOR_EACH_SSA_TREE_OPERAND (val
, stmt
, iter
, SSA_OP_USE
)
853 if (!add_dependency (val
, lim_data
, loop
, true))
856 if (gimple_vuse (stmt
))
858 mem_ref_p ref
= mem_ref_in_stmt (stmt
);
863 = outermost_indep_loop (lim_data
->max_loop
, loop
, ref
);
864 if (!lim_data
->max_loop
)
869 if ((val
= gimple_vuse (stmt
)) != NULL_TREE
)
871 if (!add_dependency (val
, lim_data
, loop
, false))
877 lim_data
->cost
+= stmt_cost (stmt
);
882 /* Suppose that some statement in ORIG_LOOP is hoisted to the loop LEVEL,
883 and that one of the operands of this statement is computed by STMT.
884 Ensure that STMT (together with all the statements that define its
885 operands) is hoisted at least out of the loop LEVEL. */
888 set_level (gimple stmt
, struct loop
*orig_loop
, struct loop
*level
)
890 struct loop
*stmt_loop
= gimple_bb (stmt
)->loop_father
;
892 struct lim_aux_data
*lim_data
;
894 stmt_loop
= find_common_loop (orig_loop
, stmt_loop
);
895 lim_data
= get_lim_data (stmt
);
896 if (lim_data
!= NULL
&& lim_data
->tgt_loop
!= NULL
)
897 stmt_loop
= find_common_loop (stmt_loop
,
898 loop_outer (lim_data
->tgt_loop
));
899 if (flow_loop_nested_p (stmt_loop
, level
))
902 gcc_assert (level
== lim_data
->max_loop
903 || flow_loop_nested_p (lim_data
->max_loop
, level
));
905 lim_data
->tgt_loop
= level
;
906 for (dep
= lim_data
->depends
; dep
; dep
= dep
->next
)
907 set_level (dep
->stmt
, orig_loop
, level
);
910 /* Determines an outermost loop from that we want to hoist the statement STMT.
911 For now we chose the outermost possible loop. TODO -- use profiling
912 information to set it more sanely. */
915 set_profitable_level (gimple stmt
)
917 set_level (stmt
, gimple_bb (stmt
)->loop_father
, get_lim_data (stmt
)->max_loop
);
920 /* Returns true if STMT is a call that has side effects. */
923 nonpure_call_p (gimple stmt
)
925 if (gimple_code (stmt
) != GIMPLE_CALL
)
928 return gimple_has_side_effects (stmt
);
931 /* Rewrite a/b to a*(1/b). Return the invariant stmt to process. */
934 rewrite_reciprocal (gimple_stmt_iterator
*bsi
)
936 gimple stmt
, stmt1
, stmt2
;
937 tree name
, lhs
, type
;
939 gimple_stmt_iterator gsi
;
941 stmt
= gsi_stmt (*bsi
);
942 lhs
= gimple_assign_lhs (stmt
);
943 type
= TREE_TYPE (lhs
);
945 real_one
= build_one_cst (type
);
947 name
= make_temp_ssa_name (type
, NULL
, "reciptmp");
948 stmt1
= gimple_build_assign_with_ops (RDIV_EXPR
, name
, real_one
,
949 gimple_assign_rhs2 (stmt
));
951 stmt2
= gimple_build_assign_with_ops (MULT_EXPR
, lhs
, name
,
952 gimple_assign_rhs1 (stmt
));
954 /* Replace division stmt with reciprocal and multiply stmts.
955 The multiply stmt is not invariant, so update iterator
956 and avoid rescanning. */
958 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
959 gsi_replace (&gsi
, stmt2
, true);
961 /* Continue processing with invariant reciprocal statement. */
965 /* Check if the pattern at *BSI is a bittest of the form
966 (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0. */
969 rewrite_bittest (gimple_stmt_iterator
*bsi
)
971 gimple stmt
, use_stmt
, stmt1
, stmt2
;
972 tree lhs
, name
, t
, a
, b
;
975 stmt
= gsi_stmt (*bsi
);
976 lhs
= gimple_assign_lhs (stmt
);
978 /* Verify that the single use of lhs is a comparison against zero. */
979 if (TREE_CODE (lhs
) != SSA_NAME
980 || !single_imm_use (lhs
, &use
, &use_stmt
)
981 || gimple_code (use_stmt
) != GIMPLE_COND
)
983 if (gimple_cond_lhs (use_stmt
) != lhs
984 || (gimple_cond_code (use_stmt
) != NE_EXPR
985 && gimple_cond_code (use_stmt
) != EQ_EXPR
)
986 || !integer_zerop (gimple_cond_rhs (use_stmt
)))
989 /* Get at the operands of the shift. The rhs is TMP1 & 1. */
990 stmt1
= SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt
));
991 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
994 /* There is a conversion in between possibly inserted by fold. */
995 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt1
)))
997 t
= gimple_assign_rhs1 (stmt1
);
998 if (TREE_CODE (t
) != SSA_NAME
999 || !has_single_use (t
))
1001 stmt1
= SSA_NAME_DEF_STMT (t
);
1002 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
1006 /* Verify that B is loop invariant but A is not. Verify that with
1007 all the stmt walking we are still in the same loop. */
1008 if (gimple_assign_rhs_code (stmt1
) != RSHIFT_EXPR
1009 || loop_containing_stmt (stmt1
) != loop_containing_stmt (stmt
))
1012 a
= gimple_assign_rhs1 (stmt1
);
1013 b
= gimple_assign_rhs2 (stmt1
);
1015 if (outermost_invariant_loop (b
, loop_containing_stmt (stmt1
)) != NULL
1016 && outermost_invariant_loop (a
, loop_containing_stmt (stmt1
)) == NULL
)
1018 gimple_stmt_iterator rsi
;
1021 t
= fold_build2 (LSHIFT_EXPR
, TREE_TYPE (a
),
1022 build_int_cst (TREE_TYPE (a
), 1), b
);
1023 name
= make_temp_ssa_name (TREE_TYPE (a
), NULL
, "shifttmp");
1024 stmt1
= gimple_build_assign (name
, t
);
1027 t
= fold_build2 (BIT_AND_EXPR
, TREE_TYPE (a
), a
, name
);
1028 name
= make_temp_ssa_name (TREE_TYPE (a
), NULL
, "shifttmp");
1029 stmt2
= gimple_build_assign (name
, t
);
1031 /* Replace the SSA_NAME we compare against zero. Adjust
1032 the type of zero accordingly. */
1033 SET_USE (use
, name
);
1034 gimple_cond_set_rhs (use_stmt
, build_int_cst_type (TREE_TYPE (name
), 0));
1036 /* Don't use gsi_replace here, none of the new assignments sets
1037 the variable originally set in stmt. Move bsi to stmt1, and
1038 then remove the original stmt, so that we get a chance to
1039 retain debug info for it. */
1041 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
1042 gsi_insert_before (&rsi
, stmt2
, GSI_SAME_STMT
);
1043 gsi_remove (&rsi
, true);
1052 /* Determine the outermost loops in that statements in basic block BB are
1053 invariant, and record them to the LIM_DATA associated with the statements.
1054 Callback for walk_dominator_tree. */
1057 determine_invariantness_stmt (struct dom_walk_data
*dw_data ATTRIBUTE_UNUSED
,
1061 gimple_stmt_iterator bsi
;
1063 bool maybe_never
= ALWAYS_EXECUTED_IN (bb
) == NULL
;
1064 struct loop
*outermost
= ALWAYS_EXECUTED_IN (bb
);
1065 struct lim_aux_data
*lim_data
;
1067 if (!loop_outer (bb
->loop_father
))
1070 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1071 fprintf (dump_file
, "Basic block %d (loop %d -- depth %d):\n\n",
1072 bb
->index
, bb
->loop_father
->num
, loop_depth (bb
->loop_father
));
1074 /* Look at PHI nodes, but only if there is at most two.
1075 ??? We could relax this further by post-processing the inserted
1076 code and transforming adjacent cond-exprs with the same predicate
1077 to control flow again. */
1078 bsi
= gsi_start_phis (bb
);
1079 if (!gsi_end_p (bsi
)
1080 && ((gsi_next (&bsi
), gsi_end_p (bsi
))
1081 || (gsi_next (&bsi
), gsi_end_p (bsi
))))
1082 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1084 stmt
= gsi_stmt (bsi
);
1086 pos
= movement_possibility (stmt
);
1087 if (pos
== MOVE_IMPOSSIBLE
)
1090 lim_data
= init_lim_data (stmt
);
1091 lim_data
->always_executed_in
= outermost
;
1093 if (!determine_max_movement (stmt
, false))
1095 lim_data
->max_loop
= NULL
;
1099 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1101 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1102 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1103 loop_depth (lim_data
->max_loop
),
1107 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1108 set_profitable_level (stmt
);
1111 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1113 stmt
= gsi_stmt (bsi
);
1115 pos
= movement_possibility (stmt
);
1116 if (pos
== MOVE_IMPOSSIBLE
)
1118 if (nonpure_call_p (stmt
))
1123 /* Make sure to note always_executed_in for stores to make
1124 store-motion work. */
1125 else if (stmt_makes_single_store (stmt
))
1127 struct lim_aux_data
*lim_data
= init_lim_data (stmt
);
1128 lim_data
->always_executed_in
= outermost
;
1133 if (is_gimple_assign (stmt
)
1134 && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt
))
1135 == GIMPLE_BINARY_RHS
))
1137 tree op0
= gimple_assign_rhs1 (stmt
);
1138 tree op1
= gimple_assign_rhs2 (stmt
);
1139 struct loop
*ol1
= outermost_invariant_loop (op1
,
1140 loop_containing_stmt (stmt
));
1142 /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal
1143 to be hoisted out of loop, saving expensive divide. */
1144 if (pos
== MOVE_POSSIBLE
1145 && gimple_assign_rhs_code (stmt
) == RDIV_EXPR
1146 && flag_unsafe_math_optimizations
1147 && !flag_trapping_math
1149 && outermost_invariant_loop (op0
, ol1
) == NULL
)
1150 stmt
= rewrite_reciprocal (&bsi
);
1152 /* If the shift count is invariant, convert (A >> B) & 1 to
1153 A & (1 << B) allowing the bit mask to be hoisted out of the loop
1154 saving an expensive shift. */
1155 if (pos
== MOVE_POSSIBLE
1156 && gimple_assign_rhs_code (stmt
) == BIT_AND_EXPR
1157 && integer_onep (op1
)
1158 && TREE_CODE (op0
) == SSA_NAME
1159 && has_single_use (op0
))
1160 stmt
= rewrite_bittest (&bsi
);
1163 lim_data
= init_lim_data (stmt
);
1164 lim_data
->always_executed_in
= outermost
;
1166 if (maybe_never
&& pos
== MOVE_PRESERVE_EXECUTION
)
1169 if (!determine_max_movement (stmt
, pos
== MOVE_PRESERVE_EXECUTION
))
1171 lim_data
->max_loop
= NULL
;
1175 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1177 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1178 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1179 loop_depth (lim_data
->max_loop
),
1183 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1184 set_profitable_level (stmt
);
1188 /* For each statement determines the outermost loop in that it is invariant,
1189 statements on whose motion it depends and the cost of the computation.
1190 This information is stored to the LIM_DATA structure associated with
1194 determine_invariantness (void)
1196 struct dom_walk_data walk_data
;
1198 memset (&walk_data
, 0, sizeof (struct dom_walk_data
));
1199 walk_data
.dom_direction
= CDI_DOMINATORS
;
1200 walk_data
.before_dom_children
= determine_invariantness_stmt
;
1202 init_walk_dominator_tree (&walk_data
);
1203 walk_dominator_tree (&walk_data
, ENTRY_BLOCK_PTR
);
1204 fini_walk_dominator_tree (&walk_data
);
1207 /* Hoist the statements in basic block BB out of the loops prescribed by
1208 data stored in LIM_DATA structures associated with each statement. Callback
1209 for walk_dominator_tree. */
1212 move_computations_stmt (struct dom_walk_data
*dw_data
,
1216 gimple_stmt_iterator bsi
;
1219 struct lim_aux_data
*lim_data
;
1221 if (!loop_outer (bb
->loop_father
))
1224 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); )
1227 stmt
= gsi_stmt (bsi
);
1229 lim_data
= get_lim_data (stmt
);
1230 if (lim_data
== NULL
)
1236 cost
= lim_data
->cost
;
1237 level
= lim_data
->tgt_loop
;
1238 clear_lim_data (stmt
);
1246 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1248 fprintf (dump_file
, "Moving PHI node\n");
1249 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1250 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1254 if (gimple_phi_num_args (stmt
) == 1)
1256 tree arg
= PHI_ARG_DEF (stmt
, 0);
1257 new_stmt
= gimple_build_assign_with_ops (TREE_CODE (arg
),
1258 gimple_phi_result (stmt
),
1260 SSA_NAME_DEF_STMT (gimple_phi_result (stmt
)) = new_stmt
;
1264 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
1265 gimple cond
= gsi_stmt (gsi_last_bb (dom
));
1266 tree arg0
= NULL_TREE
, arg1
= NULL_TREE
, t
;
1267 /* Get the PHI arguments corresponding to the true and false
1269 extract_true_false_args_from_phi (dom
, stmt
, &arg0
, &arg1
);
1270 gcc_assert (arg0
&& arg1
);
1271 t
= build2 (gimple_cond_code (cond
), boolean_type_node
,
1272 gimple_cond_lhs (cond
), gimple_cond_rhs (cond
));
1273 new_stmt
= gimple_build_assign_with_ops3 (COND_EXPR
,
1274 gimple_phi_result (stmt
),
1276 SSA_NAME_DEF_STMT (gimple_phi_result (stmt
)) = new_stmt
;
1277 *((unsigned int *)(dw_data
->global_data
)) |= TODO_cleanup_cfg
;
1279 gsi_insert_on_edge (loop_preheader_edge (level
), new_stmt
);
1280 remove_phi_node (&bsi
, false);
1283 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); )
1287 stmt
= gsi_stmt (bsi
);
1289 lim_data
= get_lim_data (stmt
);
1290 if (lim_data
== NULL
)
1296 cost
= lim_data
->cost
;
1297 level
= lim_data
->tgt_loop
;
1298 clear_lim_data (stmt
);
1306 /* We do not really want to move conditionals out of the loop; we just
1307 placed it here to force its operands to be moved if necessary. */
1308 if (gimple_code (stmt
) == GIMPLE_COND
)
1311 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1313 fprintf (dump_file
, "Moving statement\n");
1314 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1315 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1319 e
= loop_preheader_edge (level
);
1320 gcc_assert (!gimple_vdef (stmt
));
1321 if (gimple_vuse (stmt
))
1323 /* The new VUSE is the one from the virtual PHI in the loop
1324 header or the one already present. */
1325 gimple_stmt_iterator gsi2
;
1326 for (gsi2
= gsi_start_phis (e
->dest
);
1327 !gsi_end_p (gsi2
); gsi_next (&gsi2
))
1329 gimple phi
= gsi_stmt (gsi2
);
1330 if (!is_gimple_reg (gimple_phi_result (phi
)))
1332 gimple_set_vuse (stmt
, PHI_ARG_DEF_FROM_EDGE (phi
, e
));
1337 gsi_remove (&bsi
, false);
1338 gsi_insert_on_edge (e
, stmt
);
1342 /* Hoist the statements out of the loops prescribed by data stored in
1343 LIM_DATA structures associated with each statement.*/
1346 move_computations (void)
1348 struct dom_walk_data walk_data
;
1349 unsigned int todo
= 0;
1351 memset (&walk_data
, 0, sizeof (struct dom_walk_data
));
1352 walk_data
.global_data
= &todo
;
1353 walk_data
.dom_direction
= CDI_DOMINATORS
;
1354 walk_data
.before_dom_children
= move_computations_stmt
;
1356 init_walk_dominator_tree (&walk_data
);
1357 walk_dominator_tree (&walk_data
, ENTRY_BLOCK_PTR
);
1358 fini_walk_dominator_tree (&walk_data
);
1360 gsi_commit_edge_inserts ();
1361 if (need_ssa_update_p (cfun
))
1362 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
1367 /* Checks whether the statement defining variable *INDEX can be hoisted
1368 out of the loop passed in DATA. Callback for for_each_index. */
1371 may_move_till (tree ref
, tree
*index
, void *data
)
1373 struct loop
*loop
= (struct loop
*) data
, *max_loop
;
1375 /* If REF is an array reference, check also that the step and the lower
1376 bound is invariant in LOOP. */
1377 if (TREE_CODE (ref
) == ARRAY_REF
)
1379 tree step
= TREE_OPERAND (ref
, 3);
1380 tree lbound
= TREE_OPERAND (ref
, 2);
1382 max_loop
= outermost_invariant_loop (step
, loop
);
1386 max_loop
= outermost_invariant_loop (lbound
, loop
);
1391 max_loop
= outermost_invariant_loop (*index
, loop
);
1398 /* If OP is SSA NAME, force the statement that defines it to be
1399 moved out of the LOOP. ORIG_LOOP is the loop in that EXPR is used. */
1402 force_move_till_op (tree op
, struct loop
*orig_loop
, struct loop
*loop
)
1407 || is_gimple_min_invariant (op
))
1410 gcc_assert (TREE_CODE (op
) == SSA_NAME
);
1412 stmt
= SSA_NAME_DEF_STMT (op
);
1413 if (gimple_nop_p (stmt
))
1416 set_level (stmt
, orig_loop
, loop
);
1419 /* Forces statement defining invariants in REF (and *INDEX) to be moved out of
1420 the LOOP. The reference REF is used in the loop ORIG_LOOP. Callback for
1426 struct loop
*orig_loop
;
1430 force_move_till (tree ref
, tree
*index
, void *data
)
1432 struct fmt_data
*fmt_data
= (struct fmt_data
*) data
;
1434 if (TREE_CODE (ref
) == ARRAY_REF
)
1436 tree step
= TREE_OPERAND (ref
, 3);
1437 tree lbound
= TREE_OPERAND (ref
, 2);
1439 force_move_till_op (step
, fmt_data
->orig_loop
, fmt_data
->loop
);
1440 force_move_till_op (lbound
, fmt_data
->orig_loop
, fmt_data
->loop
);
1443 force_move_till_op (*index
, fmt_data
->orig_loop
, fmt_data
->loop
);
1448 /* A hash function for struct mem_ref object OBJ. */
1451 memref_hash (const void *obj
)
1453 const struct mem_ref
*const mem
= (const struct mem_ref
*) obj
;
1458 /* An equality function for struct mem_ref object OBJ1 with
1459 memory reference OBJ2. */
1462 memref_eq (const void *obj1
, const void *obj2
)
1464 const struct mem_ref
*const mem1
= (const struct mem_ref
*) obj1
;
1466 return operand_equal_p (mem1
->mem
, (const_tree
) obj2
, 0);
1469 /* Releases list of memory reference locations ACCS. */
1472 free_mem_ref_locs (mem_ref_locs_p accs
)
1480 FOR_EACH_VEC_ELT (mem_ref_loc_p
, accs
->locs
, i
, loc
)
1482 VEC_free (mem_ref_loc_p
, heap
, accs
->locs
);
1486 /* A function to free the mem_ref object OBJ. */
1489 memref_free (void *obj
)
1491 struct mem_ref
*const mem
= (struct mem_ref
*) obj
;
1493 mem_ref_locs_p accs
;
1495 BITMAP_FREE (mem
->stored
);
1496 BITMAP_FREE (mem
->indep_loop
);
1497 BITMAP_FREE (mem
->dep_loop
);
1498 BITMAP_FREE (mem
->indep_ref
);
1499 BITMAP_FREE (mem
->dep_ref
);
1501 FOR_EACH_VEC_ELT (mem_ref_locs_p
, mem
->accesses_in_loop
, i
, accs
)
1502 free_mem_ref_locs (accs
);
1503 VEC_free (mem_ref_locs_p
, heap
, mem
->accesses_in_loop
);
1508 /* Allocates and returns a memory reference description for MEM whose hash
1509 value is HASH and id is ID. */
1512 mem_ref_alloc (tree mem
, unsigned hash
, unsigned id
)
1514 mem_ref_p ref
= XNEW (struct mem_ref
);
1518 ref
->stored
= BITMAP_ALLOC (NULL
);
1519 ref
->indep_loop
= BITMAP_ALLOC (NULL
);
1520 ref
->dep_loop
= BITMAP_ALLOC (NULL
);
1521 ref
->indep_ref
= BITMAP_ALLOC (NULL
);
1522 ref
->dep_ref
= BITMAP_ALLOC (NULL
);
1523 ref
->accesses_in_loop
= NULL
;
1528 /* Allocates and returns the new list of locations. */
1530 static mem_ref_locs_p
1531 mem_ref_locs_alloc (void)
1533 mem_ref_locs_p accs
= XNEW (struct mem_ref_locs
);
1538 /* Records memory reference location *LOC in LOOP to the memory reference
1539 description REF. The reference occurs in statement STMT. */
1542 record_mem_ref_loc (mem_ref_p ref
, struct loop
*loop
, gimple stmt
, tree
*loc
)
1544 mem_ref_loc_p aref
= XNEW (struct mem_ref_loc
);
1545 mem_ref_locs_p accs
;
1546 bitmap ril
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1548 if (VEC_length (mem_ref_locs_p
, ref
->accesses_in_loop
)
1549 <= (unsigned) loop
->num
)
1550 VEC_safe_grow_cleared (mem_ref_locs_p
, heap
, ref
->accesses_in_loop
,
1552 accs
= VEC_index (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
);
1555 accs
= mem_ref_locs_alloc ();
1556 VEC_replace (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
, accs
);
1562 VEC_safe_push (mem_ref_loc_p
, heap
, accs
->locs
, aref
);
1563 bitmap_set_bit (ril
, ref
->id
);
1566 /* Marks reference REF as stored in LOOP. */
1569 mark_ref_stored (mem_ref_p ref
, struct loop
*loop
)
1572 loop
!= current_loops
->tree_root
1573 && !bitmap_bit_p (ref
->stored
, loop
->num
);
1574 loop
= loop_outer (loop
))
1575 bitmap_set_bit (ref
->stored
, loop
->num
);
1578 /* Gathers memory references in statement STMT in LOOP, storing the
1579 information about them in the memory_accesses structure. Marks
1580 the vops accessed through unrecognized statements there as
1584 gather_mem_refs_stmt (struct loop
*loop
, gimple stmt
)
1593 if (!gimple_vuse (stmt
))
1596 mem
= simple_mem_ref_in_stmt (stmt
, &is_stored
);
1599 id
= VEC_length (mem_ref_p
, memory_accesses
.refs_list
);
1600 ref
= mem_ref_alloc (error_mark_node
, 0, id
);
1601 VEC_safe_push (mem_ref_p
, heap
, memory_accesses
.refs_list
, ref
);
1602 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1604 fprintf (dump_file
, "Unanalyzed memory reference %u: ", id
);
1605 print_gimple_stmt (dump_file
, stmt
, 0, TDF_SLIM
);
1607 if (gimple_vdef (stmt
))
1608 mark_ref_stored (ref
, loop
);
1609 record_mem_ref_loc (ref
, loop
, stmt
, mem
);
1613 hash
= iterative_hash_expr (*mem
, 0);
1614 slot
= htab_find_slot_with_hash (memory_accesses
.refs
, *mem
, hash
, INSERT
);
1618 ref
= (mem_ref_p
) *slot
;
1623 id
= VEC_length (mem_ref_p
, memory_accesses
.refs_list
);
1624 ref
= mem_ref_alloc (*mem
, hash
, id
);
1625 VEC_safe_push (mem_ref_p
, heap
, memory_accesses
.refs_list
, ref
);
1628 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1630 fprintf (dump_file
, "Memory reference %u: ", id
);
1631 print_generic_expr (dump_file
, ref
->mem
, TDF_SLIM
);
1632 fprintf (dump_file
, "\n");
1637 mark_ref_stored (ref
, loop
);
1639 record_mem_ref_loc (ref
, loop
, stmt
, mem
);
1643 /* Gathers memory references in loops. */
1646 gather_mem_refs_in_loops (void)
1648 gimple_stmt_iterator bsi
;
1652 bitmap lrefs
, alrefs
, alrefso
;
1656 loop
= bb
->loop_father
;
1657 if (loop
== current_loops
->tree_root
)
1660 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1661 gather_mem_refs_stmt (loop
, gsi_stmt (bsi
));
1664 /* Propagate the information about accessed memory references up
1665 the loop hierarchy. */
1666 FOR_EACH_LOOP (li
, loop
, LI_FROM_INNERMOST
)
1668 lrefs
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1669 alrefs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
, loop
->num
);
1670 bitmap_ior_into (alrefs
, lrefs
);
1672 if (loop_outer (loop
) == current_loops
->tree_root
)
1675 alrefso
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
1676 loop_outer (loop
)->num
);
1677 bitmap_ior_into (alrefso
, alrefs
);
1681 /* Create a mapping from virtual operands to references that touch them
1685 create_vop_ref_mapping_loop (struct loop
*loop
)
1687 bitmap refs
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1693 EXECUTE_IF_SET_IN_BITMAP (refs
, 0, i
, bi
)
1695 ref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
1696 for (sloop
= loop
; sloop
!= current_loops
->tree_root
;
1697 sloop
= loop_outer (sloop
))
1698 if (bitmap_bit_p (ref
->stored
, loop
->num
))
1701 = VEC_index (bitmap
, memory_accesses
.all_refs_stored_in_loop
,
1703 bitmap_set_bit (refs_stored
, ref
->id
);
1708 /* For each non-clobbered virtual operand and each loop, record the memory
1709 references in this loop that touch the operand. */
1712 create_vop_ref_mapping (void)
1717 FOR_EACH_LOOP (li
, loop
, 0)
1719 create_vop_ref_mapping_loop (loop
);
1723 /* Gathers information about memory accesses in the loops. */
1726 analyze_memory_references (void)
1731 memory_accesses
.refs
1732 = htab_create (100, memref_hash
, memref_eq
, memref_free
);
1733 memory_accesses
.refs_list
= NULL
;
1734 memory_accesses
.refs_in_loop
= VEC_alloc (bitmap
, heap
,
1735 number_of_loops ());
1736 memory_accesses
.all_refs_in_loop
= VEC_alloc (bitmap
, heap
,
1737 number_of_loops ());
1738 memory_accesses
.all_refs_stored_in_loop
= VEC_alloc (bitmap
, heap
,
1739 number_of_loops ());
1741 for (i
= 0; i
< number_of_loops (); i
++)
1743 empty
= BITMAP_ALLOC (NULL
);
1744 VEC_quick_push (bitmap
, memory_accesses
.refs_in_loop
, empty
);
1745 empty
= BITMAP_ALLOC (NULL
);
1746 VEC_quick_push (bitmap
, memory_accesses
.all_refs_in_loop
, empty
);
1747 empty
= BITMAP_ALLOC (NULL
);
1748 VEC_quick_push (bitmap
, memory_accesses
.all_refs_stored_in_loop
, empty
);
1751 memory_accesses
.ttae_cache
= NULL
;
1753 gather_mem_refs_in_loops ();
1754 create_vop_ref_mapping ();
1757 /* Returns true if MEM1 and MEM2 may alias. TTAE_CACHE is used as a cache in
1758 tree_to_aff_combination_expand. */
1761 mem_refs_may_alias_p (tree mem1
, tree mem2
, struct pointer_map_t
**ttae_cache
)
1763 /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the same
1764 object and their offset differ in such a way that the locations cannot
1765 overlap, then they cannot alias. */
1766 double_int size1
, size2
;
1767 aff_tree off1
, off2
;
1769 /* Perform basic offset and type-based disambiguation. */
1770 if (!refs_may_alias_p (mem1
, mem2
))
1773 /* The expansion of addresses may be a bit expensive, thus we only do
1774 the check at -O2 and higher optimization levels. */
1778 get_inner_reference_aff (mem1
, &off1
, &size1
);
1779 get_inner_reference_aff (mem2
, &off2
, &size2
);
1780 aff_combination_expand (&off1
, ttae_cache
);
1781 aff_combination_expand (&off2
, ttae_cache
);
1782 aff_combination_scale (&off1
, double_int_minus_one
);
1783 aff_combination_add (&off2
, &off1
);
1785 if (aff_comb_cannot_overlap_p (&off2
, size1
, size2
))
1791 /* Rewrites location LOC by TMP_VAR. */
1794 rewrite_mem_ref_loc (mem_ref_loc_p loc
, tree tmp_var
)
1796 *loc
->ref
= tmp_var
;
1797 update_stmt (loc
->stmt
);
1800 /* Adds all locations of REF in LOOP and its subloops to LOCS. */
1803 get_all_locs_in_loop (struct loop
*loop
, mem_ref_p ref
,
1804 VEC (mem_ref_loc_p
, heap
) **locs
)
1806 mem_ref_locs_p accs
;
1809 bitmap refs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
1811 struct loop
*subloop
;
1813 if (!bitmap_bit_p (refs
, ref
->id
))
1816 if (VEC_length (mem_ref_locs_p
, ref
->accesses_in_loop
)
1817 > (unsigned) loop
->num
)
1819 accs
= VEC_index (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
);
1822 FOR_EACH_VEC_ELT (mem_ref_loc_p
, accs
->locs
, i
, loc
)
1823 VEC_safe_push (mem_ref_loc_p
, heap
, *locs
, loc
);
1827 for (subloop
= loop
->inner
; subloop
!= NULL
; subloop
= subloop
->next
)
1828 get_all_locs_in_loop (subloop
, ref
, locs
);
1831 /* Rewrites all references to REF in LOOP by variable TMP_VAR. */
1834 rewrite_mem_refs (struct loop
*loop
, mem_ref_p ref
, tree tmp_var
)
1838 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
1840 get_all_locs_in_loop (loop
, ref
, &locs
);
1841 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
1842 rewrite_mem_ref_loc (loc
, tmp_var
);
1843 VEC_free (mem_ref_loc_p
, heap
, locs
);
1846 /* The name and the length of the currently generated variable
1848 #define MAX_LSM_NAME_LENGTH 40
1849 static char lsm_tmp_name
[MAX_LSM_NAME_LENGTH
+ 1];
1850 static int lsm_tmp_name_length
;
1852 /* Adds S to lsm_tmp_name. */
1855 lsm_tmp_name_add (const char *s
)
1857 int l
= strlen (s
) + lsm_tmp_name_length
;
1858 if (l
> MAX_LSM_NAME_LENGTH
)
1861 strcpy (lsm_tmp_name
+ lsm_tmp_name_length
, s
);
1862 lsm_tmp_name_length
= l
;
1865 /* Stores the name for temporary variable that replaces REF to
1869 gen_lsm_tmp_name (tree ref
)
1873 switch (TREE_CODE (ref
))
1876 case TARGET_MEM_REF
:
1877 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1878 lsm_tmp_name_add ("_");
1882 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1886 case VIEW_CONVERT_EXPR
:
1887 case ARRAY_RANGE_REF
:
1888 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1892 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1893 lsm_tmp_name_add ("_RE");
1897 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1898 lsm_tmp_name_add ("_IM");
1902 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1903 lsm_tmp_name_add ("_");
1904 name
= get_name (TREE_OPERAND (ref
, 1));
1907 lsm_tmp_name_add (name
);
1911 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1912 lsm_tmp_name_add ("_I");
1918 name
= get_name (ref
);
1921 lsm_tmp_name_add (name
);
1925 lsm_tmp_name_add ("S");
1929 lsm_tmp_name_add ("R");
1941 /* Determines name for temporary variable that replaces REF.
1942 The name is accumulated into the lsm_tmp_name variable.
1943 N is added to the name of the temporary. */
1946 get_lsm_tmp_name (tree ref
, unsigned n
)
1950 lsm_tmp_name_length
= 0;
1951 gen_lsm_tmp_name (ref
);
1952 lsm_tmp_name_add ("_lsm");
1957 lsm_tmp_name_add (ns
);
1959 return lsm_tmp_name
;
1962 struct prev_flag_edges
{
1963 /* Edge to insert new flag comparison code. */
1964 edge append_cond_position
;
1966 /* Edge for fall through from previous flag comparison. */
1967 edge last_cond_fallthru
;
1970 /* Helper function for execute_sm. Emit code to store TMP_VAR into
1973 The store is only done if MEM has changed. We do this so no
1974 changes to MEM occur on code paths that did not originally store
1977 The common case for execute_sm will transform:
1997 This function will generate:
2016 execute_sm_if_changed (edge ex
, tree mem
, tree tmp_var
, tree flag
)
2018 basic_block new_bb
, then_bb
, old_dest
;
2019 bool loop_has_only_one_exit
;
2020 edge then_old_edge
, orig_ex
= ex
;
2021 gimple_stmt_iterator gsi
;
2023 struct prev_flag_edges
*prev_edges
= (struct prev_flag_edges
*) ex
->aux
;
2025 /* ?? Insert store after previous store if applicable. See note
2028 ex
= prev_edges
->append_cond_position
;
2030 loop_has_only_one_exit
= single_pred_p (ex
->dest
);
2032 if (loop_has_only_one_exit
)
2033 ex
= split_block_after_labels (ex
->dest
);
2035 old_dest
= ex
->dest
;
2036 new_bb
= split_edge (ex
);
2037 then_bb
= create_empty_bb (new_bb
);
2038 if (current_loops
&& new_bb
->loop_father
)
2039 add_bb_to_loop (then_bb
, new_bb
->loop_father
);
2041 gsi
= gsi_start_bb (new_bb
);
2042 stmt
= gimple_build_cond (NE_EXPR
, flag
, boolean_false_node
,
2043 NULL_TREE
, NULL_TREE
);
2044 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2046 gsi
= gsi_start_bb (then_bb
);
2047 /* Insert actual store. */
2048 stmt
= gimple_build_assign (unshare_expr (mem
), tmp_var
);
2049 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2051 make_edge (new_bb
, then_bb
, EDGE_TRUE_VALUE
);
2052 make_edge (new_bb
, old_dest
, EDGE_FALSE_VALUE
);
2053 then_old_edge
= make_edge (then_bb
, old_dest
, EDGE_FALLTHRU
);
2055 set_immediate_dominator (CDI_DOMINATORS
, then_bb
, new_bb
);
2059 basic_block prevbb
= prev_edges
->last_cond_fallthru
->src
;
2060 redirect_edge_succ (prev_edges
->last_cond_fallthru
, new_bb
);
2061 set_immediate_dominator (CDI_DOMINATORS
, new_bb
, prevbb
);
2062 set_immediate_dominator (CDI_DOMINATORS
, old_dest
,
2063 recompute_dominator (CDI_DOMINATORS
, old_dest
));
2066 /* ?? Because stores may alias, they must happen in the exact
2067 sequence they originally happened. Save the position right after
2068 the (_lsm) store we just created so we can continue appending after
2069 it and maintain the original order. */
2071 struct prev_flag_edges
*p
;
2074 orig_ex
->aux
= NULL
;
2075 alloc_aux_for_edge (orig_ex
, sizeof (struct prev_flag_edges
));
2076 p
= (struct prev_flag_edges
*) orig_ex
->aux
;
2077 p
->append_cond_position
= then_old_edge
;
2078 p
->last_cond_fallthru
= find_edge (new_bb
, old_dest
);
2079 orig_ex
->aux
= (void *) p
;
2082 if (!loop_has_only_one_exit
)
2083 for (gsi
= gsi_start_phis (old_dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2085 gimple phi
= gsi_stmt (gsi
);
2088 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
2089 if (gimple_phi_arg_edge (phi
, i
)->src
== new_bb
)
2091 tree arg
= gimple_phi_arg_def (phi
, i
);
2092 add_phi_arg (phi
, arg
, then_old_edge
, UNKNOWN_LOCATION
);
2096 /* Remove the original fall through edge. This was the
2097 single_succ_edge (new_bb). */
2098 EDGE_SUCC (new_bb
, 0)->flags
&= ~EDGE_FALLTHRU
;
2101 /* Helper function for execute_sm. On every location where REF is
2102 set, set an appropriate flag indicating the store. */
2105 execute_sm_if_changed_flag_set (struct loop
*loop
, mem_ref_p ref
)
2110 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
2111 char *str
= get_lsm_tmp_name (ref
->mem
, ~0);
2113 lsm_tmp_name_add ("_flag");
2114 flag
= create_tmp_reg (boolean_type_node
, str
);
2115 get_all_locs_in_loop (loop
, ref
, &locs
);
2116 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
2118 gimple_stmt_iterator gsi
;
2121 gsi
= gsi_for_stmt (loc
->stmt
);
2122 stmt
= gimple_build_assign (flag
, boolean_true_node
);
2123 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 sbitmap_zero (contains_call
);
2589 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
2591 if (nonpure_call_p (gsi_stmt (bsi
)))
2595 if (!gsi_end_p (bsi
))
2596 SET_BIT (contains_call
, bb
->index
);
2599 for (loop
= current_loops
->tree_root
->inner
; loop
; loop
= loop
->next
)
2600 fill_always_executed_in (loop
, contains_call
);
2602 sbitmap_free (contains_call
);
2604 lim_aux_data_map
= pointer_map_create ();
2607 compute_transaction_bits ();
2609 alloc_aux_for_edges (0);
2612 /* Cleans up after the invariant motion pass. */
2615 tree_ssa_lim_finalize (void)
2621 free_aux_for_edges ();
2624 SET_ALWAYS_EXECUTED_IN (bb
, NULL
);
2626 pointer_map_destroy (lim_aux_data_map
);
2628 VEC_free (mem_ref_p
, heap
, memory_accesses
.refs_list
);
2629 htab_delete (memory_accesses
.refs
);
2631 FOR_EACH_VEC_ELT (bitmap
, memory_accesses
.refs_in_loop
, i
, b
)
2633 VEC_free (bitmap
, heap
, memory_accesses
.refs_in_loop
);
2635 FOR_EACH_VEC_ELT (bitmap
, memory_accesses
.all_refs_in_loop
, i
, b
)
2637 VEC_free (bitmap
, heap
, memory_accesses
.all_refs_in_loop
);
2639 FOR_EACH_VEC_ELT (bitmap
, memory_accesses
.all_refs_stored_in_loop
, i
, b
)
2641 VEC_free (bitmap
, heap
, memory_accesses
.all_refs_stored_in_loop
);
2643 if (memory_accesses
.ttae_cache
)
2644 pointer_map_destroy (memory_accesses
.ttae_cache
);
2647 /* Moves invariants from loops. Only "expensive" invariants are moved out --
2648 i.e. those that are likely to be win regardless of the register pressure. */
2655 tree_ssa_lim_initialize ();
2657 /* Gathers information about memory accesses in the loops. */
2658 analyze_memory_references ();
2660 /* For each statement determine the outermost loop in that it is
2661 invariant and cost for computing the invariant. */
2662 determine_invariantness ();
2664 /* Execute store motion. Force the necessary invariants to be moved
2665 out of the loops as well. */
2668 /* Move the expressions that are expensive enough. */
2669 todo
= move_computations ();
2671 tree_ssa_lim_finalize ();