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 var
, 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 var
= create_tmp_var (type
, "reciptmp");
946 add_referenced_var (var
);
947 DECL_GIMPLE_REG_P (var
) = 1;
949 real_one
= build_one_cst (type
);
951 stmt1
= gimple_build_assign_with_ops (RDIV_EXPR
,
952 var
, real_one
, gimple_assign_rhs2 (stmt
));
953 name
= make_ssa_name (var
, stmt1
);
954 gimple_assign_set_lhs (stmt1
, name
);
956 stmt2
= gimple_build_assign_with_ops (MULT_EXPR
, lhs
, name
,
957 gimple_assign_rhs1 (stmt
));
959 /* Replace division stmt with reciprocal and multiply stmts.
960 The multiply stmt is not invariant, so update iterator
961 and avoid rescanning. */
963 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
964 gsi_replace (&gsi
, stmt2
, true);
966 /* Continue processing with invariant reciprocal statement. */
970 /* Check if the pattern at *BSI is a bittest of the form
971 (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0. */
974 rewrite_bittest (gimple_stmt_iterator
*bsi
)
976 gimple stmt
, use_stmt
, stmt1
, stmt2
;
977 tree lhs
, var
, name
, t
, a
, b
;
980 stmt
= gsi_stmt (*bsi
);
981 lhs
= gimple_assign_lhs (stmt
);
983 /* Verify that the single use of lhs is a comparison against zero. */
984 if (TREE_CODE (lhs
) != SSA_NAME
985 || !single_imm_use (lhs
, &use
, &use_stmt
)
986 || gimple_code (use_stmt
) != GIMPLE_COND
)
988 if (gimple_cond_lhs (use_stmt
) != lhs
989 || (gimple_cond_code (use_stmt
) != NE_EXPR
990 && gimple_cond_code (use_stmt
) != EQ_EXPR
)
991 || !integer_zerop (gimple_cond_rhs (use_stmt
)))
994 /* Get at the operands of the shift. The rhs is TMP1 & 1. */
995 stmt1
= SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt
));
996 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
999 /* There is a conversion in between possibly inserted by fold. */
1000 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt1
)))
1002 t
= gimple_assign_rhs1 (stmt1
);
1003 if (TREE_CODE (t
) != SSA_NAME
1004 || !has_single_use (t
))
1006 stmt1
= SSA_NAME_DEF_STMT (t
);
1007 if (gimple_code (stmt1
) != GIMPLE_ASSIGN
)
1011 /* Verify that B is loop invariant but A is not. Verify that with
1012 all the stmt walking we are still in the same loop. */
1013 if (gimple_assign_rhs_code (stmt1
) != RSHIFT_EXPR
1014 || loop_containing_stmt (stmt1
) != loop_containing_stmt (stmt
))
1017 a
= gimple_assign_rhs1 (stmt1
);
1018 b
= gimple_assign_rhs2 (stmt1
);
1020 if (outermost_invariant_loop (b
, loop_containing_stmt (stmt1
)) != NULL
1021 && outermost_invariant_loop (a
, loop_containing_stmt (stmt1
)) == NULL
)
1023 gimple_stmt_iterator rsi
;
1026 var
= create_tmp_var (TREE_TYPE (a
), "shifttmp");
1027 add_referenced_var (var
);
1028 t
= fold_build2 (LSHIFT_EXPR
, TREE_TYPE (a
),
1029 build_int_cst (TREE_TYPE (a
), 1), b
);
1030 stmt1
= gimple_build_assign (var
, t
);
1031 name
= make_ssa_name (var
, stmt1
);
1032 gimple_assign_set_lhs (stmt1
, name
);
1035 t
= fold_build2 (BIT_AND_EXPR
, TREE_TYPE (a
), a
, name
);
1036 stmt2
= gimple_build_assign (var
, t
);
1037 name
= make_ssa_name (var
, stmt2
);
1038 gimple_assign_set_lhs (stmt2
, name
);
1040 /* Replace the SSA_NAME we compare against zero. Adjust
1041 the type of zero accordingly. */
1042 SET_USE (use
, name
);
1043 gimple_cond_set_rhs (use_stmt
, build_int_cst_type (TREE_TYPE (name
), 0));
1045 /* Don't use gsi_replace here, none of the new assignments sets
1046 the variable originally set in stmt. Move bsi to stmt1, and
1047 then remove the original stmt, so that we get a chance to
1048 retain debug info for it. */
1050 gsi_insert_before (bsi
, stmt1
, GSI_NEW_STMT
);
1051 gsi_insert_before (&rsi
, stmt2
, GSI_SAME_STMT
);
1052 gsi_remove (&rsi
, true);
1061 /* Determine the outermost loops in that statements in basic block BB are
1062 invariant, and record them to the LIM_DATA associated with the statements.
1063 Callback for walk_dominator_tree. */
1066 determine_invariantness_stmt (struct dom_walk_data
*dw_data ATTRIBUTE_UNUSED
,
1070 gimple_stmt_iterator bsi
;
1072 bool maybe_never
= ALWAYS_EXECUTED_IN (bb
) == NULL
;
1073 struct loop
*outermost
= ALWAYS_EXECUTED_IN (bb
);
1074 struct lim_aux_data
*lim_data
;
1076 if (!loop_outer (bb
->loop_father
))
1079 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1080 fprintf (dump_file
, "Basic block %d (loop %d -- depth %d):\n\n",
1081 bb
->index
, bb
->loop_father
->num
, loop_depth (bb
->loop_father
));
1083 /* Look at PHI nodes, but only if there is at most two.
1084 ??? We could relax this further by post-processing the inserted
1085 code and transforming adjacent cond-exprs with the same predicate
1086 to control flow again. */
1087 bsi
= gsi_start_phis (bb
);
1088 if (!gsi_end_p (bsi
)
1089 && ((gsi_next (&bsi
), gsi_end_p (bsi
))
1090 || (gsi_next (&bsi
), gsi_end_p (bsi
))))
1091 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1093 stmt
= gsi_stmt (bsi
);
1095 pos
= movement_possibility (stmt
);
1096 if (pos
== MOVE_IMPOSSIBLE
)
1099 lim_data
= init_lim_data (stmt
);
1100 lim_data
->always_executed_in
= outermost
;
1102 if (!determine_max_movement (stmt
, false))
1104 lim_data
->max_loop
= NULL
;
1108 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1110 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1111 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1112 loop_depth (lim_data
->max_loop
),
1116 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1117 set_profitable_level (stmt
);
1120 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1122 stmt
= gsi_stmt (bsi
);
1124 pos
= movement_possibility (stmt
);
1125 if (pos
== MOVE_IMPOSSIBLE
)
1127 if (nonpure_call_p (stmt
))
1132 /* Make sure to note always_executed_in for stores to make
1133 store-motion work. */
1134 else if (stmt_makes_single_store (stmt
))
1136 struct lim_aux_data
*lim_data
= init_lim_data (stmt
);
1137 lim_data
->always_executed_in
= outermost
;
1142 if (is_gimple_assign (stmt
)
1143 && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt
))
1144 == GIMPLE_BINARY_RHS
))
1146 tree op0
= gimple_assign_rhs1 (stmt
);
1147 tree op1
= gimple_assign_rhs2 (stmt
);
1148 struct loop
*ol1
= outermost_invariant_loop (op1
,
1149 loop_containing_stmt (stmt
));
1151 /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal
1152 to be hoisted out of loop, saving expensive divide. */
1153 if (pos
== MOVE_POSSIBLE
1154 && gimple_assign_rhs_code (stmt
) == RDIV_EXPR
1155 && flag_unsafe_math_optimizations
1156 && !flag_trapping_math
1158 && outermost_invariant_loop (op0
, ol1
) == NULL
)
1159 stmt
= rewrite_reciprocal (&bsi
);
1161 /* If the shift count is invariant, convert (A >> B) & 1 to
1162 A & (1 << B) allowing the bit mask to be hoisted out of the loop
1163 saving an expensive shift. */
1164 if (pos
== MOVE_POSSIBLE
1165 && gimple_assign_rhs_code (stmt
) == BIT_AND_EXPR
1166 && integer_onep (op1
)
1167 && TREE_CODE (op0
) == SSA_NAME
1168 && has_single_use (op0
))
1169 stmt
= rewrite_bittest (&bsi
);
1172 lim_data
= init_lim_data (stmt
);
1173 lim_data
->always_executed_in
= outermost
;
1175 if (maybe_never
&& pos
== MOVE_PRESERVE_EXECUTION
)
1178 if (!determine_max_movement (stmt
, pos
== MOVE_PRESERVE_EXECUTION
))
1180 lim_data
->max_loop
= NULL
;
1184 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1186 print_gimple_stmt (dump_file
, stmt
, 2, 0);
1187 fprintf (dump_file
, " invariant up to level %d, cost %d.\n\n",
1188 loop_depth (lim_data
->max_loop
),
1192 if (lim_data
->cost
>= LIM_EXPENSIVE
)
1193 set_profitable_level (stmt
);
1197 /* For each statement determines the outermost loop in that it is invariant,
1198 statements on whose motion it depends and the cost of the computation.
1199 This information is stored to the LIM_DATA structure associated with
1203 determine_invariantness (void)
1205 struct dom_walk_data walk_data
;
1207 memset (&walk_data
, 0, sizeof (struct dom_walk_data
));
1208 walk_data
.dom_direction
= CDI_DOMINATORS
;
1209 walk_data
.before_dom_children
= determine_invariantness_stmt
;
1211 init_walk_dominator_tree (&walk_data
);
1212 walk_dominator_tree (&walk_data
, ENTRY_BLOCK_PTR
);
1213 fini_walk_dominator_tree (&walk_data
);
1216 /* Hoist the statements in basic block BB out of the loops prescribed by
1217 data stored in LIM_DATA structures associated with each statement. Callback
1218 for walk_dominator_tree. */
1221 move_computations_stmt (struct dom_walk_data
*dw_data
,
1225 gimple_stmt_iterator bsi
;
1228 struct lim_aux_data
*lim_data
;
1230 if (!loop_outer (bb
->loop_father
))
1233 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); )
1236 stmt
= gsi_stmt (bsi
);
1238 lim_data
= get_lim_data (stmt
);
1239 if (lim_data
== NULL
)
1245 cost
= lim_data
->cost
;
1246 level
= lim_data
->tgt_loop
;
1247 clear_lim_data (stmt
);
1255 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1257 fprintf (dump_file
, "Moving PHI node\n");
1258 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1259 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1263 if (gimple_phi_num_args (stmt
) == 1)
1265 tree arg
= PHI_ARG_DEF (stmt
, 0);
1266 new_stmt
= gimple_build_assign_with_ops (TREE_CODE (arg
),
1267 gimple_phi_result (stmt
),
1269 SSA_NAME_DEF_STMT (gimple_phi_result (stmt
)) = new_stmt
;
1273 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
1274 gimple cond
= gsi_stmt (gsi_last_bb (dom
));
1275 tree arg0
= NULL_TREE
, arg1
= NULL_TREE
, t
;
1276 /* Get the PHI arguments corresponding to the true and false
1278 extract_true_false_args_from_phi (dom
, stmt
, &arg0
, &arg1
);
1279 gcc_assert (arg0
&& arg1
);
1280 t
= build2 (gimple_cond_code (cond
), boolean_type_node
,
1281 gimple_cond_lhs (cond
), gimple_cond_rhs (cond
));
1282 new_stmt
= gimple_build_assign_with_ops3 (COND_EXPR
,
1283 gimple_phi_result (stmt
),
1285 SSA_NAME_DEF_STMT (gimple_phi_result (stmt
)) = new_stmt
;
1286 *((unsigned int *)(dw_data
->global_data
)) |= TODO_cleanup_cfg
;
1288 gsi_insert_on_edge (loop_preheader_edge (level
), new_stmt
);
1289 remove_phi_node (&bsi
, false);
1292 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); )
1294 stmt
= gsi_stmt (bsi
);
1296 lim_data
= get_lim_data (stmt
);
1297 if (lim_data
== NULL
)
1303 cost
= lim_data
->cost
;
1304 level
= lim_data
->tgt_loop
;
1305 clear_lim_data (stmt
);
1313 /* We do not really want to move conditionals out of the loop; we just
1314 placed it here to force its operands to be moved if necessary. */
1315 if (gimple_code (stmt
) == GIMPLE_COND
)
1318 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1320 fprintf (dump_file
, "Moving statement\n");
1321 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1322 fprintf (dump_file
, "(cost %u) out of loop %d.\n\n",
1326 mark_virtual_ops_for_renaming (stmt
);
1327 gsi_remove (&bsi
, false);
1328 gsi_insert_on_edge (loop_preheader_edge (level
), stmt
);
1332 /* Hoist the statements out of the loops prescribed by data stored in
1333 LIM_DATA structures associated with each statement.*/
1336 move_computations (void)
1338 struct dom_walk_data walk_data
;
1339 unsigned int todo
= 0;
1341 memset (&walk_data
, 0, sizeof (struct dom_walk_data
));
1342 walk_data
.global_data
= &todo
;
1343 walk_data
.dom_direction
= CDI_DOMINATORS
;
1344 walk_data
.before_dom_children
= move_computations_stmt
;
1346 init_walk_dominator_tree (&walk_data
);
1347 walk_dominator_tree (&walk_data
, ENTRY_BLOCK_PTR
);
1348 fini_walk_dominator_tree (&walk_data
);
1350 gsi_commit_edge_inserts ();
1351 if (need_ssa_update_p (cfun
))
1352 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
1357 /* Checks whether the statement defining variable *INDEX can be hoisted
1358 out of the loop passed in DATA. Callback for for_each_index. */
1361 may_move_till (tree ref
, tree
*index
, void *data
)
1363 struct loop
*loop
= (struct loop
*) data
, *max_loop
;
1365 /* If REF is an array reference, check also that the step and the lower
1366 bound is invariant in LOOP. */
1367 if (TREE_CODE (ref
) == ARRAY_REF
)
1369 tree step
= TREE_OPERAND (ref
, 3);
1370 tree lbound
= TREE_OPERAND (ref
, 2);
1372 max_loop
= outermost_invariant_loop (step
, loop
);
1376 max_loop
= outermost_invariant_loop (lbound
, loop
);
1381 max_loop
= outermost_invariant_loop (*index
, loop
);
1388 /* If OP is SSA NAME, force the statement that defines it to be
1389 moved out of the LOOP. ORIG_LOOP is the loop in that EXPR is used. */
1392 force_move_till_op (tree op
, struct loop
*orig_loop
, struct loop
*loop
)
1397 || is_gimple_min_invariant (op
))
1400 gcc_assert (TREE_CODE (op
) == SSA_NAME
);
1402 stmt
= SSA_NAME_DEF_STMT (op
);
1403 if (gimple_nop_p (stmt
))
1406 set_level (stmt
, orig_loop
, loop
);
1409 /* Forces statement defining invariants in REF (and *INDEX) to be moved out of
1410 the LOOP. The reference REF is used in the loop ORIG_LOOP. Callback for
1416 struct loop
*orig_loop
;
1420 force_move_till (tree ref
, tree
*index
, void *data
)
1422 struct fmt_data
*fmt_data
= (struct fmt_data
*) data
;
1424 if (TREE_CODE (ref
) == ARRAY_REF
)
1426 tree step
= TREE_OPERAND (ref
, 3);
1427 tree lbound
= TREE_OPERAND (ref
, 2);
1429 force_move_till_op (step
, fmt_data
->orig_loop
, fmt_data
->loop
);
1430 force_move_till_op (lbound
, fmt_data
->orig_loop
, fmt_data
->loop
);
1433 force_move_till_op (*index
, fmt_data
->orig_loop
, fmt_data
->loop
);
1438 /* A hash function for struct mem_ref object OBJ. */
1441 memref_hash (const void *obj
)
1443 const struct mem_ref
*const mem
= (const struct mem_ref
*) obj
;
1448 /* An equality function for struct mem_ref object OBJ1 with
1449 memory reference OBJ2. */
1452 memref_eq (const void *obj1
, const void *obj2
)
1454 const struct mem_ref
*const mem1
= (const struct mem_ref
*) obj1
;
1456 return operand_equal_p (mem1
->mem
, (const_tree
) obj2
, 0);
1459 /* Releases list of memory reference locations ACCS. */
1462 free_mem_ref_locs (mem_ref_locs_p accs
)
1470 FOR_EACH_VEC_ELT (mem_ref_loc_p
, accs
->locs
, i
, loc
)
1472 VEC_free (mem_ref_loc_p
, heap
, accs
->locs
);
1476 /* A function to free the mem_ref object OBJ. */
1479 memref_free (void *obj
)
1481 struct mem_ref
*const mem
= (struct mem_ref
*) obj
;
1483 mem_ref_locs_p accs
;
1485 BITMAP_FREE (mem
->stored
);
1486 BITMAP_FREE (mem
->indep_loop
);
1487 BITMAP_FREE (mem
->dep_loop
);
1488 BITMAP_FREE (mem
->indep_ref
);
1489 BITMAP_FREE (mem
->dep_ref
);
1491 FOR_EACH_VEC_ELT (mem_ref_locs_p
, mem
->accesses_in_loop
, i
, accs
)
1492 free_mem_ref_locs (accs
);
1493 VEC_free (mem_ref_locs_p
, heap
, mem
->accesses_in_loop
);
1498 /* Allocates and returns a memory reference description for MEM whose hash
1499 value is HASH and id is ID. */
1502 mem_ref_alloc (tree mem
, unsigned hash
, unsigned id
)
1504 mem_ref_p ref
= XNEW (struct mem_ref
);
1508 ref
->stored
= BITMAP_ALLOC (NULL
);
1509 ref
->indep_loop
= BITMAP_ALLOC (NULL
);
1510 ref
->dep_loop
= BITMAP_ALLOC (NULL
);
1511 ref
->indep_ref
= BITMAP_ALLOC (NULL
);
1512 ref
->dep_ref
= BITMAP_ALLOC (NULL
);
1513 ref
->accesses_in_loop
= NULL
;
1518 /* Allocates and returns the new list of locations. */
1520 static mem_ref_locs_p
1521 mem_ref_locs_alloc (void)
1523 mem_ref_locs_p accs
= XNEW (struct mem_ref_locs
);
1528 /* Records memory reference location *LOC in LOOP to the memory reference
1529 description REF. The reference occurs in statement STMT. */
1532 record_mem_ref_loc (mem_ref_p ref
, struct loop
*loop
, gimple stmt
, tree
*loc
)
1534 mem_ref_loc_p aref
= XNEW (struct mem_ref_loc
);
1535 mem_ref_locs_p accs
;
1536 bitmap ril
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1538 if (VEC_length (mem_ref_locs_p
, ref
->accesses_in_loop
)
1539 <= (unsigned) loop
->num
)
1540 VEC_safe_grow_cleared (mem_ref_locs_p
, heap
, ref
->accesses_in_loop
,
1542 accs
= VEC_index (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
);
1545 accs
= mem_ref_locs_alloc ();
1546 VEC_replace (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
, accs
);
1552 VEC_safe_push (mem_ref_loc_p
, heap
, accs
->locs
, aref
);
1553 bitmap_set_bit (ril
, ref
->id
);
1556 /* Marks reference REF as stored in LOOP. */
1559 mark_ref_stored (mem_ref_p ref
, struct loop
*loop
)
1562 loop
!= current_loops
->tree_root
1563 && !bitmap_bit_p (ref
->stored
, loop
->num
);
1564 loop
= loop_outer (loop
))
1565 bitmap_set_bit (ref
->stored
, loop
->num
);
1568 /* Gathers memory references in statement STMT in LOOP, storing the
1569 information about them in the memory_accesses structure. Marks
1570 the vops accessed through unrecognized statements there as
1574 gather_mem_refs_stmt (struct loop
*loop
, gimple stmt
)
1583 if (!gimple_vuse (stmt
))
1586 mem
= simple_mem_ref_in_stmt (stmt
, &is_stored
);
1589 id
= VEC_length (mem_ref_p
, memory_accesses
.refs_list
);
1590 ref
= mem_ref_alloc (error_mark_node
, 0, id
);
1591 VEC_safe_push (mem_ref_p
, heap
, memory_accesses
.refs_list
, ref
);
1592 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1594 fprintf (dump_file
, "Unanalyzed memory reference %u: ", id
);
1595 print_gimple_stmt (dump_file
, stmt
, 0, TDF_SLIM
);
1597 if (gimple_vdef (stmt
))
1598 mark_ref_stored (ref
, loop
);
1599 record_mem_ref_loc (ref
, loop
, stmt
, mem
);
1603 hash
= iterative_hash_expr (*mem
, 0);
1604 slot
= htab_find_slot_with_hash (memory_accesses
.refs
, *mem
, hash
, INSERT
);
1608 ref
= (mem_ref_p
) *slot
;
1613 id
= VEC_length (mem_ref_p
, memory_accesses
.refs_list
);
1614 ref
= mem_ref_alloc (*mem
, hash
, id
);
1615 VEC_safe_push (mem_ref_p
, heap
, memory_accesses
.refs_list
, ref
);
1618 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1620 fprintf (dump_file
, "Memory reference %u: ", id
);
1621 print_generic_expr (dump_file
, ref
->mem
, TDF_SLIM
);
1622 fprintf (dump_file
, "\n");
1627 mark_ref_stored (ref
, loop
);
1629 record_mem_ref_loc (ref
, loop
, stmt
, mem
);
1633 /* Gathers memory references in loops. */
1636 gather_mem_refs_in_loops (void)
1638 gimple_stmt_iterator bsi
;
1642 bitmap lrefs
, alrefs
, alrefso
;
1646 loop
= bb
->loop_father
;
1647 if (loop
== current_loops
->tree_root
)
1650 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1651 gather_mem_refs_stmt (loop
, gsi_stmt (bsi
));
1654 /* Propagate the information about accessed memory references up
1655 the loop hierarchy. */
1656 FOR_EACH_LOOP (li
, loop
, LI_FROM_INNERMOST
)
1658 lrefs
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1659 alrefs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
, loop
->num
);
1660 bitmap_ior_into (alrefs
, lrefs
);
1662 if (loop_outer (loop
) == current_loops
->tree_root
)
1665 alrefso
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
1666 loop_outer (loop
)->num
);
1667 bitmap_ior_into (alrefso
, alrefs
);
1671 /* Create a mapping from virtual operands to references that touch them
1675 create_vop_ref_mapping_loop (struct loop
*loop
)
1677 bitmap refs
= VEC_index (bitmap
, memory_accesses
.refs_in_loop
, loop
->num
);
1683 EXECUTE_IF_SET_IN_BITMAP (refs
, 0, i
, bi
)
1685 ref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
1686 for (sloop
= loop
; sloop
!= current_loops
->tree_root
;
1687 sloop
= loop_outer (sloop
))
1688 if (bitmap_bit_p (ref
->stored
, loop
->num
))
1691 = VEC_index (bitmap
, memory_accesses
.all_refs_stored_in_loop
,
1693 bitmap_set_bit (refs_stored
, ref
->id
);
1698 /* For each non-clobbered virtual operand and each loop, record the memory
1699 references in this loop that touch the operand. */
1702 create_vop_ref_mapping (void)
1707 FOR_EACH_LOOP (li
, loop
, 0)
1709 create_vop_ref_mapping_loop (loop
);
1713 /* Gathers information about memory accesses in the loops. */
1716 analyze_memory_references (void)
1721 memory_accesses
.refs
1722 = htab_create (100, memref_hash
, memref_eq
, memref_free
);
1723 memory_accesses
.refs_list
= NULL
;
1724 memory_accesses
.refs_in_loop
= VEC_alloc (bitmap
, heap
,
1725 number_of_loops ());
1726 memory_accesses
.all_refs_in_loop
= VEC_alloc (bitmap
, heap
,
1727 number_of_loops ());
1728 memory_accesses
.all_refs_stored_in_loop
= VEC_alloc (bitmap
, heap
,
1729 number_of_loops ());
1731 for (i
= 0; i
< number_of_loops (); i
++)
1733 empty
= BITMAP_ALLOC (NULL
);
1734 VEC_quick_push (bitmap
, memory_accesses
.refs_in_loop
, empty
);
1735 empty
= BITMAP_ALLOC (NULL
);
1736 VEC_quick_push (bitmap
, memory_accesses
.all_refs_in_loop
, empty
);
1737 empty
= BITMAP_ALLOC (NULL
);
1738 VEC_quick_push (bitmap
, memory_accesses
.all_refs_stored_in_loop
, empty
);
1741 memory_accesses
.ttae_cache
= NULL
;
1743 gather_mem_refs_in_loops ();
1744 create_vop_ref_mapping ();
1747 /* Returns true if MEM1 and MEM2 may alias. TTAE_CACHE is used as a cache in
1748 tree_to_aff_combination_expand. */
1751 mem_refs_may_alias_p (tree mem1
, tree mem2
, struct pointer_map_t
**ttae_cache
)
1753 /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the same
1754 object and their offset differ in such a way that the locations cannot
1755 overlap, then they cannot alias. */
1756 double_int size1
, size2
;
1757 aff_tree off1
, off2
;
1759 /* Perform basic offset and type-based disambiguation. */
1760 if (!refs_may_alias_p (mem1
, mem2
))
1763 /* The expansion of addresses may be a bit expensive, thus we only do
1764 the check at -O2 and higher optimization levels. */
1768 get_inner_reference_aff (mem1
, &off1
, &size1
);
1769 get_inner_reference_aff (mem2
, &off2
, &size2
);
1770 aff_combination_expand (&off1
, ttae_cache
);
1771 aff_combination_expand (&off2
, ttae_cache
);
1772 aff_combination_scale (&off1
, double_int_minus_one
);
1773 aff_combination_add (&off2
, &off1
);
1775 if (aff_comb_cannot_overlap_p (&off2
, size1
, size2
))
1781 /* Rewrites location LOC by TMP_VAR. */
1784 rewrite_mem_ref_loc (mem_ref_loc_p loc
, tree tmp_var
)
1786 mark_virtual_ops_for_renaming (loc
->stmt
);
1787 *loc
->ref
= tmp_var
;
1788 update_stmt (loc
->stmt
);
1791 /* Adds all locations of REF in LOOP and its subloops to LOCS. */
1794 get_all_locs_in_loop (struct loop
*loop
, mem_ref_p ref
,
1795 VEC (mem_ref_loc_p
, heap
) **locs
)
1797 mem_ref_locs_p accs
;
1800 bitmap refs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
1802 struct loop
*subloop
;
1804 if (!bitmap_bit_p (refs
, ref
->id
))
1807 if (VEC_length (mem_ref_locs_p
, ref
->accesses_in_loop
)
1808 > (unsigned) loop
->num
)
1810 accs
= VEC_index (mem_ref_locs_p
, ref
->accesses_in_loop
, loop
->num
);
1813 FOR_EACH_VEC_ELT (mem_ref_loc_p
, accs
->locs
, i
, loc
)
1814 VEC_safe_push (mem_ref_loc_p
, heap
, *locs
, loc
);
1818 for (subloop
= loop
->inner
; subloop
!= NULL
; subloop
= subloop
->next
)
1819 get_all_locs_in_loop (subloop
, ref
, locs
);
1822 /* Rewrites all references to REF in LOOP by variable TMP_VAR. */
1825 rewrite_mem_refs (struct loop
*loop
, mem_ref_p ref
, tree tmp_var
)
1829 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
1831 get_all_locs_in_loop (loop
, ref
, &locs
);
1832 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
1833 rewrite_mem_ref_loc (loc
, tmp_var
);
1834 VEC_free (mem_ref_loc_p
, heap
, locs
);
1837 /* The name and the length of the currently generated variable
1839 #define MAX_LSM_NAME_LENGTH 40
1840 static char lsm_tmp_name
[MAX_LSM_NAME_LENGTH
+ 1];
1841 static int lsm_tmp_name_length
;
1843 /* Adds S to lsm_tmp_name. */
1846 lsm_tmp_name_add (const char *s
)
1848 int l
= strlen (s
) + lsm_tmp_name_length
;
1849 if (l
> MAX_LSM_NAME_LENGTH
)
1852 strcpy (lsm_tmp_name
+ lsm_tmp_name_length
, s
);
1853 lsm_tmp_name_length
= l
;
1856 /* Stores the name for temporary variable that replaces REF to
1860 gen_lsm_tmp_name (tree ref
)
1864 switch (TREE_CODE (ref
))
1867 case TARGET_MEM_REF
:
1868 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1869 lsm_tmp_name_add ("_");
1873 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1877 case VIEW_CONVERT_EXPR
:
1878 case ARRAY_RANGE_REF
:
1879 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1883 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1884 lsm_tmp_name_add ("_RE");
1888 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1889 lsm_tmp_name_add ("_IM");
1893 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1894 lsm_tmp_name_add ("_");
1895 name
= get_name (TREE_OPERAND (ref
, 1));
1898 lsm_tmp_name_add (name
);
1902 gen_lsm_tmp_name (TREE_OPERAND (ref
, 0));
1903 lsm_tmp_name_add ("_I");
1907 ref
= SSA_NAME_VAR (ref
);
1912 name
= get_name (ref
);
1915 lsm_tmp_name_add (name
);
1919 lsm_tmp_name_add ("S");
1923 lsm_tmp_name_add ("R");
1935 /* Determines name for temporary variable that replaces REF.
1936 The name is accumulated into the lsm_tmp_name variable.
1937 N is added to the name of the temporary. */
1940 get_lsm_tmp_name (tree ref
, unsigned n
)
1944 lsm_tmp_name_length
= 0;
1945 gen_lsm_tmp_name (ref
);
1946 lsm_tmp_name_add ("_lsm");
1951 lsm_tmp_name_add (ns
);
1953 return lsm_tmp_name
;
1956 struct prev_flag_edges
{
1957 /* Edge to insert new flag comparison code. */
1958 edge append_cond_position
;
1960 /* Edge for fall through from previous flag comparison. */
1961 edge last_cond_fallthru
;
1964 /* Helper function for execute_sm. Emit code to store TMP_VAR into
1967 The store is only done if MEM has changed. We do this so no
1968 changes to MEM occur on code paths that did not originally store
1971 The common case for execute_sm will transform:
1991 This function will generate:
2010 execute_sm_if_changed (edge ex
, tree mem
, tree tmp_var
, tree flag
)
2012 basic_block new_bb
, then_bb
, old_dest
;
2013 bool loop_has_only_one_exit
;
2014 edge then_old_edge
, orig_ex
= ex
;
2015 gimple_stmt_iterator gsi
;
2017 struct prev_flag_edges
*prev_edges
= (struct prev_flag_edges
*) ex
->aux
;
2019 /* ?? Insert store after previous store if applicable. See note
2022 ex
= prev_edges
->append_cond_position
;
2024 loop_has_only_one_exit
= single_pred_p (ex
->dest
);
2026 if (loop_has_only_one_exit
)
2027 ex
= split_block_after_labels (ex
->dest
);
2029 old_dest
= ex
->dest
;
2030 new_bb
= split_edge (ex
);
2031 then_bb
= create_empty_bb (new_bb
);
2032 if (current_loops
&& new_bb
->loop_father
)
2033 add_bb_to_loop (then_bb
, new_bb
->loop_father
);
2035 gsi
= gsi_start_bb (new_bb
);
2036 stmt
= gimple_build_cond (NE_EXPR
, flag
, boolean_false_node
,
2037 NULL_TREE
, NULL_TREE
);
2038 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2040 gsi
= gsi_start_bb (then_bb
);
2041 /* Insert actual store. */
2042 stmt
= gimple_build_assign (unshare_expr (mem
), tmp_var
);
2043 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2045 make_edge (new_bb
, then_bb
, EDGE_TRUE_VALUE
);
2046 make_edge (new_bb
, old_dest
, EDGE_FALSE_VALUE
);
2047 then_old_edge
= make_edge (then_bb
, old_dest
, EDGE_FALLTHRU
);
2049 set_immediate_dominator (CDI_DOMINATORS
, then_bb
, new_bb
);
2053 basic_block prevbb
= prev_edges
->last_cond_fallthru
->src
;
2054 redirect_edge_succ (prev_edges
->last_cond_fallthru
, new_bb
);
2055 set_immediate_dominator (CDI_DOMINATORS
, new_bb
, prevbb
);
2056 set_immediate_dominator (CDI_DOMINATORS
, old_dest
,
2057 recompute_dominator (CDI_DOMINATORS
, old_dest
));
2060 /* ?? Because stores may alias, they must happen in the exact
2061 sequence they originally happened. Save the position right after
2062 the (_lsm) store we just created so we can continue appending after
2063 it and maintain the original order. */
2065 struct prev_flag_edges
*p
;
2068 orig_ex
->aux
= NULL
;
2069 alloc_aux_for_edge (orig_ex
, sizeof (struct prev_flag_edges
));
2070 p
= (struct prev_flag_edges
*) orig_ex
->aux
;
2071 p
->append_cond_position
= then_old_edge
;
2072 p
->last_cond_fallthru
= find_edge (new_bb
, old_dest
);
2073 orig_ex
->aux
= (void *) p
;
2076 if (!loop_has_only_one_exit
)
2077 for (gsi
= gsi_start_phis (old_dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2079 gimple phi
= gsi_stmt (gsi
);
2082 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
2083 if (gimple_phi_arg_edge (phi
, i
)->src
== new_bb
)
2085 tree arg
= gimple_phi_arg_def (phi
, i
);
2086 add_phi_arg (phi
, arg
, then_old_edge
, UNKNOWN_LOCATION
);
2090 /* Remove the original fall through edge. This was the
2091 single_succ_edge (new_bb). */
2092 EDGE_SUCC (new_bb
, 0)->flags
&= ~EDGE_FALLTHRU
;
2095 /* Helper function for execute_sm. On every location where REF is
2096 set, set an appropriate flag indicating the store. */
2099 execute_sm_if_changed_flag_set (struct loop
*loop
, mem_ref_p ref
)
2104 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
2105 char *str
= get_lsm_tmp_name (ref
->mem
, ~0);
2107 lsm_tmp_name_add ("_flag");
2108 flag
= make_rename_temp (boolean_type_node
, str
);
2109 get_all_locs_in_loop (loop
, ref
, &locs
);
2110 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
2112 gimple_stmt_iterator gsi
;
2115 gsi
= gsi_for_stmt (loc
->stmt
);
2116 stmt
= gimple_build_assign (flag
, boolean_true_node
);
2117 gsi_insert_after (&gsi
, stmt
, GSI_CONTINUE_LINKING
);
2119 VEC_free (mem_ref_loc_p
, heap
, locs
);
2123 /* Executes store motion of memory reference REF from LOOP.
2124 Exits from the LOOP are stored in EXITS. The initialization of the
2125 temporary variable is put to the preheader of the loop, and assignments
2126 to the reference from the temporary variable are emitted to exits. */
2129 execute_sm (struct loop
*loop
, VEC (edge
, heap
) *exits
, mem_ref_p ref
)
2131 tree tmp_var
, store_flag
;
2134 struct fmt_data fmt_data
;
2135 edge ex
, latch_edge
;
2136 struct lim_aux_data
*lim_data
;
2137 bool multi_threaded_model_p
= false;
2139 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2141 fprintf (dump_file
, "Executing store motion of ");
2142 print_generic_expr (dump_file
, ref
->mem
, 0);
2143 fprintf (dump_file
, " from loop %d\n", loop
->num
);
2146 tmp_var
= make_rename_temp (TREE_TYPE (ref
->mem
),
2147 get_lsm_tmp_name (ref
->mem
, ~0));
2149 fmt_data
.loop
= loop
;
2150 fmt_data
.orig_loop
= loop
;
2151 for_each_index (&ref
->mem
, force_move_till
, &fmt_data
);
2153 if (block_in_transaction (loop_preheader_edge (loop
)->src
)
2154 || !PARAM_VALUE (PARAM_ALLOW_STORE_DATA_RACES
))
2155 multi_threaded_model_p
= true;
2157 if (multi_threaded_model_p
)
2158 store_flag
= execute_sm_if_changed_flag_set (loop
, ref
);
2160 rewrite_mem_refs (loop
, ref
, tmp_var
);
2162 /* Emit the load code into the latch, so that we are sure it will
2163 be processed after all dependencies. */
2164 latch_edge
= loop_latch_edge (loop
);
2166 /* FIXME/TODO: For the multi-threaded variant, we could avoid this
2167 load altogether, since the store is predicated by a flag. We
2168 could, do the load only if it was originally in the loop. */
2169 load
= gimple_build_assign (tmp_var
, unshare_expr (ref
->mem
));
2170 lim_data
= init_lim_data (load
);
2171 lim_data
->max_loop
= loop
;
2172 lim_data
->tgt_loop
= loop
;
2173 gsi_insert_on_edge (latch_edge
, load
);
2175 if (multi_threaded_model_p
)
2177 load
= gimple_build_assign (store_flag
, boolean_false_node
);
2178 lim_data
= init_lim_data (load
);
2179 lim_data
->max_loop
= loop
;
2180 lim_data
->tgt_loop
= loop
;
2181 gsi_insert_on_edge (latch_edge
, load
);
2184 /* Sink the store to every exit from the loop. */
2185 FOR_EACH_VEC_ELT (edge
, exits
, i
, ex
)
2186 if (!multi_threaded_model_p
)
2189 store
= gimple_build_assign (unshare_expr (ref
->mem
), tmp_var
);
2190 gsi_insert_on_edge (ex
, store
);
2193 execute_sm_if_changed (ex
, ref
->mem
, tmp_var
, store_flag
);
2196 /* Hoists memory references MEM_REFS out of LOOP. EXITS is the list of exit
2197 edges of the LOOP. */
2200 hoist_memory_references (struct loop
*loop
, bitmap mem_refs
,
2201 VEC (edge
, heap
) *exits
)
2207 EXECUTE_IF_SET_IN_BITMAP (mem_refs
, 0, i
, bi
)
2209 ref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
2210 execute_sm (loop
, exits
, ref
);
2214 /* Returns true if REF is always accessed in LOOP. If STORED_P is true
2215 make sure REF is always stored to in LOOP. */
2218 ref_always_accessed_p (struct loop
*loop
, mem_ref_p ref
, bool stored_p
)
2220 VEC (mem_ref_loc_p
, heap
) *locs
= NULL
;
2224 struct loop
*must_exec
;
2227 base
= get_base_address (ref
->mem
);
2228 if (INDIRECT_REF_P (base
)
2229 || TREE_CODE (base
) == MEM_REF
)
2230 base
= TREE_OPERAND (base
, 0);
2232 get_all_locs_in_loop (loop
, ref
, &locs
);
2233 FOR_EACH_VEC_ELT (mem_ref_loc_p
, locs
, i
, loc
)
2235 if (!get_lim_data (loc
->stmt
))
2238 /* If we require an always executed store make sure the statement
2239 stores to the reference. */
2243 if (!gimple_get_lhs (loc
->stmt
))
2245 lhs
= get_base_address (gimple_get_lhs (loc
->stmt
));
2248 if (INDIRECT_REF_P (lhs
)
2249 || TREE_CODE (lhs
) == MEM_REF
)
2250 lhs
= TREE_OPERAND (lhs
, 0);
2255 must_exec
= get_lim_data (loc
->stmt
)->always_executed_in
;
2259 if (must_exec
== loop
2260 || flow_loop_nested_p (must_exec
, loop
))
2266 VEC_free (mem_ref_loc_p
, heap
, locs
);
2271 /* Returns true if REF1 and REF2 are independent. */
2274 refs_independent_p (mem_ref_p ref1
, mem_ref_p ref2
)
2277 || bitmap_bit_p (ref1
->indep_ref
, ref2
->id
))
2279 if (bitmap_bit_p (ref1
->dep_ref
, ref2
->id
))
2281 if (!MEM_ANALYZABLE (ref1
)
2282 || !MEM_ANALYZABLE (ref2
))
2285 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2286 fprintf (dump_file
, "Querying dependency of refs %u and %u: ",
2287 ref1
->id
, ref2
->id
);
2289 if (mem_refs_may_alias_p (ref1
->mem
, ref2
->mem
,
2290 &memory_accesses
.ttae_cache
))
2292 bitmap_set_bit (ref1
->dep_ref
, ref2
->id
);
2293 bitmap_set_bit (ref2
->dep_ref
, ref1
->id
);
2294 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2295 fprintf (dump_file
, "dependent.\n");
2300 bitmap_set_bit (ref1
->indep_ref
, ref2
->id
);
2301 bitmap_set_bit (ref2
->indep_ref
, ref1
->id
);
2302 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2303 fprintf (dump_file
, "independent.\n");
2308 /* Records the information whether REF is independent in LOOP (according
2312 record_indep_loop (struct loop
*loop
, mem_ref_p ref
, bool indep
)
2315 bitmap_set_bit (ref
->indep_loop
, loop
->num
);
2317 bitmap_set_bit (ref
->dep_loop
, loop
->num
);
2320 /* Returns true if REF is independent on all other memory references in
2324 ref_indep_loop_p_1 (struct loop
*loop
, mem_ref_p ref
)
2326 bitmap refs_to_check
;
2329 bool ret
= true, stored
= bitmap_bit_p (ref
->stored
, loop
->num
);
2333 refs_to_check
= VEC_index (bitmap
,
2334 memory_accesses
.all_refs_in_loop
, loop
->num
);
2336 refs_to_check
= VEC_index (bitmap
,
2337 memory_accesses
.all_refs_stored_in_loop
,
2340 EXECUTE_IF_SET_IN_BITMAP (refs_to_check
, 0, i
, bi
)
2342 aref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
2343 if (!MEM_ANALYZABLE (aref
)
2344 || !refs_independent_p (ref
, aref
))
2347 record_indep_loop (loop
, aref
, false);
2355 /* Returns true if REF is independent on all other memory references in
2356 LOOP. Wrapper over ref_indep_loop_p_1, caching its results. */
2359 ref_indep_loop_p (struct loop
*loop
, mem_ref_p ref
)
2363 if (bitmap_bit_p (ref
->indep_loop
, loop
->num
))
2365 if (bitmap_bit_p (ref
->dep_loop
, loop
->num
))
2368 ret
= ref_indep_loop_p_1 (loop
, ref
);
2370 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2371 fprintf (dump_file
, "Querying dependencies of ref %u in loop %d: %s\n",
2372 ref
->id
, loop
->num
, ret
? "independent" : "dependent");
2374 record_indep_loop (loop
, ref
, ret
);
2379 /* Returns true if we can perform store motion of REF from LOOP. */
2382 can_sm_ref_p (struct loop
*loop
, mem_ref_p ref
)
2386 /* Can't hoist unanalyzable refs. */
2387 if (!MEM_ANALYZABLE (ref
))
2390 /* Unless the reference is stored in the loop, there is nothing to do. */
2391 if (!bitmap_bit_p (ref
->stored
, loop
->num
))
2394 /* It should be movable. */
2395 if (!is_gimple_reg_type (TREE_TYPE (ref
->mem
))
2396 || TREE_THIS_VOLATILE (ref
->mem
)
2397 || !for_each_index (&ref
->mem
, may_move_till
, loop
))
2400 /* If it can throw fail, we do not properly update EH info. */
2401 if (tree_could_throw_p (ref
->mem
))
2404 /* If it can trap, it must be always executed in LOOP.
2405 Readonly memory locations may trap when storing to them, but
2406 tree_could_trap_p is a predicate for rvalues, so check that
2408 base
= get_base_address (ref
->mem
);
2409 if ((tree_could_trap_p (ref
->mem
)
2410 || (DECL_P (base
) && TREE_READONLY (base
)))
2411 && !ref_always_accessed_p (loop
, ref
, true))
2414 /* And it must be independent on all other memory references
2416 if (!ref_indep_loop_p (loop
, ref
))
2422 /* Marks the references in LOOP for that store motion should be performed
2423 in REFS_TO_SM. SM_EXECUTED is the set of references for that store
2424 motion was performed in one of the outer loops. */
2427 find_refs_for_sm (struct loop
*loop
, bitmap sm_executed
, bitmap refs_to_sm
)
2429 bitmap refs
= VEC_index (bitmap
, memory_accesses
.all_refs_in_loop
,
2435 EXECUTE_IF_AND_COMPL_IN_BITMAP (refs
, sm_executed
, 0, i
, bi
)
2437 ref
= VEC_index (mem_ref_p
, memory_accesses
.refs_list
, i
);
2438 if (can_sm_ref_p (loop
, ref
))
2439 bitmap_set_bit (refs_to_sm
, i
);
2443 /* Checks whether LOOP (with exits stored in EXITS array) is suitable
2444 for a store motion optimization (i.e. whether we can insert statement
2448 loop_suitable_for_sm (struct loop
*loop ATTRIBUTE_UNUSED
,
2449 VEC (edge
, heap
) *exits
)
2454 FOR_EACH_VEC_ELT (edge
, exits
, i
, ex
)
2455 if (ex
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
2461 /* Try to perform store motion for all memory references modified inside
2462 LOOP. SM_EXECUTED is the bitmap of the memory references for that
2463 store motion was executed in one of the outer loops. */
2466 store_motion_loop (struct loop
*loop
, bitmap sm_executed
)
2468 VEC (edge
, heap
) *exits
= get_loop_exit_edges (loop
);
2469 struct loop
*subloop
;
2470 bitmap sm_in_loop
= BITMAP_ALLOC (NULL
);
2472 if (loop_suitable_for_sm (loop
, exits
))
2474 find_refs_for_sm (loop
, sm_executed
, sm_in_loop
);
2475 hoist_memory_references (loop
, sm_in_loop
, exits
);
2477 VEC_free (edge
, heap
, exits
);
2479 bitmap_ior_into (sm_executed
, sm_in_loop
);
2480 for (subloop
= loop
->inner
; subloop
!= NULL
; subloop
= subloop
->next
)
2481 store_motion_loop (subloop
, sm_executed
);
2482 bitmap_and_compl_into (sm_executed
, sm_in_loop
);
2483 BITMAP_FREE (sm_in_loop
);
2486 /* Try to perform store motion for all memory references modified inside
2493 bitmap sm_executed
= BITMAP_ALLOC (NULL
);
2495 for (loop
= current_loops
->tree_root
->inner
; loop
!= NULL
; loop
= loop
->next
)
2496 store_motion_loop (loop
, sm_executed
);
2498 BITMAP_FREE (sm_executed
);
2499 gsi_commit_edge_inserts ();
2502 /* Fills ALWAYS_EXECUTED_IN information for basic blocks of LOOP, i.e.
2503 for each such basic block bb records the outermost loop for that execution
2504 of its header implies execution of bb. CONTAINS_CALL is the bitmap of
2505 blocks that contain a nonpure call. */
2508 fill_always_executed_in (struct loop
*loop
, sbitmap contains_call
)
2510 basic_block bb
= NULL
, *bbs
, last
= NULL
;
2513 struct loop
*inn_loop
= loop
;
2515 if (ALWAYS_EXECUTED_IN (loop
->header
) == NULL
)
2517 bbs
= get_loop_body_in_dom_order (loop
);
2519 for (i
= 0; i
< loop
->num_nodes
; i
++)
2524 if (dominated_by_p (CDI_DOMINATORS
, loop
->latch
, bb
))
2527 if (TEST_BIT (contains_call
, bb
->index
))
2530 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2531 if (!flow_bb_inside_loop_p (loop
, e
->dest
))
2536 /* A loop might be infinite (TODO use simple loop analysis
2537 to disprove this if possible). */
2538 if (bb
->flags
& BB_IRREDUCIBLE_LOOP
)
2541 if (!flow_bb_inside_loop_p (inn_loop
, bb
))
2544 if (bb
->loop_father
->header
== bb
)
2546 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, bb
))
2549 /* In a loop that is always entered we may proceed anyway.
2550 But record that we entered it and stop once we leave it. */
2551 inn_loop
= bb
->loop_father
;
2557 SET_ALWAYS_EXECUTED_IN (last
, loop
);
2558 if (last
== loop
->header
)
2560 last
= get_immediate_dominator (CDI_DOMINATORS
, last
);
2566 for (loop
= loop
->inner
; loop
; loop
= loop
->next
)
2567 fill_always_executed_in (loop
, contains_call
);
2570 /* Compute the global information needed by the loop invariant motion pass. */
2573 tree_ssa_lim_initialize (void)
2575 sbitmap contains_call
= sbitmap_alloc (last_basic_block
);
2576 gimple_stmt_iterator bsi
;
2580 sbitmap_zero (contains_call
);
2583 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
2585 if (nonpure_call_p (gsi_stmt (bsi
)))
2589 if (!gsi_end_p (bsi
))
2590 SET_BIT (contains_call
, bb
->index
);
2593 for (loop
= current_loops
->tree_root
->inner
; loop
; loop
= loop
->next
)
2594 fill_always_executed_in (loop
, contains_call
);
2596 sbitmap_free (contains_call
);
2598 lim_aux_data_map
= pointer_map_create ();
2601 compute_transaction_bits ();
2603 alloc_aux_for_edges (0);
2606 /* Cleans up after the invariant motion pass. */
2609 tree_ssa_lim_finalize (void)
2615 free_aux_for_edges ();
2618 SET_ALWAYS_EXECUTED_IN (bb
, NULL
);
2620 pointer_map_destroy (lim_aux_data_map
);
2622 VEC_free (mem_ref_p
, heap
, memory_accesses
.refs_list
);
2623 htab_delete (memory_accesses
.refs
);
2625 FOR_EACH_VEC_ELT (bitmap
, memory_accesses
.refs_in_loop
, i
, b
)
2627 VEC_free (bitmap
, heap
, memory_accesses
.refs_in_loop
);
2629 FOR_EACH_VEC_ELT (bitmap
, memory_accesses
.all_refs_in_loop
, i
, b
)
2631 VEC_free (bitmap
, heap
, memory_accesses
.all_refs_in_loop
);
2633 FOR_EACH_VEC_ELT (bitmap
, memory_accesses
.all_refs_stored_in_loop
, i
, b
)
2635 VEC_free (bitmap
, heap
, memory_accesses
.all_refs_stored_in_loop
);
2637 if (memory_accesses
.ttae_cache
)
2638 pointer_map_destroy (memory_accesses
.ttae_cache
);
2641 /* Moves invariants from loops. Only "expensive" invariants are moved out --
2642 i.e. those that are likely to be win regardless of the register pressure. */
2649 tree_ssa_lim_initialize ();
2651 /* Gathers information about memory accesses in the loops. */
2652 analyze_memory_references ();
2654 /* For each statement determine the outermost loop in that it is
2655 invariant and cost for computing the invariant. */
2656 determine_invariantness ();
2658 /* Execute store motion. Force the necessary invariants to be moved
2659 out of the loops as well. */
2662 /* Move the expressions that are expensive enough. */
2663 todo
= move_computations ();
2665 tree_ssa_lim_finalize ();