1 /* High-level loop manipulation functions.
2 Copyright (C) 2004-2020 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 3, or (at your option) any
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
27 #include "tree-pass.h" /* ??? for TODO_update_ssa but this isn't a pass. */
29 #include "gimple-pretty-print.h"
30 #include "fold-const.h"
33 #include "gimple-iterator.h"
34 #include "gimplify-me.h"
36 #include "tree-ssa-loop-ivopts.h"
37 #include "tree-ssa-loop-manip.h"
38 #include "tree-ssa-loop-niter.h"
39 #include "tree-ssa-loop.h"
40 #include "tree-into-ssa.h"
43 #include "tree-scalar-evolution.h"
44 #include "tree-inline.h"
46 /* All bitmaps for rewriting into loop-closed SSA go on this obstack,
47 so that we can free them all at once. */
48 static bitmap_obstack loop_renamer_obstack
;
50 /* Creates an induction variable with value BASE + STEP * iteration in LOOP.
51 It is expected that neither BASE nor STEP are shared with other expressions
52 (unless the sharing rules allow this). Use VAR as a base var_decl for it
53 (if NULL, a new temporary will be created). The increment will occur at
54 INCR_POS (after it if AFTER is true, before it otherwise). INCR_POS and
55 AFTER can be computed using standard_iv_increment_position. The ssa versions
56 of the variable before and after increment will be stored in VAR_BEFORE and
57 VAR_AFTER (unless they are NULL). */
60 create_iv (tree base
, tree step
, tree var
, class loop
*loop
,
61 gimple_stmt_iterator
*incr_pos
, bool after
,
62 tree
*var_before
, tree
*var_after
)
69 enum tree_code incr_op
= PLUS_EXPR
;
70 edge pe
= loop_preheader_edge (loop
);
74 vb
= make_ssa_name (var
);
75 va
= make_ssa_name (var
);
79 vb
= make_temp_ssa_name (TREE_TYPE (base
), NULL
, "ivtmp");
80 va
= make_temp_ssa_name (TREE_TYPE (base
), NULL
, "ivtmp");
87 /* For easier readability of the created code, produce MINUS_EXPRs
89 if (TREE_CODE (step
) == INTEGER_CST
)
91 if (TYPE_UNSIGNED (TREE_TYPE (step
)))
93 step1
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (step
), step
);
94 if (tree_int_cst_lt (step1
, step
))
104 if (!tree_expr_nonnegative_warnv_p (step
, &ovf
)
105 && may_negate_without_overflow_p (step
))
107 incr_op
= MINUS_EXPR
;
108 step
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (step
), step
);
112 if (POINTER_TYPE_P (TREE_TYPE (base
)))
114 if (TREE_CODE (base
) == ADDR_EXPR
)
115 mark_addressable (TREE_OPERAND (base
, 0));
116 step
= convert_to_ptrofftype (step
);
117 if (incr_op
== MINUS_EXPR
)
118 step
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (step
), step
);
119 incr_op
= POINTER_PLUS_EXPR
;
121 /* Gimplify the step if necessary. We put the computations in front of the
122 loop (i.e. the step should be loop invariant). */
123 step
= force_gimple_operand (step
, &stmts
, true, NULL_TREE
);
125 gsi_insert_seq_on_edge_immediate (pe
, stmts
);
127 stmt
= gimple_build_assign (va
, incr_op
, vb
, step
);
128 /* Prevent the increment from inheriting a bogus location if it is not put
129 immediately after a statement whose location is known. */
132 if (gsi_end_p (*incr_pos
)
133 || (is_gimple_debug (gsi_stmt (*incr_pos
))
134 && gsi_bb (*incr_pos
)
135 && gsi_end_p (gsi_last_nondebug_bb (gsi_bb (*incr_pos
)))))
137 edge e
= single_succ_edge (gsi_bb (*incr_pos
));
138 gimple_set_location (stmt
, e
->goto_locus
);
140 gsi_insert_after (incr_pos
, stmt
, GSI_NEW_STMT
);
144 gimple_stmt_iterator gsi
= *incr_pos
;
145 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
146 gsi_next_nondebug (&gsi
);
147 if (!gsi_end_p (gsi
))
148 gimple_set_location (stmt
, gimple_location (gsi_stmt (gsi
)));
149 gsi_insert_before (incr_pos
, stmt
, GSI_NEW_STMT
);
152 initial
= force_gimple_operand (base
, &stmts
, true, var
);
154 gsi_insert_seq_on_edge_immediate (pe
, stmts
);
156 phi
= create_phi_node (vb
, loop
->header
);
157 add_phi_arg (phi
, initial
, loop_preheader_edge (loop
), UNKNOWN_LOCATION
);
158 add_phi_arg (phi
, va
, loop_latch_edge (loop
), UNKNOWN_LOCATION
);
161 /* Return the innermost superloop LOOP of USE_LOOP that is a superloop of
162 both DEF_LOOP and USE_LOOP. */
164 static inline class loop
*
165 find_sibling_superloop (class loop
*use_loop
, class loop
*def_loop
)
167 unsigned ud
= loop_depth (use_loop
);
168 unsigned dd
= loop_depth (def_loop
);
169 gcc_assert (ud
> 0 && dd
> 0);
171 use_loop
= superloop_at_depth (use_loop
, dd
);
173 def_loop
= superloop_at_depth (def_loop
, ud
);
174 while (loop_outer (use_loop
) != loop_outer (def_loop
))
176 use_loop
= loop_outer (use_loop
);
177 def_loop
= loop_outer (def_loop
);
178 gcc_assert (use_loop
&& def_loop
);
183 /* DEF_BB is a basic block containing a DEF that needs rewriting into
184 loop-closed SSA form. USE_BLOCKS is the set of basic blocks containing
185 uses of DEF that "escape" from the loop containing DEF_BB (i.e. blocks in
186 USE_BLOCKS are dominated by DEF_BB but not in the loop father of DEF_B).
187 ALL_EXITS[I] is the set of all basic blocks that exit loop I.
189 Compute the subset of LOOP_EXITS that exit the loop containing DEF_BB
190 or one of its loop fathers, in which DEF is live. This set is returned
191 in the bitmap LIVE_EXITS.
193 Instead of computing the complete livein set of the def, we use the loop
194 nesting tree as a form of poor man's structure analysis. This greatly
195 speeds up the analysis, which is important because this function may be
196 called on all SSA names that need rewriting, one at a time. */
199 compute_live_loop_exits (bitmap live_exits
, bitmap use_blocks
,
200 bitmap
*loop_exits
, basic_block def_bb
)
204 class loop
*def_loop
= def_bb
->loop_father
;
205 unsigned def_loop_depth
= loop_depth (def_loop
);
206 bitmap def_loop_exits
;
208 /* Normally the work list size is bounded by the number of basic
209 blocks in the largest loop. We don't know this number, but we
210 can be fairly sure that it will be relatively small. */
211 auto_vec
<basic_block
> worklist (MAX (8, n_basic_blocks_for_fn (cfun
) / 128));
213 EXECUTE_IF_SET_IN_BITMAP (use_blocks
, 0, i
, bi
)
215 basic_block use_bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
216 class loop
*use_loop
= use_bb
->loop_father
;
217 gcc_checking_assert (def_loop
!= use_loop
218 && ! flow_loop_nested_p (def_loop
, use_loop
));
219 if (! flow_loop_nested_p (use_loop
, def_loop
))
220 use_bb
= find_sibling_superloop (use_loop
, def_loop
)->header
;
221 if (bitmap_set_bit (live_exits
, use_bb
->index
))
222 worklist
.safe_push (use_bb
);
225 /* Iterate until the worklist is empty. */
226 while (! worklist
.is_empty ())
231 /* Pull a block off the worklist. */
232 basic_block bb
= worklist
.pop ();
234 /* Make sure we have at least enough room in the work list
235 for all predecessors of this block. */
236 worklist
.reserve (EDGE_COUNT (bb
->preds
));
238 /* For each predecessor block. */
239 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
241 basic_block pred
= e
->src
;
242 class loop
*pred_loop
= pred
->loop_father
;
243 unsigned pred_loop_depth
= loop_depth (pred_loop
);
246 /* We should have met DEF_BB along the way. */
247 gcc_assert (pred
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
));
249 if (pred_loop_depth
>= def_loop_depth
)
251 if (pred_loop_depth
> def_loop_depth
)
252 pred_loop
= superloop_at_depth (pred_loop
, def_loop_depth
);
253 /* If we've reached DEF_LOOP, our train ends here. */
254 if (pred_loop
== def_loop
)
257 else if (! flow_loop_nested_p (pred_loop
, def_loop
))
258 pred
= find_sibling_superloop (pred_loop
, def_loop
)->header
;
260 /* Add PRED to the LIVEIN set. PRED_VISITED is true if
261 we had already added PRED to LIVEIN before. */
262 pred_visited
= !bitmap_set_bit (live_exits
, pred
->index
);
264 /* If we have visited PRED before, don't add it to the worklist.
265 If BB dominates PRED, then we're probably looking at a loop.
266 We're only interested in looking up in the dominance tree
267 because DEF_BB dominates all the uses. */
268 if (pred_visited
|| dominated_by_p (CDI_DOMINATORS
, pred
, bb
))
271 worklist
.quick_push (pred
);
275 def_loop_exits
= BITMAP_ALLOC (&loop_renamer_obstack
);
276 for (class loop
*loop
= def_loop
;
277 loop
!= current_loops
->tree_root
;
278 loop
= loop_outer (loop
))
279 bitmap_ior_into (def_loop_exits
, loop_exits
[loop
->num
]);
280 bitmap_and_into (live_exits
, def_loop_exits
);
281 BITMAP_FREE (def_loop_exits
);
284 /* Add a loop-closing PHI for VAR in basic block EXIT. */
287 add_exit_phi (basic_block exit
, tree var
)
293 /* Check that at least one of the edges entering the EXIT block exits
294 the loop, or a superloop of that loop, that VAR is defined in. */
297 gimple
*def_stmt
= SSA_NAME_DEF_STMT (var
);
298 basic_block def_bb
= gimple_bb (def_stmt
);
299 FOR_EACH_EDGE (e
, ei
, exit
->preds
)
301 class loop
*aloop
= find_common_loop (def_bb
->loop_father
,
302 e
->src
->loop_father
);
303 if (!flow_bb_inside_loop_p (aloop
, e
->dest
))
309 phi
= create_phi_node (NULL_TREE
, exit
);
310 create_new_def_for (var
, phi
, gimple_phi_result_ptr (phi
));
311 FOR_EACH_EDGE (e
, ei
, exit
->preds
)
312 add_phi_arg (phi
, var
, e
, UNKNOWN_LOCATION
);
314 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
316 fprintf (dump_file
, ";; Created LCSSA PHI: ");
317 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
321 /* Add exit phis for VAR that is used in LIVEIN.
322 Exits of the loops are stored in LOOP_EXITS. */
325 add_exit_phis_var (tree var
, bitmap use_blocks
, bitmap
*loop_exits
)
329 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (var
));
330 bitmap live_exits
= BITMAP_ALLOC (&loop_renamer_obstack
);
332 gcc_checking_assert (! bitmap_bit_p (use_blocks
, def_bb
->index
));
334 compute_live_loop_exits (live_exits
, use_blocks
, loop_exits
, def_bb
);
336 EXECUTE_IF_SET_IN_BITMAP (live_exits
, 0, index
, bi
)
338 add_exit_phi (BASIC_BLOCK_FOR_FN (cfun
, index
), var
);
341 BITMAP_FREE (live_exits
);
344 /* Add exit phis for the names marked in NAMES_TO_RENAME.
345 Exits of the loops are stored in EXITS. Sets of blocks where the ssa
346 names are used are stored in USE_BLOCKS. */
349 add_exit_phis (bitmap names_to_rename
, bitmap
*use_blocks
, bitmap
*loop_exits
)
354 EXECUTE_IF_SET_IN_BITMAP (names_to_rename
, 0, i
, bi
)
356 add_exit_phis_var (ssa_name (i
), use_blocks
[i
], loop_exits
);
360 /* Fill the array of bitmaps LOOP_EXITS with all loop exit edge targets. */
363 get_loops_exits (bitmap
*loop_exits
)
369 FOR_EACH_LOOP (loop
, 0)
371 vec
<edge
> exit_edges
= get_loop_exit_edges (loop
);
372 loop_exits
[loop
->num
] = BITMAP_ALLOC (&loop_renamer_obstack
);
373 FOR_EACH_VEC_ELT (exit_edges
, j
, e
)
374 bitmap_set_bit (loop_exits
[loop
->num
], e
->dest
->index
);
375 exit_edges
.release ();
379 /* For USE in BB, if it is used outside of the loop it is defined in,
380 mark it for rewrite. Record basic block BB where it is used
381 to USE_BLOCKS. Record the ssa name index to NEED_PHIS bitmap.
382 Note that for USEs in phis, BB should be the src of the edge corresponding to
383 the use, rather than the bb containing the phi. */
386 find_uses_to_rename_use (basic_block bb
, tree use
, bitmap
*use_blocks
,
391 class loop
*def_loop
;
393 if (TREE_CODE (use
) != SSA_NAME
)
396 ver
= SSA_NAME_VERSION (use
);
397 def_bb
= gimple_bb (SSA_NAME_DEF_STMT (use
));
400 def_loop
= def_bb
->loop_father
;
402 /* If the definition is not inside a loop, it is not interesting. */
403 if (!loop_outer (def_loop
))
406 /* If the use is not outside of the loop it is defined in, it is not
408 if (flow_bb_inside_loop_p (def_loop
, bb
))
411 /* If we're seeing VER for the first time, we still have to allocate
412 a bitmap for its uses. */
413 if (bitmap_set_bit (need_phis
, ver
))
414 use_blocks
[ver
] = BITMAP_ALLOC (&loop_renamer_obstack
);
415 bitmap_set_bit (use_blocks
[ver
], bb
->index
);
418 /* For uses matching USE_FLAGS in STMT, mark names that are used outside of the
419 loop they are defined to rewrite. Record the set of blocks in which the ssa
420 names are used to USE_BLOCKS, and the ssa names themselves to NEED_PHIS. */
423 find_uses_to_rename_stmt (gimple
*stmt
, bitmap
*use_blocks
, bitmap need_phis
,
428 basic_block bb
= gimple_bb (stmt
);
430 if (is_gimple_debug (stmt
))
433 /* FOR_EACH_SSA_TREE_OPERAND iterator does not allows SSA_OP_VIRTUAL_USES
435 if (use_flags
== SSA_OP_VIRTUAL_USES
)
437 tree vuse
= gimple_vuse (stmt
);
438 if (vuse
!= NULL_TREE
)
439 find_uses_to_rename_use (bb
, gimple_vuse (stmt
), use_blocks
, need_phis
);
442 FOR_EACH_SSA_TREE_OPERAND (var
, stmt
, iter
, use_flags
)
443 find_uses_to_rename_use (bb
, var
, use_blocks
, need_phis
);
446 /* Marks names matching USE_FLAGS that are used in BB and outside of the loop
447 they are defined in for rewrite. Records the set of blocks in which the ssa
448 names are used to USE_BLOCKS. Record the SSA names that will
449 need exit PHIs in NEED_PHIS. */
452 find_uses_to_rename_bb (basic_block bb
, bitmap
*use_blocks
, bitmap need_phis
,
457 bool do_virtuals
= (use_flags
& SSA_OP_VIRTUAL_USES
) != 0;
458 bool do_nonvirtuals
= (use_flags
& SSA_OP_USE
) != 0;
460 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
461 for (gphi_iterator bsi
= gsi_start_phis (e
->dest
); !gsi_end_p (bsi
);
464 gphi
*phi
= bsi
.phi ();
465 bool virtual_p
= virtual_operand_p (gimple_phi_result (phi
));
466 if ((virtual_p
&& do_virtuals
)
467 || (!virtual_p
&& do_nonvirtuals
))
468 find_uses_to_rename_use (bb
, PHI_ARG_DEF_FROM_EDGE (phi
, e
),
469 use_blocks
, need_phis
);
472 for (gimple_stmt_iterator bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
);
474 find_uses_to_rename_stmt (gsi_stmt (bsi
), use_blocks
, need_phis
,
478 /* Marks names matching USE_FLAGS that are used outside of the loop they are
479 defined in for rewrite. Records the set of blocks in which the ssa names are
480 used to USE_BLOCKS. Record the SSA names that will need exit PHIs in
481 NEED_PHIS. If CHANGED_BBS is not NULL, scan only blocks in this set. */
484 find_uses_to_rename (bitmap changed_bbs
, bitmap
*use_blocks
, bitmap need_phis
,
492 EXECUTE_IF_SET_IN_BITMAP (changed_bbs
, 0, index
, bi
)
494 bb
= BASIC_BLOCK_FOR_FN (cfun
, index
);
496 find_uses_to_rename_bb (bb
, use_blocks
, need_phis
, use_flags
);
499 FOR_EACH_BB_FN (bb
, cfun
)
500 find_uses_to_rename_bb (bb
, use_blocks
, need_phis
, use_flags
);
503 /* Mark uses of DEF that are used outside of the loop they are defined in for
504 rewrite. Record the set of blocks in which the ssa names are used to
505 USE_BLOCKS. Record the SSA names that will need exit PHIs in NEED_PHIS. */
508 find_uses_to_rename_def (tree def
, bitmap
*use_blocks
, bitmap need_phis
)
511 imm_use_iterator imm_iter
;
513 FOR_EACH_IMM_USE_STMT (use_stmt
, imm_iter
, def
)
515 if (is_gimple_debug (use_stmt
))
518 basic_block use_bb
= gimple_bb (use_stmt
);
521 FOR_EACH_IMM_USE_ON_STMT (use_p
, imm_iter
)
523 if (gimple_code (use_stmt
) == GIMPLE_PHI
)
525 edge e
= gimple_phi_arg_edge (as_a
<gphi
*> (use_stmt
),
526 PHI_ARG_INDEX_FROM_USE (use_p
));
529 find_uses_to_rename_use (use_bb
, USE_FROM_PTR (use_p
), use_blocks
,
535 /* Marks names matching USE_FLAGS that are defined in LOOP and used outside of
536 it for rewrite. Records the set of blocks in which the ssa names are used to
537 USE_BLOCKS. Record the SSA names that will need exit PHIs in NEED_PHIS. */
540 find_uses_to_rename_in_loop (class loop
*loop
, bitmap
*use_blocks
,
541 bitmap need_phis
, int use_flags
)
543 bool do_virtuals
= (use_flags
& SSA_OP_VIRTUAL_USES
) != 0;
544 bool do_nonvirtuals
= (use_flags
& SSA_OP_USE
) != 0;
545 int def_flags
= ((do_virtuals
? SSA_OP_VIRTUAL_DEFS
: 0)
546 | (do_nonvirtuals
? SSA_OP_DEF
: 0));
549 basic_block
*bbs
= get_loop_body (loop
);
551 for (unsigned int i
= 0; i
< loop
->num_nodes
; i
++)
553 basic_block bb
= bbs
[i
];
555 for (gphi_iterator bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
);
558 gphi
*phi
= bsi
.phi ();
559 tree res
= gimple_phi_result (phi
);
560 bool virtual_p
= virtual_operand_p (res
);
561 if ((virtual_p
&& do_virtuals
)
562 || (!virtual_p
&& do_nonvirtuals
))
563 find_uses_to_rename_def (res
, use_blocks
, need_phis
);
566 for (gimple_stmt_iterator bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
);
569 gimple
*stmt
= gsi_stmt (bsi
);
570 /* FOR_EACH_SSA_TREE_OPERAND iterator does not allows
571 SSA_OP_VIRTUAL_DEFS only. */
572 if (def_flags
== SSA_OP_VIRTUAL_DEFS
)
574 tree vdef
= gimple_vdef (stmt
);
576 find_uses_to_rename_def (vdef
, use_blocks
, need_phis
);
582 FOR_EACH_SSA_TREE_OPERAND (var
, stmt
, iter
, def_flags
)
583 find_uses_to_rename_def (var
, use_blocks
, need_phis
);
591 /* Rewrites the program into a loop closed ssa form -- i.e. inserts extra
592 phi nodes to ensure that no variable is used outside the loop it is
595 This strengthening of the basic ssa form has several advantages:
597 1) Updating it during unrolling/peeling/versioning is trivial, since
598 we do not need to care about the uses outside of the loop.
599 The same applies to virtual operands which are also rewritten into
600 loop closed SSA form. Note that virtual operands are always live
602 2) The behavior of all uses of an induction variable is the same.
603 Without this, you need to distinguish the case when the variable
604 is used outside of the loop it is defined in, for example
606 for (i = 0; i < 100; i++)
608 for (j = 0; j < 100; j++)
616 Looking from the outer loop with the normal SSA form, the first use of k
617 is not well-behaved, while the second one is an induction variable with
620 If LOOP is non-null, only rewrite uses that have defs in LOOP. Otherwise,
621 if CHANGED_BBS is not NULL, we look for uses outside loops only in the
622 basic blocks in this set.
624 USE_FLAGS allows us to specify whether we want virtual, non-virtual or
625 both variables rewritten.
627 UPDATE_FLAG is used in the call to update_ssa. See
628 TODO_update_ssa* for documentation. */
631 rewrite_into_loop_closed_ssa_1 (bitmap changed_bbs
, unsigned update_flag
,
632 int use_flags
, class loop
*loop
)
635 bitmap names_to_rename
;
637 loops_state_set (LOOP_CLOSED_SSA
);
638 if (number_of_loops (cfun
) <= 1)
641 /* If the pass has caused the SSA form to be out-of-date, update it
643 if (update_flag
!= 0)
644 update_ssa (update_flag
);
645 else if (flag_checking
)
646 verify_ssa (true, true);
648 bitmap_obstack_initialize (&loop_renamer_obstack
);
650 names_to_rename
= BITMAP_ALLOC (&loop_renamer_obstack
);
652 /* Uses of names to rename. We don't have to initialize this array,
653 because we know that we will only have entries for the SSA names
654 in NAMES_TO_RENAME. */
655 use_blocks
= XNEWVEC (bitmap
, num_ssa_names
);
659 gcc_assert (changed_bbs
== NULL
);
660 find_uses_to_rename_in_loop (loop
, use_blocks
, names_to_rename
,
665 gcc_assert (loop
== NULL
);
666 find_uses_to_rename (changed_bbs
, use_blocks
, names_to_rename
, use_flags
);
669 if (!bitmap_empty_p (names_to_rename
))
671 /* An array of bitmaps where LOOP_EXITS[I] is the set of basic blocks
672 that are the destination of an edge exiting loop number I. */
673 bitmap
*loop_exits
= XNEWVEC (bitmap
, number_of_loops (cfun
));
674 get_loops_exits (loop_exits
);
676 /* Add the PHI nodes on exits of the loops for the names we need to
678 add_exit_phis (names_to_rename
, use_blocks
, loop_exits
);
682 /* Fix up all the names found to be used outside their original
684 update_ssa (TODO_update_ssa
);
687 bitmap_obstack_release (&loop_renamer_obstack
);
691 /* Rewrites the non-virtual defs and uses into a loop closed ssa form. If
692 CHANGED_BBS is not NULL, we look for uses outside loops only in the basic
693 blocks in this set. UPDATE_FLAG is used in the call to update_ssa. See
694 TODO_update_ssa* for documentation. */
697 rewrite_into_loop_closed_ssa (bitmap changed_bbs
, unsigned update_flag
)
699 rewrite_into_loop_closed_ssa_1 (changed_bbs
, update_flag
, SSA_OP_USE
, NULL
);
702 /* Rewrites virtual defs and uses with def in LOOP into loop closed ssa
706 rewrite_virtuals_into_loop_closed_ssa (class loop
*loop
)
708 rewrite_into_loop_closed_ssa_1 (NULL
, 0, SSA_OP_VIRTUAL_USES
, loop
);
711 /* Check invariants of the loop closed ssa form for the def in DEF_BB. */
714 check_loop_closed_ssa_def (basic_block def_bb
, tree def
)
717 imm_use_iterator iterator
;
718 FOR_EACH_IMM_USE_FAST (use_p
, iterator
, def
)
720 if (is_gimple_debug (USE_STMT (use_p
)))
723 basic_block use_bb
= gimple_bb (USE_STMT (use_p
));
724 if (is_a
<gphi
*> (USE_STMT (use_p
)))
725 use_bb
= EDGE_PRED (use_bb
, PHI_ARG_INDEX_FROM_USE (use_p
))->src
;
727 gcc_assert (flow_bb_inside_loop_p (def_bb
->loop_father
, use_bb
));
731 /* Checks invariants of loop closed ssa form in BB. */
734 check_loop_closed_ssa_bb (basic_block bb
)
736 for (gphi_iterator bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
);
739 gphi
*phi
= bsi
.phi ();
741 if (!virtual_operand_p (PHI_RESULT (phi
)))
742 check_loop_closed_ssa_def (bb
, PHI_RESULT (phi
));
745 for (gimple_stmt_iterator bsi
= gsi_start_nondebug_bb (bb
); !gsi_end_p (bsi
);
746 gsi_next_nondebug (&bsi
))
750 gimple
*stmt
= gsi_stmt (bsi
);
752 FOR_EACH_SSA_TREE_OPERAND (var
, stmt
, iter
, SSA_OP_DEF
)
753 check_loop_closed_ssa_def (bb
, var
);
757 /* Checks that invariants of the loop closed ssa form are preserved.
758 Call verify_ssa when VERIFY_SSA_P is true. Note all loops are checked
759 if LOOP is NULL, otherwise, only LOOP is checked. */
762 verify_loop_closed_ssa (bool verify_ssa_p
, class loop
*loop
)
764 if (number_of_loops (cfun
) <= 1)
768 verify_ssa (false, true);
770 timevar_push (TV_VERIFY_LOOP_CLOSED
);
776 FOR_EACH_BB_FN (bb
, cfun
)
777 if (bb
->loop_father
&& bb
->loop_father
->num
> 0)
778 check_loop_closed_ssa_bb (bb
);
782 basic_block
*bbs
= get_loop_body (loop
);
784 for (unsigned i
= 0; i
< loop
->num_nodes
; ++i
)
785 check_loop_closed_ssa_bb (bbs
[i
]);
790 timevar_pop (TV_VERIFY_LOOP_CLOSED
);
793 /* Split loop exit edge EXIT. The things are a bit complicated by a need to
794 preserve the loop closed ssa form. If COPY_CONSTANTS_P is true then
795 forwarder PHIs are also created for constant arguments.
796 The newly created block is returned. */
799 split_loop_exit_edge (edge exit
, bool copy_constants_p
)
801 basic_block dest
= exit
->dest
;
802 basic_block bb
= split_edge (exit
);
809 for (psi
= gsi_start_phis (dest
); !gsi_end_p (psi
); gsi_next (&psi
))
812 op_p
= PHI_ARG_DEF_PTR_FROM_EDGE (phi
, single_succ_edge (bb
));
813 locus
= gimple_phi_arg_location_from_edge (phi
, single_succ_edge (bb
));
815 name
= USE_FROM_PTR (op_p
);
817 /* If the argument of the PHI node is a constant, we do not need
818 to keep it inside loop. */
819 if (TREE_CODE (name
) != SSA_NAME
820 && !copy_constants_p
)
823 /* Otherwise create an auxiliary phi node that will copy the value
824 of the SSA name out of the loop. */
825 new_name
= duplicate_ssa_name (PHI_RESULT (phi
), NULL
);
826 new_phi
= create_phi_node (new_name
, bb
);
827 add_phi_arg (new_phi
, name
, exit
, locus
);
828 SET_USE (op_p
, new_name
);
834 /* Returns the basic block in that statements should be emitted for induction
835 variables incremented at the end of the LOOP. */
838 ip_end_pos (class loop
*loop
)
843 /* Returns the basic block in that statements should be emitted for induction
844 variables incremented just before exit condition of a LOOP. */
847 ip_normal_pos (class loop
*loop
)
853 if (!single_pred_p (loop
->latch
))
856 bb
= single_pred (loop
->latch
);
857 last
= last_stmt (bb
);
859 || gimple_code (last
) != GIMPLE_COND
)
862 exit
= EDGE_SUCC (bb
, 0);
863 if (exit
->dest
== loop
->latch
)
864 exit
= EDGE_SUCC (bb
, 1);
866 if (flow_bb_inside_loop_p (loop
, exit
->dest
))
872 /* Stores the standard position for induction variable increment in LOOP
873 (just before the exit condition if it is available and latch block is empty,
874 end of the latch block otherwise) to BSI. INSERT_AFTER is set to true if
875 the increment should be inserted after *BSI. */
878 standard_iv_increment_position (class loop
*loop
, gimple_stmt_iterator
*bsi
,
881 basic_block bb
= ip_normal_pos (loop
), latch
= ip_end_pos (loop
);
882 gimple
*last
= last_stmt (latch
);
885 || (last
&& gimple_code (last
) != GIMPLE_LABEL
))
887 *bsi
= gsi_last_bb (latch
);
888 *insert_after
= true;
892 *bsi
= gsi_last_bb (bb
);
893 *insert_after
= false;
897 /* Copies phi node arguments for duplicated blocks. The index of the first
898 duplicated block is FIRST_NEW_BLOCK. */
901 copy_phi_node_args (unsigned first_new_block
)
905 for (i
= first_new_block
; i
< (unsigned) last_basic_block_for_fn (cfun
); i
++)
906 BASIC_BLOCK_FOR_FN (cfun
, i
)->flags
|= BB_DUPLICATED
;
908 for (i
= first_new_block
; i
< (unsigned) last_basic_block_for_fn (cfun
); i
++)
909 add_phi_args_after_copy_bb (BASIC_BLOCK_FOR_FN (cfun
, i
));
911 for (i
= first_new_block
; i
< (unsigned) last_basic_block_for_fn (cfun
); i
++)
912 BASIC_BLOCK_FOR_FN (cfun
, i
)->flags
&= ~BB_DUPLICATED
;
916 /* The same as cfgloopmanip.c:duplicate_loop_to_header_edge, but also
917 updates the PHI nodes at start of the copied region. In order to
918 achieve this, only loops whose exits all lead to the same location
921 Notice that we do not completely update the SSA web after
922 duplication. The caller is responsible for calling update_ssa
923 after the loop has been duplicated. */
926 gimple_duplicate_loop_to_header_edge (class loop
*loop
, edge e
,
927 unsigned int ndupl
, sbitmap wont_exit
,
928 edge orig
, vec
<edge
> *to_remove
,
931 unsigned first_new_block
;
933 if (!loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES
))
935 if (!loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS
))
938 first_new_block
= last_basic_block_for_fn (cfun
);
939 if (!duplicate_loop_to_header_edge (loop
, e
, ndupl
, wont_exit
,
940 orig
, to_remove
, flags
))
943 /* Readd the removed phi args for e. */
944 flush_pending_stmts (e
);
946 /* Copy the phi node arguments. */
947 copy_phi_node_args (first_new_block
);
954 /* Returns true if we can unroll LOOP FACTOR times. Number
955 of iterations of the loop is returned in NITER. */
958 can_unroll_loop_p (class loop
*loop
, unsigned factor
,
959 class tree_niter_desc
*niter
)
963 /* Check whether unrolling is possible. We only want to unroll loops
964 for that we are able to determine number of iterations. We also
965 want to split the extra iterations of the loop from its end,
966 therefore we require that the loop has precisely one
969 exit
= single_dom_exit (loop
);
973 if (!number_of_iterations_exit (loop
, exit
, niter
, false)
974 || niter
->cmp
== ERROR_MARK
975 /* Scalar evolutions analysis might have copy propagated
976 the abnormal ssa names into these expressions, hence
977 emitting the computations based on them during loop
978 unrolling might create overlapping life ranges for
979 them, and failures in out-of-ssa. */
980 || contains_abnormal_ssa_name_p (niter
->may_be_zero
)
981 || contains_abnormal_ssa_name_p (niter
->control
.base
)
982 || contains_abnormal_ssa_name_p (niter
->control
.step
)
983 || contains_abnormal_ssa_name_p (niter
->bound
))
986 /* And of course, we must be able to duplicate the loop. */
987 if (!can_duplicate_loop_p (loop
))
990 /* The final loop should be small enough. */
991 if (tree_num_loop_insns (loop
, &eni_size_weights
) * factor
992 > (unsigned) param_max_unrolled_insns
)
998 /* Determines the conditions that control execution of LOOP unrolled FACTOR
999 times. DESC is number of iterations of LOOP. ENTER_COND is set to
1000 condition that must be true if the main loop can be entered.
1001 EXIT_BASE, EXIT_STEP, EXIT_CMP and EXIT_BOUND are set to values describing
1002 how the exit from the unrolled loop should be controlled. */
1005 determine_exit_conditions (class loop
*loop
, class tree_niter_desc
*desc
,
1006 unsigned factor
, tree
*enter_cond
,
1007 tree
*exit_base
, tree
*exit_step
,
1008 enum tree_code
*exit_cmp
, tree
*exit_bound
)
1011 tree base
= desc
->control
.base
;
1012 tree step
= desc
->control
.step
;
1013 tree bound
= desc
->bound
;
1014 tree type
= TREE_TYPE (step
);
1015 tree bigstep
, delta
;
1016 tree min
= lower_bound_in_type (type
, type
);
1017 tree max
= upper_bound_in_type (type
, type
);
1018 enum tree_code cmp
= desc
->cmp
;
1019 tree cond
= boolean_true_node
, assum
;
1021 /* For pointers, do the arithmetics in the type of step. */
1022 base
= fold_convert (type
, base
);
1023 bound
= fold_convert (type
, bound
);
1025 *enter_cond
= boolean_false_node
;
1026 *exit_base
= NULL_TREE
;
1027 *exit_step
= NULL_TREE
;
1028 *exit_cmp
= ERROR_MARK
;
1029 *exit_bound
= NULL_TREE
;
1030 gcc_assert (cmp
!= ERROR_MARK
);
1032 /* We only need to be correct when we answer question
1033 "Do at least FACTOR more iterations remain?" in the unrolled loop.
1034 Thus, transforming BASE + STEP * i <> BOUND to
1035 BASE + STEP * i < BOUND is ok. */
1038 if (tree_int_cst_sign_bit (step
))
1043 else if (cmp
== LT_EXPR
)
1045 gcc_assert (!tree_int_cst_sign_bit (step
));
1047 else if (cmp
== GT_EXPR
)
1049 gcc_assert (tree_int_cst_sign_bit (step
));
1054 /* The main body of the loop may be entered iff:
1056 1) desc->may_be_zero is false.
1057 2) it is possible to check that there are at least FACTOR iterations
1058 of the loop, i.e., BOUND - step * FACTOR does not overflow.
1059 3) # of iterations is at least FACTOR */
1061 if (!integer_zerop (desc
->may_be_zero
))
1062 cond
= fold_build2 (TRUTH_AND_EXPR
, boolean_type_node
,
1063 invert_truthvalue (desc
->may_be_zero
),
1066 bigstep
= fold_build2 (MULT_EXPR
, type
, step
,
1067 build_int_cst_type (type
, factor
));
1068 delta
= fold_build2 (MINUS_EXPR
, type
, bigstep
, step
);
1070 assum
= fold_build2 (GE_EXPR
, boolean_type_node
,
1072 fold_build2 (PLUS_EXPR
, type
, min
, delta
));
1074 assum
= fold_build2 (LE_EXPR
, boolean_type_node
,
1076 fold_build2 (PLUS_EXPR
, type
, max
, delta
));
1077 cond
= fold_build2 (TRUTH_AND_EXPR
, boolean_type_node
, assum
, cond
);
1079 bound
= fold_build2 (MINUS_EXPR
, type
, bound
, delta
);
1080 assum
= fold_build2 (cmp
, boolean_type_node
, base
, bound
);
1081 cond
= fold_build2 (TRUTH_AND_EXPR
, boolean_type_node
, assum
, cond
);
1083 cond
= force_gimple_operand (unshare_expr (cond
), &stmts
, false, NULL_TREE
);
1085 gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop
), stmts
);
1086 /* cond now may be a gimple comparison, which would be OK, but also any
1087 other gimple rhs (say a && b). In this case we need to force it to
1089 if (!is_gimple_condexpr (cond
))
1091 cond
= force_gimple_operand (cond
, &stmts
, true, NULL_TREE
);
1093 gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop
), stmts
);
1097 base
= force_gimple_operand (unshare_expr (base
), &stmts
, true, NULL_TREE
);
1099 gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop
), stmts
);
1100 bound
= force_gimple_operand (unshare_expr (bound
), &stmts
, true, NULL_TREE
);
1102 gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop
), stmts
);
1105 *exit_step
= bigstep
;
1107 *exit_bound
= bound
;
1110 /* Scales the frequencies of all basic blocks in LOOP that are strictly
1111 dominated by BB by NUM/DEN. */
1114 scale_dominated_blocks_in_loop (class loop
*loop
, basic_block bb
,
1115 profile_count num
, profile_count den
)
1119 if (!den
.nonzero_p () && !(num
== profile_count::zero ()))
1122 for (son
= first_dom_son (CDI_DOMINATORS
, bb
);
1124 son
= next_dom_son (CDI_DOMINATORS
, son
))
1126 if (!flow_bb_inside_loop_p (loop
, son
))
1128 scale_bbs_frequencies_profile_count (&son
, 1, num
, den
);
1129 scale_dominated_blocks_in_loop (loop
, son
, num
, den
);
1133 /* Return estimated niter for LOOP after unrolling by FACTOR times. */
1136 niter_for_unrolled_loop (class loop
*loop
, unsigned factor
)
1138 gcc_assert (factor
!= 0);
1139 bool profile_p
= false;
1140 gcov_type est_niter
= expected_loop_iterations_unbounded (loop
, &profile_p
);
1141 /* Note that this is really CEIL (est_niter + 1, factor) - 1, where the
1142 "+ 1" converts latch iterations to loop iterations and the "- 1"
1144 gcov_type new_est_niter
= est_niter
/ factor
;
1146 if (est_niter
== -1)
1149 /* Without profile feedback, loops for which we do not know a better estimate
1150 are assumed to roll 10 times. When we unroll such loop, it appears to
1151 roll too little, and it may even seem to be cold. To avoid this, we
1152 ensure that the created loop appears to roll at least 5 times (but at
1153 most as many times as before unrolling). Don't do adjustment if profile
1154 feedback is present. */
1155 if (new_est_niter
< 5 && !profile_p
)
1158 new_est_niter
= est_niter
;
1163 if (loop
->any_upper_bound
)
1165 /* As above, this is really CEIL (upper_bound + 1, factor) - 1. */
1166 widest_int bound
= wi::udiv_floor (loop
->nb_iterations_upper_bound
,
1168 if (wi::ltu_p (bound
, new_est_niter
))
1169 new_est_niter
= bound
.to_uhwi ();
1172 return new_est_niter
;
1175 /* Unroll LOOP FACTOR times. DESC describes number of iterations of LOOP.
1176 EXIT is the exit of the loop to that DESC corresponds.
1178 If N is number of iterations of the loop and MAY_BE_ZERO is the condition
1179 under that loop exits in the first iteration even if N != 0,
1183 x = phi (init, next);
1191 becomes (with possibly the exit conditions formulated a bit differently,
1192 avoiding the need to create a new iv):
1194 if (MAY_BE_ZERO || N < FACTOR)
1199 x = phi (init, next);
1210 } while (N >= FACTOR);
1213 init' = phi (init, x);
1217 x = phi (init', next);
1225 Before the loop is unrolled, TRANSFORM is called for it (only for the
1226 unrolled loop, but not for its versioned copy). DATA is passed to
1229 /* Probability in % that the unrolled loop is entered. Just a guess. */
1230 #define PROB_UNROLLED_LOOP_ENTERED 90
1233 tree_transform_and_unroll_loop (class loop
*loop
, unsigned factor
,
1234 edge exit
, class tree_niter_desc
*desc
,
1235 transform_callback transform
,
1239 tree ctr_before
, ctr_after
;
1240 tree enter_main_cond
, exit_base
, exit_step
, exit_bound
;
1241 enum tree_code exit_cmp
;
1242 gphi
*phi_old_loop
, *phi_new_loop
, *phi_rest
;
1243 gphi_iterator psi_old_loop
, psi_new_loop
;
1244 tree init
, next
, new_init
;
1245 class loop
*new_loop
;
1246 basic_block rest
, exit_bb
;
1247 edge old_entry
, new_entry
, old_latch
, precond_edge
, new_exit
;
1248 edge new_nonexit
, e
;
1249 gimple_stmt_iterator bsi
;
1253 profile_probability prob
, prob_entry
, scale_unrolled
;
1254 profile_count freq_e
, freq_h
;
1255 gcov_type new_est_niter
= niter_for_unrolled_loop (loop
, factor
);
1256 unsigned irr
= loop_preheader_edge (loop
)->flags
& EDGE_IRREDUCIBLE_LOOP
;
1257 auto_vec
<edge
> to_remove
;
1259 determine_exit_conditions (loop
, desc
, factor
,
1260 &enter_main_cond
, &exit_base
, &exit_step
,
1261 &exit_cmp
, &exit_bound
);
1263 /* Let us assume that the unrolled loop is quite likely to be entered. */
1264 if (integer_nonzerop (enter_main_cond
))
1265 prob_entry
= profile_probability::always ();
1267 prob_entry
= profile_probability::guessed_always ()
1268 .apply_scale (PROB_UNROLLED_LOOP_ENTERED
, 100);
1270 /* The values for scales should keep profile consistent, and somewhat close
1273 TODO: The current value of SCALE_REST makes it appear that the loop that
1274 is created by splitting the remaining iterations of the unrolled loop is
1275 executed the same number of times as the original loop, and with the same
1276 frequencies, which is obviously wrong. This does not appear to cause
1277 problems, so we do not bother with fixing it for now. To make the profile
1278 correct, we would need to change the probability of the exit edge of the
1279 loop, and recompute the distribution of frequencies in its body because
1280 of this change (scale the frequencies of blocks before and after the exit
1281 by appropriate factors). */
1282 scale_unrolled
= prob_entry
;
1284 new_loop
= loop_version (loop
, enter_main_cond
, NULL
, prob_entry
,
1285 prob_entry
.invert (), scale_unrolled
,
1286 profile_probability::guessed_always (),
1288 gcc_assert (new_loop
!= NULL
);
1289 update_ssa (TODO_update_ssa
);
1291 /* Prepare the cfg and update the phi nodes. Move the loop exit to the
1292 loop latch (and make its condition dummy, for the moment). */
1293 rest
= loop_preheader_edge (new_loop
)->src
;
1294 precond_edge
= single_pred_edge (rest
);
1295 split_edge (loop_latch_edge (loop
));
1296 exit_bb
= single_pred (loop
->latch
);
1298 /* Since the exit edge will be removed, the frequency of all the blocks
1299 in the loop that are dominated by it must be scaled by
1300 1 / (1 - exit->probability). */
1301 if (exit
->probability
.initialized_p ())
1302 scale_dominated_blocks_in_loop (loop
, exit
->src
,
1303 /* We are scaling up here so probability
1305 loop
->header
->count
,
1307 - loop
->header
->count
.apply_probability
1308 (exit
->probability
));
1310 bsi
= gsi_last_bb (exit_bb
);
1311 exit_if
= gimple_build_cond (EQ_EXPR
, integer_zero_node
,
1313 NULL_TREE
, NULL_TREE
);
1315 gsi_insert_after (&bsi
, exit_if
, GSI_NEW_STMT
);
1316 new_exit
= make_edge (exit_bb
, rest
, EDGE_FALSE_VALUE
| irr
);
1317 rescan_loop_exit (new_exit
, true, false);
1319 /* Set the probability of new exit to the same of the old one. Fix
1320 the frequency of the latch block, by scaling it back by
1321 1 - exit->probability. */
1322 new_exit
->probability
= exit
->probability
;
1323 new_nonexit
= single_pred_edge (loop
->latch
);
1324 new_nonexit
->probability
= exit
->probability
.invert ();
1325 new_nonexit
->flags
= EDGE_TRUE_VALUE
;
1326 if (new_nonexit
->probability
.initialized_p ())
1327 scale_bbs_frequencies (&loop
->latch
, 1, new_nonexit
->probability
);
1329 old_entry
= loop_preheader_edge (loop
);
1330 new_entry
= loop_preheader_edge (new_loop
);
1331 old_latch
= loop_latch_edge (loop
);
1332 for (psi_old_loop
= gsi_start_phis (loop
->header
),
1333 psi_new_loop
= gsi_start_phis (new_loop
->header
);
1334 !gsi_end_p (psi_old_loop
);
1335 gsi_next (&psi_old_loop
), gsi_next (&psi_new_loop
))
1337 phi_old_loop
= psi_old_loop
.phi ();
1338 phi_new_loop
= psi_new_loop
.phi ();
1340 init
= PHI_ARG_DEF_FROM_EDGE (phi_old_loop
, old_entry
);
1341 op
= PHI_ARG_DEF_PTR_FROM_EDGE (phi_new_loop
, new_entry
);
1342 gcc_assert (operand_equal_for_phi_arg_p (init
, USE_FROM_PTR (op
)));
1343 next
= PHI_ARG_DEF_FROM_EDGE (phi_old_loop
, old_latch
);
1345 /* Prefer using original variable as a base for the new ssa name.
1346 This is necessary for virtual ops, and useful in order to avoid
1347 losing debug info for real ops. */
1348 if (TREE_CODE (next
) == SSA_NAME
1349 && useless_type_conversion_p (TREE_TYPE (next
),
1351 new_init
= copy_ssa_name (next
);
1352 else if (TREE_CODE (init
) == SSA_NAME
1353 && useless_type_conversion_p (TREE_TYPE (init
),
1355 new_init
= copy_ssa_name (init
);
1356 else if (useless_type_conversion_p (TREE_TYPE (next
), TREE_TYPE (init
)))
1357 new_init
= make_temp_ssa_name (TREE_TYPE (next
), NULL
, "unrinittmp");
1359 new_init
= make_temp_ssa_name (TREE_TYPE (init
), NULL
, "unrinittmp");
1361 phi_rest
= create_phi_node (new_init
, rest
);
1363 add_phi_arg (phi_rest
, init
, precond_edge
, UNKNOWN_LOCATION
);
1364 add_phi_arg (phi_rest
, next
, new_exit
, UNKNOWN_LOCATION
);
1365 SET_USE (op
, new_init
);
1370 /* Transform the loop. */
1372 (*transform
) (loop
, data
);
1374 /* Unroll the loop and remove the exits in all iterations except for the
1376 auto_sbitmap
wont_exit (factor
);
1377 bitmap_ones (wont_exit
);
1378 bitmap_clear_bit (wont_exit
, factor
- 1);
1380 ok
= gimple_duplicate_loop_to_header_edge
1381 (loop
, loop_latch_edge (loop
), factor
- 1,
1382 wont_exit
, new_exit
, &to_remove
, DLTHE_FLAG_UPDATE_FREQ
);
1385 FOR_EACH_VEC_ELT (to_remove
, i
, e
)
1387 ok
= remove_path (e
);
1390 update_ssa (TODO_update_ssa
);
1392 /* Ensure that the frequencies in the loop match the new estimated
1393 number of iterations, and change the probability of the new
1396 freq_h
= loop
->header
->count
;
1397 freq_e
= (loop_preheader_edge (loop
))->count ();
1398 if (freq_h
.nonzero_p ())
1400 /* Avoid dropping loop body profile counter to 0 because of zero count
1401 in loop's preheader. */
1402 if (freq_h
.nonzero_p () && !(freq_e
== profile_count::zero ()))
1403 freq_e
= freq_e
.force_nonzero ();
1404 scale_loop_frequencies (loop
, freq_e
.probability_in (freq_h
));
1407 exit_bb
= single_pred (loop
->latch
);
1408 new_exit
= find_edge (exit_bb
, rest
);
1409 new_exit
->probability
= profile_probability::always ()
1410 .apply_scale (1, new_est_niter
+ 1);
1412 rest
->count
+= new_exit
->count ();
1414 new_nonexit
= single_pred_edge (loop
->latch
);
1415 prob
= new_nonexit
->probability
;
1416 new_nonexit
->probability
= new_exit
->probability
.invert ();
1417 prob
= new_nonexit
->probability
/ prob
;
1418 if (prob
.initialized_p ())
1419 scale_bbs_frequencies (&loop
->latch
, 1, prob
);
1421 /* Finally create the new counter for number of iterations and add the new
1422 exit instruction. */
1423 bsi
= gsi_last_nondebug_bb (exit_bb
);
1424 exit_if
= as_a
<gcond
*> (gsi_stmt (bsi
));
1425 create_iv (exit_base
, exit_step
, NULL_TREE
, loop
,
1426 &bsi
, false, &ctr_before
, &ctr_after
);
1427 gimple_cond_set_code (exit_if
, exit_cmp
);
1428 gimple_cond_set_lhs (exit_if
, ctr_after
);
1429 gimple_cond_set_rhs (exit_if
, exit_bound
);
1430 update_stmt (exit_if
);
1432 checking_verify_flow_info ();
1433 checking_verify_loop_structure ();
1434 checking_verify_loop_closed_ssa (true, loop
);
1435 checking_verify_loop_closed_ssa (true, new_loop
);
1438 /* Wrapper over tree_transform_and_unroll_loop for case we do not
1439 want to transform the loop before unrolling. The meaning
1440 of the arguments is the same as for tree_transform_and_unroll_loop. */
1443 tree_unroll_loop (class loop
*loop
, unsigned factor
,
1444 edge exit
, class tree_niter_desc
*desc
)
1446 tree_transform_and_unroll_loop (loop
, factor
, exit
, desc
,
1450 /* Rewrite the phi node at position PSI in function of the main
1451 induction variable MAIN_IV and insert the generated code at GSI. */
1454 rewrite_phi_with_iv (loop_p loop
,
1456 gimple_stmt_iterator
*gsi
,
1461 gphi
*phi
= psi
->phi ();
1462 tree atype
, mtype
, val
, res
= PHI_RESULT (phi
);
1464 if (virtual_operand_p (res
) || res
== main_iv
)
1470 if (!simple_iv (loop
, loop
, res
, &iv
, true))
1476 remove_phi_node (psi
, false);
1478 atype
= TREE_TYPE (res
);
1479 mtype
= POINTER_TYPE_P (atype
) ? sizetype
: atype
;
1480 val
= fold_build2 (MULT_EXPR
, mtype
, unshare_expr (iv
.step
),
1481 fold_convert (mtype
, main_iv
));
1482 val
= fold_build2 (POINTER_TYPE_P (atype
)
1483 ? POINTER_PLUS_EXPR
: PLUS_EXPR
,
1484 atype
, unshare_expr (iv
.base
), val
);
1485 val
= force_gimple_operand_gsi (gsi
, val
, false, NULL_TREE
, true,
1487 stmt
= gimple_build_assign (res
, val
);
1488 gsi_insert_before (gsi
, stmt
, GSI_SAME_STMT
);
1491 /* Rewrite all the phi nodes of LOOP in function of the main induction
1492 variable MAIN_IV. */
1495 rewrite_all_phi_nodes_with_iv (loop_p loop
, tree main_iv
)
1498 basic_block
*bbs
= get_loop_body_in_dom_order (loop
);
1501 for (i
= 0; i
< loop
->num_nodes
; i
++)
1503 basic_block bb
= bbs
[i
];
1504 gimple_stmt_iterator gsi
= gsi_after_labels (bb
);
1506 if (bb
->loop_father
!= loop
)
1509 for (psi
= gsi_start_phis (bb
); !gsi_end_p (psi
); )
1510 rewrite_phi_with_iv (loop
, &psi
, &gsi
, main_iv
);
1516 /* Bases all the induction variables in LOOP on a single induction variable
1517 (with base 0 and step 1), whose final value is compared with *NIT. When the
1518 IV type precision has to be larger than *NIT type precision, *NIT is
1519 converted to the larger type, the conversion code is inserted before the
1520 loop, and *NIT is updated to the new definition. When BUMP_IN_LATCH is true,
1521 the induction variable is incremented in the loop latch, otherwise it is
1522 incremented in the loop header. Return the induction variable that was
1526 canonicalize_loop_ivs (class loop
*loop
, tree
*nit
, bool bump_in_latch
)
1528 unsigned precision
= TYPE_PRECISION (TREE_TYPE (*nit
));
1529 unsigned original_precision
= precision
;
1530 tree type
, var_before
;
1531 gimple_stmt_iterator gsi
;
1534 edge exit
= single_dom_exit (loop
);
1536 bool unsigned_p
= false;
1538 for (psi
= gsi_start_phis (loop
->header
);
1539 !gsi_end_p (psi
); gsi_next (&psi
))
1541 gphi
*phi
= psi
.phi ();
1542 tree res
= PHI_RESULT (phi
);
1545 type
= TREE_TYPE (res
);
1546 if (virtual_operand_p (res
)
1547 || (!INTEGRAL_TYPE_P (type
)
1548 && !POINTER_TYPE_P (type
))
1549 || TYPE_PRECISION (type
) < precision
)
1552 uns
= POINTER_TYPE_P (type
) | TYPE_UNSIGNED (type
);
1554 if (TYPE_PRECISION (type
) > precision
)
1559 precision
= TYPE_PRECISION (type
);
1562 scalar_int_mode mode
= smallest_int_mode_for_size (precision
);
1563 precision
= GET_MODE_PRECISION (mode
);
1564 type
= build_nonstandard_integer_type (precision
, unsigned_p
);
1566 if (original_precision
!= precision
1567 || TYPE_UNSIGNED (TREE_TYPE (*nit
)) != unsigned_p
)
1569 *nit
= fold_convert (type
, *nit
);
1570 *nit
= force_gimple_operand (*nit
, &stmts
, true, NULL_TREE
);
1572 gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop
), stmts
);
1576 gsi
= gsi_last_bb (loop
->latch
);
1578 gsi
= gsi_last_nondebug_bb (loop
->header
);
1579 create_iv (build_int_cst_type (type
, 0), build_int_cst (type
, 1), NULL_TREE
,
1580 loop
, &gsi
, bump_in_latch
, &var_before
, NULL
);
1582 rewrite_all_phi_nodes_with_iv (loop
, var_before
);
1584 stmt
= as_a
<gcond
*> (last_stmt (exit
->src
));
1585 /* Make the loop exit if the control condition is not satisfied. */
1586 if (exit
->flags
& EDGE_TRUE_VALUE
)
1590 extract_true_false_edges_from_block (exit
->src
, &te
, &fe
);
1591 te
->flags
= EDGE_FALSE_VALUE
;
1592 fe
->flags
= EDGE_TRUE_VALUE
;
1594 gimple_cond_set_code (stmt
, LT_EXPR
);
1595 gimple_cond_set_lhs (stmt
, var_before
);
1596 gimple_cond_set_rhs (stmt
, *nit
);