1 /* Optimization of PHI nodes by converting them into straightline code.
2 Copyright (C) 2004-2019 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"
24 #include "insn-codes.h"
29 #include "tree-pass.h"
31 #include "optabs-tree.h"
32 #include "insn-config.h"
33 #include "gimple-pretty-print.h"
34 #include "fold-const.h"
35 #include "stor-layout.h"
38 #include "gimple-iterator.h"
39 #include "gimplify-me.h"
44 #include "tree-data-ref.h"
45 #include "tree-scalar-evolution.h"
46 #include "tree-inline.h"
47 #include "case-cfn-macros.h"
49 static unsigned int tree_ssa_phiopt_worker (bool, bool, bool);
50 static bool two_value_replacement (basic_block
, basic_block
, edge
, gphi
*,
52 static bool conditional_replacement (basic_block
, basic_block
,
53 edge
, edge
, gphi
*, tree
, tree
);
54 static gphi
*factor_out_conditional_conversion (edge
, edge
, gphi
*, tree
, tree
,
56 static int value_replacement (basic_block
, basic_block
,
57 edge
, edge
, gimple
*, tree
, tree
);
58 static bool minmax_replacement (basic_block
, basic_block
,
59 edge
, edge
, gimple
*, tree
, tree
);
60 static bool abs_replacement (basic_block
, basic_block
,
61 edge
, edge
, gimple
*, tree
, tree
);
62 static bool cond_removal_in_popcount_pattern (basic_block
, basic_block
,
63 edge
, edge
, gimple
*, tree
, tree
);
64 static bool cond_store_replacement (basic_block
, basic_block
, edge
, edge
,
66 static bool cond_if_else_store_replacement (basic_block
, basic_block
, basic_block
);
67 static hash_set
<tree
> * get_non_trapping ();
68 static void replace_phi_edge_with_variable (basic_block
, edge
, gimple
*, tree
);
69 static void hoist_adjacent_loads (basic_block
, basic_block
,
70 basic_block
, basic_block
);
71 static bool gate_hoist_loads (void);
73 /* This pass tries to transform conditional stores into unconditional
74 ones, enabling further simplifications with the simpler then and else
75 blocks. In particular it replaces this:
78 if (cond) goto bb2; else goto bb1;
86 if (cond) goto bb1; else goto bb2;
90 condtmp = PHI <RHS, condtmp'>
93 This transformation can only be done under several constraints,
94 documented below. It also replaces:
97 if (cond) goto bb2; else goto bb1;
108 if (cond) goto bb3; else goto bb1;
111 condtmp = PHI <RHS1, RHS2>
115 tree_ssa_cs_elim (void)
118 /* ??? We are not interested in loop related info, but the following
119 will create it, ICEing as we didn't init loops with pre-headers.
120 An interfacing issue of find_data_references_in_bb. */
121 loop_optimizer_init (LOOPS_NORMAL
);
123 todo
= tree_ssa_phiopt_worker (true, false, false);
125 loop_optimizer_finalize ();
129 /* Return the singleton PHI in the SEQ of PHIs for edges E0 and E1. */
132 single_non_singleton_phi_for_edges (gimple_seq seq
, edge e0
, edge e1
)
134 gimple_stmt_iterator i
;
136 if (gimple_seq_singleton_p (seq
))
137 return as_a
<gphi
*> (gsi_stmt (gsi_start (seq
)));
138 for (i
= gsi_start (seq
); !gsi_end_p (i
); gsi_next (&i
))
140 gphi
*p
= as_a
<gphi
*> (gsi_stmt (i
));
141 /* If the PHI arguments are equal then we can skip this PHI. */
142 if (operand_equal_for_phi_arg_p (gimple_phi_arg_def (p
, e0
->dest_idx
),
143 gimple_phi_arg_def (p
, e1
->dest_idx
)))
146 /* If we already have a PHI that has the two edge arguments are
147 different, then return it is not a singleton for these PHIs. */
156 /* The core routine of conditional store replacement and normal
157 phi optimizations. Both share much of the infrastructure in how
158 to match applicable basic block patterns. DO_STORE_ELIM is true
159 when we want to do conditional store replacement, false otherwise.
160 DO_HOIST_LOADS is true when we want to hoist adjacent loads out
161 of diamond control flow patterns, false otherwise. */
163 tree_ssa_phiopt_worker (bool do_store_elim
, bool do_hoist_loads
, bool early_p
)
166 basic_block
*bb_order
;
168 bool cfgchanged
= false;
169 hash_set
<tree
> *nontrap
= 0;
172 /* Calculate the set of non-trapping memory accesses. */
173 nontrap
= get_non_trapping ();
175 /* Search every basic block for COND_EXPR we may be able to optimize.
177 We walk the blocks in order that guarantees that a block with
178 a single predecessor is processed before the predecessor.
179 This ensures that we collapse inner ifs before visiting the
180 outer ones, and also that we do not try to visit a removed
182 bb_order
= single_pred_before_succ_order ();
183 n
= n_basic_blocks_for_fn (cfun
) - NUM_FIXED_BLOCKS
;
185 for (i
= 0; i
< n
; i
++)
189 basic_block bb1
, bb2
;
195 cond_stmt
= last_stmt (bb
);
196 /* Check to see if the last statement is a GIMPLE_COND. */
198 || gimple_code (cond_stmt
) != GIMPLE_COND
)
201 e1
= EDGE_SUCC (bb
, 0);
203 e2
= EDGE_SUCC (bb
, 1);
206 /* We cannot do the optimization on abnormal edges. */
207 if ((e1
->flags
& EDGE_ABNORMAL
) != 0
208 || (e2
->flags
& EDGE_ABNORMAL
) != 0)
211 /* If either bb1's succ or bb2 or bb2's succ is non NULL. */
212 if (EDGE_COUNT (bb1
->succs
) == 0
214 || EDGE_COUNT (bb2
->succs
) == 0)
217 /* Find the bb which is the fall through to the other. */
218 if (EDGE_SUCC (bb1
, 0)->dest
== bb2
)
220 else if (EDGE_SUCC (bb2
, 0)->dest
== bb1
)
222 std::swap (bb1
, bb2
);
225 else if (do_store_elim
226 && EDGE_SUCC (bb1
, 0)->dest
== EDGE_SUCC (bb2
, 0)->dest
)
228 basic_block bb3
= EDGE_SUCC (bb1
, 0)->dest
;
230 if (!single_succ_p (bb1
)
231 || (EDGE_SUCC (bb1
, 0)->flags
& EDGE_FALLTHRU
) == 0
232 || !single_succ_p (bb2
)
233 || (EDGE_SUCC (bb2
, 0)->flags
& EDGE_FALLTHRU
) == 0
234 || EDGE_COUNT (bb3
->preds
) != 2)
236 if (cond_if_else_store_replacement (bb1
, bb2
, bb3
))
240 else if (do_hoist_loads
241 && EDGE_SUCC (bb1
, 0)->dest
== EDGE_SUCC (bb2
, 0)->dest
)
243 basic_block bb3
= EDGE_SUCC (bb1
, 0)->dest
;
245 if (!FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (cond_stmt
)))
246 && single_succ_p (bb1
)
247 && single_succ_p (bb2
)
248 && single_pred_p (bb1
)
249 && single_pred_p (bb2
)
250 && EDGE_COUNT (bb
->succs
) == 2
251 && EDGE_COUNT (bb3
->preds
) == 2
252 /* If one edge or the other is dominant, a conditional move
253 is likely to perform worse than the well-predicted branch. */
254 && !predictable_edge_p (EDGE_SUCC (bb
, 0))
255 && !predictable_edge_p (EDGE_SUCC (bb
, 1)))
256 hoist_adjacent_loads (bb
, bb1
, bb2
, bb3
);
262 e1
= EDGE_SUCC (bb1
, 0);
264 /* Make sure that bb1 is just a fall through. */
265 if (!single_succ_p (bb1
)
266 || (e1
->flags
& EDGE_FALLTHRU
) == 0)
269 /* Also make sure that bb1 only have one predecessor and that it
271 if (!single_pred_p (bb1
)
272 || single_pred (bb1
) != bb
)
277 /* bb1 is the middle block, bb2 the join block, bb the split block,
278 e1 the fallthrough edge from bb1 to bb2. We can't do the
279 optimization if the join block has more than two predecessors. */
280 if (EDGE_COUNT (bb2
->preds
) > 2)
282 if (cond_store_replacement (bb1
, bb2
, e1
, e2
, nontrap
))
287 gimple_seq phis
= phi_nodes (bb2
);
288 gimple_stmt_iterator gsi
;
289 bool candorest
= true;
291 /* Value replacement can work with more than one PHI
292 so try that first. */
294 for (gsi
= gsi_start (phis
); !gsi_end_p (gsi
); gsi_next (&gsi
))
296 phi
= as_a
<gphi
*> (gsi_stmt (gsi
));
297 arg0
= gimple_phi_arg_def (phi
, e1
->dest_idx
);
298 arg1
= gimple_phi_arg_def (phi
, e2
->dest_idx
);
299 if (value_replacement (bb
, bb1
, e1
, e2
, phi
, arg0
, arg1
) == 2)
310 phi
= single_non_singleton_phi_for_edges (phis
, e1
, e2
);
314 arg0
= gimple_phi_arg_def (phi
, e1
->dest_idx
);
315 arg1
= gimple_phi_arg_def (phi
, e2
->dest_idx
);
317 /* Something is wrong if we cannot find the arguments in the PHI
319 gcc_assert (arg0
!= NULL_TREE
&& arg1
!= NULL_TREE
);
321 gphi
*newphi
= factor_out_conditional_conversion (e1
, e2
, phi
,
327 /* factor_out_conditional_conversion may create a new PHI in
328 BB2 and eliminate an existing PHI in BB2. Recompute values
329 that may be affected by that change. */
330 arg0
= gimple_phi_arg_def (phi
, e1
->dest_idx
);
331 arg1
= gimple_phi_arg_def (phi
, e2
->dest_idx
);
332 gcc_assert (arg0
!= NULL_TREE
&& arg1
!= NULL_TREE
);
335 /* Do the replacement of conditional if it can be done. */
336 if (two_value_replacement (bb
, bb1
, e2
, phi
, arg0
, arg1
))
339 && conditional_replacement (bb
, bb1
, e1
, e2
, phi
,
342 else if (abs_replacement (bb
, bb1
, e1
, e2
, phi
, arg0
, arg1
))
345 && cond_removal_in_popcount_pattern (bb
, bb1
, e1
, e2
,
348 else if (minmax_replacement (bb
, bb1
, e1
, e2
, phi
, arg0
, arg1
))
357 /* If the CFG has changed, we should cleanup the CFG. */
358 if (cfgchanged
&& do_store_elim
)
360 /* In cond-store replacement we have added some loads on edges
361 and new VOPS (as we moved the store, and created a load). */
362 gsi_commit_edge_inserts ();
363 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
366 return TODO_cleanup_cfg
;
370 /* Replace PHI node element whose edge is E in block BB with variable NEW.
371 Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK
372 is known to have two edges, one of which must reach BB). */
375 replace_phi_edge_with_variable (basic_block cond_block
,
376 edge e
, gimple
*phi
, tree new_tree
)
378 basic_block bb
= gimple_bb (phi
);
379 basic_block block_to_remove
;
380 gimple_stmt_iterator gsi
;
382 /* Change the PHI argument to new. */
383 SET_USE (PHI_ARG_DEF_PTR (phi
, e
->dest_idx
), new_tree
);
385 /* Remove the empty basic block. */
386 if (EDGE_SUCC (cond_block
, 0)->dest
== bb
)
388 EDGE_SUCC (cond_block
, 0)->flags
|= EDGE_FALLTHRU
;
389 EDGE_SUCC (cond_block
, 0)->flags
&= ~(EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
);
390 EDGE_SUCC (cond_block
, 0)->probability
= profile_probability::always ();
392 block_to_remove
= EDGE_SUCC (cond_block
, 1)->dest
;
396 EDGE_SUCC (cond_block
, 1)->flags
|= EDGE_FALLTHRU
;
397 EDGE_SUCC (cond_block
, 1)->flags
398 &= ~(EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
);
399 EDGE_SUCC (cond_block
, 1)->probability
= profile_probability::always ();
401 block_to_remove
= EDGE_SUCC (cond_block
, 0)->dest
;
403 delete_basic_block (block_to_remove
);
405 /* Eliminate the COND_EXPR at the end of COND_BLOCK. */
406 gsi
= gsi_last_bb (cond_block
);
407 gsi_remove (&gsi
, true);
409 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
411 "COND_EXPR in block %d and PHI in block %d converted to straightline code.\n",
416 /* PR66726: Factor conversion out of COND_EXPR. If the arguments of the PHI
417 stmt are CONVERT_STMT, factor out the conversion and perform the conversion
418 to the result of PHI stmt. COND_STMT is the controlling predicate.
419 Return the newly-created PHI, if any. */
422 factor_out_conditional_conversion (edge e0
, edge e1
, gphi
*phi
,
423 tree arg0
, tree arg1
, gimple
*cond_stmt
)
425 gimple
*arg0_def_stmt
= NULL
, *arg1_def_stmt
= NULL
, *new_stmt
;
426 tree new_arg0
= NULL_TREE
, new_arg1
= NULL_TREE
;
429 gimple_stmt_iterator gsi
, gsi_for_def
;
430 location_t locus
= gimple_location (phi
);
431 enum tree_code convert_code
;
433 /* Handle only PHI statements with two arguments. TODO: If all
434 other arguments to PHI are INTEGER_CST or if their defining
435 statement have the same unary operation, we can handle more
436 than two arguments too. */
437 if (gimple_phi_num_args (phi
) != 2)
440 /* First canonicalize to simplify tests. */
441 if (TREE_CODE (arg0
) != SSA_NAME
)
443 std::swap (arg0
, arg1
);
447 if (TREE_CODE (arg0
) != SSA_NAME
448 || (TREE_CODE (arg1
) != SSA_NAME
449 && TREE_CODE (arg1
) != INTEGER_CST
))
452 /* Check if arg0 is an SSA_NAME and the stmt which defines arg0 is
454 arg0_def_stmt
= SSA_NAME_DEF_STMT (arg0
);
455 if (!gimple_assign_cast_p (arg0_def_stmt
))
458 /* Use the RHS as new_arg0. */
459 convert_code
= gimple_assign_rhs_code (arg0_def_stmt
);
460 new_arg0
= gimple_assign_rhs1 (arg0_def_stmt
);
461 if (convert_code
== VIEW_CONVERT_EXPR
)
463 new_arg0
= TREE_OPERAND (new_arg0
, 0);
464 if (!is_gimple_reg_type (TREE_TYPE (new_arg0
)))
468 if (TREE_CODE (arg1
) == SSA_NAME
)
470 /* Check if arg1 is an SSA_NAME and the stmt which defines arg1
472 arg1_def_stmt
= SSA_NAME_DEF_STMT (arg1
);
473 if (!is_gimple_assign (arg1_def_stmt
)
474 || gimple_assign_rhs_code (arg1_def_stmt
) != convert_code
)
477 /* Use the RHS as new_arg1. */
478 new_arg1
= gimple_assign_rhs1 (arg1_def_stmt
);
479 if (convert_code
== VIEW_CONVERT_EXPR
)
480 new_arg1
= TREE_OPERAND (new_arg1
, 0);
484 /* If arg1 is an INTEGER_CST, fold it to new type. */
485 if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0
))
486 && int_fits_type_p (arg1
, TREE_TYPE (new_arg0
)))
488 if (gimple_assign_cast_p (arg0_def_stmt
))
490 /* For the INTEGER_CST case, we are just moving the
491 conversion from one place to another, which can often
492 hurt as the conversion moves further away from the
493 statement that computes the value. So, perform this
494 only if new_arg0 is an operand of COND_STMT, or
495 if arg0_def_stmt is the only non-debug stmt in
496 its basic block, because then it is possible this
497 could enable further optimizations (minmax replacement
498 etc.). See PR71016. */
499 if (new_arg0
!= gimple_cond_lhs (cond_stmt
)
500 && new_arg0
!= gimple_cond_rhs (cond_stmt
)
501 && gimple_bb (arg0_def_stmt
) == e0
->src
)
503 gsi
= gsi_for_stmt (arg0_def_stmt
);
504 gsi_prev_nondebug (&gsi
);
505 if (!gsi_end_p (gsi
))
508 = dyn_cast
<gassign
*> (gsi_stmt (gsi
)))
510 tree lhs
= gimple_assign_lhs (assign
);
511 enum tree_code ass_code
512 = gimple_assign_rhs_code (assign
);
513 if (ass_code
!= MAX_EXPR
&& ass_code
!= MIN_EXPR
)
515 if (lhs
!= gimple_assign_rhs1 (arg0_def_stmt
))
517 gsi_prev_nondebug (&gsi
);
518 if (!gsi_end_p (gsi
))
524 gsi
= gsi_for_stmt (arg0_def_stmt
);
525 gsi_next_nondebug (&gsi
);
526 if (!gsi_end_p (gsi
))
529 new_arg1
= fold_convert (TREE_TYPE (new_arg0
), arg1
);
538 /* If arg0/arg1 have > 1 use, then this transformation actually increases
539 the number of expressions evaluated at runtime. */
540 if (!has_single_use (arg0
)
541 || (arg1_def_stmt
&& !has_single_use (arg1
)))
544 /* If types of new_arg0 and new_arg1 are different bailout. */
545 if (!types_compatible_p (TREE_TYPE (new_arg0
), TREE_TYPE (new_arg1
)))
548 /* Create a new PHI stmt. */
549 result
= PHI_RESULT (phi
);
550 temp
= make_ssa_name (TREE_TYPE (new_arg0
), NULL
);
551 newphi
= create_phi_node (temp
, gimple_bb (phi
));
553 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
555 fprintf (dump_file
, "PHI ");
556 print_generic_expr (dump_file
, gimple_phi_result (phi
));
558 " changed to factor conversion out from COND_EXPR.\n");
559 fprintf (dump_file
, "New stmt with CAST that defines ");
560 print_generic_expr (dump_file
, result
);
561 fprintf (dump_file
, ".\n");
564 /* Remove the old cast(s) that has single use. */
565 gsi_for_def
= gsi_for_stmt (arg0_def_stmt
);
566 gsi_remove (&gsi_for_def
, true);
567 release_defs (arg0_def_stmt
);
571 gsi_for_def
= gsi_for_stmt (arg1_def_stmt
);
572 gsi_remove (&gsi_for_def
, true);
573 release_defs (arg1_def_stmt
);
576 add_phi_arg (newphi
, new_arg0
, e0
, locus
);
577 add_phi_arg (newphi
, new_arg1
, e1
, locus
);
579 /* Create the conversion stmt and insert it. */
580 if (convert_code
== VIEW_CONVERT_EXPR
)
582 temp
= fold_build1 (VIEW_CONVERT_EXPR
, TREE_TYPE (result
), temp
);
583 new_stmt
= gimple_build_assign (result
, temp
);
586 new_stmt
= gimple_build_assign (result
, convert_code
, temp
);
587 gsi
= gsi_after_labels (gimple_bb (phi
));
588 gsi_insert_before (&gsi
, new_stmt
, GSI_SAME_STMT
);
590 /* Remove the original PHI stmt. */
591 gsi
= gsi_for_stmt (phi
);
592 gsi_remove (&gsi
, true);
597 # x_5 in range [cst1, cst2] where cst2 = cst1 + 1
598 if (x_5 op cstN) # where op is == or != and N is 1 or 2
604 # r_6 = PHI<cst3(2), cst4(3)> # where cst3 == cst4 + 1 or cst4 == cst3 + 1
606 to r_6 = x_5 + (min (cst3, cst4) - cst1) or
607 r_6 = (min (cst3, cst4) + cst1) - x_5 depending on op, N and which
608 of cst3 and cst4 is smaller. */
611 two_value_replacement (basic_block cond_bb
, basic_block middle_bb
,
612 edge e1
, gphi
*phi
, tree arg0
, tree arg1
)
614 /* Only look for adjacent integer constants. */
615 if (!INTEGRAL_TYPE_P (TREE_TYPE (arg0
))
616 || !INTEGRAL_TYPE_P (TREE_TYPE (arg1
))
617 || TREE_CODE (arg0
) != INTEGER_CST
618 || TREE_CODE (arg1
) != INTEGER_CST
619 || (tree_int_cst_lt (arg0
, arg1
)
620 ? wi::to_widest (arg0
) + 1 != wi::to_widest (arg1
)
621 : wi::to_widest (arg1
) + 1 != wi::to_widest (arg0
)))
624 if (!empty_block_p (middle_bb
))
627 gimple
*stmt
= last_stmt (cond_bb
);
628 tree lhs
= gimple_cond_lhs (stmt
);
629 tree rhs
= gimple_cond_rhs (stmt
);
631 if (TREE_CODE (lhs
) != SSA_NAME
632 || !INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
633 || TREE_CODE (TREE_TYPE (lhs
)) == BOOLEAN_TYPE
634 || TREE_CODE (rhs
) != INTEGER_CST
)
637 switch (gimple_cond_code (stmt
))
647 if (get_range_info (lhs
, &min
, &max
) != VR_RANGE
649 || (wi::to_wide (rhs
) != min
650 && wi::to_wide (rhs
) != max
))
653 /* We need to know which is the true edge and which is the false
654 edge so that we know when to invert the condition below. */
655 edge true_edge
, false_edge
;
656 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
657 if ((gimple_cond_code (stmt
) == EQ_EXPR
)
658 ^ (wi::to_wide (rhs
) == max
)
659 ^ (e1
== false_edge
))
660 std::swap (arg0
, arg1
);
663 if (TYPE_PRECISION (TREE_TYPE (lhs
)) == TYPE_PRECISION (TREE_TYPE (arg0
)))
665 /* Avoid performing the arithmetics in bool type which has different
666 semantics, otherwise prefer unsigned types from the two with
667 the same precision. */
668 if (TREE_CODE (TREE_TYPE (arg0
)) == BOOLEAN_TYPE
669 || !TYPE_UNSIGNED (TREE_TYPE (arg0
)))
670 type
= TREE_TYPE (lhs
);
672 type
= TREE_TYPE (arg0
);
674 else if (TYPE_PRECISION (TREE_TYPE (lhs
)) > TYPE_PRECISION (TREE_TYPE (arg0
)))
675 type
= TREE_TYPE (lhs
);
677 type
= TREE_TYPE (arg0
);
679 min
= wide_int::from (min
, TYPE_PRECISION (type
),
680 TYPE_SIGN (TREE_TYPE (lhs
)));
681 wide_int a
= wide_int::from (wi::to_wide (arg0
), TYPE_PRECISION (type
),
682 TYPE_SIGN (TREE_TYPE (arg0
)));
684 wi::overflow_type ovf
;
685 if (tree_int_cst_lt (arg0
, arg1
))
689 if (!TYPE_UNSIGNED (type
))
691 /* lhs is known to be in range [min, min+1] and we want to add a
692 to it. Check if that operation can overflow for those 2 values
693 and if yes, force unsigned type. */
694 wi::add (min
+ (wi::neg_p (a
) ? 0 : 1), a
, SIGNED
, &ovf
);
696 type
= unsigned_type_for (type
);
703 if (!TYPE_UNSIGNED (type
))
705 /* lhs is known to be in range [min, min+1] and we want to subtract
706 it from a. Check if that operation can overflow for those 2
707 values and if yes, force unsigned type. */
708 wi::sub (a
, min
+ (wi::neg_p (min
) ? 0 : 1), SIGNED
, &ovf
);
710 type
= unsigned_type_for (type
);
714 tree arg
= wide_int_to_tree (type
, a
);
715 gimple_stmt_iterator gsi
= gsi_for_stmt (stmt
);
716 if (!useless_type_conversion_p (type
, TREE_TYPE (lhs
)))
717 lhs
= gimplify_build1 (&gsi
, NOP_EXPR
, type
, lhs
);
719 if (code
== PLUS_EXPR
)
720 new_rhs
= gimplify_build2 (&gsi
, PLUS_EXPR
, type
, lhs
, arg
);
722 new_rhs
= gimplify_build2 (&gsi
, MINUS_EXPR
, type
, arg
, lhs
);
723 if (!useless_type_conversion_p (TREE_TYPE (arg0
), type
))
724 new_rhs
= gimplify_build1 (&gsi
, NOP_EXPR
, TREE_TYPE (arg0
), new_rhs
);
726 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, new_rhs
);
728 /* Note that we optimized this PHI. */
732 /* The function conditional_replacement does the main work of doing the
733 conditional replacement. Return true if the replacement is done.
734 Otherwise return false.
735 BB is the basic block where the replacement is going to be done on. ARG0
736 is argument 0 from PHI. Likewise for ARG1. */
739 conditional_replacement (basic_block cond_bb
, basic_block middle_bb
,
740 edge e0
, edge e1
, gphi
*phi
,
741 tree arg0
, tree arg1
)
747 gimple_stmt_iterator gsi
;
748 edge true_edge
, false_edge
;
749 tree new_var
, new_var2
;
752 /* FIXME: Gimplification of complex type is too hard for now. */
753 /* We aren't prepared to handle vectors either (and it is a question
754 if it would be worthwhile anyway). */
755 if (!(INTEGRAL_TYPE_P (TREE_TYPE (arg0
))
756 || POINTER_TYPE_P (TREE_TYPE (arg0
)))
757 || !(INTEGRAL_TYPE_P (TREE_TYPE (arg1
))
758 || POINTER_TYPE_P (TREE_TYPE (arg1
))))
761 /* The PHI arguments have the constants 0 and 1, or 0 and -1, then
762 convert it to the conditional. */
763 if ((integer_zerop (arg0
) && integer_onep (arg1
))
764 || (integer_zerop (arg1
) && integer_onep (arg0
)))
766 else if ((integer_zerop (arg0
) && integer_all_onesp (arg1
))
767 || (integer_zerop (arg1
) && integer_all_onesp (arg0
)))
772 if (!empty_block_p (middle_bb
))
775 /* At this point we know we have a GIMPLE_COND with two successors.
776 One successor is BB, the other successor is an empty block which
777 falls through into BB.
779 There is a single PHI node at the join point (BB) and its arguments
780 are constants (0, 1) or (0, -1).
782 So, given the condition COND, and the two PHI arguments, we can
783 rewrite this PHI into non-branching code:
785 dest = (COND) or dest = COND'
787 We use the condition as-is if the argument associated with the
788 true edge has the value one or the argument associated with the
789 false edge as the value zero. Note that those conditions are not
790 the same since only one of the outgoing edges from the GIMPLE_COND
791 will directly reach BB and thus be associated with an argument. */
793 stmt
= last_stmt (cond_bb
);
794 result
= PHI_RESULT (phi
);
796 /* To handle special cases like floating point comparison, it is easier and
797 less error-prone to build a tree and gimplify it on the fly though it is
799 cond
= fold_build2_loc (gimple_location (stmt
),
800 gimple_cond_code (stmt
), boolean_type_node
,
801 gimple_cond_lhs (stmt
), gimple_cond_rhs (stmt
));
803 /* We need to know which is the true edge and which is the false
804 edge so that we know when to invert the condition below. */
805 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
806 if ((e0
== true_edge
&& integer_zerop (arg0
))
807 || (e0
== false_edge
&& !integer_zerop (arg0
))
808 || (e1
== true_edge
&& integer_zerop (arg1
))
809 || (e1
== false_edge
&& !integer_zerop (arg1
)))
810 cond
= fold_build1_loc (gimple_location (stmt
),
811 TRUTH_NOT_EXPR
, TREE_TYPE (cond
), cond
);
815 cond
= fold_convert_loc (gimple_location (stmt
),
816 TREE_TYPE (result
), cond
);
817 cond
= fold_build1_loc (gimple_location (stmt
),
818 NEGATE_EXPR
, TREE_TYPE (cond
), cond
);
821 /* Insert our new statements at the end of conditional block before the
823 gsi
= gsi_for_stmt (stmt
);
824 new_var
= force_gimple_operand_gsi (&gsi
, cond
, true, NULL
, true,
827 if (!useless_type_conversion_p (TREE_TYPE (result
), TREE_TYPE (new_var
)))
829 location_t locus_0
, locus_1
;
831 new_var2
= make_ssa_name (TREE_TYPE (result
));
832 new_stmt
= gimple_build_assign (new_var2
, CONVERT_EXPR
, new_var
);
833 gsi_insert_before (&gsi
, new_stmt
, GSI_SAME_STMT
);
836 /* Set the locus to the first argument, unless is doesn't have one. */
837 locus_0
= gimple_phi_arg_location (phi
, 0);
838 locus_1
= gimple_phi_arg_location (phi
, 1);
839 if (locus_0
== UNKNOWN_LOCATION
)
841 gimple_set_location (new_stmt
, locus_0
);
844 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, new_var
);
846 /* Note that we optimized this PHI. */
850 /* Update *ARG which is defined in STMT so that it contains the
851 computed value if that seems profitable. Return true if the
852 statement is made dead by that rewriting. */
855 jump_function_from_stmt (tree
*arg
, gimple
*stmt
)
857 enum tree_code code
= gimple_assign_rhs_code (stmt
);
858 if (code
== ADDR_EXPR
)
860 /* For arg = &p->i transform it to p, if possible. */
861 tree rhs1
= gimple_assign_rhs1 (stmt
);
863 tree tem
= get_addr_base_and_unit_offset (TREE_OPERAND (rhs1
, 0),
866 && TREE_CODE (tem
) == MEM_REF
867 && known_eq (mem_ref_offset (tem
) + offset
, 0))
869 *arg
= TREE_OPERAND (tem
, 0);
873 /* TODO: Much like IPA-CP jump-functions we want to handle constant
874 additions symbolically here, and we'd need to update the comparison
875 code that compares the arg + cst tuples in our caller. For now the
876 code above exactly handles the VEC_BASE pattern from vec.h. */
880 /* RHS is a source argument in a BIT_AND_EXPR which feeds a conditional
881 of the form SSA_NAME NE 0.
883 If RHS is fed by a simple EQ_EXPR comparison of two values, see if
884 the two input values of the EQ_EXPR match arg0 and arg1.
886 If so update *code and return TRUE. Otherwise return FALSE. */
889 rhs_is_fed_for_value_replacement (const_tree arg0
, const_tree arg1
,
890 enum tree_code
*code
, const_tree rhs
)
892 /* Obviously if RHS is not an SSA_NAME, we can't look at the defining
894 if (TREE_CODE (rhs
) == SSA_NAME
)
896 gimple
*def1
= SSA_NAME_DEF_STMT (rhs
);
898 /* Verify the defining statement has an EQ_EXPR on the RHS. */
899 if (is_gimple_assign (def1
) && gimple_assign_rhs_code (def1
) == EQ_EXPR
)
901 /* Finally verify the source operands of the EQ_EXPR are equal
903 tree op0
= gimple_assign_rhs1 (def1
);
904 tree op1
= gimple_assign_rhs2 (def1
);
905 if ((operand_equal_for_phi_arg_p (arg0
, op0
)
906 && operand_equal_for_phi_arg_p (arg1
, op1
))
907 || (operand_equal_for_phi_arg_p (arg0
, op1
)
908 && operand_equal_for_phi_arg_p (arg1
, op0
)))
910 /* We will perform the optimization. */
911 *code
= gimple_assign_rhs_code (def1
);
919 /* Return TRUE if arg0/arg1 are equal to the rhs/lhs or lhs/rhs of COND.
921 Also return TRUE if arg0/arg1 are equal to the source arguments of a
922 an EQ comparison feeding a BIT_AND_EXPR which feeds COND.
924 Return FALSE otherwise. */
927 operand_equal_for_value_replacement (const_tree arg0
, const_tree arg1
,
928 enum tree_code
*code
, gimple
*cond
)
931 tree lhs
= gimple_cond_lhs (cond
);
932 tree rhs
= gimple_cond_rhs (cond
);
934 if ((operand_equal_for_phi_arg_p (arg0
, lhs
)
935 && operand_equal_for_phi_arg_p (arg1
, rhs
))
936 || (operand_equal_for_phi_arg_p (arg1
, lhs
)
937 && operand_equal_for_phi_arg_p (arg0
, rhs
)))
940 /* Now handle more complex case where we have an EQ comparison
941 which feeds a BIT_AND_EXPR which feeds COND.
943 First verify that COND is of the form SSA_NAME NE 0. */
944 if (*code
!= NE_EXPR
|| !integer_zerop (rhs
)
945 || TREE_CODE (lhs
) != SSA_NAME
)
948 /* Now ensure that SSA_NAME is set by a BIT_AND_EXPR. */
949 def
= SSA_NAME_DEF_STMT (lhs
);
950 if (!is_gimple_assign (def
) || gimple_assign_rhs_code (def
) != BIT_AND_EXPR
)
953 /* Now verify arg0/arg1 correspond to the source arguments of an
954 EQ comparison feeding the BIT_AND_EXPR. */
956 tree tmp
= gimple_assign_rhs1 (def
);
957 if (rhs_is_fed_for_value_replacement (arg0
, arg1
, code
, tmp
))
960 tmp
= gimple_assign_rhs2 (def
);
961 if (rhs_is_fed_for_value_replacement (arg0
, arg1
, code
, tmp
))
967 /* Returns true if ARG is a neutral element for operation CODE
968 on the RIGHT side. */
971 neutral_element_p (tree_code code
, tree arg
, bool right
)
978 return integer_zerop (arg
);
985 case POINTER_PLUS_EXPR
:
986 return right
&& integer_zerop (arg
);
989 return integer_onep (arg
);
996 return right
&& integer_onep (arg
);
999 return integer_all_onesp (arg
);
1006 /* Returns true if ARG is an absorbing element for operation CODE. */
1009 absorbing_element_p (tree_code code
, tree arg
, bool right
, tree rval
)
1014 return integer_all_onesp (arg
);
1018 return integer_zerop (arg
);
1024 return !right
&& integer_zerop (arg
);
1026 case TRUNC_DIV_EXPR
:
1028 case FLOOR_DIV_EXPR
:
1029 case ROUND_DIV_EXPR
:
1030 case EXACT_DIV_EXPR
:
1031 case TRUNC_MOD_EXPR
:
1033 case FLOOR_MOD_EXPR
:
1034 case ROUND_MOD_EXPR
:
1036 && integer_zerop (arg
)
1037 && tree_single_nonzero_warnv_p (rval
, NULL
));
1044 /* The function value_replacement does the main work of doing the value
1045 replacement. Return non-zero if the replacement is done. Otherwise return
1046 0. If we remove the middle basic block, return 2.
1047 BB is the basic block where the replacement is going to be done on. ARG0
1048 is argument 0 from the PHI. Likewise for ARG1. */
1051 value_replacement (basic_block cond_bb
, basic_block middle_bb
,
1052 edge e0
, edge e1
, gimple
*phi
,
1053 tree arg0
, tree arg1
)
1055 gimple_stmt_iterator gsi
;
1057 edge true_edge
, false_edge
;
1058 enum tree_code code
;
1059 bool emtpy_or_with_defined_p
= true;
1061 /* If the type says honor signed zeros we cannot do this
1063 if (HONOR_SIGNED_ZEROS (arg1
))
1066 /* If there is a statement in MIDDLE_BB that defines one of the PHI
1067 arguments, then adjust arg0 or arg1. */
1068 gsi
= gsi_start_nondebug_after_labels_bb (middle_bb
);
1069 while (!gsi_end_p (gsi
))
1071 gimple
*stmt
= gsi_stmt (gsi
);
1073 gsi_next_nondebug (&gsi
);
1074 if (!is_gimple_assign (stmt
))
1076 if (gimple_code (stmt
) != GIMPLE_PREDICT
1077 && gimple_code (stmt
) != GIMPLE_NOP
)
1078 emtpy_or_with_defined_p
= false;
1081 /* Now try to adjust arg0 or arg1 according to the computation
1082 in the statement. */
1083 lhs
= gimple_assign_lhs (stmt
);
1085 && jump_function_from_stmt (&arg0
, stmt
))
1087 && jump_function_from_stmt (&arg1
, stmt
)))
1088 emtpy_or_with_defined_p
= false;
1091 cond
= last_stmt (cond_bb
);
1092 code
= gimple_cond_code (cond
);
1094 /* This transformation is only valid for equality comparisons. */
1095 if (code
!= NE_EXPR
&& code
!= EQ_EXPR
)
1098 /* We need to know which is the true edge and which is the false
1099 edge so that we know if have abs or negative abs. */
1100 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
1102 /* At this point we know we have a COND_EXPR with two successors.
1103 One successor is BB, the other successor is an empty block which
1104 falls through into BB.
1106 The condition for the COND_EXPR is known to be NE_EXPR or EQ_EXPR.
1108 There is a single PHI node at the join point (BB) with two arguments.
1110 We now need to verify that the two arguments in the PHI node match
1111 the two arguments to the equality comparison. */
1113 if (operand_equal_for_value_replacement (arg0
, arg1
, &code
, cond
))
1118 /* For NE_EXPR, we want to build an assignment result = arg where
1119 arg is the PHI argument associated with the true edge. For
1120 EQ_EXPR we want the PHI argument associated with the false edge. */
1121 e
= (code
== NE_EXPR
? true_edge
: false_edge
);
1123 /* Unfortunately, E may not reach BB (it may instead have gone to
1124 OTHER_BLOCK). If that is the case, then we want the single outgoing
1125 edge from OTHER_BLOCK which reaches BB and represents the desired
1126 path from COND_BLOCK. */
1127 if (e
->dest
== middle_bb
)
1128 e
= single_succ_edge (e
->dest
);
1130 /* Now we know the incoming edge to BB that has the argument for the
1131 RHS of our new assignment statement. */
1137 /* If the middle basic block was empty or is defining the
1138 PHI arguments and this is a single phi where the args are different
1139 for the edges e0 and e1 then we can remove the middle basic block. */
1140 if (emtpy_or_with_defined_p
1141 && single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi
)),
1144 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, arg
);
1145 /* Note that we optimized this PHI. */
1150 /* Replace the PHI arguments with arg. */
1151 SET_PHI_ARG_DEF (phi
, e0
->dest_idx
, arg
);
1152 SET_PHI_ARG_DEF (phi
, e1
->dest_idx
, arg
);
1153 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1155 fprintf (dump_file
, "PHI ");
1156 print_generic_expr (dump_file
, gimple_phi_result (phi
));
1157 fprintf (dump_file
, " reduced for COND_EXPR in block %d to ",
1159 print_generic_expr (dump_file
, arg
);
1160 fprintf (dump_file
, ".\n");
1167 /* Now optimize (x != 0) ? x + y : y to just x + y. */
1168 gsi
= gsi_last_nondebug_bb (middle_bb
);
1169 if (gsi_end_p (gsi
))
1172 gimple
*assign
= gsi_stmt (gsi
);
1173 if (!is_gimple_assign (assign
)
1174 || gimple_assign_rhs_class (assign
) != GIMPLE_BINARY_RHS
1175 || (!INTEGRAL_TYPE_P (TREE_TYPE (arg0
))
1176 && !POINTER_TYPE_P (TREE_TYPE (arg0
))))
1179 /* Punt if there are (degenerate) PHIs in middle_bb, there should not be. */
1180 if (!gimple_seq_empty_p (phi_nodes (middle_bb
)))
1183 /* Allow up to 2 cheap preparation statements that prepare argument
1191 iftmp.0_6 = x_5(D) r<< _1;
1193 # iftmp.0_2 = PHI <iftmp.0_6(3), x_5(D)(2)>
1204 # _2 = PHI <x_5(D)(2), _6(3)> */
1205 gimple
*prep_stmt
[2] = { NULL
, NULL
};
1207 for (prep_cnt
= 0; ; prep_cnt
++)
1209 gsi_prev_nondebug (&gsi
);
1210 if (gsi_end_p (gsi
))
1213 gimple
*g
= gsi_stmt (gsi
);
1214 if (gimple_code (g
) == GIMPLE_LABEL
)
1217 if (prep_cnt
== 2 || !is_gimple_assign (g
))
1220 tree lhs
= gimple_assign_lhs (g
);
1221 tree rhs1
= gimple_assign_rhs1 (g
);
1222 use_operand_p use_p
;
1224 if (TREE_CODE (lhs
) != SSA_NAME
1225 || TREE_CODE (rhs1
) != SSA_NAME
1226 || !INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
1227 || !INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
1228 || !single_imm_use (lhs
, &use_p
, &use_stmt
)
1229 || use_stmt
!= (prep_cnt
? prep_stmt
[prep_cnt
- 1] : assign
))
1231 switch (gimple_assign_rhs_code (g
))
1239 if (TREE_CODE (gimple_assign_rhs2 (g
)) != INTEGER_CST
)
1245 prep_stmt
[prep_cnt
] = g
;
1248 /* Only transform if it removes the condition. */
1249 if (!single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi
)), e0
, e1
))
1252 /* Size-wise, this is always profitable. */
1253 if (optimize_bb_for_speed_p (cond_bb
)
1254 /* The special case is useless if it has a low probability. */
1255 && profile_status_for_fn (cfun
) != PROFILE_ABSENT
1256 && EDGE_PRED (middle_bb
, 0)->probability
< profile_probability::even ()
1257 /* If assign is cheap, there is no point avoiding it. */
1258 && estimate_num_insns (bb_seq (middle_bb
), &eni_time_weights
)
1259 >= 3 * estimate_num_insns (cond
, &eni_time_weights
))
1262 tree lhs
= gimple_assign_lhs (assign
);
1263 tree rhs1
= gimple_assign_rhs1 (assign
);
1264 tree rhs2
= gimple_assign_rhs2 (assign
);
1265 enum tree_code code_def
= gimple_assign_rhs_code (assign
);
1266 tree cond_lhs
= gimple_cond_lhs (cond
);
1267 tree cond_rhs
= gimple_cond_rhs (cond
);
1269 /* Propagate the cond_rhs constant through preparation stmts,
1270 make sure UB isn't invoked while doing that. */
1271 for (int i
= prep_cnt
- 1; i
>= 0; --i
)
1273 gimple
*g
= prep_stmt
[i
];
1274 tree grhs1
= gimple_assign_rhs1 (g
);
1275 if (!operand_equal_for_phi_arg_p (cond_lhs
, grhs1
))
1277 cond_lhs
= gimple_assign_lhs (g
);
1278 cond_rhs
= fold_convert (TREE_TYPE (grhs1
), cond_rhs
);
1279 if (TREE_CODE (cond_rhs
) != INTEGER_CST
1280 || TREE_OVERFLOW (cond_rhs
))
1282 if (gimple_assign_rhs_class (g
) == GIMPLE_BINARY_RHS
)
1284 cond_rhs
= int_const_binop (gimple_assign_rhs_code (g
), cond_rhs
,
1285 gimple_assign_rhs2 (g
));
1286 if (TREE_OVERFLOW (cond_rhs
))
1289 cond_rhs
= fold_convert (TREE_TYPE (cond_lhs
), cond_rhs
);
1290 if (TREE_CODE (cond_rhs
) != INTEGER_CST
1291 || TREE_OVERFLOW (cond_rhs
))
1295 if (((code
== NE_EXPR
&& e1
== false_edge
)
1296 || (code
== EQ_EXPR
&& e1
== true_edge
))
1299 && operand_equal_for_phi_arg_p (rhs2
, cond_lhs
)
1300 && neutral_element_p (code_def
, cond_rhs
, true))
1302 && operand_equal_for_phi_arg_p (rhs1
, cond_lhs
)
1303 && neutral_element_p (code_def
, cond_rhs
, false))
1304 || (operand_equal_for_phi_arg_p (arg1
, cond_rhs
)
1305 && ((operand_equal_for_phi_arg_p (rhs2
, cond_lhs
)
1306 && absorbing_element_p (code_def
, cond_rhs
, true, rhs2
))
1307 || (operand_equal_for_phi_arg_p (rhs1
, cond_lhs
)
1308 && absorbing_element_p (code_def
,
1309 cond_rhs
, false, rhs2
))))))
1311 gsi
= gsi_for_stmt (cond
);
1312 /* Moving ASSIGN might change VR of lhs, e.g. when moving u_6
1320 # RANGE [0, 4294967294]
1321 u_6 = n_5 + 4294967295;
1324 # u_3 = PHI <u_6(3), 4294967295(2)> */
1325 reset_flow_sensitive_info (lhs
);
1326 if (INTEGRAL_TYPE_P (TREE_TYPE (lhs
)))
1328 /* If available, we can use VR of phi result at least. */
1329 tree phires
= gimple_phi_result (phi
);
1330 struct range_info_def
*phires_range_info
1331 = SSA_NAME_RANGE_INFO (phires
);
1332 if (phires_range_info
)
1333 duplicate_ssa_name_range_info (lhs
, SSA_NAME_RANGE_TYPE (phires
),
1336 gimple_stmt_iterator gsi_from
;
1337 for (int i
= prep_cnt
- 1; i
>= 0; --i
)
1339 tree plhs
= gimple_assign_lhs (prep_stmt
[i
]);
1340 reset_flow_sensitive_info (plhs
);
1341 gsi_from
= gsi_for_stmt (prep_stmt
[i
]);
1342 gsi_move_before (&gsi_from
, &gsi
);
1344 gsi_from
= gsi_for_stmt (assign
);
1345 gsi_move_before (&gsi_from
, &gsi
);
1346 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, lhs
);
1353 /* The function minmax_replacement does the main work of doing the minmax
1354 replacement. Return true if the replacement is done. Otherwise return
1356 BB is the basic block where the replacement is going to be done on. ARG0
1357 is argument 0 from the PHI. Likewise for ARG1. */
1360 minmax_replacement (basic_block cond_bb
, basic_block middle_bb
,
1361 edge e0
, edge e1
, gimple
*phi
,
1362 tree arg0
, tree arg1
)
1364 tree result
, type
, rhs
;
1367 edge true_edge
, false_edge
;
1368 enum tree_code cmp
, minmax
, ass_code
;
1369 tree smaller
, alt_smaller
, larger
, alt_larger
, arg_true
, arg_false
;
1370 gimple_stmt_iterator gsi
, gsi_from
;
1372 type
= TREE_TYPE (PHI_RESULT (phi
));
1374 /* The optimization may be unsafe due to NaNs. */
1375 if (HONOR_NANS (type
) || HONOR_SIGNED_ZEROS (type
))
1378 cond
= as_a
<gcond
*> (last_stmt (cond_bb
));
1379 cmp
= gimple_cond_code (cond
);
1380 rhs
= gimple_cond_rhs (cond
);
1382 /* Turn EQ/NE of extreme values to order comparisons. */
1383 if ((cmp
== NE_EXPR
|| cmp
== EQ_EXPR
)
1384 && TREE_CODE (rhs
) == INTEGER_CST
1385 && INTEGRAL_TYPE_P (TREE_TYPE (rhs
)))
1387 if (wi::eq_p (wi::to_wide (rhs
), wi::min_value (TREE_TYPE (rhs
))))
1389 cmp
= (cmp
== EQ_EXPR
) ? LT_EXPR
: GE_EXPR
;
1390 rhs
= wide_int_to_tree (TREE_TYPE (rhs
),
1391 wi::min_value (TREE_TYPE (rhs
)) + 1);
1393 else if (wi::eq_p (wi::to_wide (rhs
), wi::max_value (TREE_TYPE (rhs
))))
1395 cmp
= (cmp
== EQ_EXPR
) ? GT_EXPR
: LE_EXPR
;
1396 rhs
= wide_int_to_tree (TREE_TYPE (rhs
),
1397 wi::max_value (TREE_TYPE (rhs
)) - 1);
1401 /* This transformation is only valid for order comparisons. Record which
1402 operand is smaller/larger if the result of the comparison is true. */
1403 alt_smaller
= NULL_TREE
;
1404 alt_larger
= NULL_TREE
;
1405 if (cmp
== LT_EXPR
|| cmp
== LE_EXPR
)
1407 smaller
= gimple_cond_lhs (cond
);
1409 /* If we have smaller < CST it is equivalent to smaller <= CST-1.
1410 Likewise smaller <= CST is equivalent to smaller < CST+1. */
1411 if (TREE_CODE (larger
) == INTEGER_CST
1412 && INTEGRAL_TYPE_P (TREE_TYPE (larger
)))
1416 wi::overflow_type overflow
;
1417 wide_int alt
= wi::sub (wi::to_wide (larger
), 1,
1418 TYPE_SIGN (TREE_TYPE (larger
)),
1421 alt_larger
= wide_int_to_tree (TREE_TYPE (larger
), alt
);
1425 wi::overflow_type overflow
;
1426 wide_int alt
= wi::add (wi::to_wide (larger
), 1,
1427 TYPE_SIGN (TREE_TYPE (larger
)),
1430 alt_larger
= wide_int_to_tree (TREE_TYPE (larger
), alt
);
1434 else if (cmp
== GT_EXPR
|| cmp
== GE_EXPR
)
1437 larger
= gimple_cond_lhs (cond
);
1438 /* If we have larger > CST it is equivalent to larger >= CST+1.
1439 Likewise larger >= CST is equivalent to larger > CST-1. */
1440 if (TREE_CODE (smaller
) == INTEGER_CST
1441 && INTEGRAL_TYPE_P (TREE_TYPE (smaller
)))
1443 wi::overflow_type overflow
;
1446 wide_int alt
= wi::add (wi::to_wide (smaller
), 1,
1447 TYPE_SIGN (TREE_TYPE (smaller
)),
1450 alt_smaller
= wide_int_to_tree (TREE_TYPE (smaller
), alt
);
1454 wide_int alt
= wi::sub (wi::to_wide (smaller
), 1,
1455 TYPE_SIGN (TREE_TYPE (smaller
)),
1458 alt_smaller
= wide_int_to_tree (TREE_TYPE (smaller
), alt
);
1465 /* We need to know which is the true edge and which is the false
1466 edge so that we know if have abs or negative abs. */
1467 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
1469 /* Forward the edges over the middle basic block. */
1470 if (true_edge
->dest
== middle_bb
)
1471 true_edge
= EDGE_SUCC (true_edge
->dest
, 0);
1472 if (false_edge
->dest
== middle_bb
)
1473 false_edge
= EDGE_SUCC (false_edge
->dest
, 0);
1475 if (true_edge
== e0
)
1477 gcc_assert (false_edge
== e1
);
1483 gcc_assert (false_edge
== e0
);
1484 gcc_assert (true_edge
== e1
);
1489 if (empty_block_p (middle_bb
))
1491 if ((operand_equal_for_phi_arg_p (arg_true
, smaller
)
1493 && operand_equal_for_phi_arg_p (arg_true
, alt_smaller
)))
1494 && (operand_equal_for_phi_arg_p (arg_false
, larger
)
1496 && operand_equal_for_phi_arg_p (arg_true
, alt_larger
))))
1500 if (smaller < larger)
1506 else if ((operand_equal_for_phi_arg_p (arg_false
, smaller
)
1508 && operand_equal_for_phi_arg_p (arg_false
, alt_smaller
)))
1509 && (operand_equal_for_phi_arg_p (arg_true
, larger
)
1511 && operand_equal_for_phi_arg_p (arg_true
, alt_larger
))))
1518 /* Recognize the following case, assuming d <= u:
1524 This is equivalent to
1529 gimple
*assign
= last_and_only_stmt (middle_bb
);
1530 tree lhs
, op0
, op1
, bound
;
1533 || gimple_code (assign
) != GIMPLE_ASSIGN
)
1536 lhs
= gimple_assign_lhs (assign
);
1537 ass_code
= gimple_assign_rhs_code (assign
);
1538 if (ass_code
!= MAX_EXPR
&& ass_code
!= MIN_EXPR
)
1540 op0
= gimple_assign_rhs1 (assign
);
1541 op1
= gimple_assign_rhs2 (assign
);
1543 if (true_edge
->src
== middle_bb
)
1545 /* We got here if the condition is true, i.e., SMALLER < LARGER. */
1546 if (!operand_equal_for_phi_arg_p (lhs
, arg_true
))
1549 if (operand_equal_for_phi_arg_p (arg_false
, larger
)
1551 && operand_equal_for_phi_arg_p (arg_false
, alt_larger
)))
1555 if (smaller < larger)
1557 r' = MAX_EXPR (smaller, bound)
1559 r = PHI <r', larger> --> to be turned to MIN_EXPR. */
1560 if (ass_code
!= MAX_EXPR
)
1564 if (operand_equal_for_phi_arg_p (op0
, smaller
)
1566 && operand_equal_for_phi_arg_p (op0
, alt_smaller
)))
1568 else if (operand_equal_for_phi_arg_p (op1
, smaller
)
1570 && operand_equal_for_phi_arg_p (op1
, alt_smaller
)))
1575 /* We need BOUND <= LARGER. */
1576 if (!integer_nonzerop (fold_build2 (LE_EXPR
, boolean_type_node
,
1580 else if (operand_equal_for_phi_arg_p (arg_false
, smaller
)
1582 && operand_equal_for_phi_arg_p (arg_false
, alt_smaller
)))
1586 if (smaller < larger)
1588 r' = MIN_EXPR (larger, bound)
1590 r = PHI <r', smaller> --> to be turned to MAX_EXPR. */
1591 if (ass_code
!= MIN_EXPR
)
1595 if (operand_equal_for_phi_arg_p (op0
, larger
)
1597 && operand_equal_for_phi_arg_p (op0
, alt_larger
)))
1599 else if (operand_equal_for_phi_arg_p (op1
, larger
)
1601 && operand_equal_for_phi_arg_p (op1
, alt_larger
)))
1606 /* We need BOUND >= SMALLER. */
1607 if (!integer_nonzerop (fold_build2 (GE_EXPR
, boolean_type_node
,
1616 /* We got here if the condition is false, i.e., SMALLER > LARGER. */
1617 if (!operand_equal_for_phi_arg_p (lhs
, arg_false
))
1620 if (operand_equal_for_phi_arg_p (arg_true
, larger
)
1622 && operand_equal_for_phi_arg_p (arg_true
, alt_larger
)))
1626 if (smaller > larger)
1628 r' = MIN_EXPR (smaller, bound)
1630 r = PHI <r', larger> --> to be turned to MAX_EXPR. */
1631 if (ass_code
!= MIN_EXPR
)
1635 if (operand_equal_for_phi_arg_p (op0
, smaller
)
1637 && operand_equal_for_phi_arg_p (op0
, alt_smaller
)))
1639 else if (operand_equal_for_phi_arg_p (op1
, smaller
)
1641 && operand_equal_for_phi_arg_p (op1
, alt_smaller
)))
1646 /* We need BOUND >= LARGER. */
1647 if (!integer_nonzerop (fold_build2 (GE_EXPR
, boolean_type_node
,
1651 else if (operand_equal_for_phi_arg_p (arg_true
, smaller
)
1653 && operand_equal_for_phi_arg_p (arg_true
, alt_smaller
)))
1657 if (smaller > larger)
1659 r' = MAX_EXPR (larger, bound)
1661 r = PHI <r', smaller> --> to be turned to MIN_EXPR. */
1662 if (ass_code
!= MAX_EXPR
)
1666 if (operand_equal_for_phi_arg_p (op0
, larger
))
1668 else if (operand_equal_for_phi_arg_p (op1
, larger
))
1673 /* We need BOUND <= SMALLER. */
1674 if (!integer_nonzerop (fold_build2 (LE_EXPR
, boolean_type_node
,
1682 /* Move the statement from the middle block. */
1683 gsi
= gsi_last_bb (cond_bb
);
1684 gsi_from
= gsi_last_nondebug_bb (middle_bb
);
1685 reset_flow_sensitive_info (SINGLE_SSA_TREE_OPERAND (gsi_stmt (gsi_from
),
1687 gsi_move_before (&gsi_from
, &gsi
);
1690 /* Create an SSA var to hold the min/max result. If we're the only
1691 things setting the target PHI, then we can clone the PHI
1692 variable. Otherwise we must create a new one. */
1693 result
= PHI_RESULT (phi
);
1694 if (EDGE_COUNT (gimple_bb (phi
)->preds
) == 2)
1695 result
= duplicate_ssa_name (result
, NULL
);
1697 result
= make_ssa_name (TREE_TYPE (result
));
1699 /* Emit the statement to compute min/max. */
1700 new_stmt
= gimple_build_assign (result
, minmax
, arg0
, arg1
);
1701 gsi
= gsi_last_bb (cond_bb
);
1702 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
1704 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, result
);
1718 _2 = (unsigned long) b_4(D);
1719 _9 = __builtin_popcountl (_2);
1721 _9 = __builtin_popcountl (b_4(D));
1724 c_12 = PHI <0(2), _9(3)>
1728 _2 = (unsigned long) b_4(D);
1729 _9 = __builtin_popcountl (_2);
1731 _9 = __builtin_popcountl (b_4(D));
1738 cond_removal_in_popcount_pattern (basic_block cond_bb
, basic_block middle_bb
,
1740 gimple
*phi
, tree arg0
, tree arg1
)
1743 gimple_stmt_iterator gsi
, gsi_from
;
1745 gimple
*cast
= NULL
;
1749 _2 = (unsigned long) b_4(D);
1750 _9 = __builtin_popcountl (_2);
1752 _9 = __builtin_popcountl (b_4(D));
1753 are the only stmts in the middle_bb. */
1755 gsi
= gsi_start_nondebug_after_labels_bb (middle_bb
);
1756 if (gsi_end_p (gsi
))
1758 cast
= gsi_stmt (gsi
);
1759 gsi_next_nondebug (&gsi
);
1760 if (!gsi_end_p (gsi
))
1762 popcount
= gsi_stmt (gsi
);
1763 gsi_next_nondebug (&gsi
);
1764 if (!gsi_end_p (gsi
))
1773 /* Check that we have a popcount builtin. */
1774 if (!is_gimple_call (popcount
))
1776 combined_fn cfn
= gimple_call_combined_fn (popcount
);
1785 arg
= gimple_call_arg (popcount
, 0);
1786 lhs
= gimple_get_lhs (popcount
);
1790 /* We have a cast stmt feeding popcount builtin. */
1791 /* Check that we have a cast prior to that. */
1792 if (gimple_code (cast
) != GIMPLE_ASSIGN
1793 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (cast
)))
1795 /* Result of the cast stmt is the argument to the builtin. */
1796 if (arg
!= gimple_assign_lhs (cast
))
1798 arg
= gimple_assign_rhs1 (cast
);
1801 cond
= last_stmt (cond_bb
);
1803 /* Cond_bb has a check for b_4 [!=|==] 0 before calling the popcount
1805 if (gimple_code (cond
) != GIMPLE_COND
1806 || (gimple_cond_code (cond
) != NE_EXPR
1807 && gimple_cond_code (cond
) != EQ_EXPR
)
1808 || !integer_zerop (gimple_cond_rhs (cond
))
1809 || arg
!= gimple_cond_lhs (cond
))
1813 if ((e2
->flags
& EDGE_TRUE_VALUE
1814 && gimple_cond_code (cond
) == NE_EXPR
)
1815 || (e1
->flags
& EDGE_TRUE_VALUE
1816 && gimple_cond_code (cond
) == EQ_EXPR
))
1818 std::swap (arg0
, arg1
);
1822 /* Check PHI arguments. */
1823 if (lhs
!= arg0
|| !integer_zerop (arg1
))
1826 /* And insert the popcount builtin and cast stmt before the cond_bb. */
1827 gsi
= gsi_last_bb (cond_bb
);
1830 gsi_from
= gsi_for_stmt (cast
);
1831 gsi_move_before (&gsi_from
, &gsi
);
1832 reset_flow_sensitive_info (gimple_get_lhs (cast
));
1834 gsi_from
= gsi_for_stmt (popcount
);
1835 gsi_move_before (&gsi_from
, &gsi
);
1836 reset_flow_sensitive_info (gimple_get_lhs (popcount
));
1838 /* Now update the PHI and remove unneeded bbs. */
1839 replace_phi_edge_with_variable (cond_bb
, e2
, phi
, lhs
);
1843 /* The function absolute_replacement does the main work of doing the absolute
1844 replacement. Return true if the replacement is done. Otherwise return
1846 bb is the basic block where the replacement is going to be done on. arg0
1847 is argument 0 from the phi. Likewise for arg1. */
1850 abs_replacement (basic_block cond_bb
, basic_block middle_bb
,
1851 edge e0 ATTRIBUTE_UNUSED
, edge e1
,
1852 gimple
*phi
, tree arg0
, tree arg1
)
1857 gimple_stmt_iterator gsi
;
1858 edge true_edge
, false_edge
;
1863 enum tree_code cond_code
;
1865 /* If the type says honor signed zeros we cannot do this
1867 if (HONOR_SIGNED_ZEROS (arg1
))
1870 /* OTHER_BLOCK must have only one executable statement which must have the
1871 form arg0 = -arg1 or arg1 = -arg0. */
1873 assign
= last_and_only_stmt (middle_bb
);
1874 /* If we did not find the proper negation assignment, then we cannot
1879 /* If we got here, then we have found the only executable statement
1880 in OTHER_BLOCK. If it is anything other than arg = -arg1 or
1881 arg1 = -arg0, then we cannot optimize. */
1882 if (gimple_code (assign
) != GIMPLE_ASSIGN
)
1885 lhs
= gimple_assign_lhs (assign
);
1887 if (gimple_assign_rhs_code (assign
) != NEGATE_EXPR
)
1890 rhs
= gimple_assign_rhs1 (assign
);
1892 /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */
1893 if (!(lhs
== arg0
&& rhs
== arg1
)
1894 && !(lhs
== arg1
&& rhs
== arg0
))
1897 cond
= last_stmt (cond_bb
);
1898 result
= PHI_RESULT (phi
);
1900 /* Only relationals comparing arg[01] against zero are interesting. */
1901 cond_code
= gimple_cond_code (cond
);
1902 if (cond_code
!= GT_EXPR
&& cond_code
!= GE_EXPR
1903 && cond_code
!= LT_EXPR
&& cond_code
!= LE_EXPR
)
1906 /* Make sure the conditional is arg[01] OP y. */
1907 if (gimple_cond_lhs (cond
) != rhs
)
1910 if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond
)))
1911 ? real_zerop (gimple_cond_rhs (cond
))
1912 : integer_zerop (gimple_cond_rhs (cond
)))
1917 /* We need to know which is the true edge and which is the false
1918 edge so that we know if have abs or negative abs. */
1919 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
1921 /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we
1922 will need to negate the result. Similarly for LT_EXPR/LE_EXPR if
1923 the false edge goes to OTHER_BLOCK. */
1924 if (cond_code
== GT_EXPR
|| cond_code
== GE_EXPR
)
1929 if (e
->dest
== middle_bb
)
1934 /* If the code negates only iff positive then make sure to not
1935 introduce undefined behavior when negating or computing the absolute.
1936 ??? We could use range info if present to check for arg1 == INT_MIN. */
1938 && (ANY_INTEGRAL_TYPE_P (TREE_TYPE (arg1
))
1939 && ! TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg1
))))
1942 result
= duplicate_ssa_name (result
, NULL
);
1945 lhs
= make_ssa_name (TREE_TYPE (result
));
1949 /* Build the modify expression with abs expression. */
1950 new_stmt
= gimple_build_assign (lhs
, ABS_EXPR
, rhs
);
1952 gsi
= gsi_last_bb (cond_bb
);
1953 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
1957 /* Get the right GSI. We want to insert after the recently
1958 added ABS_EXPR statement (which we know is the first statement
1960 new_stmt
= gimple_build_assign (result
, NEGATE_EXPR
, lhs
);
1962 gsi_insert_after (&gsi
, new_stmt
, GSI_NEW_STMT
);
1965 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, result
);
1967 /* Note that we optimized this PHI. */
1971 /* Auxiliary functions to determine the set of memory accesses which
1972 can't trap because they are preceded by accesses to the same memory
1973 portion. We do that for MEM_REFs, so we only need to track
1974 the SSA_NAME of the pointer indirectly referenced. The algorithm
1975 simply is a walk over all instructions in dominator order. When
1976 we see an MEM_REF we determine if we've already seen a same
1977 ref anywhere up to the root of the dominator tree. If we do the
1978 current access can't trap. If we don't see any dominating access
1979 the current access might trap, but might also make later accesses
1980 non-trapping, so we remember it. We need to be careful with loads
1981 or stores, for instance a load might not trap, while a store would,
1982 so if we see a dominating read access this doesn't mean that a later
1983 write access would not trap. Hence we also need to differentiate the
1984 type of access(es) seen.
1986 ??? We currently are very conservative and assume that a load might
1987 trap even if a store doesn't (write-only memory). This probably is
1988 overly conservative. */
1990 /* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF
1991 through it was seen, which would constitute a no-trap region for
1995 unsigned int ssa_name_ver
;
1998 HOST_WIDE_INT offset
, size
;
2002 /* Hashtable helpers. */
2004 struct ssa_names_hasher
: free_ptr_hash
<name_to_bb
>
2006 static inline hashval_t
hash (const name_to_bb
*);
2007 static inline bool equal (const name_to_bb
*, const name_to_bb
*);
2010 /* Used for quick clearing of the hash-table when we see calls.
2011 Hash entries with phase < nt_call_phase are invalid. */
2012 static unsigned int nt_call_phase
;
2014 /* The hash function. */
2017 ssa_names_hasher::hash (const name_to_bb
*n
)
2019 return n
->ssa_name_ver
^ (((hashval_t
) n
->store
) << 31)
2020 ^ (n
->offset
<< 6) ^ (n
->size
<< 3);
2023 /* The equality function of *P1 and *P2. */
2026 ssa_names_hasher::equal (const name_to_bb
*n1
, const name_to_bb
*n2
)
2028 return n1
->ssa_name_ver
== n2
->ssa_name_ver
2029 && n1
->store
== n2
->store
2030 && n1
->offset
== n2
->offset
2031 && n1
->size
== n2
->size
;
2034 class nontrapping_dom_walker
: public dom_walker
2037 nontrapping_dom_walker (cdi_direction direction
, hash_set
<tree
> *ps
)
2038 : dom_walker (direction
), m_nontrapping (ps
), m_seen_ssa_names (128) {}
2040 virtual edge
before_dom_children (basic_block
);
2041 virtual void after_dom_children (basic_block
);
2045 /* We see the expression EXP in basic block BB. If it's an interesting
2046 expression (an MEM_REF through an SSA_NAME) possibly insert the
2047 expression into the set NONTRAP or the hash table of seen expressions.
2048 STORE is true if this expression is on the LHS, otherwise it's on
2050 void add_or_mark_expr (basic_block
, tree
, bool);
2052 hash_set
<tree
> *m_nontrapping
;
2054 /* The hash table for remembering what we've seen. */
2055 hash_table
<ssa_names_hasher
> m_seen_ssa_names
;
2058 /* Called by walk_dominator_tree, when entering the block BB. */
2060 nontrapping_dom_walker::before_dom_children (basic_block bb
)
2064 gimple_stmt_iterator gsi
;
2066 /* If we haven't seen all our predecessors, clear the hash-table. */
2067 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
2068 if ((((size_t)e
->src
->aux
) & 2) == 0)
2074 /* Mark this BB as being on the path to dominator root and as visited. */
2075 bb
->aux
= (void*)(1 | 2);
2077 /* And walk the statements in order. */
2078 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2080 gimple
*stmt
= gsi_stmt (gsi
);
2082 if ((gimple_code (stmt
) == GIMPLE_ASM
&& gimple_vdef (stmt
))
2083 || (is_gimple_call (stmt
)
2084 && (!nonfreeing_call_p (stmt
) || !nonbarrier_call_p (stmt
))))
2086 else if (gimple_assign_single_p (stmt
) && !gimple_has_volatile_ops (stmt
))
2088 add_or_mark_expr (bb
, gimple_assign_lhs (stmt
), true);
2089 add_or_mark_expr (bb
, gimple_assign_rhs1 (stmt
), false);
2095 /* Called by walk_dominator_tree, when basic block BB is exited. */
2097 nontrapping_dom_walker::after_dom_children (basic_block bb
)
2099 /* This BB isn't on the path to dominator root anymore. */
2103 /* We see the expression EXP in basic block BB. If it's an interesting
2104 expression (an MEM_REF through an SSA_NAME) possibly insert the
2105 expression into the set NONTRAP or the hash table of seen expressions.
2106 STORE is true if this expression is on the LHS, otherwise it's on
2109 nontrapping_dom_walker::add_or_mark_expr (basic_block bb
, tree exp
, bool store
)
2113 if (TREE_CODE (exp
) == MEM_REF
2114 && TREE_CODE (TREE_OPERAND (exp
, 0)) == SSA_NAME
2115 && tree_fits_shwi_p (TREE_OPERAND (exp
, 1))
2116 && (size
= int_size_in_bytes (TREE_TYPE (exp
))) > 0)
2118 tree name
= TREE_OPERAND (exp
, 0);
2119 struct name_to_bb map
;
2121 struct name_to_bb
*n2bb
;
2122 basic_block found_bb
= 0;
2124 /* Try to find the last seen MEM_REF through the same
2125 SSA_NAME, which can trap. */
2126 map
.ssa_name_ver
= SSA_NAME_VERSION (name
);
2130 map
.offset
= tree_to_shwi (TREE_OPERAND (exp
, 1));
2133 slot
= m_seen_ssa_names
.find_slot (&map
, INSERT
);
2135 if (n2bb
&& n2bb
->phase
>= nt_call_phase
)
2136 found_bb
= n2bb
->bb
;
2138 /* If we've found a trapping MEM_REF, _and_ it dominates EXP
2139 (it's in a basic block on the path from us to the dominator root)
2140 then we can't trap. */
2141 if (found_bb
&& (((size_t)found_bb
->aux
) & 1) == 1)
2143 m_nontrapping
->add (exp
);
2147 /* EXP might trap, so insert it into the hash table. */
2150 n2bb
->phase
= nt_call_phase
;
2155 n2bb
= XNEW (struct name_to_bb
);
2156 n2bb
->ssa_name_ver
= SSA_NAME_VERSION (name
);
2157 n2bb
->phase
= nt_call_phase
;
2159 n2bb
->store
= store
;
2160 n2bb
->offset
= map
.offset
;
2168 /* This is the entry point of gathering non trapping memory accesses.
2169 It will do a dominator walk over the whole function, and it will
2170 make use of the bb->aux pointers. It returns a set of trees
2171 (the MEM_REFs itself) which can't trap. */
2172 static hash_set
<tree
> *
2173 get_non_trapping (void)
2176 hash_set
<tree
> *nontrap
= new hash_set
<tree
>;
2177 /* We're going to do a dominator walk, so ensure that we have
2178 dominance information. */
2179 calculate_dominance_info (CDI_DOMINATORS
);
2181 nontrapping_dom_walker (CDI_DOMINATORS
, nontrap
)
2182 .walk (cfun
->cfg
->x_entry_block_ptr
);
2184 clear_aux_for_blocks ();
2188 /* Do the main work of conditional store replacement. We already know
2189 that the recognized pattern looks like so:
2192 if (cond) goto MIDDLE_BB; else goto JOIN_BB (edge E1)
2195 fallthrough (edge E0)
2199 We check that MIDDLE_BB contains only one store, that that store
2200 doesn't trap (not via NOTRAP, but via checking if an access to the same
2201 memory location dominates us, or the store is to a local addressable
2202 object) and that the store has a "simple" RHS. */
2205 cond_store_replacement (basic_block middle_bb
, basic_block join_bb
,
2206 edge e0
, edge e1
, hash_set
<tree
> *nontrap
)
2208 gimple
*assign
= last_and_only_stmt (middle_bb
);
2209 tree lhs
, rhs
, name
, name2
;
2212 gimple_stmt_iterator gsi
;
2215 /* Check if middle_bb contains of only one store. */
2217 || !gimple_assign_single_p (assign
)
2218 || gimple_has_volatile_ops (assign
))
2221 /* And no PHI nodes so all uses in the single stmt are also
2222 available where we insert to. */
2223 if (!gimple_seq_empty_p (phi_nodes (middle_bb
)))
2226 locus
= gimple_location (assign
);
2227 lhs
= gimple_assign_lhs (assign
);
2228 rhs
= gimple_assign_rhs1 (assign
);
2229 if ((TREE_CODE (lhs
) != MEM_REF
2230 && TREE_CODE (lhs
) != ARRAY_REF
2231 && TREE_CODE (lhs
) != COMPONENT_REF
)
2232 || !is_gimple_reg_type (TREE_TYPE (lhs
)))
2235 /* Prove that we can move the store down. We could also check
2236 TREE_THIS_NOTRAP here, but in that case we also could move stores,
2237 whose value is not available readily, which we want to avoid. */
2238 if (!nontrap
->contains (lhs
))
2240 /* If LHS is a local variable without address-taken, we could
2241 always safely move down the store. */
2242 tree base
= get_base_address (lhs
);
2243 if (!auto_var_p (base
) || TREE_ADDRESSABLE (base
))
2247 /* Now we've checked the constraints, so do the transformation:
2248 1) Remove the single store. */
2249 gsi
= gsi_for_stmt (assign
);
2250 unlink_stmt_vdef (assign
);
2251 gsi_remove (&gsi
, true);
2252 release_defs (assign
);
2254 /* Make both store and load use alias-set zero as we have to
2255 deal with the case of the store being a conditional change
2256 of the dynamic type. */
2257 lhs
= unshare_expr (lhs
);
2259 while (handled_component_p (*basep
))
2260 basep
= &TREE_OPERAND (*basep
, 0);
2261 if (TREE_CODE (*basep
) == MEM_REF
2262 || TREE_CODE (*basep
) == TARGET_MEM_REF
)
2263 TREE_OPERAND (*basep
, 1)
2264 = fold_convert (ptr_type_node
, TREE_OPERAND (*basep
, 1));
2266 *basep
= build2 (MEM_REF
, TREE_TYPE (*basep
),
2267 build_fold_addr_expr (*basep
),
2268 build_zero_cst (ptr_type_node
));
2270 /* 2) Insert a load from the memory of the store to the temporary
2271 on the edge which did not contain the store. */
2272 name
= make_temp_ssa_name (TREE_TYPE (lhs
), NULL
, "cstore");
2273 new_stmt
= gimple_build_assign (name
, lhs
);
2274 gimple_set_location (new_stmt
, locus
);
2275 lhs
= unshare_expr (lhs
);
2276 /* Set TREE_NO_WARNING on the rhs of the load to avoid uninit
2278 TREE_NO_WARNING (gimple_assign_rhs1 (new_stmt
)) = 1;
2279 gsi_insert_on_edge (e1
, new_stmt
);
2281 /* 3) Create a PHI node at the join block, with one argument
2282 holding the old RHS, and the other holding the temporary
2283 where we stored the old memory contents. */
2284 name2
= make_temp_ssa_name (TREE_TYPE (lhs
), NULL
, "cstore");
2285 newphi
= create_phi_node (name2
, join_bb
);
2286 add_phi_arg (newphi
, rhs
, e0
, locus
);
2287 add_phi_arg (newphi
, name
, e1
, locus
);
2289 new_stmt
= gimple_build_assign (lhs
, PHI_RESULT (newphi
));
2291 /* 4) Insert that PHI node. */
2292 gsi
= gsi_after_labels (join_bb
);
2293 if (gsi_end_p (gsi
))
2295 gsi
= gsi_last_bb (join_bb
);
2296 gsi_insert_after (&gsi
, new_stmt
, GSI_NEW_STMT
);
2299 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
2301 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2303 fprintf (dump_file
, "\nConditional store replacement happened!");
2304 fprintf (dump_file
, "\nReplaced the store with a load.");
2305 fprintf (dump_file
, "\nInserted a new PHI statement in joint block:\n");
2306 print_gimple_stmt (dump_file
, new_stmt
, 0, TDF_VOPS
|TDF_MEMSYMS
);
2312 /* Do the main work of conditional store replacement. */
2315 cond_if_else_store_replacement_1 (basic_block then_bb
, basic_block else_bb
,
2316 basic_block join_bb
, gimple
*then_assign
,
2317 gimple
*else_assign
)
2319 tree lhs_base
, lhs
, then_rhs
, else_rhs
, name
;
2320 location_t then_locus
, else_locus
;
2321 gimple_stmt_iterator gsi
;
2325 if (then_assign
== NULL
2326 || !gimple_assign_single_p (then_assign
)
2327 || gimple_clobber_p (then_assign
)
2328 || gimple_has_volatile_ops (then_assign
)
2329 || else_assign
== NULL
2330 || !gimple_assign_single_p (else_assign
)
2331 || gimple_clobber_p (else_assign
)
2332 || gimple_has_volatile_ops (else_assign
))
2335 lhs
= gimple_assign_lhs (then_assign
);
2336 if (!is_gimple_reg_type (TREE_TYPE (lhs
))
2337 || !operand_equal_p (lhs
, gimple_assign_lhs (else_assign
), 0))
2340 lhs_base
= get_base_address (lhs
);
2341 if (lhs_base
== NULL_TREE
2342 || (!DECL_P (lhs_base
) && TREE_CODE (lhs_base
) != MEM_REF
))
2345 then_rhs
= gimple_assign_rhs1 (then_assign
);
2346 else_rhs
= gimple_assign_rhs1 (else_assign
);
2347 then_locus
= gimple_location (then_assign
);
2348 else_locus
= gimple_location (else_assign
);
2350 /* Now we've checked the constraints, so do the transformation:
2351 1) Remove the stores. */
2352 gsi
= gsi_for_stmt (then_assign
);
2353 unlink_stmt_vdef (then_assign
);
2354 gsi_remove (&gsi
, true);
2355 release_defs (then_assign
);
2357 gsi
= gsi_for_stmt (else_assign
);
2358 unlink_stmt_vdef (else_assign
);
2359 gsi_remove (&gsi
, true);
2360 release_defs (else_assign
);
2362 /* 2) Create a PHI node at the join block, with one argument
2363 holding the old RHS, and the other holding the temporary
2364 where we stored the old memory contents. */
2365 name
= make_temp_ssa_name (TREE_TYPE (lhs
), NULL
, "cstore");
2366 newphi
= create_phi_node (name
, join_bb
);
2367 add_phi_arg (newphi
, then_rhs
, EDGE_SUCC (then_bb
, 0), then_locus
);
2368 add_phi_arg (newphi
, else_rhs
, EDGE_SUCC (else_bb
, 0), else_locus
);
2370 new_stmt
= gimple_build_assign (lhs
, PHI_RESULT (newphi
));
2372 /* 3) Insert that PHI node. */
2373 gsi
= gsi_after_labels (join_bb
);
2374 if (gsi_end_p (gsi
))
2376 gsi
= gsi_last_bb (join_bb
);
2377 gsi_insert_after (&gsi
, new_stmt
, GSI_NEW_STMT
);
2380 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
2385 /* Return the single store in BB with VDEF or NULL if there are
2386 other stores in the BB or loads following the store. */
2389 single_trailing_store_in_bb (basic_block bb
, tree vdef
)
2391 if (SSA_NAME_IS_DEFAULT_DEF (vdef
))
2393 gimple
*store
= SSA_NAME_DEF_STMT (vdef
);
2394 if (gimple_bb (store
) != bb
2395 || gimple_code (store
) == GIMPLE_PHI
)
2398 /* Verify there is no other store in this BB. */
2399 if (!SSA_NAME_IS_DEFAULT_DEF (gimple_vuse (store
))
2400 && gimple_bb (SSA_NAME_DEF_STMT (gimple_vuse (store
))) == bb
2401 && gimple_code (SSA_NAME_DEF_STMT (gimple_vuse (store
))) != GIMPLE_PHI
)
2404 /* Verify there is no load or store after the store. */
2405 use_operand_p use_p
;
2406 imm_use_iterator imm_iter
;
2407 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, gimple_vdef (store
))
2408 if (USE_STMT (use_p
) != store
2409 && gimple_bb (USE_STMT (use_p
)) == bb
)
2415 /* Conditional store replacement. We already know
2416 that the recognized pattern looks like so:
2419 if (cond) goto THEN_BB; else goto ELSE_BB (edge E1)
2429 fallthrough (edge E0)
2433 We check that it is safe to sink the store to JOIN_BB by verifying that
2434 there are no read-after-write or write-after-write dependencies in
2435 THEN_BB and ELSE_BB. */
2438 cond_if_else_store_replacement (basic_block then_bb
, basic_block else_bb
,
2439 basic_block join_bb
)
2441 vec
<data_reference_p
> then_datarefs
, else_datarefs
;
2442 vec
<ddr_p
> then_ddrs
, else_ddrs
;
2443 gimple
*then_store
, *else_store
;
2444 bool found
, ok
= false, res
;
2445 struct data_dependence_relation
*ddr
;
2446 data_reference_p then_dr
, else_dr
;
2448 tree then_lhs
, else_lhs
;
2449 basic_block blocks
[3];
2451 /* Handle the case with single store in THEN_BB and ELSE_BB. That is
2452 cheap enough to always handle as it allows us to elide dependence
2455 for (gphi_iterator si
= gsi_start_phis (join_bb
); !gsi_end_p (si
);
2457 if (virtual_operand_p (gimple_phi_result (si
.phi ())))
2464 tree then_vdef
= PHI_ARG_DEF_FROM_EDGE (vphi
, single_succ_edge (then_bb
));
2465 tree else_vdef
= PHI_ARG_DEF_FROM_EDGE (vphi
, single_succ_edge (else_bb
));
2466 gimple
*then_assign
= single_trailing_store_in_bb (then_bb
, then_vdef
);
2469 gimple
*else_assign
= single_trailing_store_in_bb (else_bb
, else_vdef
);
2471 return cond_if_else_store_replacement_1 (then_bb
, else_bb
, join_bb
,
2472 then_assign
, else_assign
);
2475 /* If either vectorization or if-conversion is disabled then do
2476 not sink any stores. */
2477 if (param_max_stores_to_sink
== 0
2478 || (!flag_tree_loop_vectorize
&& !flag_tree_slp_vectorize
)
2479 || !flag_tree_loop_if_convert
)
2482 /* Find data references. */
2483 then_datarefs
.create (1);
2484 else_datarefs
.create (1);
2485 if ((find_data_references_in_bb (NULL
, then_bb
, &then_datarefs
)
2487 || !then_datarefs
.length ()
2488 || (find_data_references_in_bb (NULL
, else_bb
, &else_datarefs
)
2490 || !else_datarefs
.length ())
2492 free_data_refs (then_datarefs
);
2493 free_data_refs (else_datarefs
);
2497 /* Find pairs of stores with equal LHS. */
2498 auto_vec
<gimple
*, 1> then_stores
, else_stores
;
2499 FOR_EACH_VEC_ELT (then_datarefs
, i
, then_dr
)
2501 if (DR_IS_READ (then_dr
))
2504 then_store
= DR_STMT (then_dr
);
2505 then_lhs
= gimple_get_lhs (then_store
);
2506 if (then_lhs
== NULL_TREE
)
2510 FOR_EACH_VEC_ELT (else_datarefs
, j
, else_dr
)
2512 if (DR_IS_READ (else_dr
))
2515 else_store
= DR_STMT (else_dr
);
2516 else_lhs
= gimple_get_lhs (else_store
);
2517 if (else_lhs
== NULL_TREE
)
2520 if (operand_equal_p (then_lhs
, else_lhs
, 0))
2530 then_stores
.safe_push (then_store
);
2531 else_stores
.safe_push (else_store
);
2534 /* No pairs of stores found. */
2535 if (!then_stores
.length ()
2536 || then_stores
.length () > (unsigned) param_max_stores_to_sink
)
2538 free_data_refs (then_datarefs
);
2539 free_data_refs (else_datarefs
);
2543 /* Compute and check data dependencies in both basic blocks. */
2544 then_ddrs
.create (1);
2545 else_ddrs
.create (1);
2546 if (!compute_all_dependences (then_datarefs
, &then_ddrs
,
2548 || !compute_all_dependences (else_datarefs
, &else_ddrs
,
2551 free_dependence_relations (then_ddrs
);
2552 free_dependence_relations (else_ddrs
);
2553 free_data_refs (then_datarefs
);
2554 free_data_refs (else_datarefs
);
2557 blocks
[0] = then_bb
;
2558 blocks
[1] = else_bb
;
2559 blocks
[2] = join_bb
;
2560 renumber_gimple_stmt_uids_in_blocks (blocks
, 3);
2562 /* Check that there are no read-after-write or write-after-write dependencies
2564 FOR_EACH_VEC_ELT (then_ddrs
, i
, ddr
)
2566 struct data_reference
*dra
= DDR_A (ddr
);
2567 struct data_reference
*drb
= DDR_B (ddr
);
2569 if (DDR_ARE_DEPENDENT (ddr
) != chrec_known
2570 && ((DR_IS_READ (dra
) && DR_IS_WRITE (drb
)
2571 && gimple_uid (DR_STMT (dra
)) > gimple_uid (DR_STMT (drb
)))
2572 || (DR_IS_READ (drb
) && DR_IS_WRITE (dra
)
2573 && gimple_uid (DR_STMT (drb
)) > gimple_uid (DR_STMT (dra
)))
2574 || (DR_IS_WRITE (dra
) && DR_IS_WRITE (drb
))))
2576 free_dependence_relations (then_ddrs
);
2577 free_dependence_relations (else_ddrs
);
2578 free_data_refs (then_datarefs
);
2579 free_data_refs (else_datarefs
);
2584 /* Check that there are no read-after-write or write-after-write dependencies
2586 FOR_EACH_VEC_ELT (else_ddrs
, i
, ddr
)
2588 struct data_reference
*dra
= DDR_A (ddr
);
2589 struct data_reference
*drb
= DDR_B (ddr
);
2591 if (DDR_ARE_DEPENDENT (ddr
) != chrec_known
2592 && ((DR_IS_READ (dra
) && DR_IS_WRITE (drb
)
2593 && gimple_uid (DR_STMT (dra
)) > gimple_uid (DR_STMT (drb
)))
2594 || (DR_IS_READ (drb
) && DR_IS_WRITE (dra
)
2595 && gimple_uid (DR_STMT (drb
)) > gimple_uid (DR_STMT (dra
)))
2596 || (DR_IS_WRITE (dra
) && DR_IS_WRITE (drb
))))
2598 free_dependence_relations (then_ddrs
);
2599 free_dependence_relations (else_ddrs
);
2600 free_data_refs (then_datarefs
);
2601 free_data_refs (else_datarefs
);
2606 /* Sink stores with same LHS. */
2607 FOR_EACH_VEC_ELT (then_stores
, i
, then_store
)
2609 else_store
= else_stores
[i
];
2610 res
= cond_if_else_store_replacement_1 (then_bb
, else_bb
, join_bb
,
2611 then_store
, else_store
);
2615 free_dependence_relations (then_ddrs
);
2616 free_dependence_relations (else_ddrs
);
2617 free_data_refs (then_datarefs
);
2618 free_data_refs (else_datarefs
);
2623 /* Return TRUE if STMT has a VUSE whose corresponding VDEF is in BB. */
2626 local_mem_dependence (gimple
*stmt
, basic_block bb
)
2628 tree vuse
= gimple_vuse (stmt
);
2634 def
= SSA_NAME_DEF_STMT (vuse
);
2635 return (def
&& gimple_bb (def
) == bb
);
2638 /* Given a "diamond" control-flow pattern where BB0 tests a condition,
2639 BB1 and BB2 are "then" and "else" blocks dependent on this test,
2640 and BB3 rejoins control flow following BB1 and BB2, look for
2641 opportunities to hoist loads as follows. If BB3 contains a PHI of
2642 two loads, one each occurring in BB1 and BB2, and the loads are
2643 provably of adjacent fields in the same structure, then move both
2644 loads into BB0. Of course this can only be done if there are no
2645 dependencies preventing such motion.
2647 One of the hoisted loads will always be speculative, so the
2648 transformation is currently conservative:
2650 - The fields must be strictly adjacent.
2651 - The two fields must occupy a single memory block that is
2652 guaranteed to not cross a page boundary.
2654 The last is difficult to prove, as such memory blocks should be
2655 aligned on the minimum of the stack alignment boundary and the
2656 alignment guaranteed by heap allocation interfaces. Thus we rely
2657 on a parameter for the alignment value.
2659 Provided a good value is used for the last case, the first
2660 restriction could possibly be relaxed. */
2663 hoist_adjacent_loads (basic_block bb0
, basic_block bb1
,
2664 basic_block bb2
, basic_block bb3
)
2666 int param_align
= param_l1_cache_line_size
;
2667 unsigned param_align_bits
= (unsigned) (param_align
* BITS_PER_UNIT
);
2670 /* Walk the phis in bb3 looking for an opportunity. We are looking
2671 for phis of two SSA names, one each of which is defined in bb1 and
2673 for (gsi
= gsi_start_phis (bb3
); !gsi_end_p (gsi
); gsi_next (&gsi
))
2675 gphi
*phi_stmt
= gsi
.phi ();
2676 gimple
*def1
, *def2
;
2677 tree arg1
, arg2
, ref1
, ref2
, field1
, field2
;
2678 tree tree_offset1
, tree_offset2
, tree_size2
, next
;
2679 int offset1
, offset2
, size2
;
2681 gimple_stmt_iterator gsi2
;
2682 basic_block bb_for_def1
, bb_for_def2
;
2684 if (gimple_phi_num_args (phi_stmt
) != 2
2685 || virtual_operand_p (gimple_phi_result (phi_stmt
)))
2688 arg1
= gimple_phi_arg_def (phi_stmt
, 0);
2689 arg2
= gimple_phi_arg_def (phi_stmt
, 1);
2691 if (TREE_CODE (arg1
) != SSA_NAME
2692 || TREE_CODE (arg2
) != SSA_NAME
2693 || SSA_NAME_IS_DEFAULT_DEF (arg1
)
2694 || SSA_NAME_IS_DEFAULT_DEF (arg2
))
2697 def1
= SSA_NAME_DEF_STMT (arg1
);
2698 def2
= SSA_NAME_DEF_STMT (arg2
);
2700 if ((gimple_bb (def1
) != bb1
|| gimple_bb (def2
) != bb2
)
2701 && (gimple_bb (def2
) != bb1
|| gimple_bb (def1
) != bb2
))
2704 /* Check the mode of the arguments to be sure a conditional move
2705 can be generated for it. */
2706 if (optab_handler (movcc_optab
, TYPE_MODE (TREE_TYPE (arg1
)))
2707 == CODE_FOR_nothing
)
2710 /* Both statements must be assignments whose RHS is a COMPONENT_REF. */
2711 if (!gimple_assign_single_p (def1
)
2712 || !gimple_assign_single_p (def2
)
2713 || gimple_has_volatile_ops (def1
)
2714 || gimple_has_volatile_ops (def2
))
2717 ref1
= gimple_assign_rhs1 (def1
);
2718 ref2
= gimple_assign_rhs1 (def2
);
2720 if (TREE_CODE (ref1
) != COMPONENT_REF
2721 || TREE_CODE (ref2
) != COMPONENT_REF
)
2724 /* The zeroth operand of the two component references must be
2725 identical. It is not sufficient to compare get_base_address of
2726 the two references, because this could allow for different
2727 elements of the same array in the two trees. It is not safe to
2728 assume that the existence of one array element implies the
2729 existence of a different one. */
2730 if (!operand_equal_p (TREE_OPERAND (ref1
, 0), TREE_OPERAND (ref2
, 0), 0))
2733 field1
= TREE_OPERAND (ref1
, 1);
2734 field2
= TREE_OPERAND (ref2
, 1);
2736 /* Check for field adjacency, and ensure field1 comes first. */
2737 for (next
= DECL_CHAIN (field1
);
2738 next
&& TREE_CODE (next
) != FIELD_DECL
;
2739 next
= DECL_CHAIN (next
))
2744 for (next
= DECL_CHAIN (field2
);
2745 next
&& TREE_CODE (next
) != FIELD_DECL
;
2746 next
= DECL_CHAIN (next
))
2752 std::swap (field1
, field2
);
2753 std::swap (def1
, def2
);
2756 bb_for_def1
= gimple_bb (def1
);
2757 bb_for_def2
= gimple_bb (def2
);
2759 /* Check for proper alignment of the first field. */
2760 tree_offset1
= bit_position (field1
);
2761 tree_offset2
= bit_position (field2
);
2762 tree_size2
= DECL_SIZE (field2
);
2764 if (!tree_fits_uhwi_p (tree_offset1
)
2765 || !tree_fits_uhwi_p (tree_offset2
)
2766 || !tree_fits_uhwi_p (tree_size2
))
2769 offset1
= tree_to_uhwi (tree_offset1
);
2770 offset2
= tree_to_uhwi (tree_offset2
);
2771 size2
= tree_to_uhwi (tree_size2
);
2772 align1
= DECL_ALIGN (field1
) % param_align_bits
;
2774 if (offset1
% BITS_PER_UNIT
!= 0)
2777 /* For profitability, the two field references should fit within
2778 a single cache line. */
2779 if (align1
+ offset2
- offset1
+ size2
> param_align_bits
)
2782 /* The two expressions cannot be dependent upon vdefs defined
2784 if (local_mem_dependence (def1
, bb_for_def1
)
2785 || local_mem_dependence (def2
, bb_for_def2
))
2788 /* The conditions are satisfied; hoist the loads from bb1 and bb2 into
2789 bb0. We hoist the first one first so that a cache miss is handled
2790 efficiently regardless of hardware cache-fill policy. */
2791 gsi2
= gsi_for_stmt (def1
);
2792 gsi_move_to_bb_end (&gsi2
, bb0
);
2793 gsi2
= gsi_for_stmt (def2
);
2794 gsi_move_to_bb_end (&gsi2
, bb0
);
2796 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2799 "\nHoisting adjacent loads from %d and %d into %d: \n",
2800 bb_for_def1
->index
, bb_for_def2
->index
, bb0
->index
);
2801 print_gimple_stmt (dump_file
, def1
, 0, TDF_VOPS
|TDF_MEMSYMS
);
2802 print_gimple_stmt (dump_file
, def2
, 0, TDF_VOPS
|TDF_MEMSYMS
);
2807 /* Determine whether we should attempt to hoist adjacent loads out of
2808 diamond patterns in pass_phiopt. Always hoist loads if
2809 -fhoist-adjacent-loads is specified and the target machine has
2810 both a conditional move instruction and a defined cache line size. */
2813 gate_hoist_loads (void)
2815 return (flag_hoist_adjacent_loads
== 1
2816 && param_l1_cache_line_size
2817 && HAVE_conditional_move
);
2820 /* This pass tries to replaces an if-then-else block with an
2821 assignment. We have four kinds of transformations. Some of these
2822 transformations are also performed by the ifcvt RTL optimizer.
2824 Conditional Replacement
2825 -----------------------
2827 This transformation, implemented in conditional_replacement,
2831 if (cond) goto bb2; else goto bb1;
2834 x = PHI <0 (bb1), 1 (bb0), ...>;
2842 x = PHI <x' (bb0), ...>;
2844 We remove bb1 as it becomes unreachable. This occurs often due to
2845 gimplification of conditionals.
2850 This transformation, implemented in value_replacement, replaces
2853 if (a != b) goto bb2; else goto bb1;
2856 x = PHI <a (bb1), b (bb0), ...>;
2862 x = PHI <b (bb0), ...>;
2864 This opportunity can sometimes occur as a result of other
2868 Another case caught by value replacement looks like this:
2874 if (t3 != 0) goto bb1; else goto bb2;
2890 This transformation, implemented in abs_replacement, replaces
2893 if (a >= 0) goto bb2; else goto bb1;
2897 x = PHI <x (bb1), a (bb0), ...>;
2904 x = PHI <x' (bb0), ...>;
2909 This transformation, minmax_replacement replaces
2912 if (a <= b) goto bb2; else goto bb1;
2915 x = PHI <b (bb1), a (bb0), ...>;
2920 x' = MIN_EXPR (a, b)
2922 x = PHI <x' (bb0), ...>;
2924 A similar transformation is done for MAX_EXPR.
2927 This pass also performs a fifth transformation of a slightly different
2930 Factor conversion in COND_EXPR
2931 ------------------------------
2933 This transformation factors the conversion out of COND_EXPR with
2934 factor_out_conditional_conversion.
2937 if (a <= CST) goto <bb 3>; else goto <bb 4>;
2941 tmp = PHI <tmp, CST>
2944 if (a <= CST) goto <bb 3>; else goto <bb 4>;
2950 Adjacent Load Hoisting
2951 ----------------------
2953 This transformation replaces
2956 if (...) goto bb2; else goto bb1;
2958 x1 = (<expr>).field1;
2961 x2 = (<expr>).field2;
2968 x1 = (<expr>).field1;
2969 x2 = (<expr>).field2;
2970 if (...) goto bb2; else goto bb1;
2977 The purpose of this transformation is to enable generation of conditional
2978 move instructions such as Intel CMOVE or PowerPC ISEL. Because one of
2979 the loads is speculative, the transformation is restricted to very
2980 specific cases to avoid introducing a page fault. We are looking for
2988 where left and right are typically adjacent pointers in a tree structure. */
2992 const pass_data pass_data_phiopt
=
2994 GIMPLE_PASS
, /* type */
2995 "phiopt", /* name */
2996 OPTGROUP_NONE
, /* optinfo_flags */
2997 TV_TREE_PHIOPT
, /* tv_id */
2998 ( PROP_cfg
| PROP_ssa
), /* properties_required */
2999 0, /* properties_provided */
3000 0, /* properties_destroyed */
3001 0, /* todo_flags_start */
3002 0, /* todo_flags_finish */
3005 class pass_phiopt
: public gimple_opt_pass
3008 pass_phiopt (gcc::context
*ctxt
)
3009 : gimple_opt_pass (pass_data_phiopt
, ctxt
), early_p (false)
3012 /* opt_pass methods: */
3013 opt_pass
* clone () { return new pass_phiopt (m_ctxt
); }
3014 void set_pass_param (unsigned n
, bool param
)
3016 gcc_assert (n
== 0);
3019 virtual bool gate (function
*) { return flag_ssa_phiopt
; }
3020 virtual unsigned int execute (function
*)
3022 return tree_ssa_phiopt_worker (false,
3023 !early_p
? gate_hoist_loads () : false,
3029 }; // class pass_phiopt
3034 make_pass_phiopt (gcc::context
*ctxt
)
3036 return new pass_phiopt (ctxt
);
3041 const pass_data pass_data_cselim
=
3043 GIMPLE_PASS
, /* type */
3044 "cselim", /* name */
3045 OPTGROUP_NONE
, /* optinfo_flags */
3046 TV_TREE_PHIOPT
, /* tv_id */
3047 ( PROP_cfg
| PROP_ssa
), /* properties_required */
3048 0, /* properties_provided */
3049 0, /* properties_destroyed */
3050 0, /* todo_flags_start */
3051 0, /* todo_flags_finish */
3054 class pass_cselim
: public gimple_opt_pass
3057 pass_cselim (gcc::context
*ctxt
)
3058 : gimple_opt_pass (pass_data_cselim
, ctxt
)
3061 /* opt_pass methods: */
3062 virtual bool gate (function
*) { return flag_tree_cselim
; }
3063 virtual unsigned int execute (function
*) { return tree_ssa_cs_elim (); }
3065 }; // class pass_cselim
3070 make_pass_cselim (gcc::context
*ctxt
)
3072 return new pass_cselim (ctxt
);