Use hard_regno_nregs instead of HARD_REGNO_NREGS
[official-gcc.git] / gcc / tree-ssa-ccp.c
blob3940d538ca77997a43e2a02b803c5c5f1ded9763
1 /* Conditional constant propagation pass for the GNU compiler.
2 Copyright (C) 2000-2017 Free Software Foundation, Inc.
3 Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org>
4 Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by the
10 Free Software Foundation; either version 3, or (at your option) any
11 later version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Conditional constant propagation (CCP) is based on the SSA
23 propagation engine (tree-ssa-propagate.c). Constant assignments of
24 the form VAR = CST are propagated from the assignments into uses of
25 VAR, which in turn may generate new constants. The simulation uses
26 a four level lattice to keep track of constant values associated
27 with SSA names. Given an SSA name V_i, it may take one of the
28 following values:
30 UNINITIALIZED -> the initial state of the value. This value
31 is replaced with a correct initial value
32 the first time the value is used, so the
33 rest of the pass does not need to care about
34 it. Using this value simplifies initialization
35 of the pass, and prevents us from needlessly
36 scanning statements that are never reached.
38 UNDEFINED -> V_i is a local variable whose definition
39 has not been processed yet. Therefore we
40 don't yet know if its value is a constant
41 or not.
43 CONSTANT -> V_i has been found to hold a constant
44 value C.
46 VARYING -> V_i cannot take a constant value, or if it
47 does, it is not possible to determine it
48 at compile time.
50 The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node:
52 1- In ccp_visit_stmt, we are interested in assignments whose RHS
53 evaluates into a constant and conditional jumps whose predicate
54 evaluates into a boolean true or false. When an assignment of
55 the form V_i = CONST is found, V_i's lattice value is set to
56 CONSTANT and CONST is associated with it. This causes the
57 propagation engine to add all the SSA edges coming out the
58 assignment into the worklists, so that statements that use V_i
59 can be visited.
61 If the statement is a conditional with a constant predicate, we
62 mark the outgoing edges as executable or not executable
63 depending on the predicate's value. This is then used when
64 visiting PHI nodes to know when a PHI argument can be ignored.
67 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the
68 same constant C, then the LHS of the PHI is set to C. This
69 evaluation is known as the "meet operation". Since one of the
70 goals of this evaluation is to optimistically return constant
71 values as often as possible, it uses two main short cuts:
73 - If an argument is flowing in through a non-executable edge, it
74 is ignored. This is useful in cases like this:
76 if (PRED)
77 a_9 = 3;
78 else
79 a_10 = 100;
80 a_11 = PHI (a_9, a_10)
82 If PRED is known to always evaluate to false, then we can
83 assume that a_11 will always take its value from a_10, meaning
84 that instead of consider it VARYING (a_9 and a_10 have
85 different values), we can consider it CONSTANT 100.
87 - If an argument has an UNDEFINED value, then it does not affect
88 the outcome of the meet operation. If a variable V_i has an
89 UNDEFINED value, it means that either its defining statement
90 hasn't been visited yet or V_i has no defining statement, in
91 which case the original symbol 'V' is being used
92 uninitialized. Since 'V' is a local variable, the compiler
93 may assume any initial value for it.
96 After propagation, every variable V_i that ends up with a lattice
97 value of CONSTANT will have the associated constant value in the
98 array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for
99 final substitution and folding.
101 This algorithm uses wide-ints at the max precision of the target.
102 This means that, with one uninteresting exception, variables with
103 UNSIGNED types never go to VARYING because the bits above the
104 precision of the type of the variable are always zero. The
105 uninteresting case is a variable of UNSIGNED type that has the
106 maximum precision of the target. Such variables can go to VARYING,
107 but this causes no loss of infomation since these variables will
108 never be extended.
110 References:
112 Constant propagation with conditional branches,
113 Wegman and Zadeck, ACM TOPLAS 13(2):181-210.
115 Building an Optimizing Compiler,
116 Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9.
118 Advanced Compiler Design and Implementation,
119 Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */
121 #include "config.h"
122 #include "system.h"
123 #include "coretypes.h"
124 #include "backend.h"
125 #include "target.h"
126 #include "tree.h"
127 #include "gimple.h"
128 #include "tree-pass.h"
129 #include "ssa.h"
130 #include "gimple-pretty-print.h"
131 #include "fold-const.h"
132 #include "gimple-fold.h"
133 #include "tree-eh.h"
134 #include "gimplify.h"
135 #include "gimple-iterator.h"
136 #include "tree-cfg.h"
137 #include "tree-ssa-propagate.h"
138 #include "dbgcnt.h"
139 #include "params.h"
140 #include "builtins.h"
141 #include "tree-chkp.h"
142 #include "cfgloop.h"
143 #include "stor-layout.h"
144 #include "optabs-query.h"
145 #include "tree-ssa-ccp.h"
146 #include "tree-dfa.h"
147 #include "diagnostic-core.h"
148 #include "stringpool.h"
149 #include "attribs.h"
151 /* Possible lattice values. */
152 typedef enum
154 UNINITIALIZED,
155 UNDEFINED,
156 CONSTANT,
157 VARYING
158 } ccp_lattice_t;
160 struct ccp_prop_value_t {
161 /* Lattice value. */
162 ccp_lattice_t lattice_val;
164 /* Propagated value. */
165 tree value;
167 /* Mask that applies to the propagated value during CCP. For X
168 with a CONSTANT lattice value X & ~mask == value & ~mask. The
169 zero bits in the mask cover constant values. The ones mean no
170 information. */
171 widest_int mask;
174 /* Array of propagated constant values. After propagation,
175 CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If
176 the constant is held in an SSA name representing a memory store
177 (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual
178 memory reference used to store (i.e., the LHS of the assignment
179 doing the store). */
180 static ccp_prop_value_t *const_val;
181 static unsigned n_const_val;
183 static void canonicalize_value (ccp_prop_value_t *);
184 static bool ccp_fold_stmt (gimple_stmt_iterator *);
185 static void ccp_lattice_meet (ccp_prop_value_t *, ccp_prop_value_t *);
187 /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */
189 static void
190 dump_lattice_value (FILE *outf, const char *prefix, ccp_prop_value_t val)
192 switch (val.lattice_val)
194 case UNINITIALIZED:
195 fprintf (outf, "%sUNINITIALIZED", prefix);
196 break;
197 case UNDEFINED:
198 fprintf (outf, "%sUNDEFINED", prefix);
199 break;
200 case VARYING:
201 fprintf (outf, "%sVARYING", prefix);
202 break;
203 case CONSTANT:
204 if (TREE_CODE (val.value) != INTEGER_CST
205 || val.mask == 0)
207 fprintf (outf, "%sCONSTANT ", prefix);
208 print_generic_expr (outf, val.value, dump_flags);
210 else
212 widest_int cval = wi::bit_and_not (wi::to_widest (val.value),
213 val.mask);
214 fprintf (outf, "%sCONSTANT ", prefix);
215 print_hex (cval, outf);
216 fprintf (outf, " (");
217 print_hex (val.mask, outf);
218 fprintf (outf, ")");
220 break;
221 default:
222 gcc_unreachable ();
227 /* Print lattice value VAL to stderr. */
229 void debug_lattice_value (ccp_prop_value_t val);
231 DEBUG_FUNCTION void
232 debug_lattice_value (ccp_prop_value_t val)
234 dump_lattice_value (stderr, "", val);
235 fprintf (stderr, "\n");
238 /* Extend NONZERO_BITS to a full mask, based on sgn. */
240 static widest_int
241 extend_mask (const wide_int &nonzero_bits, signop sgn)
243 return widest_int::from (nonzero_bits, sgn);
246 /* Compute a default value for variable VAR and store it in the
247 CONST_VAL array. The following rules are used to get default
248 values:
250 1- Global and static variables that are declared constant are
251 considered CONSTANT.
253 2- Any other value is considered UNDEFINED. This is useful when
254 considering PHI nodes. PHI arguments that are undefined do not
255 change the constant value of the PHI node, which allows for more
256 constants to be propagated.
258 3- Variables defined by statements other than assignments and PHI
259 nodes are considered VARYING.
261 4- Initial values of variables that are not GIMPLE registers are
262 considered VARYING. */
264 static ccp_prop_value_t
265 get_default_value (tree var)
267 ccp_prop_value_t val = { UNINITIALIZED, NULL_TREE, 0 };
268 gimple *stmt;
270 stmt = SSA_NAME_DEF_STMT (var);
272 if (gimple_nop_p (stmt))
274 /* Variables defined by an empty statement are those used
275 before being initialized. If VAR is a local variable, we
276 can assume initially that it is UNDEFINED, otherwise we must
277 consider it VARYING. */
278 if (!virtual_operand_p (var)
279 && SSA_NAME_VAR (var)
280 && TREE_CODE (SSA_NAME_VAR (var)) == VAR_DECL)
281 val.lattice_val = UNDEFINED;
282 else
284 val.lattice_val = VARYING;
285 val.mask = -1;
286 if (flag_tree_bit_ccp)
288 wide_int nonzero_bits = get_nonzero_bits (var);
289 if (nonzero_bits != -1)
291 val.lattice_val = CONSTANT;
292 val.value = build_zero_cst (TREE_TYPE (var));
293 val.mask = extend_mask (nonzero_bits, TYPE_SIGN (TREE_TYPE (var)));
298 else if (is_gimple_assign (stmt))
300 tree cst;
301 if (gimple_assign_single_p (stmt)
302 && DECL_P (gimple_assign_rhs1 (stmt))
303 && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt))))
305 val.lattice_val = CONSTANT;
306 val.value = cst;
308 else
310 /* Any other variable defined by an assignment is considered
311 UNDEFINED. */
312 val.lattice_val = UNDEFINED;
315 else if ((is_gimple_call (stmt)
316 && gimple_call_lhs (stmt) != NULL_TREE)
317 || gimple_code (stmt) == GIMPLE_PHI)
319 /* A variable defined by a call or a PHI node is considered
320 UNDEFINED. */
321 val.lattice_val = UNDEFINED;
323 else
325 /* Otherwise, VAR will never take on a constant value. */
326 val.lattice_val = VARYING;
327 val.mask = -1;
330 return val;
334 /* Get the constant value associated with variable VAR. */
336 static inline ccp_prop_value_t *
337 get_value (tree var)
339 ccp_prop_value_t *val;
341 if (const_val == NULL
342 || SSA_NAME_VERSION (var) >= n_const_val)
343 return NULL;
345 val = &const_val[SSA_NAME_VERSION (var)];
346 if (val->lattice_val == UNINITIALIZED)
347 *val = get_default_value (var);
349 canonicalize_value (val);
351 return val;
354 /* Return the constant tree value associated with VAR. */
356 static inline tree
357 get_constant_value (tree var)
359 ccp_prop_value_t *val;
360 if (TREE_CODE (var) != SSA_NAME)
362 if (is_gimple_min_invariant (var))
363 return var;
364 return NULL_TREE;
366 val = get_value (var);
367 if (val
368 && val->lattice_val == CONSTANT
369 && (TREE_CODE (val->value) != INTEGER_CST
370 || val->mask == 0))
371 return val->value;
372 return NULL_TREE;
375 /* Sets the value associated with VAR to VARYING. */
377 static inline void
378 set_value_varying (tree var)
380 ccp_prop_value_t *val = &const_val[SSA_NAME_VERSION (var)];
382 val->lattice_val = VARYING;
383 val->value = NULL_TREE;
384 val->mask = -1;
387 /* For integer constants, make sure to drop TREE_OVERFLOW. */
389 static void
390 canonicalize_value (ccp_prop_value_t *val)
392 if (val->lattice_val != CONSTANT)
393 return;
395 if (TREE_OVERFLOW_P (val->value))
396 val->value = drop_tree_overflow (val->value);
399 /* Return whether the lattice transition is valid. */
401 static bool
402 valid_lattice_transition (ccp_prop_value_t old_val, ccp_prop_value_t new_val)
404 /* Lattice transitions must always be monotonically increasing in
405 value. */
406 if (old_val.lattice_val < new_val.lattice_val)
407 return true;
409 if (old_val.lattice_val != new_val.lattice_val)
410 return false;
412 if (!old_val.value && !new_val.value)
413 return true;
415 /* Now both lattice values are CONSTANT. */
417 /* Allow arbitrary copy changes as we might look through PHI <a_1, ...>
418 when only a single copy edge is executable. */
419 if (TREE_CODE (old_val.value) == SSA_NAME
420 && TREE_CODE (new_val.value) == SSA_NAME)
421 return true;
423 /* Allow transitioning from a constant to a copy. */
424 if (is_gimple_min_invariant (old_val.value)
425 && TREE_CODE (new_val.value) == SSA_NAME)
426 return true;
428 /* Allow transitioning from PHI <&x, not executable> == &x
429 to PHI <&x, &y> == common alignment. */
430 if (TREE_CODE (old_val.value) != INTEGER_CST
431 && TREE_CODE (new_val.value) == INTEGER_CST)
432 return true;
434 /* Bit-lattices have to agree in the still valid bits. */
435 if (TREE_CODE (old_val.value) == INTEGER_CST
436 && TREE_CODE (new_val.value) == INTEGER_CST)
437 return (wi::bit_and_not (wi::to_widest (old_val.value), new_val.mask)
438 == wi::bit_and_not (wi::to_widest (new_val.value), new_val.mask));
440 /* Otherwise constant values have to agree. */
441 if (operand_equal_p (old_val.value, new_val.value, 0))
442 return true;
444 /* At least the kinds and types should agree now. */
445 if (TREE_CODE (old_val.value) != TREE_CODE (new_val.value)
446 || !types_compatible_p (TREE_TYPE (old_val.value),
447 TREE_TYPE (new_val.value)))
448 return false;
450 /* For floats and !HONOR_NANS allow transitions from (partial) NaN
451 to non-NaN. */
452 tree type = TREE_TYPE (new_val.value);
453 if (SCALAR_FLOAT_TYPE_P (type)
454 && !HONOR_NANS (type))
456 if (REAL_VALUE_ISNAN (TREE_REAL_CST (old_val.value)))
457 return true;
459 else if (VECTOR_FLOAT_TYPE_P (type)
460 && !HONOR_NANS (type))
462 for (unsigned i = 0; i < VECTOR_CST_NELTS (old_val.value); ++i)
463 if (!REAL_VALUE_ISNAN
464 (TREE_REAL_CST (VECTOR_CST_ELT (old_val.value, i)))
465 && !operand_equal_p (VECTOR_CST_ELT (old_val.value, i),
466 VECTOR_CST_ELT (new_val.value, i), 0))
467 return false;
468 return true;
470 else if (COMPLEX_FLOAT_TYPE_P (type)
471 && !HONOR_NANS (type))
473 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_REALPART (old_val.value)))
474 && !operand_equal_p (TREE_REALPART (old_val.value),
475 TREE_REALPART (new_val.value), 0))
476 return false;
477 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_IMAGPART (old_val.value)))
478 && !operand_equal_p (TREE_IMAGPART (old_val.value),
479 TREE_IMAGPART (new_val.value), 0))
480 return false;
481 return true;
483 return false;
486 /* Set the value for variable VAR to NEW_VAL. Return true if the new
487 value is different from VAR's previous value. */
489 static bool
490 set_lattice_value (tree var, ccp_prop_value_t *new_val)
492 /* We can deal with old UNINITIALIZED values just fine here. */
493 ccp_prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)];
495 canonicalize_value (new_val);
497 /* We have to be careful to not go up the bitwise lattice
498 represented by the mask. Instead of dropping to VARYING
499 use the meet operator to retain a conservative value.
500 Missed optimizations like PR65851 makes this necessary.
501 It also ensures we converge to a stable lattice solution. */
502 if (old_val->lattice_val != UNINITIALIZED)
503 ccp_lattice_meet (new_val, old_val);
505 gcc_checking_assert (valid_lattice_transition (*old_val, *new_val));
507 /* If *OLD_VAL and NEW_VAL are the same, return false to inform the
508 caller that this was a non-transition. */
509 if (old_val->lattice_val != new_val->lattice_val
510 || (new_val->lattice_val == CONSTANT
511 && (TREE_CODE (new_val->value) != TREE_CODE (old_val->value)
512 || (TREE_CODE (new_val->value) == INTEGER_CST
513 && (new_val->mask != old_val->mask
514 || (wi::bit_and_not (wi::to_widest (old_val->value),
515 new_val->mask)
516 != wi::bit_and_not (wi::to_widest (new_val->value),
517 new_val->mask))))
518 || (TREE_CODE (new_val->value) != INTEGER_CST
519 && !operand_equal_p (new_val->value, old_val->value, 0)))))
521 /* ??? We would like to delay creation of INTEGER_CSTs from
522 partially constants here. */
524 if (dump_file && (dump_flags & TDF_DETAILS))
526 dump_lattice_value (dump_file, "Lattice value changed to ", *new_val);
527 fprintf (dump_file, ". Adding SSA edges to worklist.\n");
530 *old_val = *new_val;
532 gcc_assert (new_val->lattice_val != UNINITIALIZED);
533 return true;
536 return false;
539 static ccp_prop_value_t get_value_for_expr (tree, bool);
540 static ccp_prop_value_t bit_value_binop (enum tree_code, tree, tree, tree);
541 void bit_value_binop (enum tree_code, signop, int, widest_int *, widest_int *,
542 signop, int, const widest_int &, const widest_int &,
543 signop, int, const widest_int &, const widest_int &);
545 /* Return a widest_int that can be used for bitwise simplifications
546 from VAL. */
548 static widest_int
549 value_to_wide_int (ccp_prop_value_t val)
551 if (val.value
552 && TREE_CODE (val.value) == INTEGER_CST)
553 return wi::to_widest (val.value);
555 return 0;
558 /* Return the value for the address expression EXPR based on alignment
559 information. */
561 static ccp_prop_value_t
562 get_value_from_alignment (tree expr)
564 tree type = TREE_TYPE (expr);
565 ccp_prop_value_t val;
566 unsigned HOST_WIDE_INT bitpos;
567 unsigned int align;
569 gcc_assert (TREE_CODE (expr) == ADDR_EXPR);
571 get_pointer_alignment_1 (expr, &align, &bitpos);
572 val.mask = (POINTER_TYPE_P (type) || TYPE_UNSIGNED (type)
573 ? wi::mask <widest_int> (TYPE_PRECISION (type), false)
574 : -1).and_not (align / BITS_PER_UNIT - 1);
575 val.lattice_val
576 = wi::sext (val.mask, TYPE_PRECISION (type)) == -1 ? VARYING : CONSTANT;
577 if (val.lattice_val == CONSTANT)
578 val.value = build_int_cstu (type, bitpos / BITS_PER_UNIT);
579 else
580 val.value = NULL_TREE;
582 return val;
585 /* Return the value for the tree operand EXPR. If FOR_BITS_P is true
586 return constant bits extracted from alignment information for
587 invariant addresses. */
589 static ccp_prop_value_t
590 get_value_for_expr (tree expr, bool for_bits_p)
592 ccp_prop_value_t val;
594 if (TREE_CODE (expr) == SSA_NAME)
596 ccp_prop_value_t *val_ = get_value (expr);
597 if (val_)
598 val = *val_;
599 else
601 val.lattice_val = VARYING;
602 val.value = NULL_TREE;
603 val.mask = -1;
605 if (for_bits_p
606 && val.lattice_val == CONSTANT
607 && TREE_CODE (val.value) == ADDR_EXPR)
608 val = get_value_from_alignment (val.value);
609 /* Fall back to a copy value. */
610 if (!for_bits_p
611 && val.lattice_val == VARYING
612 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr))
614 val.lattice_val = CONSTANT;
615 val.value = expr;
616 val.mask = -1;
619 else if (is_gimple_min_invariant (expr)
620 && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR))
622 val.lattice_val = CONSTANT;
623 val.value = expr;
624 val.mask = 0;
625 canonicalize_value (&val);
627 else if (TREE_CODE (expr) == ADDR_EXPR)
628 val = get_value_from_alignment (expr);
629 else
631 val.lattice_val = VARYING;
632 val.mask = -1;
633 val.value = NULL_TREE;
636 if (val.lattice_val == VARYING
637 && TYPE_UNSIGNED (TREE_TYPE (expr)))
638 val.mask = wi::zext (val.mask, TYPE_PRECISION (TREE_TYPE (expr)));
640 return val;
643 /* Return the likely CCP lattice value for STMT.
645 If STMT has no operands, then return CONSTANT.
647 Else if undefinedness of operands of STMT cause its value to be
648 undefined, then return UNDEFINED.
650 Else if any operands of STMT are constants, then return CONSTANT.
652 Else return VARYING. */
654 static ccp_lattice_t
655 likely_value (gimple *stmt)
657 bool has_constant_operand, has_undefined_operand, all_undefined_operands;
658 bool has_nsa_operand;
659 tree use;
660 ssa_op_iter iter;
661 unsigned i;
663 enum gimple_code code = gimple_code (stmt);
665 /* This function appears to be called only for assignments, calls,
666 conditionals, and switches, due to the logic in visit_stmt. */
667 gcc_assert (code == GIMPLE_ASSIGN
668 || code == GIMPLE_CALL
669 || code == GIMPLE_COND
670 || code == GIMPLE_SWITCH);
672 /* If the statement has volatile operands, it won't fold to a
673 constant value. */
674 if (gimple_has_volatile_ops (stmt))
675 return VARYING;
677 /* Arrive here for more complex cases. */
678 has_constant_operand = false;
679 has_undefined_operand = false;
680 all_undefined_operands = true;
681 has_nsa_operand = false;
682 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
684 ccp_prop_value_t *val = get_value (use);
686 if (val && val->lattice_val == UNDEFINED)
687 has_undefined_operand = true;
688 else
689 all_undefined_operands = false;
691 if (val && val->lattice_val == CONSTANT)
692 has_constant_operand = true;
694 if (SSA_NAME_IS_DEFAULT_DEF (use)
695 || !prop_simulate_again_p (SSA_NAME_DEF_STMT (use)))
696 has_nsa_operand = true;
699 /* There may be constants in regular rhs operands. For calls we
700 have to ignore lhs, fndecl and static chain, otherwise only
701 the lhs. */
702 for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt);
703 i < gimple_num_ops (stmt); ++i)
705 tree op = gimple_op (stmt, i);
706 if (!op || TREE_CODE (op) == SSA_NAME)
707 continue;
708 if (is_gimple_min_invariant (op))
709 has_constant_operand = true;
712 if (has_constant_operand)
713 all_undefined_operands = false;
715 if (has_undefined_operand
716 && code == GIMPLE_CALL
717 && gimple_call_internal_p (stmt))
718 switch (gimple_call_internal_fn (stmt))
720 /* These 3 builtins use the first argument just as a magic
721 way how to find out a decl uid. */
722 case IFN_GOMP_SIMD_LANE:
723 case IFN_GOMP_SIMD_VF:
724 case IFN_GOMP_SIMD_LAST_LANE:
725 has_undefined_operand = false;
726 break;
727 default:
728 break;
731 /* If the operation combines operands like COMPLEX_EXPR make sure to
732 not mark the result UNDEFINED if only one part of the result is
733 undefined. */
734 if (has_undefined_operand && all_undefined_operands)
735 return UNDEFINED;
736 else if (code == GIMPLE_ASSIGN && has_undefined_operand)
738 switch (gimple_assign_rhs_code (stmt))
740 /* Unary operators are handled with all_undefined_operands. */
741 case PLUS_EXPR:
742 case MINUS_EXPR:
743 case POINTER_PLUS_EXPR:
744 case BIT_XOR_EXPR:
745 /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected.
746 Not bitwise operators, one VARYING operand may specify the
747 result completely.
748 Not logical operators for the same reason, apart from XOR.
749 Not COMPLEX_EXPR as one VARYING operand makes the result partly
750 not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because
751 the undefined operand may be promoted. */
752 return UNDEFINED;
754 case ADDR_EXPR:
755 /* If any part of an address is UNDEFINED, like the index
756 of an ARRAY_EXPR, then treat the result as UNDEFINED. */
757 return UNDEFINED;
759 default:
763 /* If there was an UNDEFINED operand but the result may be not UNDEFINED
764 fall back to CONSTANT. During iteration UNDEFINED may still drop
765 to CONSTANT. */
766 if (has_undefined_operand)
767 return CONSTANT;
769 /* We do not consider virtual operands here -- load from read-only
770 memory may have only VARYING virtual operands, but still be
771 constant. Also we can combine the stmt with definitions from
772 operands whose definitions are not simulated again. */
773 if (has_constant_operand
774 || has_nsa_operand
775 || gimple_references_memory_p (stmt))
776 return CONSTANT;
778 return VARYING;
781 /* Returns true if STMT cannot be constant. */
783 static bool
784 surely_varying_stmt_p (gimple *stmt)
786 /* If the statement has operands that we cannot handle, it cannot be
787 constant. */
788 if (gimple_has_volatile_ops (stmt))
789 return true;
791 /* If it is a call and does not return a value or is not a
792 builtin and not an indirect call or a call to function with
793 assume_aligned/alloc_align attribute, it is varying. */
794 if (is_gimple_call (stmt))
796 tree fndecl, fntype = gimple_call_fntype (stmt);
797 if (!gimple_call_lhs (stmt)
798 || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE
799 && !DECL_BUILT_IN (fndecl)
800 && !lookup_attribute ("assume_aligned",
801 TYPE_ATTRIBUTES (fntype))
802 && !lookup_attribute ("alloc_align",
803 TYPE_ATTRIBUTES (fntype))))
804 return true;
807 /* Any other store operation is not interesting. */
808 else if (gimple_vdef (stmt))
809 return true;
811 /* Anything other than assignments and conditional jumps are not
812 interesting for CCP. */
813 if (gimple_code (stmt) != GIMPLE_ASSIGN
814 && gimple_code (stmt) != GIMPLE_COND
815 && gimple_code (stmt) != GIMPLE_SWITCH
816 && gimple_code (stmt) != GIMPLE_CALL)
817 return true;
819 return false;
822 /* Initialize local data structures for CCP. */
824 static void
825 ccp_initialize (void)
827 basic_block bb;
829 n_const_val = num_ssa_names;
830 const_val = XCNEWVEC (ccp_prop_value_t, n_const_val);
832 /* Initialize simulation flags for PHI nodes and statements. */
833 FOR_EACH_BB_FN (bb, cfun)
835 gimple_stmt_iterator i;
837 for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
839 gimple *stmt = gsi_stmt (i);
840 bool is_varying;
842 /* If the statement is a control insn, then we do not
843 want to avoid simulating the statement once. Failure
844 to do so means that those edges will never get added. */
845 if (stmt_ends_bb_p (stmt))
846 is_varying = false;
847 else
848 is_varying = surely_varying_stmt_p (stmt);
850 if (is_varying)
852 tree def;
853 ssa_op_iter iter;
855 /* If the statement will not produce a constant, mark
856 all its outputs VARYING. */
857 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
858 set_value_varying (def);
860 prop_set_simulate_again (stmt, !is_varying);
864 /* Now process PHI nodes. We never clear the simulate_again flag on
865 phi nodes, since we do not know which edges are executable yet,
866 except for phi nodes for virtual operands when we do not do store ccp. */
867 FOR_EACH_BB_FN (bb, cfun)
869 gphi_iterator i;
871 for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i))
873 gphi *phi = i.phi ();
875 if (virtual_operand_p (gimple_phi_result (phi)))
876 prop_set_simulate_again (phi, false);
877 else
878 prop_set_simulate_again (phi, true);
883 /* Debug count support. Reset the values of ssa names
884 VARYING when the total number ssa names analyzed is
885 beyond the debug count specified. */
887 static void
888 do_dbg_cnt (void)
890 unsigned i;
891 for (i = 0; i < num_ssa_names; i++)
893 if (!dbg_cnt (ccp))
895 const_val[i].lattice_val = VARYING;
896 const_val[i].mask = -1;
897 const_val[i].value = NULL_TREE;
903 /* Do final substitution of propagated values, cleanup the flowgraph and
904 free allocated storage. If NONZERO_P, record nonzero bits.
906 Return TRUE when something was optimized. */
908 static bool
909 ccp_finalize (bool nonzero_p)
911 bool something_changed;
912 unsigned i;
913 tree name;
915 do_dbg_cnt ();
917 /* Derive alignment and misalignment information from partially
918 constant pointers in the lattice or nonzero bits from partially
919 constant integers. */
920 FOR_EACH_SSA_NAME (i, name, cfun)
922 ccp_prop_value_t *val;
923 unsigned int tem, align;
925 if (!POINTER_TYPE_P (TREE_TYPE (name))
926 && (!INTEGRAL_TYPE_P (TREE_TYPE (name))
927 /* Don't record nonzero bits before IPA to avoid
928 using too much memory. */
929 || !nonzero_p))
930 continue;
932 val = get_value (name);
933 if (val->lattice_val != CONSTANT
934 || TREE_CODE (val->value) != INTEGER_CST
935 || val->mask == 0)
936 continue;
938 if (POINTER_TYPE_P (TREE_TYPE (name)))
940 /* Trailing mask bits specify the alignment, trailing value
941 bits the misalignment. */
942 tem = val->mask.to_uhwi ();
943 align = least_bit_hwi (tem);
944 if (align > 1)
945 set_ptr_info_alignment (get_ptr_info (name), align,
946 (TREE_INT_CST_LOW (val->value)
947 & (align - 1)));
949 else
951 unsigned int precision = TYPE_PRECISION (TREE_TYPE (val->value));
952 wide_int nonzero_bits = wide_int::from (val->mask, precision,
953 UNSIGNED) | val->value;
954 nonzero_bits &= get_nonzero_bits (name);
955 set_nonzero_bits (name, nonzero_bits);
959 /* Perform substitutions based on the known constant values. */
960 something_changed = substitute_and_fold (get_constant_value, ccp_fold_stmt);
962 free (const_val);
963 const_val = NULL;
964 return something_changed;;
968 /* Compute the meet operator between *VAL1 and *VAL2. Store the result
969 in VAL1.
971 any M UNDEFINED = any
972 any M VARYING = VARYING
973 Ci M Cj = Ci if (i == j)
974 Ci M Cj = VARYING if (i != j)
977 static void
978 ccp_lattice_meet (ccp_prop_value_t *val1, ccp_prop_value_t *val2)
980 if (val1->lattice_val == UNDEFINED
981 /* For UNDEFINED M SSA we can't always SSA because its definition
982 may not dominate the PHI node. Doing optimistic copy propagation
983 also causes a lot of gcc.dg/uninit-pred*.c FAILs. */
984 && (val2->lattice_val != CONSTANT
985 || TREE_CODE (val2->value) != SSA_NAME))
987 /* UNDEFINED M any = any */
988 *val1 = *val2;
990 else if (val2->lattice_val == UNDEFINED
991 /* See above. */
992 && (val1->lattice_val != CONSTANT
993 || TREE_CODE (val1->value) != SSA_NAME))
995 /* any M UNDEFINED = any
996 Nothing to do. VAL1 already contains the value we want. */
999 else if (val1->lattice_val == VARYING
1000 || val2->lattice_val == VARYING)
1002 /* any M VARYING = VARYING. */
1003 val1->lattice_val = VARYING;
1004 val1->mask = -1;
1005 val1->value = NULL_TREE;
1007 else if (val1->lattice_val == CONSTANT
1008 && val2->lattice_val == CONSTANT
1009 && TREE_CODE (val1->value) == INTEGER_CST
1010 && TREE_CODE (val2->value) == INTEGER_CST)
1012 /* Ci M Cj = Ci if (i == j)
1013 Ci M Cj = VARYING if (i != j)
1015 For INTEGER_CSTs mask unequal bits. If no equal bits remain,
1016 drop to varying. */
1017 val1->mask = (val1->mask | val2->mask
1018 | (wi::to_widest (val1->value)
1019 ^ wi::to_widest (val2->value)));
1020 if (wi::sext (val1->mask, TYPE_PRECISION (TREE_TYPE (val1->value))) == -1)
1022 val1->lattice_val = VARYING;
1023 val1->value = NULL_TREE;
1026 else if (val1->lattice_val == CONSTANT
1027 && val2->lattice_val == CONSTANT
1028 && operand_equal_p (val1->value, val2->value, 0))
1030 /* Ci M Cj = Ci if (i == j)
1031 Ci M Cj = VARYING if (i != j)
1033 VAL1 already contains the value we want for equivalent values. */
1035 else if (val1->lattice_val == CONSTANT
1036 && val2->lattice_val == CONSTANT
1037 && (TREE_CODE (val1->value) == ADDR_EXPR
1038 || TREE_CODE (val2->value) == ADDR_EXPR))
1040 /* When not equal addresses are involved try meeting for
1041 alignment. */
1042 ccp_prop_value_t tem = *val2;
1043 if (TREE_CODE (val1->value) == ADDR_EXPR)
1044 *val1 = get_value_for_expr (val1->value, true);
1045 if (TREE_CODE (val2->value) == ADDR_EXPR)
1046 tem = get_value_for_expr (val2->value, true);
1047 ccp_lattice_meet (val1, &tem);
1049 else
1051 /* Any other combination is VARYING. */
1052 val1->lattice_val = VARYING;
1053 val1->mask = -1;
1054 val1->value = NULL_TREE;
1059 /* Loop through the PHI_NODE's parameters for BLOCK and compare their
1060 lattice values to determine PHI_NODE's lattice value. The value of a
1061 PHI node is determined calling ccp_lattice_meet with all the arguments
1062 of the PHI node that are incoming via executable edges. */
1064 static enum ssa_prop_result
1065 ccp_visit_phi_node (gphi *phi)
1067 unsigned i;
1068 ccp_prop_value_t new_val;
1070 if (dump_file && (dump_flags & TDF_DETAILS))
1072 fprintf (dump_file, "\nVisiting PHI node: ");
1073 print_gimple_stmt (dump_file, phi, 0, dump_flags);
1076 new_val.lattice_val = UNDEFINED;
1077 new_val.value = NULL_TREE;
1078 new_val.mask = 0;
1080 bool first = true;
1081 bool non_exec_edge = false;
1082 for (i = 0; i < gimple_phi_num_args (phi); i++)
1084 /* Compute the meet operator over all the PHI arguments flowing
1085 through executable edges. */
1086 edge e = gimple_phi_arg_edge (phi, i);
1088 if (dump_file && (dump_flags & TDF_DETAILS))
1090 fprintf (dump_file,
1091 "\n Argument #%d (%d -> %d %sexecutable)\n",
1092 i, e->src->index, e->dest->index,
1093 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
1096 /* If the incoming edge is executable, Compute the meet operator for
1097 the existing value of the PHI node and the current PHI argument. */
1098 if (e->flags & EDGE_EXECUTABLE)
1100 tree arg = gimple_phi_arg (phi, i)->def;
1101 ccp_prop_value_t arg_val = get_value_for_expr (arg, false);
1103 if (first)
1105 new_val = arg_val;
1106 first = false;
1108 else
1109 ccp_lattice_meet (&new_val, &arg_val);
1111 if (dump_file && (dump_flags & TDF_DETAILS))
1113 fprintf (dump_file, "\t");
1114 print_generic_expr (dump_file, arg, dump_flags);
1115 dump_lattice_value (dump_file, "\tValue: ", arg_val);
1116 fprintf (dump_file, "\n");
1119 if (new_val.lattice_val == VARYING)
1120 break;
1122 else
1123 non_exec_edge = true;
1126 /* In case there were non-executable edges and the value is a copy
1127 make sure its definition dominates the PHI node. */
1128 if (non_exec_edge
1129 && new_val.lattice_val == CONSTANT
1130 && TREE_CODE (new_val.value) == SSA_NAME
1131 && ! SSA_NAME_IS_DEFAULT_DEF (new_val.value)
1132 && ! dominated_by_p (CDI_DOMINATORS, gimple_bb (phi),
1133 gimple_bb (SSA_NAME_DEF_STMT (new_val.value))))
1135 new_val.lattice_val = VARYING;
1136 new_val.value = NULL_TREE;
1137 new_val.mask = -1;
1140 if (dump_file && (dump_flags & TDF_DETAILS))
1142 dump_lattice_value (dump_file, "\n PHI node value: ", new_val);
1143 fprintf (dump_file, "\n\n");
1146 /* Make the transition to the new value. */
1147 if (set_lattice_value (gimple_phi_result (phi), &new_val))
1149 if (new_val.lattice_val == VARYING)
1150 return SSA_PROP_VARYING;
1151 else
1152 return SSA_PROP_INTERESTING;
1154 else
1155 return SSA_PROP_NOT_INTERESTING;
1158 /* Return the constant value for OP or OP otherwise. */
1160 static tree
1161 valueize_op (tree op)
1163 if (TREE_CODE (op) == SSA_NAME)
1165 tree tem = get_constant_value (op);
1166 if (tem)
1167 return tem;
1169 return op;
1172 /* Return the constant value for OP, but signal to not follow SSA
1173 edges if the definition may be simulated again. */
1175 static tree
1176 valueize_op_1 (tree op)
1178 if (TREE_CODE (op) == SSA_NAME)
1180 /* If the definition may be simulated again we cannot follow
1181 this SSA edge as the SSA propagator does not necessarily
1182 re-visit the use. */
1183 gimple *def_stmt = SSA_NAME_DEF_STMT (op);
1184 if (!gimple_nop_p (def_stmt)
1185 && prop_simulate_again_p (def_stmt))
1186 return NULL_TREE;
1187 tree tem = get_constant_value (op);
1188 if (tem)
1189 return tem;
1191 return op;
1194 /* CCP specific front-end to the non-destructive constant folding
1195 routines.
1197 Attempt to simplify the RHS of STMT knowing that one or more
1198 operands are constants.
1200 If simplification is possible, return the simplified RHS,
1201 otherwise return the original RHS or NULL_TREE. */
1203 static tree
1204 ccp_fold (gimple *stmt)
1206 location_t loc = gimple_location (stmt);
1207 switch (gimple_code (stmt))
1209 case GIMPLE_COND:
1211 /* Handle comparison operators that can appear in GIMPLE form. */
1212 tree op0 = valueize_op (gimple_cond_lhs (stmt));
1213 tree op1 = valueize_op (gimple_cond_rhs (stmt));
1214 enum tree_code code = gimple_cond_code (stmt);
1215 return fold_binary_loc (loc, code, boolean_type_node, op0, op1);
1218 case GIMPLE_SWITCH:
1220 /* Return the constant switch index. */
1221 return valueize_op (gimple_switch_index (as_a <gswitch *> (stmt)));
1224 case GIMPLE_ASSIGN:
1225 case GIMPLE_CALL:
1226 return gimple_fold_stmt_to_constant_1 (stmt,
1227 valueize_op, valueize_op_1);
1229 default:
1230 gcc_unreachable ();
1234 /* Apply the operation CODE in type TYPE to the value, mask pair
1235 RVAL and RMASK representing a value of type RTYPE and set
1236 the value, mask pair *VAL and *MASK to the result. */
1238 void
1239 bit_value_unop (enum tree_code code, signop type_sgn, int type_precision,
1240 widest_int *val, widest_int *mask,
1241 signop rtype_sgn, int rtype_precision,
1242 const widest_int &rval, const widest_int &rmask)
1244 switch (code)
1246 case BIT_NOT_EXPR:
1247 *mask = rmask;
1248 *val = ~rval;
1249 break;
1251 case NEGATE_EXPR:
1253 widest_int temv, temm;
1254 /* Return ~rval + 1. */
1255 bit_value_unop (BIT_NOT_EXPR, type_sgn, type_precision, &temv, &temm,
1256 type_sgn, type_precision, rval, rmask);
1257 bit_value_binop (PLUS_EXPR, type_sgn, type_precision, val, mask,
1258 type_sgn, type_precision, temv, temm,
1259 type_sgn, type_precision, 1, 0);
1260 break;
1263 CASE_CONVERT:
1265 /* First extend mask and value according to the original type. */
1266 *mask = wi::ext (rmask, rtype_precision, rtype_sgn);
1267 *val = wi::ext (rval, rtype_precision, rtype_sgn);
1269 /* Then extend mask and value according to the target type. */
1270 *mask = wi::ext (*mask, type_precision, type_sgn);
1271 *val = wi::ext (*val, type_precision, type_sgn);
1272 break;
1275 default:
1276 *mask = -1;
1277 break;
1281 /* Apply the operation CODE in type TYPE to the value, mask pairs
1282 R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE
1283 and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */
1285 void
1286 bit_value_binop (enum tree_code code, signop sgn, int width,
1287 widest_int *val, widest_int *mask,
1288 signop r1type_sgn, int r1type_precision,
1289 const widest_int &r1val, const widest_int &r1mask,
1290 signop r2type_sgn, int r2type_precision,
1291 const widest_int &r2val, const widest_int &r2mask)
1293 bool swap_p = false;
1295 /* Assume we'll get a constant result. Use an initial non varying
1296 value, we fall back to varying in the end if necessary. */
1297 *mask = -1;
1299 switch (code)
1301 case BIT_AND_EXPR:
1302 /* The mask is constant where there is a known not
1303 set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */
1304 *mask = (r1mask | r2mask) & (r1val | r1mask) & (r2val | r2mask);
1305 *val = r1val & r2val;
1306 break;
1308 case BIT_IOR_EXPR:
1309 /* The mask is constant where there is a known
1310 set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */
1311 *mask = (r1mask | r2mask)
1312 .and_not (r1val.and_not (r1mask) | r2val.and_not (r2mask));
1313 *val = r1val | r2val;
1314 break;
1316 case BIT_XOR_EXPR:
1317 /* m1 | m2 */
1318 *mask = r1mask | r2mask;
1319 *val = r1val ^ r2val;
1320 break;
1322 case LROTATE_EXPR:
1323 case RROTATE_EXPR:
1324 if (r2mask == 0)
1326 widest_int shift = r2val;
1327 if (shift == 0)
1329 *mask = r1mask;
1330 *val = r1val;
1332 else
1334 if (wi::neg_p (shift))
1336 shift = -shift;
1337 if (code == RROTATE_EXPR)
1338 code = LROTATE_EXPR;
1339 else
1340 code = RROTATE_EXPR;
1342 if (code == RROTATE_EXPR)
1344 *mask = wi::rrotate (r1mask, shift, width);
1345 *val = wi::rrotate (r1val, shift, width);
1347 else
1349 *mask = wi::lrotate (r1mask, shift, width);
1350 *val = wi::lrotate (r1val, shift, width);
1354 break;
1356 case LSHIFT_EXPR:
1357 case RSHIFT_EXPR:
1358 /* ??? We can handle partially known shift counts if we know
1359 its sign. That way we can tell that (x << (y | 8)) & 255
1360 is zero. */
1361 if (r2mask == 0)
1363 widest_int shift = r2val;
1364 if (shift == 0)
1366 *mask = r1mask;
1367 *val = r1val;
1369 else
1371 if (wi::neg_p (shift))
1373 shift = -shift;
1374 if (code == RSHIFT_EXPR)
1375 code = LSHIFT_EXPR;
1376 else
1377 code = RSHIFT_EXPR;
1379 if (code == RSHIFT_EXPR)
1381 *mask = wi::rshift (wi::ext (r1mask, width, sgn), shift, sgn);
1382 *val = wi::rshift (wi::ext (r1val, width, sgn), shift, sgn);
1384 else
1386 *mask = wi::ext (r1mask << shift, width, sgn);
1387 *val = wi::ext (r1val << shift, width, sgn);
1391 break;
1393 case PLUS_EXPR:
1394 case POINTER_PLUS_EXPR:
1396 /* Do the addition with unknown bits set to zero, to give carry-ins of
1397 zero wherever possible. */
1398 widest_int lo = r1val.and_not (r1mask) + r2val.and_not (r2mask);
1399 lo = wi::ext (lo, width, sgn);
1400 /* Do the addition with unknown bits set to one, to give carry-ins of
1401 one wherever possible. */
1402 widest_int hi = (r1val | r1mask) + (r2val | r2mask);
1403 hi = wi::ext (hi, width, sgn);
1404 /* Each bit in the result is known if (a) the corresponding bits in
1405 both inputs are known, and (b) the carry-in to that bit position
1406 is known. We can check condition (b) by seeing if we got the same
1407 result with minimised carries as with maximised carries. */
1408 *mask = r1mask | r2mask | (lo ^ hi);
1409 *mask = wi::ext (*mask, width, sgn);
1410 /* It shouldn't matter whether we choose lo or hi here. */
1411 *val = lo;
1412 break;
1415 case MINUS_EXPR:
1417 widest_int temv, temm;
1418 bit_value_unop (NEGATE_EXPR, r2type_sgn, r2type_precision, &temv, &temm,
1419 r2type_sgn, r2type_precision, r2val, r2mask);
1420 bit_value_binop (PLUS_EXPR, sgn, width, val, mask,
1421 r1type_sgn, r1type_precision, r1val, r1mask,
1422 r2type_sgn, r2type_precision, temv, temm);
1423 break;
1426 case MULT_EXPR:
1428 /* Just track trailing zeros in both operands and transfer
1429 them to the other. */
1430 int r1tz = wi::ctz (r1val | r1mask);
1431 int r2tz = wi::ctz (r2val | r2mask);
1432 if (r1tz + r2tz >= width)
1434 *mask = 0;
1435 *val = 0;
1437 else if (r1tz + r2tz > 0)
1439 *mask = wi::ext (wi::mask <widest_int> (r1tz + r2tz, true),
1440 width, sgn);
1441 *val = 0;
1443 break;
1446 case EQ_EXPR:
1447 case NE_EXPR:
1449 widest_int m = r1mask | r2mask;
1450 if (r1val.and_not (m) != r2val.and_not (m))
1452 *mask = 0;
1453 *val = ((code == EQ_EXPR) ? 0 : 1);
1455 else
1457 /* We know the result of a comparison is always one or zero. */
1458 *mask = 1;
1459 *val = 0;
1461 break;
1464 case GE_EXPR:
1465 case GT_EXPR:
1466 swap_p = true;
1467 code = swap_tree_comparison (code);
1468 /* Fall through. */
1469 case LT_EXPR:
1470 case LE_EXPR:
1472 int minmax, maxmin;
1474 const widest_int &o1val = swap_p ? r2val : r1val;
1475 const widest_int &o1mask = swap_p ? r2mask : r1mask;
1476 const widest_int &o2val = swap_p ? r1val : r2val;
1477 const widest_int &o2mask = swap_p ? r1mask : r2mask;
1479 /* If the most significant bits are not known we know nothing. */
1480 if (wi::neg_p (o1mask) || wi::neg_p (o2mask))
1481 break;
1483 /* For comparisons the signedness is in the comparison operands. */
1484 sgn = r1type_sgn;
1486 /* If we know the most significant bits we know the values
1487 value ranges by means of treating varying bits as zero
1488 or one. Do a cross comparison of the max/min pairs. */
1489 maxmin = wi::cmp (o1val | o1mask, o2val.and_not (o2mask), sgn);
1490 minmax = wi::cmp (o1val.and_not (o1mask), o2val | o2mask, sgn);
1491 if (maxmin < 0) /* o1 is less than o2. */
1493 *mask = 0;
1494 *val = 1;
1496 else if (minmax > 0) /* o1 is not less or equal to o2. */
1498 *mask = 0;
1499 *val = 0;
1501 else if (maxmin == minmax) /* o1 and o2 are equal. */
1503 /* This probably should never happen as we'd have
1504 folded the thing during fully constant value folding. */
1505 *mask = 0;
1506 *val = (code == LE_EXPR ? 1 : 0);
1508 else
1510 /* We know the result of a comparison is always one or zero. */
1511 *mask = 1;
1512 *val = 0;
1514 break;
1517 default:;
1521 /* Return the propagation value when applying the operation CODE to
1522 the value RHS yielding type TYPE. */
1524 static ccp_prop_value_t
1525 bit_value_unop (enum tree_code code, tree type, tree rhs)
1527 ccp_prop_value_t rval = get_value_for_expr (rhs, true);
1528 widest_int value, mask;
1529 ccp_prop_value_t val;
1531 if (rval.lattice_val == UNDEFINED)
1532 return rval;
1534 gcc_assert ((rval.lattice_val == CONSTANT
1535 && TREE_CODE (rval.value) == INTEGER_CST)
1536 || wi::sext (rval.mask, TYPE_PRECISION (TREE_TYPE (rhs))) == -1);
1537 bit_value_unop (code, TYPE_SIGN (type), TYPE_PRECISION (type), &value, &mask,
1538 TYPE_SIGN (TREE_TYPE (rhs)), TYPE_PRECISION (TREE_TYPE (rhs)),
1539 value_to_wide_int (rval), rval.mask);
1540 if (wi::sext (mask, TYPE_PRECISION (type)) != -1)
1542 val.lattice_val = CONSTANT;
1543 val.mask = mask;
1544 /* ??? Delay building trees here. */
1545 val.value = wide_int_to_tree (type, value);
1547 else
1549 val.lattice_val = VARYING;
1550 val.value = NULL_TREE;
1551 val.mask = -1;
1553 return val;
1556 /* Return the propagation value when applying the operation CODE to
1557 the values RHS1 and RHS2 yielding type TYPE. */
1559 static ccp_prop_value_t
1560 bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2)
1562 ccp_prop_value_t r1val = get_value_for_expr (rhs1, true);
1563 ccp_prop_value_t r2val = get_value_for_expr (rhs2, true);
1564 widest_int value, mask;
1565 ccp_prop_value_t val;
1567 if (r1val.lattice_val == UNDEFINED
1568 || r2val.lattice_val == UNDEFINED)
1570 val.lattice_val = VARYING;
1571 val.value = NULL_TREE;
1572 val.mask = -1;
1573 return val;
1576 gcc_assert ((r1val.lattice_val == CONSTANT
1577 && TREE_CODE (r1val.value) == INTEGER_CST)
1578 || wi::sext (r1val.mask,
1579 TYPE_PRECISION (TREE_TYPE (rhs1))) == -1);
1580 gcc_assert ((r2val.lattice_val == CONSTANT
1581 && TREE_CODE (r2val.value) == INTEGER_CST)
1582 || wi::sext (r2val.mask,
1583 TYPE_PRECISION (TREE_TYPE (rhs2))) == -1);
1584 bit_value_binop (code, TYPE_SIGN (type), TYPE_PRECISION (type), &value, &mask,
1585 TYPE_SIGN (TREE_TYPE (rhs1)), TYPE_PRECISION (TREE_TYPE (rhs1)),
1586 value_to_wide_int (r1val), r1val.mask,
1587 TYPE_SIGN (TREE_TYPE (rhs2)), TYPE_PRECISION (TREE_TYPE (rhs2)),
1588 value_to_wide_int (r2val), r2val.mask);
1590 if (wi::sext (mask, TYPE_PRECISION (type)) != -1)
1592 val.lattice_val = CONSTANT;
1593 val.mask = mask;
1594 /* ??? Delay building trees here. */
1595 val.value = wide_int_to_tree (type, value);
1597 else
1599 val.lattice_val = VARYING;
1600 val.value = NULL_TREE;
1601 val.mask = -1;
1603 return val;
1606 /* Return the propagation value for __builtin_assume_aligned
1607 and functions with assume_aligned or alloc_aligned attribute.
1608 For __builtin_assume_aligned, ATTR is NULL_TREE,
1609 for assume_aligned attribute ATTR is non-NULL and ALLOC_ALIGNED
1610 is false, for alloc_aligned attribute ATTR is non-NULL and
1611 ALLOC_ALIGNED is true. */
1613 static ccp_prop_value_t
1614 bit_value_assume_aligned (gimple *stmt, tree attr, ccp_prop_value_t ptrval,
1615 bool alloc_aligned)
1617 tree align, misalign = NULL_TREE, type;
1618 unsigned HOST_WIDE_INT aligni, misaligni = 0;
1619 ccp_prop_value_t alignval;
1620 widest_int value, mask;
1621 ccp_prop_value_t val;
1623 if (attr == NULL_TREE)
1625 tree ptr = gimple_call_arg (stmt, 0);
1626 type = TREE_TYPE (ptr);
1627 ptrval = get_value_for_expr (ptr, true);
1629 else
1631 tree lhs = gimple_call_lhs (stmt);
1632 type = TREE_TYPE (lhs);
1635 if (ptrval.lattice_val == UNDEFINED)
1636 return ptrval;
1637 gcc_assert ((ptrval.lattice_val == CONSTANT
1638 && TREE_CODE (ptrval.value) == INTEGER_CST)
1639 || wi::sext (ptrval.mask, TYPE_PRECISION (type)) == -1);
1640 if (attr == NULL_TREE)
1642 /* Get aligni and misaligni from __builtin_assume_aligned. */
1643 align = gimple_call_arg (stmt, 1);
1644 if (!tree_fits_uhwi_p (align))
1645 return ptrval;
1646 aligni = tree_to_uhwi (align);
1647 if (gimple_call_num_args (stmt) > 2)
1649 misalign = gimple_call_arg (stmt, 2);
1650 if (!tree_fits_uhwi_p (misalign))
1651 return ptrval;
1652 misaligni = tree_to_uhwi (misalign);
1655 else
1657 /* Get aligni and misaligni from assume_aligned or
1658 alloc_align attributes. */
1659 if (TREE_VALUE (attr) == NULL_TREE)
1660 return ptrval;
1661 attr = TREE_VALUE (attr);
1662 align = TREE_VALUE (attr);
1663 if (!tree_fits_uhwi_p (align))
1664 return ptrval;
1665 aligni = tree_to_uhwi (align);
1666 if (alloc_aligned)
1668 if (aligni == 0 || aligni > gimple_call_num_args (stmt))
1669 return ptrval;
1670 align = gimple_call_arg (stmt, aligni - 1);
1671 if (!tree_fits_uhwi_p (align))
1672 return ptrval;
1673 aligni = tree_to_uhwi (align);
1675 else if (TREE_CHAIN (attr) && TREE_VALUE (TREE_CHAIN (attr)))
1677 misalign = TREE_VALUE (TREE_CHAIN (attr));
1678 if (!tree_fits_uhwi_p (misalign))
1679 return ptrval;
1680 misaligni = tree_to_uhwi (misalign);
1683 if (aligni <= 1 || (aligni & (aligni - 1)) != 0 || misaligni >= aligni)
1684 return ptrval;
1686 align = build_int_cst_type (type, -aligni);
1687 alignval = get_value_for_expr (align, true);
1688 bit_value_binop (BIT_AND_EXPR, TYPE_SIGN (type), TYPE_PRECISION (type), &value, &mask,
1689 TYPE_SIGN (type), TYPE_PRECISION (type), value_to_wide_int (ptrval), ptrval.mask,
1690 TYPE_SIGN (type), TYPE_PRECISION (type), value_to_wide_int (alignval), alignval.mask);
1692 if (wi::sext (mask, TYPE_PRECISION (type)) != -1)
1694 val.lattice_val = CONSTANT;
1695 val.mask = mask;
1696 gcc_assert ((mask.to_uhwi () & (aligni - 1)) == 0);
1697 gcc_assert ((value.to_uhwi () & (aligni - 1)) == 0);
1698 value |= misaligni;
1699 /* ??? Delay building trees here. */
1700 val.value = wide_int_to_tree (type, value);
1702 else
1704 val.lattice_val = VARYING;
1705 val.value = NULL_TREE;
1706 val.mask = -1;
1708 return val;
1711 /* Evaluate statement STMT.
1712 Valid only for assignments, calls, conditionals, and switches. */
1714 static ccp_prop_value_t
1715 evaluate_stmt (gimple *stmt)
1717 ccp_prop_value_t val;
1718 tree simplified = NULL_TREE;
1719 ccp_lattice_t likelyvalue = likely_value (stmt);
1720 bool is_constant = false;
1721 unsigned int align;
1723 if (dump_file && (dump_flags & TDF_DETAILS))
1725 fprintf (dump_file, "which is likely ");
1726 switch (likelyvalue)
1728 case CONSTANT:
1729 fprintf (dump_file, "CONSTANT");
1730 break;
1731 case UNDEFINED:
1732 fprintf (dump_file, "UNDEFINED");
1733 break;
1734 case VARYING:
1735 fprintf (dump_file, "VARYING");
1736 break;
1737 default:;
1739 fprintf (dump_file, "\n");
1742 /* If the statement is likely to have a CONSTANT result, then try
1743 to fold the statement to determine the constant value. */
1744 /* FIXME. This is the only place that we call ccp_fold.
1745 Since likely_value never returns CONSTANT for calls, we will
1746 not attempt to fold them, including builtins that may profit. */
1747 if (likelyvalue == CONSTANT)
1749 fold_defer_overflow_warnings ();
1750 simplified = ccp_fold (stmt);
1751 if (simplified
1752 && TREE_CODE (simplified) == SSA_NAME)
1754 /* We may not use values of something that may be simulated again,
1755 see valueize_op_1. */
1756 if (SSA_NAME_IS_DEFAULT_DEF (simplified)
1757 || ! prop_simulate_again_p (SSA_NAME_DEF_STMT (simplified)))
1759 ccp_prop_value_t *val = get_value (simplified);
1760 if (val && val->lattice_val != VARYING)
1762 fold_undefer_overflow_warnings (true, stmt, 0);
1763 return *val;
1766 else
1767 /* We may also not place a non-valueized copy in the lattice
1768 as that might become stale if we never re-visit this stmt. */
1769 simplified = NULL_TREE;
1771 is_constant = simplified && is_gimple_min_invariant (simplified);
1772 fold_undefer_overflow_warnings (is_constant, stmt, 0);
1773 if (is_constant)
1775 /* The statement produced a constant value. */
1776 val.lattice_val = CONSTANT;
1777 val.value = simplified;
1778 val.mask = 0;
1779 return val;
1782 /* If the statement is likely to have a VARYING result, then do not
1783 bother folding the statement. */
1784 else if (likelyvalue == VARYING)
1786 enum gimple_code code = gimple_code (stmt);
1787 if (code == GIMPLE_ASSIGN)
1789 enum tree_code subcode = gimple_assign_rhs_code (stmt);
1791 /* Other cases cannot satisfy is_gimple_min_invariant
1792 without folding. */
1793 if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS)
1794 simplified = gimple_assign_rhs1 (stmt);
1796 else if (code == GIMPLE_SWITCH)
1797 simplified = gimple_switch_index (as_a <gswitch *> (stmt));
1798 else
1799 /* These cannot satisfy is_gimple_min_invariant without folding. */
1800 gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND);
1801 is_constant = simplified && is_gimple_min_invariant (simplified);
1802 if (is_constant)
1804 /* The statement produced a constant value. */
1805 val.lattice_val = CONSTANT;
1806 val.value = simplified;
1807 val.mask = 0;
1810 /* If the statement result is likely UNDEFINED, make it so. */
1811 else if (likelyvalue == UNDEFINED)
1813 val.lattice_val = UNDEFINED;
1814 val.value = NULL_TREE;
1815 val.mask = 0;
1816 return val;
1819 /* Resort to simplification for bitwise tracking. */
1820 if (flag_tree_bit_ccp
1821 && (likelyvalue == CONSTANT || is_gimple_call (stmt)
1822 || (gimple_assign_single_p (stmt)
1823 && gimple_assign_rhs_code (stmt) == ADDR_EXPR))
1824 && !is_constant)
1826 enum gimple_code code = gimple_code (stmt);
1827 val.lattice_val = VARYING;
1828 val.value = NULL_TREE;
1829 val.mask = -1;
1830 if (code == GIMPLE_ASSIGN)
1832 enum tree_code subcode = gimple_assign_rhs_code (stmt);
1833 tree rhs1 = gimple_assign_rhs1 (stmt);
1834 tree lhs = gimple_assign_lhs (stmt);
1835 if ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
1836 || POINTER_TYPE_P (TREE_TYPE (lhs)))
1837 && (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
1838 || POINTER_TYPE_P (TREE_TYPE (rhs1))))
1839 switch (get_gimple_rhs_class (subcode))
1841 case GIMPLE_SINGLE_RHS:
1842 val = get_value_for_expr (rhs1, true);
1843 break;
1845 case GIMPLE_UNARY_RHS:
1846 val = bit_value_unop (subcode, TREE_TYPE (lhs), rhs1);
1847 break;
1849 case GIMPLE_BINARY_RHS:
1850 val = bit_value_binop (subcode, TREE_TYPE (lhs), rhs1,
1851 gimple_assign_rhs2 (stmt));
1852 break;
1854 default:;
1857 else if (code == GIMPLE_COND)
1859 enum tree_code code = gimple_cond_code (stmt);
1860 tree rhs1 = gimple_cond_lhs (stmt);
1861 tree rhs2 = gimple_cond_rhs (stmt);
1862 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
1863 || POINTER_TYPE_P (TREE_TYPE (rhs1)))
1864 val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2);
1866 else if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
1868 tree fndecl = gimple_call_fndecl (stmt);
1869 switch (DECL_FUNCTION_CODE (fndecl))
1871 case BUILT_IN_MALLOC:
1872 case BUILT_IN_REALLOC:
1873 case BUILT_IN_CALLOC:
1874 case BUILT_IN_STRDUP:
1875 case BUILT_IN_STRNDUP:
1876 val.lattice_val = CONSTANT;
1877 val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0);
1878 val.mask = ~((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT
1879 / BITS_PER_UNIT - 1);
1880 break;
1882 case BUILT_IN_ALLOCA:
1883 case BUILT_IN_ALLOCA_WITH_ALIGN:
1884 align = (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA_WITH_ALIGN
1885 ? TREE_INT_CST_LOW (gimple_call_arg (stmt, 1))
1886 : BIGGEST_ALIGNMENT);
1887 val.lattice_val = CONSTANT;
1888 val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0);
1889 val.mask = ~((HOST_WIDE_INT) align / BITS_PER_UNIT - 1);
1890 break;
1892 /* These builtins return their first argument, unmodified. */
1893 case BUILT_IN_MEMCPY:
1894 case BUILT_IN_MEMMOVE:
1895 case BUILT_IN_MEMSET:
1896 case BUILT_IN_STRCPY:
1897 case BUILT_IN_STRNCPY:
1898 case BUILT_IN_MEMCPY_CHK:
1899 case BUILT_IN_MEMMOVE_CHK:
1900 case BUILT_IN_MEMSET_CHK:
1901 case BUILT_IN_STRCPY_CHK:
1902 case BUILT_IN_STRNCPY_CHK:
1903 val = get_value_for_expr (gimple_call_arg (stmt, 0), true);
1904 break;
1906 case BUILT_IN_ASSUME_ALIGNED:
1907 val = bit_value_assume_aligned (stmt, NULL_TREE, val, false);
1908 break;
1910 case BUILT_IN_ALIGNED_ALLOC:
1912 tree align = get_constant_value (gimple_call_arg (stmt, 0));
1913 if (align
1914 && tree_fits_uhwi_p (align))
1916 unsigned HOST_WIDE_INT aligni = tree_to_uhwi (align);
1917 if (aligni > 1
1918 /* align must be power-of-two */
1919 && (aligni & (aligni - 1)) == 0)
1921 val.lattice_val = CONSTANT;
1922 val.value = build_int_cst (ptr_type_node, 0);
1923 val.mask = -aligni;
1926 break;
1929 default:;
1932 if (is_gimple_call (stmt) && gimple_call_lhs (stmt))
1934 tree fntype = gimple_call_fntype (stmt);
1935 if (fntype)
1937 tree attrs = lookup_attribute ("assume_aligned",
1938 TYPE_ATTRIBUTES (fntype));
1939 if (attrs)
1940 val = bit_value_assume_aligned (stmt, attrs, val, false);
1941 attrs = lookup_attribute ("alloc_align",
1942 TYPE_ATTRIBUTES (fntype));
1943 if (attrs)
1944 val = bit_value_assume_aligned (stmt, attrs, val, true);
1947 is_constant = (val.lattice_val == CONSTANT);
1950 if (flag_tree_bit_ccp
1951 && ((is_constant && TREE_CODE (val.value) == INTEGER_CST)
1952 || !is_constant)
1953 && gimple_get_lhs (stmt)
1954 && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME)
1956 tree lhs = gimple_get_lhs (stmt);
1957 wide_int nonzero_bits = get_nonzero_bits (lhs);
1958 if (nonzero_bits != -1)
1960 if (!is_constant)
1962 val.lattice_val = CONSTANT;
1963 val.value = build_zero_cst (TREE_TYPE (lhs));
1964 val.mask = extend_mask (nonzero_bits, TYPE_SIGN (TREE_TYPE (lhs)));
1965 is_constant = true;
1967 else
1969 if (wi::bit_and_not (val.value, nonzero_bits) != 0)
1970 val.value = wide_int_to_tree (TREE_TYPE (lhs),
1971 nonzero_bits & val.value);
1972 if (nonzero_bits == 0)
1973 val.mask = 0;
1974 else
1975 val.mask = val.mask & extend_mask (nonzero_bits,
1976 TYPE_SIGN (TREE_TYPE (lhs)));
1981 /* The statement produced a nonconstant value. */
1982 if (!is_constant)
1984 /* The statement produced a copy. */
1985 if (simplified && TREE_CODE (simplified) == SSA_NAME
1986 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (simplified))
1988 val.lattice_val = CONSTANT;
1989 val.value = simplified;
1990 val.mask = -1;
1992 /* The statement is VARYING. */
1993 else
1995 val.lattice_val = VARYING;
1996 val.value = NULL_TREE;
1997 val.mask = -1;
2001 return val;
2004 typedef hash_table<nofree_ptr_hash<gimple> > gimple_htab;
2006 /* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before
2007 each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */
2009 static void
2010 insert_clobber_before_stack_restore (tree saved_val, tree var,
2011 gimple_htab **visited)
2013 gimple *stmt;
2014 gassign *clobber_stmt;
2015 tree clobber;
2016 imm_use_iterator iter;
2017 gimple_stmt_iterator i;
2018 gimple **slot;
2020 FOR_EACH_IMM_USE_STMT (stmt, iter, saved_val)
2021 if (gimple_call_builtin_p (stmt, BUILT_IN_STACK_RESTORE))
2023 clobber = build_constructor (TREE_TYPE (var),
2024 NULL);
2025 TREE_THIS_VOLATILE (clobber) = 1;
2026 clobber_stmt = gimple_build_assign (var, clobber);
2028 i = gsi_for_stmt (stmt);
2029 gsi_insert_before (&i, clobber_stmt, GSI_SAME_STMT);
2031 else if (gimple_code (stmt) == GIMPLE_PHI)
2033 if (!*visited)
2034 *visited = new gimple_htab (10);
2036 slot = (*visited)->find_slot (stmt, INSERT);
2037 if (*slot != NULL)
2038 continue;
2040 *slot = stmt;
2041 insert_clobber_before_stack_restore (gimple_phi_result (stmt), var,
2042 visited);
2044 else if (gimple_assign_ssa_name_copy_p (stmt))
2045 insert_clobber_before_stack_restore (gimple_assign_lhs (stmt), var,
2046 visited);
2047 else if (chkp_gimple_call_builtin_p (stmt, BUILT_IN_CHKP_BNDRET))
2048 continue;
2049 else
2050 gcc_assert (is_gimple_debug (stmt));
2053 /* Advance the iterator to the previous non-debug gimple statement in the same
2054 or dominating basic block. */
2056 static inline void
2057 gsi_prev_dom_bb_nondebug (gimple_stmt_iterator *i)
2059 basic_block dom;
2061 gsi_prev_nondebug (i);
2062 while (gsi_end_p (*i))
2064 dom = get_immediate_dominator (CDI_DOMINATORS, i->bb);
2065 if (dom == NULL || dom == ENTRY_BLOCK_PTR_FOR_FN (cfun))
2066 return;
2068 *i = gsi_last_bb (dom);
2072 /* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert
2073 a clobber of VAR before each matching BUILT_IN_STACK_RESTORE.
2075 It is possible that BUILT_IN_STACK_SAVE cannot be find in a dominator when a
2076 previous pass (such as DOM) duplicated it along multiple paths to a BB. In
2077 that case the function gives up without inserting the clobbers. */
2079 static void
2080 insert_clobbers_for_var (gimple_stmt_iterator i, tree var)
2082 gimple *stmt;
2083 tree saved_val;
2084 gimple_htab *visited = NULL;
2086 for (; !gsi_end_p (i); gsi_prev_dom_bb_nondebug (&i))
2088 stmt = gsi_stmt (i);
2090 if (!gimple_call_builtin_p (stmt, BUILT_IN_STACK_SAVE))
2091 continue;
2093 saved_val = gimple_call_lhs (stmt);
2094 if (saved_val == NULL_TREE)
2095 continue;
2097 insert_clobber_before_stack_restore (saved_val, var, &visited);
2098 break;
2101 delete visited;
2104 /* Detects a __builtin_alloca_with_align with constant size argument. Declares
2105 fixed-size array and returns the address, if found, otherwise returns
2106 NULL_TREE. */
2108 static tree
2109 fold_builtin_alloca_with_align (gimple *stmt)
2111 unsigned HOST_WIDE_INT size, threshold, n_elem;
2112 tree lhs, arg, block, var, elem_type, array_type;
2114 /* Get lhs. */
2115 lhs = gimple_call_lhs (stmt);
2116 if (lhs == NULL_TREE)
2117 return NULL_TREE;
2119 /* Detect constant argument. */
2120 arg = get_constant_value (gimple_call_arg (stmt, 0));
2121 if (arg == NULL_TREE
2122 || TREE_CODE (arg) != INTEGER_CST
2123 || !tree_fits_uhwi_p (arg))
2124 return NULL_TREE;
2126 size = tree_to_uhwi (arg);
2128 /* Heuristic: don't fold large allocas. */
2129 threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME);
2130 /* In case the alloca is located at function entry, it has the same lifetime
2131 as a declared array, so we allow a larger size. */
2132 block = gimple_block (stmt);
2133 if (!(cfun->after_inlining
2134 && block
2135 && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL))
2136 threshold /= 10;
2137 if (size > threshold)
2138 return NULL_TREE;
2140 /* Declare array. */
2141 elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1);
2142 n_elem = size * 8 / BITS_PER_UNIT;
2143 array_type = build_array_type_nelts (elem_type, n_elem);
2144 var = create_tmp_var (array_type);
2145 SET_DECL_ALIGN (var, TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)));
2147 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (lhs);
2148 if (pi != NULL && !pi->pt.anything)
2150 bool singleton_p;
2151 unsigned uid;
2152 singleton_p = pt_solution_singleton_or_null_p (&pi->pt, &uid);
2153 gcc_assert (singleton_p);
2154 SET_DECL_PT_UID (var, uid);
2158 /* Fold alloca to the address of the array. */
2159 return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var));
2162 /* Fold the stmt at *GSI with CCP specific information that propagating
2163 and regular folding does not catch. */
2165 static bool
2166 ccp_fold_stmt (gimple_stmt_iterator *gsi)
2168 gimple *stmt = gsi_stmt (*gsi);
2170 switch (gimple_code (stmt))
2172 case GIMPLE_COND:
2174 gcond *cond_stmt = as_a <gcond *> (stmt);
2175 ccp_prop_value_t val;
2176 /* Statement evaluation will handle type mismatches in constants
2177 more gracefully than the final propagation. This allows us to
2178 fold more conditionals here. */
2179 val = evaluate_stmt (stmt);
2180 if (val.lattice_val != CONSTANT
2181 || val.mask != 0)
2182 return false;
2184 if (dump_file)
2186 fprintf (dump_file, "Folding predicate ");
2187 print_gimple_expr (dump_file, stmt, 0);
2188 fprintf (dump_file, " to ");
2189 print_generic_expr (dump_file, val.value);
2190 fprintf (dump_file, "\n");
2193 if (integer_zerop (val.value))
2194 gimple_cond_make_false (cond_stmt);
2195 else
2196 gimple_cond_make_true (cond_stmt);
2198 return true;
2201 case GIMPLE_CALL:
2203 tree lhs = gimple_call_lhs (stmt);
2204 int flags = gimple_call_flags (stmt);
2205 tree val;
2206 tree argt;
2207 bool changed = false;
2208 unsigned i;
2210 /* If the call was folded into a constant make sure it goes
2211 away even if we cannot propagate into all uses because of
2212 type issues. */
2213 if (lhs
2214 && TREE_CODE (lhs) == SSA_NAME
2215 && (val = get_constant_value (lhs))
2216 /* Don't optimize away calls that have side-effects. */
2217 && (flags & (ECF_CONST|ECF_PURE)) != 0
2218 && (flags & ECF_LOOPING_CONST_OR_PURE) == 0)
2220 tree new_rhs = unshare_expr (val);
2221 bool res;
2222 if (!useless_type_conversion_p (TREE_TYPE (lhs),
2223 TREE_TYPE (new_rhs)))
2224 new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs);
2225 res = update_call_from_tree (gsi, new_rhs);
2226 gcc_assert (res);
2227 return true;
2230 /* Internal calls provide no argument types, so the extra laxity
2231 for normal calls does not apply. */
2232 if (gimple_call_internal_p (stmt))
2233 return false;
2235 /* The heuristic of fold_builtin_alloca_with_align differs before and
2236 after inlining, so we don't require the arg to be changed into a
2237 constant for folding, but just to be constant. */
2238 if (gimple_call_builtin_p (stmt, BUILT_IN_ALLOCA_WITH_ALIGN))
2240 tree new_rhs = fold_builtin_alloca_with_align (stmt);
2241 if (new_rhs)
2243 bool res = update_call_from_tree (gsi, new_rhs);
2244 tree var = TREE_OPERAND (TREE_OPERAND (new_rhs, 0),0);
2245 gcc_assert (res);
2246 insert_clobbers_for_var (*gsi, var);
2247 return true;
2251 /* Propagate into the call arguments. Compared to replace_uses_in
2252 this can use the argument slot types for type verification
2253 instead of the current argument type. We also can safely
2254 drop qualifiers here as we are dealing with constants anyway. */
2255 argt = TYPE_ARG_TYPES (gimple_call_fntype (stmt));
2256 for (i = 0; i < gimple_call_num_args (stmt) && argt;
2257 ++i, argt = TREE_CHAIN (argt))
2259 tree arg = gimple_call_arg (stmt, i);
2260 if (TREE_CODE (arg) == SSA_NAME
2261 && (val = get_constant_value (arg))
2262 && useless_type_conversion_p
2263 (TYPE_MAIN_VARIANT (TREE_VALUE (argt)),
2264 TYPE_MAIN_VARIANT (TREE_TYPE (val))))
2266 gimple_call_set_arg (stmt, i, unshare_expr (val));
2267 changed = true;
2271 return changed;
2274 case GIMPLE_ASSIGN:
2276 tree lhs = gimple_assign_lhs (stmt);
2277 tree val;
2279 /* If we have a load that turned out to be constant replace it
2280 as we cannot propagate into all uses in all cases. */
2281 if (gimple_assign_single_p (stmt)
2282 && TREE_CODE (lhs) == SSA_NAME
2283 && (val = get_constant_value (lhs)))
2285 tree rhs = unshare_expr (val);
2286 if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
2287 rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs);
2288 gimple_assign_set_rhs_from_tree (gsi, rhs);
2289 return true;
2292 return false;
2295 default:
2296 return false;
2300 /* Visit the assignment statement STMT. Set the value of its LHS to the
2301 value computed by the RHS and store LHS in *OUTPUT_P. If STMT
2302 creates virtual definitions, set the value of each new name to that
2303 of the RHS (if we can derive a constant out of the RHS).
2304 Value-returning call statements also perform an assignment, and
2305 are handled here. */
2307 static enum ssa_prop_result
2308 visit_assignment (gimple *stmt, tree *output_p)
2310 ccp_prop_value_t val;
2311 enum ssa_prop_result retval = SSA_PROP_NOT_INTERESTING;
2313 tree lhs = gimple_get_lhs (stmt);
2314 if (TREE_CODE (lhs) == SSA_NAME)
2316 /* Evaluate the statement, which could be
2317 either a GIMPLE_ASSIGN or a GIMPLE_CALL. */
2318 val = evaluate_stmt (stmt);
2320 /* If STMT is an assignment to an SSA_NAME, we only have one
2321 value to set. */
2322 if (set_lattice_value (lhs, &val))
2324 *output_p = lhs;
2325 if (val.lattice_val == VARYING)
2326 retval = SSA_PROP_VARYING;
2327 else
2328 retval = SSA_PROP_INTERESTING;
2332 return retval;
2336 /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING
2337 if it can determine which edge will be taken. Otherwise, return
2338 SSA_PROP_VARYING. */
2340 static enum ssa_prop_result
2341 visit_cond_stmt (gimple *stmt, edge *taken_edge_p)
2343 ccp_prop_value_t val;
2344 basic_block block;
2346 block = gimple_bb (stmt);
2347 val = evaluate_stmt (stmt);
2348 if (val.lattice_val != CONSTANT
2349 || val.mask != 0)
2350 return SSA_PROP_VARYING;
2352 /* Find which edge out of the conditional block will be taken and add it
2353 to the worklist. If no single edge can be determined statically,
2354 return SSA_PROP_VARYING to feed all the outgoing edges to the
2355 propagation engine. */
2356 *taken_edge_p = find_taken_edge (block, val.value);
2357 if (*taken_edge_p)
2358 return SSA_PROP_INTERESTING;
2359 else
2360 return SSA_PROP_VARYING;
2364 /* Evaluate statement STMT. If the statement produces an output value and
2365 its evaluation changes the lattice value of its output, return
2366 SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the
2367 output value.
2369 If STMT is a conditional branch and we can determine its truth
2370 value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying
2371 value, return SSA_PROP_VARYING. */
2373 static enum ssa_prop_result
2374 ccp_visit_stmt (gimple *stmt, edge *taken_edge_p, tree *output_p)
2376 tree def;
2377 ssa_op_iter iter;
2379 if (dump_file && (dump_flags & TDF_DETAILS))
2381 fprintf (dump_file, "\nVisiting statement:\n");
2382 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
2385 switch (gimple_code (stmt))
2387 case GIMPLE_ASSIGN:
2388 /* If the statement is an assignment that produces a single
2389 output value, evaluate its RHS to see if the lattice value of
2390 its output has changed. */
2391 return visit_assignment (stmt, output_p);
2393 case GIMPLE_CALL:
2394 /* A value-returning call also performs an assignment. */
2395 if (gimple_call_lhs (stmt) != NULL_TREE)
2396 return visit_assignment (stmt, output_p);
2397 break;
2399 case GIMPLE_COND:
2400 case GIMPLE_SWITCH:
2401 /* If STMT is a conditional branch, see if we can determine
2402 which branch will be taken. */
2403 /* FIXME. It appears that we should be able to optimize
2404 computed GOTOs here as well. */
2405 return visit_cond_stmt (stmt, taken_edge_p);
2407 default:
2408 break;
2411 /* Any other kind of statement is not interesting for constant
2412 propagation and, therefore, not worth simulating. */
2413 if (dump_file && (dump_flags & TDF_DETAILS))
2414 fprintf (dump_file, "No interesting values produced. Marked VARYING.\n");
2416 /* Definitions made by statements other than assignments to
2417 SSA_NAMEs represent unknown modifications to their outputs.
2418 Mark them VARYING. */
2419 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
2420 set_value_varying (def);
2422 return SSA_PROP_VARYING;
2426 /* Main entry point for SSA Conditional Constant Propagation. If NONZERO_P,
2427 record nonzero bits. */
2429 static unsigned int
2430 do_ssa_ccp (bool nonzero_p)
2432 unsigned int todo = 0;
2433 calculate_dominance_info (CDI_DOMINATORS);
2435 ccp_initialize ();
2436 ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node);
2437 if (ccp_finalize (nonzero_p || flag_ipa_bit_cp))
2439 todo = (TODO_cleanup_cfg | TODO_update_ssa);
2441 /* ccp_finalize does not preserve loop-closed ssa. */
2442 loops_state_clear (LOOP_CLOSED_SSA);
2445 free_dominance_info (CDI_DOMINATORS);
2446 return todo;
2450 namespace {
2452 const pass_data pass_data_ccp =
2454 GIMPLE_PASS, /* type */
2455 "ccp", /* name */
2456 OPTGROUP_NONE, /* optinfo_flags */
2457 TV_TREE_CCP, /* tv_id */
2458 ( PROP_cfg | PROP_ssa ), /* properties_required */
2459 0, /* properties_provided */
2460 0, /* properties_destroyed */
2461 0, /* todo_flags_start */
2462 TODO_update_address_taken, /* todo_flags_finish */
2465 class pass_ccp : public gimple_opt_pass
2467 public:
2468 pass_ccp (gcc::context *ctxt)
2469 : gimple_opt_pass (pass_data_ccp, ctxt), nonzero_p (false)
2472 /* opt_pass methods: */
2473 opt_pass * clone () { return new pass_ccp (m_ctxt); }
2474 void set_pass_param (unsigned int n, bool param)
2476 gcc_assert (n == 0);
2477 nonzero_p = param;
2479 virtual bool gate (function *) { return flag_tree_ccp != 0; }
2480 virtual unsigned int execute (function *) { return do_ssa_ccp (nonzero_p); }
2482 private:
2483 /* Determines whether the pass instance records nonzero bits. */
2484 bool nonzero_p;
2485 }; // class pass_ccp
2487 } // anon namespace
2489 gimple_opt_pass *
2490 make_pass_ccp (gcc::context *ctxt)
2492 return new pass_ccp (ctxt);
2497 /* Try to optimize out __builtin_stack_restore. Optimize it out
2498 if there is another __builtin_stack_restore in the same basic
2499 block and no calls or ASM_EXPRs are in between, or if this block's
2500 only outgoing edge is to EXIT_BLOCK and there are no calls or
2501 ASM_EXPRs after this __builtin_stack_restore. */
2503 static tree
2504 optimize_stack_restore (gimple_stmt_iterator i)
2506 tree callee;
2507 gimple *stmt;
2509 basic_block bb = gsi_bb (i);
2510 gimple *call = gsi_stmt (i);
2512 if (gimple_code (call) != GIMPLE_CALL
2513 || gimple_call_num_args (call) != 1
2514 || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME
2515 || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0))))
2516 return NULL_TREE;
2518 for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i))
2520 stmt = gsi_stmt (i);
2521 if (gimple_code (stmt) == GIMPLE_ASM)
2522 return NULL_TREE;
2523 if (gimple_code (stmt) != GIMPLE_CALL)
2524 continue;
2526 callee = gimple_call_fndecl (stmt);
2527 if (!callee
2528 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL
2529 /* All regular builtins are ok, just obviously not alloca. */
2530 || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA
2531 || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA_WITH_ALIGN)
2532 return NULL_TREE;
2534 if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE)
2535 goto second_stack_restore;
2538 if (!gsi_end_p (i))
2539 return NULL_TREE;
2541 /* Allow one successor of the exit block, or zero successors. */
2542 switch (EDGE_COUNT (bb->succs))
2544 case 0:
2545 break;
2546 case 1:
2547 if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
2548 return NULL_TREE;
2549 break;
2550 default:
2551 return NULL_TREE;
2553 second_stack_restore:
2555 /* If there's exactly one use, then zap the call to __builtin_stack_save.
2556 If there are multiple uses, then the last one should remove the call.
2557 In any case, whether the call to __builtin_stack_save can be removed
2558 or not is irrelevant to removing the call to __builtin_stack_restore. */
2559 if (has_single_use (gimple_call_arg (call, 0)))
2561 gimple *stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0));
2562 if (is_gimple_call (stack_save))
2564 callee = gimple_call_fndecl (stack_save);
2565 if (callee
2566 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL
2567 && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE)
2569 gimple_stmt_iterator stack_save_gsi;
2570 tree rhs;
2572 stack_save_gsi = gsi_for_stmt (stack_save);
2573 rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0);
2574 update_call_from_tree (&stack_save_gsi, rhs);
2579 /* No effect, so the statement will be deleted. */
2580 return integer_zero_node;
2583 /* If va_list type is a simple pointer and nothing special is needed,
2584 optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0),
2585 __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple
2586 pointer assignment. */
2588 static tree
2589 optimize_stdarg_builtin (gimple *call)
2591 tree callee, lhs, rhs, cfun_va_list;
2592 bool va_list_simple_ptr;
2593 location_t loc = gimple_location (call);
2595 if (gimple_code (call) != GIMPLE_CALL)
2596 return NULL_TREE;
2598 callee = gimple_call_fndecl (call);
2600 cfun_va_list = targetm.fn_abi_va_list (callee);
2601 va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list)
2602 && (TREE_TYPE (cfun_va_list) == void_type_node
2603 || TREE_TYPE (cfun_va_list) == char_type_node);
2605 switch (DECL_FUNCTION_CODE (callee))
2607 case BUILT_IN_VA_START:
2608 if (!va_list_simple_ptr
2609 || targetm.expand_builtin_va_start != NULL
2610 || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG))
2611 return NULL_TREE;
2613 if (gimple_call_num_args (call) != 2)
2614 return NULL_TREE;
2616 lhs = gimple_call_arg (call, 0);
2617 if (!POINTER_TYPE_P (TREE_TYPE (lhs))
2618 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs)))
2619 != TYPE_MAIN_VARIANT (cfun_va_list))
2620 return NULL_TREE;
2622 lhs = build_fold_indirect_ref_loc (loc, lhs);
2623 rhs = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_NEXT_ARG),
2624 1, integer_zero_node);
2625 rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs);
2626 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs);
2628 case BUILT_IN_VA_COPY:
2629 if (!va_list_simple_ptr)
2630 return NULL_TREE;
2632 if (gimple_call_num_args (call) != 2)
2633 return NULL_TREE;
2635 lhs = gimple_call_arg (call, 0);
2636 if (!POINTER_TYPE_P (TREE_TYPE (lhs))
2637 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs)))
2638 != TYPE_MAIN_VARIANT (cfun_va_list))
2639 return NULL_TREE;
2641 lhs = build_fold_indirect_ref_loc (loc, lhs);
2642 rhs = gimple_call_arg (call, 1);
2643 if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs))
2644 != TYPE_MAIN_VARIANT (cfun_va_list))
2645 return NULL_TREE;
2647 rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs);
2648 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs);
2650 case BUILT_IN_VA_END:
2651 /* No effect, so the statement will be deleted. */
2652 return integer_zero_node;
2654 default:
2655 gcc_unreachable ();
2659 /* Attemp to make the block of __builtin_unreachable I unreachable by changing
2660 the incoming jumps. Return true if at least one jump was changed. */
2662 static bool
2663 optimize_unreachable (gimple_stmt_iterator i)
2665 basic_block bb = gsi_bb (i);
2666 gimple_stmt_iterator gsi;
2667 gimple *stmt;
2668 edge_iterator ei;
2669 edge e;
2670 bool ret;
2672 if (flag_sanitize & SANITIZE_UNREACHABLE)
2673 return false;
2675 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
2677 stmt = gsi_stmt (gsi);
2679 if (is_gimple_debug (stmt))
2680 continue;
2682 if (glabel *label_stmt = dyn_cast <glabel *> (stmt))
2684 /* Verify we do not need to preserve the label. */
2685 if (FORCED_LABEL (gimple_label_label (label_stmt)))
2686 return false;
2688 continue;
2691 /* Only handle the case that __builtin_unreachable is the first statement
2692 in the block. We rely on DCE to remove stmts without side-effects
2693 before __builtin_unreachable. */
2694 if (gsi_stmt (gsi) != gsi_stmt (i))
2695 return false;
2698 ret = false;
2699 FOR_EACH_EDGE (e, ei, bb->preds)
2701 gsi = gsi_last_bb (e->src);
2702 if (gsi_end_p (gsi))
2703 continue;
2705 stmt = gsi_stmt (gsi);
2706 if (gcond *cond_stmt = dyn_cast <gcond *> (stmt))
2708 if (e->flags & EDGE_TRUE_VALUE)
2709 gimple_cond_make_false (cond_stmt);
2710 else if (e->flags & EDGE_FALSE_VALUE)
2711 gimple_cond_make_true (cond_stmt);
2712 else
2713 gcc_unreachable ();
2714 update_stmt (cond_stmt);
2716 else
2718 /* Todo: handle other cases. Note that unreachable switch case
2719 statements have already been removed. */
2720 continue;
2723 ret = true;
2726 return ret;
2729 /* Optimize
2730 mask_2 = 1 << cnt_1;
2731 _4 = __atomic_fetch_or_* (ptr_6, mask_2, _3);
2732 _5 = _4 & mask_2;
2734 _4 = ATOMIC_BIT_TEST_AND_SET (ptr_6, cnt_1, 0, _3);
2735 _5 = _4;
2736 If _5 is only used in _5 != 0 or _5 == 0 comparisons, 1
2737 is passed instead of 0, and the builtin just returns a zero
2738 or 1 value instead of the actual bit.
2739 Similarly for __sync_fetch_and_or_* (without the ", _3" part
2740 in there), and/or if mask_2 is a power of 2 constant.
2741 Similarly for xor instead of or, use ATOMIC_BIT_TEST_AND_COMPLEMENT
2742 in that case. And similarly for and instead of or, except that
2743 the second argument to the builtin needs to be one's complement
2744 of the mask instead of mask. */
2746 static void
2747 optimize_atomic_bit_test_and (gimple_stmt_iterator *gsip,
2748 enum internal_fn fn, bool has_model_arg,
2749 bool after)
2751 gimple *call = gsi_stmt (*gsip);
2752 tree lhs = gimple_call_lhs (call);
2753 use_operand_p use_p;
2754 gimple *use_stmt;
2755 tree mask, bit;
2756 optab optab;
2758 if (!flag_inline_atomics
2759 || optimize_debug
2760 || !gimple_call_builtin_p (call, BUILT_IN_NORMAL)
2761 || !lhs
2762 || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)
2763 || !single_imm_use (lhs, &use_p, &use_stmt)
2764 || !is_gimple_assign (use_stmt)
2765 || gimple_assign_rhs_code (use_stmt) != BIT_AND_EXPR
2766 || !gimple_vdef (call))
2767 return;
2769 switch (fn)
2771 case IFN_ATOMIC_BIT_TEST_AND_SET:
2772 optab = atomic_bit_test_and_set_optab;
2773 break;
2774 case IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT:
2775 optab = atomic_bit_test_and_complement_optab;
2776 break;
2777 case IFN_ATOMIC_BIT_TEST_AND_RESET:
2778 optab = atomic_bit_test_and_reset_optab;
2779 break;
2780 default:
2781 return;
2784 if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs))) == CODE_FOR_nothing)
2785 return;
2787 mask = gimple_call_arg (call, 1);
2788 tree use_lhs = gimple_assign_lhs (use_stmt);
2789 if (!use_lhs)
2790 return;
2792 if (TREE_CODE (mask) == INTEGER_CST)
2794 if (fn == IFN_ATOMIC_BIT_TEST_AND_RESET)
2795 mask = const_unop (BIT_NOT_EXPR, TREE_TYPE (mask), mask);
2796 mask = fold_convert (TREE_TYPE (lhs), mask);
2797 int ibit = tree_log2 (mask);
2798 if (ibit < 0)
2799 return;
2800 bit = build_int_cst (TREE_TYPE (lhs), ibit);
2802 else if (TREE_CODE (mask) == SSA_NAME)
2804 gimple *g = SSA_NAME_DEF_STMT (mask);
2805 if (fn == IFN_ATOMIC_BIT_TEST_AND_RESET)
2807 if (!is_gimple_assign (g)
2808 || gimple_assign_rhs_code (g) != BIT_NOT_EXPR)
2809 return;
2810 mask = gimple_assign_rhs1 (g);
2811 if (TREE_CODE (mask) != SSA_NAME)
2812 return;
2813 g = SSA_NAME_DEF_STMT (mask);
2815 if (!is_gimple_assign (g)
2816 || gimple_assign_rhs_code (g) != LSHIFT_EXPR
2817 || !integer_onep (gimple_assign_rhs1 (g)))
2818 return;
2819 bit = gimple_assign_rhs2 (g);
2821 else
2822 return;
2824 if (gimple_assign_rhs1 (use_stmt) == lhs)
2826 if (!operand_equal_p (gimple_assign_rhs2 (use_stmt), mask, 0))
2827 return;
2829 else if (gimple_assign_rhs2 (use_stmt) != lhs
2830 || !operand_equal_p (gimple_assign_rhs1 (use_stmt), mask, 0))
2831 return;
2833 bool use_bool = true;
2834 bool has_debug_uses = false;
2835 imm_use_iterator iter;
2836 gimple *g;
2838 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs))
2839 use_bool = false;
2840 FOR_EACH_IMM_USE_STMT (g, iter, use_lhs)
2842 enum tree_code code = ERROR_MARK;
2843 tree op0 = NULL_TREE, op1 = NULL_TREE;
2844 if (is_gimple_debug (g))
2846 has_debug_uses = true;
2847 continue;
2849 else if (is_gimple_assign (g))
2850 switch (gimple_assign_rhs_code (g))
2852 case COND_EXPR:
2853 op1 = gimple_assign_rhs1 (g);
2854 code = TREE_CODE (op1);
2855 op0 = TREE_OPERAND (op1, 0);
2856 op1 = TREE_OPERAND (op1, 1);
2857 break;
2858 case EQ_EXPR:
2859 case NE_EXPR:
2860 code = gimple_assign_rhs_code (g);
2861 op0 = gimple_assign_rhs1 (g);
2862 op1 = gimple_assign_rhs2 (g);
2863 break;
2864 default:
2865 break;
2867 else if (gimple_code (g) == GIMPLE_COND)
2869 code = gimple_cond_code (g);
2870 op0 = gimple_cond_lhs (g);
2871 op1 = gimple_cond_rhs (g);
2874 if ((code == EQ_EXPR || code == NE_EXPR)
2875 && op0 == use_lhs
2876 && integer_zerop (op1))
2878 use_operand_p use_p;
2879 int n = 0;
2880 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
2881 n++;
2882 if (n == 1)
2883 continue;
2886 use_bool = false;
2887 BREAK_FROM_IMM_USE_STMT (iter);
2890 tree new_lhs = make_ssa_name (TREE_TYPE (lhs));
2891 tree flag = build_int_cst (TREE_TYPE (lhs), use_bool);
2892 if (has_model_arg)
2893 g = gimple_build_call_internal (fn, 4, gimple_call_arg (call, 0),
2894 bit, flag, gimple_call_arg (call, 2));
2895 else
2896 g = gimple_build_call_internal (fn, 3, gimple_call_arg (call, 0),
2897 bit, flag);
2898 gimple_call_set_lhs (g, new_lhs);
2899 gimple_set_location (g, gimple_location (call));
2900 gimple_set_vuse (g, gimple_vuse (call));
2901 gimple_set_vdef (g, gimple_vdef (call));
2902 bool throws = stmt_can_throw_internal (call);
2903 gimple_call_set_nothrow (as_a <gcall *> (g),
2904 gimple_call_nothrow_p (as_a <gcall *> (call)));
2905 SSA_NAME_DEF_STMT (gimple_vdef (call)) = g;
2906 gimple_stmt_iterator gsi = *gsip;
2907 gsi_insert_after (&gsi, g, GSI_NEW_STMT);
2908 edge e = NULL;
2909 if (throws)
2911 maybe_clean_or_replace_eh_stmt (call, g);
2912 if (after || (use_bool && has_debug_uses))
2913 e = find_fallthru_edge (gsi_bb (gsi)->succs);
2915 if (after)
2917 /* The internal function returns the value of the specified bit
2918 before the atomic operation. If we are interested in the value
2919 of the specified bit after the atomic operation (makes only sense
2920 for xor, otherwise the bit content is compile time known),
2921 we need to invert the bit. */
2922 g = gimple_build_assign (make_ssa_name (TREE_TYPE (lhs)),
2923 BIT_XOR_EXPR, new_lhs,
2924 use_bool ? build_int_cst (TREE_TYPE (lhs), 1)
2925 : mask);
2926 new_lhs = gimple_assign_lhs (g);
2927 if (throws)
2929 gsi_insert_on_edge_immediate (e, g);
2930 gsi = gsi_for_stmt (g);
2932 else
2933 gsi_insert_after (&gsi, g, GSI_NEW_STMT);
2935 if (use_bool && has_debug_uses)
2937 tree temp = NULL_TREE;
2938 if (!throws || after || single_pred_p (e->dest))
2940 temp = make_node (DEBUG_EXPR_DECL);
2941 DECL_ARTIFICIAL (temp) = 1;
2942 TREE_TYPE (temp) = TREE_TYPE (lhs);
2943 SET_DECL_MODE (temp, TYPE_MODE (TREE_TYPE (lhs)));
2944 tree t = build2 (LSHIFT_EXPR, TREE_TYPE (lhs), new_lhs, bit);
2945 g = gimple_build_debug_bind (temp, t, g);
2946 if (throws && !after)
2948 gsi = gsi_after_labels (e->dest);
2949 gsi_insert_before (&gsi, g, GSI_SAME_STMT);
2951 else
2952 gsi_insert_after (&gsi, g, GSI_NEW_STMT);
2954 FOR_EACH_IMM_USE_STMT (g, iter, use_lhs)
2955 if (is_gimple_debug (g))
2957 use_operand_p use_p;
2958 if (temp == NULL_TREE)
2959 gimple_debug_bind_reset_value (g);
2960 else
2961 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
2962 SET_USE (use_p, temp);
2963 update_stmt (g);
2966 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_lhs)
2967 = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs);
2968 replace_uses_by (use_lhs, new_lhs);
2969 gsi = gsi_for_stmt (use_stmt);
2970 gsi_remove (&gsi, true);
2971 release_defs (use_stmt);
2972 gsi_remove (gsip, true);
2973 release_ssa_name (lhs);
2976 /* Optimize
2977 a = {};
2978 b = a;
2979 into
2980 a = {};
2981 b = {};
2982 Similarly for memset (&a, ..., sizeof (a)); instead of a = {};
2983 and/or memcpy (&b, &a, sizeof (a)); instead of b = a; */
2985 static void
2986 optimize_memcpy (gimple_stmt_iterator *gsip, tree dest, tree src, tree len)
2988 gimple *stmt = gsi_stmt (*gsip);
2989 if (gimple_has_volatile_ops (stmt))
2990 return;
2992 tree vuse = gimple_vuse (stmt);
2993 if (vuse == NULL)
2994 return;
2996 gimple *defstmt = SSA_NAME_DEF_STMT (vuse);
2997 tree src2 = NULL_TREE, len2 = NULL_TREE;
2998 HOST_WIDE_INT offset, offset2;
2999 tree val = integer_zero_node;
3000 if (gimple_store_p (defstmt)
3001 && gimple_assign_single_p (defstmt)
3002 && TREE_CODE (gimple_assign_rhs1 (defstmt)) == CONSTRUCTOR
3003 && !gimple_clobber_p (defstmt))
3004 src2 = gimple_assign_lhs (defstmt);
3005 else if (gimple_call_builtin_p (defstmt, BUILT_IN_MEMSET)
3006 && TREE_CODE (gimple_call_arg (defstmt, 0)) == ADDR_EXPR
3007 && TREE_CODE (gimple_call_arg (defstmt, 1)) == INTEGER_CST)
3009 src2 = TREE_OPERAND (gimple_call_arg (defstmt, 0), 0);
3010 len2 = gimple_call_arg (defstmt, 2);
3011 val = gimple_call_arg (defstmt, 1);
3012 /* For non-0 val, we'd have to transform stmt from assignment
3013 into memset (only if dest is addressable). */
3014 if (!integer_zerop (val) && is_gimple_assign (stmt))
3015 src2 = NULL_TREE;
3018 if (src2 == NULL_TREE)
3019 return;
3021 if (len == NULL_TREE)
3022 len = (TREE_CODE (src) == COMPONENT_REF
3023 ? DECL_SIZE_UNIT (TREE_OPERAND (src, 1))
3024 : TYPE_SIZE_UNIT (TREE_TYPE (src)));
3025 if (len2 == NULL_TREE)
3026 len2 = (TREE_CODE (src2) == COMPONENT_REF
3027 ? DECL_SIZE_UNIT (TREE_OPERAND (src2, 1))
3028 : TYPE_SIZE_UNIT (TREE_TYPE (src2)));
3029 if (len == NULL_TREE
3030 || TREE_CODE (len) != INTEGER_CST
3031 || len2 == NULL_TREE
3032 || TREE_CODE (len2) != INTEGER_CST)
3033 return;
3035 src = get_addr_base_and_unit_offset (src, &offset);
3036 src2 = get_addr_base_and_unit_offset (src2, &offset2);
3037 if (src == NULL_TREE
3038 || src2 == NULL_TREE
3039 || offset < offset2)
3040 return;
3042 if (!operand_equal_p (src, src2, 0))
3043 return;
3045 /* [ src + offset2, src + offset2 + len2 - 1 ] is set to val.
3046 Make sure that
3047 [ src + offset, src + offset + len - 1 ] is a subset of that. */
3048 if (wi::to_offset (len) + (offset - offset2) > wi::to_offset (len2))
3049 return;
3051 if (dump_file && (dump_flags & TDF_DETAILS))
3053 fprintf (dump_file, "Simplified\n ");
3054 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
3055 fprintf (dump_file, "after previous\n ");
3056 print_gimple_stmt (dump_file, defstmt, 0, dump_flags);
3059 /* For simplicity, don't change the kind of the stmt,
3060 turn dest = src; into dest = {}; and memcpy (&dest, &src, len);
3061 into memset (&dest, val, len);
3062 In theory we could change dest = src into memset if dest
3063 is addressable (maybe beneficial if val is not 0), or
3064 memcpy (&dest, &src, len) into dest = {} if len is the size
3065 of dest, dest isn't volatile. */
3066 if (is_gimple_assign (stmt))
3068 tree ctor = build_constructor (TREE_TYPE (dest), NULL);
3069 gimple_assign_set_rhs_from_tree (gsip, ctor);
3070 update_stmt (stmt);
3072 else /* If stmt is memcpy, transform it into memset. */
3074 gcall *call = as_a <gcall *> (stmt);
3075 tree fndecl = builtin_decl_implicit (BUILT_IN_MEMSET);
3076 gimple_call_set_fndecl (call, fndecl);
3077 gimple_call_set_fntype (call, TREE_TYPE (fndecl));
3078 gimple_call_set_arg (call, 1, val);
3079 update_stmt (stmt);
3082 if (dump_file && (dump_flags & TDF_DETAILS))
3084 fprintf (dump_file, "into\n ");
3085 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
3089 /* A simple pass that attempts to fold all builtin functions. This pass
3090 is run after we've propagated as many constants as we can. */
3092 namespace {
3094 const pass_data pass_data_fold_builtins =
3096 GIMPLE_PASS, /* type */
3097 "fab", /* name */
3098 OPTGROUP_NONE, /* optinfo_flags */
3099 TV_NONE, /* tv_id */
3100 ( PROP_cfg | PROP_ssa ), /* properties_required */
3101 0, /* properties_provided */
3102 0, /* properties_destroyed */
3103 0, /* todo_flags_start */
3104 TODO_update_ssa, /* todo_flags_finish */
3107 class pass_fold_builtins : public gimple_opt_pass
3109 public:
3110 pass_fold_builtins (gcc::context *ctxt)
3111 : gimple_opt_pass (pass_data_fold_builtins, ctxt)
3114 /* opt_pass methods: */
3115 opt_pass * clone () { return new pass_fold_builtins (m_ctxt); }
3116 virtual unsigned int execute (function *);
3118 }; // class pass_fold_builtins
3120 unsigned int
3121 pass_fold_builtins::execute (function *fun)
3123 bool cfg_changed = false;
3124 basic_block bb;
3125 unsigned int todoflags = 0;
3127 FOR_EACH_BB_FN (bb, fun)
3129 gimple_stmt_iterator i;
3130 for (i = gsi_start_bb (bb); !gsi_end_p (i); )
3132 gimple *stmt, *old_stmt;
3133 tree callee;
3134 enum built_in_function fcode;
3136 stmt = gsi_stmt (i);
3138 if (gimple_code (stmt) != GIMPLE_CALL)
3140 /* Remove all *ssaname_N ={v} {CLOBBER}; stmts,
3141 after the last GIMPLE DSE they aren't needed and might
3142 unnecessarily keep the SSA_NAMEs live. */
3143 if (gimple_clobber_p (stmt))
3145 tree lhs = gimple_assign_lhs (stmt);
3146 if (TREE_CODE (lhs) == MEM_REF
3147 && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME)
3149 unlink_stmt_vdef (stmt);
3150 gsi_remove (&i, true);
3151 release_defs (stmt);
3152 continue;
3155 else if (gimple_assign_load_p (stmt) && gimple_store_p (stmt))
3156 optimize_memcpy (&i, gimple_assign_lhs (stmt),
3157 gimple_assign_rhs1 (stmt), NULL_TREE);
3158 gsi_next (&i);
3159 continue;
3162 callee = gimple_call_fndecl (stmt);
3163 if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL)
3165 gsi_next (&i);
3166 continue;
3169 fcode = DECL_FUNCTION_CODE (callee);
3170 if (fold_stmt (&i))
3172 else
3174 tree result = NULL_TREE;
3175 switch (DECL_FUNCTION_CODE (callee))
3177 case BUILT_IN_CONSTANT_P:
3178 /* Resolve __builtin_constant_p. If it hasn't been
3179 folded to integer_one_node by now, it's fairly
3180 certain that the value simply isn't constant. */
3181 result = integer_zero_node;
3182 break;
3184 case BUILT_IN_ASSUME_ALIGNED:
3185 /* Remove __builtin_assume_aligned. */
3186 result = gimple_call_arg (stmt, 0);
3187 break;
3189 case BUILT_IN_STACK_RESTORE:
3190 result = optimize_stack_restore (i);
3191 if (result)
3192 break;
3193 gsi_next (&i);
3194 continue;
3196 case BUILT_IN_UNREACHABLE:
3197 if (optimize_unreachable (i))
3198 cfg_changed = true;
3199 break;
3201 case BUILT_IN_ATOMIC_FETCH_OR_1:
3202 case BUILT_IN_ATOMIC_FETCH_OR_2:
3203 case BUILT_IN_ATOMIC_FETCH_OR_4:
3204 case BUILT_IN_ATOMIC_FETCH_OR_8:
3205 case BUILT_IN_ATOMIC_FETCH_OR_16:
3206 optimize_atomic_bit_test_and (&i,
3207 IFN_ATOMIC_BIT_TEST_AND_SET,
3208 true, false);
3209 break;
3210 case BUILT_IN_SYNC_FETCH_AND_OR_1:
3211 case BUILT_IN_SYNC_FETCH_AND_OR_2:
3212 case BUILT_IN_SYNC_FETCH_AND_OR_4:
3213 case BUILT_IN_SYNC_FETCH_AND_OR_8:
3214 case BUILT_IN_SYNC_FETCH_AND_OR_16:
3215 optimize_atomic_bit_test_and (&i,
3216 IFN_ATOMIC_BIT_TEST_AND_SET,
3217 false, false);
3218 break;
3220 case BUILT_IN_ATOMIC_FETCH_XOR_1:
3221 case BUILT_IN_ATOMIC_FETCH_XOR_2:
3222 case BUILT_IN_ATOMIC_FETCH_XOR_4:
3223 case BUILT_IN_ATOMIC_FETCH_XOR_8:
3224 case BUILT_IN_ATOMIC_FETCH_XOR_16:
3225 optimize_atomic_bit_test_and
3226 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, true, false);
3227 break;
3228 case BUILT_IN_SYNC_FETCH_AND_XOR_1:
3229 case BUILT_IN_SYNC_FETCH_AND_XOR_2:
3230 case BUILT_IN_SYNC_FETCH_AND_XOR_4:
3231 case BUILT_IN_SYNC_FETCH_AND_XOR_8:
3232 case BUILT_IN_SYNC_FETCH_AND_XOR_16:
3233 optimize_atomic_bit_test_and
3234 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, false, false);
3235 break;
3237 case BUILT_IN_ATOMIC_XOR_FETCH_1:
3238 case BUILT_IN_ATOMIC_XOR_FETCH_2:
3239 case BUILT_IN_ATOMIC_XOR_FETCH_4:
3240 case BUILT_IN_ATOMIC_XOR_FETCH_8:
3241 case BUILT_IN_ATOMIC_XOR_FETCH_16:
3242 optimize_atomic_bit_test_and
3243 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, true, true);
3244 break;
3245 case BUILT_IN_SYNC_XOR_AND_FETCH_1:
3246 case BUILT_IN_SYNC_XOR_AND_FETCH_2:
3247 case BUILT_IN_SYNC_XOR_AND_FETCH_4:
3248 case BUILT_IN_SYNC_XOR_AND_FETCH_8:
3249 case BUILT_IN_SYNC_XOR_AND_FETCH_16:
3250 optimize_atomic_bit_test_and
3251 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, false, true);
3252 break;
3254 case BUILT_IN_ATOMIC_FETCH_AND_1:
3255 case BUILT_IN_ATOMIC_FETCH_AND_2:
3256 case BUILT_IN_ATOMIC_FETCH_AND_4:
3257 case BUILT_IN_ATOMIC_FETCH_AND_8:
3258 case BUILT_IN_ATOMIC_FETCH_AND_16:
3259 optimize_atomic_bit_test_and (&i,
3260 IFN_ATOMIC_BIT_TEST_AND_RESET,
3261 true, false);
3262 break;
3263 case BUILT_IN_SYNC_FETCH_AND_AND_1:
3264 case BUILT_IN_SYNC_FETCH_AND_AND_2:
3265 case BUILT_IN_SYNC_FETCH_AND_AND_4:
3266 case BUILT_IN_SYNC_FETCH_AND_AND_8:
3267 case BUILT_IN_SYNC_FETCH_AND_AND_16:
3268 optimize_atomic_bit_test_and (&i,
3269 IFN_ATOMIC_BIT_TEST_AND_RESET,
3270 false, false);
3271 break;
3273 case BUILT_IN_MEMCPY:
3274 if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)
3275 && TREE_CODE (gimple_call_arg (stmt, 0)) == ADDR_EXPR
3276 && TREE_CODE (gimple_call_arg (stmt, 1)) == ADDR_EXPR
3277 && TREE_CODE (gimple_call_arg (stmt, 2)) == INTEGER_CST)
3279 tree dest = TREE_OPERAND (gimple_call_arg (stmt, 0), 0);
3280 tree src = TREE_OPERAND (gimple_call_arg (stmt, 1), 0);
3281 tree len = gimple_call_arg (stmt, 2);
3282 optimize_memcpy (&i, dest, src, len);
3284 break;
3286 case BUILT_IN_VA_START:
3287 case BUILT_IN_VA_END:
3288 case BUILT_IN_VA_COPY:
3289 /* These shouldn't be folded before pass_stdarg. */
3290 result = optimize_stdarg_builtin (stmt);
3291 break;
3293 default:;
3296 if (!result)
3298 gsi_next (&i);
3299 continue;
3302 if (!update_call_from_tree (&i, result))
3303 gimplify_and_update_call_from_tree (&i, result);
3306 todoflags |= TODO_update_address_taken;
3308 if (dump_file && (dump_flags & TDF_DETAILS))
3310 fprintf (dump_file, "Simplified\n ");
3311 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
3314 old_stmt = stmt;
3315 stmt = gsi_stmt (i);
3316 update_stmt (stmt);
3318 if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt)
3319 && gimple_purge_dead_eh_edges (bb))
3320 cfg_changed = true;
3322 if (dump_file && (dump_flags & TDF_DETAILS))
3324 fprintf (dump_file, "to\n ");
3325 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
3326 fprintf (dump_file, "\n");
3329 /* Retry the same statement if it changed into another
3330 builtin, there might be new opportunities now. */
3331 if (gimple_code (stmt) != GIMPLE_CALL)
3333 gsi_next (&i);
3334 continue;
3336 callee = gimple_call_fndecl (stmt);
3337 if (!callee
3338 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL
3339 || DECL_FUNCTION_CODE (callee) == fcode)
3340 gsi_next (&i);
3344 /* Delete unreachable blocks. */
3345 if (cfg_changed)
3346 todoflags |= TODO_cleanup_cfg;
3348 return todoflags;
3351 } // anon namespace
3353 gimple_opt_pass *
3354 make_pass_fold_builtins (gcc::context *ctxt)
3356 return new pass_fold_builtins (ctxt);
3359 /* A simple pass that emits some warnings post IPA. */
3361 namespace {
3363 const pass_data pass_data_post_ipa_warn =
3365 GIMPLE_PASS, /* type */
3366 "post_ipa_warn", /* name */
3367 OPTGROUP_NONE, /* optinfo_flags */
3368 TV_NONE, /* tv_id */
3369 ( PROP_cfg | PROP_ssa ), /* properties_required */
3370 0, /* properties_provided */
3371 0, /* properties_destroyed */
3372 0, /* todo_flags_start */
3373 0, /* todo_flags_finish */
3376 class pass_post_ipa_warn : public gimple_opt_pass
3378 public:
3379 pass_post_ipa_warn (gcc::context *ctxt)
3380 : gimple_opt_pass (pass_data_post_ipa_warn, ctxt)
3383 /* opt_pass methods: */
3384 opt_pass * clone () { return new pass_post_ipa_warn (m_ctxt); }
3385 virtual bool gate (function *) { return warn_nonnull != 0; }
3386 virtual unsigned int execute (function *);
3388 }; // class pass_fold_builtins
3390 unsigned int
3391 pass_post_ipa_warn::execute (function *fun)
3393 basic_block bb;
3395 FOR_EACH_BB_FN (bb, fun)
3397 gimple_stmt_iterator gsi;
3398 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
3400 gimple *stmt = gsi_stmt (gsi);
3401 if (!is_gimple_call (stmt) || gimple_no_warning_p (stmt))
3402 continue;
3404 if (warn_nonnull)
3406 bitmap nonnullargs
3407 = get_nonnull_args (gimple_call_fntype (stmt));
3408 if (nonnullargs)
3410 for (unsigned i = 0; i < gimple_call_num_args (stmt); i++)
3412 tree arg = gimple_call_arg (stmt, i);
3413 if (TREE_CODE (TREE_TYPE (arg)) != POINTER_TYPE)
3414 continue;
3415 if (!integer_zerop (arg))
3416 continue;
3417 if (!bitmap_empty_p (nonnullargs)
3418 && !bitmap_bit_p (nonnullargs, i))
3419 continue;
3421 location_t loc = gimple_location (stmt);
3422 if (warning_at (loc, OPT_Wnonnull,
3423 "argument %u null where non-null "
3424 "expected", i + 1))
3426 tree fndecl = gimple_call_fndecl (stmt);
3427 if (fndecl && DECL_IS_BUILTIN (fndecl))
3428 inform (loc, "in a call to built-in function %qD",
3429 fndecl);
3430 else if (fndecl)
3431 inform (DECL_SOURCE_LOCATION (fndecl),
3432 "in a call to function %qD declared here",
3433 fndecl);
3437 BITMAP_FREE (nonnullargs);
3442 return 0;
3445 } // anon namespace
3447 gimple_opt_pass *
3448 make_pass_post_ipa_warn (gcc::context *ctxt)
3450 return new pass_post_ipa_warn (ctxt);