1 /* Conditional constant propagation pass for the GNU compiler.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
3 Free Software Foundation, Inc.
4 Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org>
5 Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com>
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify it
10 under the terms of the GNU General Public License as published by the
11 Free Software Foundation; either version 3, or (at your option) any
14 GCC is distributed in the hope that it will be useful, but WITHOUT
15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
23 /* Conditional constant propagation (CCP) is based on the SSA
24 propagation engine (tree-ssa-propagate.c). Constant assignments of
25 the form VAR = CST are propagated from the assignments into uses of
26 VAR, which in turn may generate new constants. The simulation uses
27 a four level lattice to keep track of constant values associated
28 with SSA names. Given an SSA name V_i, it may take one of the
31 UNINITIALIZED -> the initial state of the value. This value
32 is replaced with a correct initial value
33 the first time the value is used, so the
34 rest of the pass does not need to care about
35 it. Using this value simplifies initialization
36 of the pass, and prevents us from needlessly
37 scanning statements that are never reached.
39 UNDEFINED -> V_i is a local variable whose definition
40 has not been processed yet. Therefore we
41 don't yet know if its value is a constant
44 CONSTANT -> V_i has been found to hold a constant
47 VARYING -> V_i cannot take a constant value, or if it
48 does, it is not possible to determine it
51 The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node:
53 1- In ccp_visit_stmt, we are interested in assignments whose RHS
54 evaluates into a constant and conditional jumps whose predicate
55 evaluates into a boolean true or false. When an assignment of
56 the form V_i = CONST is found, V_i's lattice value is set to
57 CONSTANT and CONST is associated with it. This causes the
58 propagation engine to add all the SSA edges coming out the
59 assignment into the worklists, so that statements that use V_i
62 If the statement is a conditional with a constant predicate, we
63 mark the outgoing edges as executable or not executable
64 depending on the predicate's value. This is then used when
65 visiting PHI nodes to know when a PHI argument can be ignored.
68 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the
69 same constant C, then the LHS of the PHI is set to C. This
70 evaluation is known as the "meet operation". Since one of the
71 goals of this evaluation is to optimistically return constant
72 values as often as possible, it uses two main short cuts:
74 - If an argument is flowing in through a non-executable edge, it
75 is ignored. This is useful in cases like this:
81 a_11 = PHI (a_9, a_10)
83 If PRED is known to always evaluate to false, then we can
84 assume that a_11 will always take its value from a_10, meaning
85 that instead of consider it VARYING (a_9 and a_10 have
86 different values), we can consider it CONSTANT 100.
88 - If an argument has an UNDEFINED value, then it does not affect
89 the outcome of the meet operation. If a variable V_i has an
90 UNDEFINED value, it means that either its defining statement
91 hasn't been visited yet or V_i has no defining statement, in
92 which case the original symbol 'V' is being used
93 uninitialized. Since 'V' is a local variable, the compiler
94 may assume any initial value for it.
97 After propagation, every variable V_i that ends up with a lattice
98 value of CONSTANT will have the associated constant value in the
99 array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for
100 final substitution and folding.
103 Constant propagation in stores and loads (STORE-CCP)
104 ----------------------------------------------------
106 While CCP has all the logic to propagate constants in GIMPLE
107 registers, it is missing the ability to associate constants with
108 stores and loads (i.e., pointer dereferences, structures and
109 global/aliased variables). We don't keep loads and stores in
110 SSA, but we do build a factored use-def web for them (in the
113 For instance, consider the following code fragment:
132 We should be able to deduce that the predicate 'a.a != B' is always
133 false. To achieve this, we associate constant values to the SSA
134 names in the VDEF operands for each store. Additionally,
135 since we also glob partial loads/stores with the base symbol, we
136 also keep track of the memory reference where the constant value
137 was stored (in the MEM_REF field of PROP_VALUE_T). For instance,
145 In the example above, CCP will associate value '2' with 'a_5', but
146 it would be wrong to replace the load from 'a.b' with '2', because
147 '2' had been stored into a.a.
149 Note that the initial value of virtual operands is VARYING, not
150 UNDEFINED. Consider, for instance global variables:
158 # A_5 = PHI (A_4, A_2);
166 The value of A_2 cannot be assumed to be UNDEFINED, as it may have
167 been defined outside of foo. If we were to assume it UNDEFINED, we
168 would erroneously optimize the above into 'return 3;'.
170 Though STORE-CCP is not too expensive, it does have to do more work
171 than regular CCP, so it is only enabled at -O2. Both regular CCP
172 and STORE-CCP use the exact same algorithm. The only distinction
173 is that when doing STORE-CCP, the boolean variable DO_STORE_CCP is
174 set to true. This affects the evaluation of statements and PHI
179 Constant propagation with conditional branches,
180 Wegman and Zadeck, ACM TOPLAS 13(2):181-210.
182 Building an Optimizing Compiler,
183 Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9.
185 Advanced Compiler Design and Implementation,
186 Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */
190 #include "coretypes.h"
197 #include "basic-block.h"
200 #include "function.h"
201 #include "diagnostic.h"
203 #include "tree-dump.h"
204 #include "tree-flow.h"
205 #include "tree-pass.h"
206 #include "tree-ssa-propagate.h"
207 #include "value-prof.h"
208 #include "langhooks.h"
214 /* Possible lattice values. */
223 /* Array of propagated constant values. After propagation,
224 CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If
225 the constant is held in an SSA name representing a memory store
226 (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual
227 memory reference used to store (i.e., the LHS of the assignment
229 static prop_value_t
*const_val
;
231 static void canonicalize_float_value (prop_value_t
*);
233 /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */
236 dump_lattice_value (FILE *outf
, const char *prefix
, prop_value_t val
)
238 switch (val
.lattice_val
)
241 fprintf (outf
, "%sUNINITIALIZED", prefix
);
244 fprintf (outf
, "%sUNDEFINED", prefix
);
247 fprintf (outf
, "%sVARYING", prefix
);
250 fprintf (outf
, "%sCONSTANT ", prefix
);
251 print_generic_expr (outf
, val
.value
, dump_flags
);
259 /* Print lattice value VAL to stderr. */
261 void debug_lattice_value (prop_value_t val
);
264 debug_lattice_value (prop_value_t val
)
266 dump_lattice_value (stderr
, "", val
);
267 fprintf (stderr
, "\n");
272 /* If SYM is a constant variable with known value, return the value.
273 NULL_TREE is returned otherwise. */
276 get_symbol_constant_value (tree sym
)
278 if (TREE_STATIC (sym
)
279 && TREE_READONLY (sym
))
281 tree val
= DECL_INITIAL (sym
);
284 STRIP_USELESS_TYPE_CONVERSION (val
);
285 if (is_gimple_min_invariant (val
))
287 if (TREE_CODE (val
) == ADDR_EXPR
)
289 tree base
= get_base_address (TREE_OPERAND (val
, 0));
290 if (base
&& TREE_CODE (base
) == VAR_DECL
)
291 add_referenced_var (base
);
296 /* Variables declared 'const' without an initializer
297 have zero as the initializer if they may not be
298 overridden at link or run time. */
300 && !DECL_EXTERNAL (sym
)
301 && targetm
.binds_local_p (sym
)
302 && (INTEGRAL_TYPE_P (TREE_TYPE (sym
))
303 || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym
))))
304 return fold_convert (TREE_TYPE (sym
), integer_zero_node
);
310 /* Compute a default value for variable VAR and store it in the
311 CONST_VAL array. The following rules are used to get default
314 1- Global and static variables that are declared constant are
317 2- Any other value is considered UNDEFINED. This is useful when
318 considering PHI nodes. PHI arguments that are undefined do not
319 change the constant value of the PHI node, which allows for more
320 constants to be propagated.
322 3- Variables defined by statements other than assignments and PHI
323 nodes are considered VARYING.
325 4- Initial values of variables that are not GIMPLE registers are
326 considered VARYING. */
329 get_default_value (tree var
)
331 tree sym
= SSA_NAME_VAR (var
);
332 prop_value_t val
= { UNINITIALIZED
, NULL_TREE
};
335 stmt
= SSA_NAME_DEF_STMT (var
);
337 if (gimple_nop_p (stmt
))
339 /* Variables defined by an empty statement are those used
340 before being initialized. If VAR is a local variable, we
341 can assume initially that it is UNDEFINED, otherwise we must
342 consider it VARYING. */
343 if (is_gimple_reg (sym
) && TREE_CODE (sym
) != PARM_DECL
)
344 val
.lattice_val
= UNDEFINED
;
346 val
.lattice_val
= VARYING
;
348 else if (is_gimple_assign (stmt
)
349 /* Value-returning GIMPLE_CALL statements assign to
350 a variable, and are treated similarly to GIMPLE_ASSIGN. */
351 || (is_gimple_call (stmt
)
352 && gimple_call_lhs (stmt
) != NULL_TREE
)
353 || gimple_code (stmt
) == GIMPLE_PHI
)
356 if (gimple_assign_single_p (stmt
)
357 && DECL_P (gimple_assign_rhs1 (stmt
))
358 && (cst
= get_symbol_constant_value (gimple_assign_rhs1 (stmt
))))
360 val
.lattice_val
= CONSTANT
;
364 /* Any other variable defined by an assignment or a PHI node
365 is considered UNDEFINED. */
366 val
.lattice_val
= UNDEFINED
;
370 /* Otherwise, VAR will never take on a constant value. */
371 val
.lattice_val
= VARYING
;
378 /* Get the constant value associated with variable VAR. */
380 static inline prop_value_t
*
385 if (const_val
== NULL
)
388 val
= &const_val
[SSA_NAME_VERSION (var
)];
389 if (val
->lattice_val
== UNINITIALIZED
)
390 *val
= get_default_value (var
);
392 canonicalize_float_value (val
);
397 /* Sets the value associated with VAR to VARYING. */
400 set_value_varying (tree var
)
402 prop_value_t
*val
= &const_val
[SSA_NAME_VERSION (var
)];
404 val
->lattice_val
= VARYING
;
405 val
->value
= NULL_TREE
;
408 /* For float types, modify the value of VAL to make ccp work correctly
409 for non-standard values (-0, NaN):
411 If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0.
412 If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED.
413 This is to fix the following problem (see PR 29921): Suppose we have
417 and we set value of y to NaN. This causes value of x to be set to NaN.
418 When we later determine that y is in fact VARYING, fold uses the fact
419 that HONOR_NANS is false, and we try to change the value of x to 0,
420 causing an ICE. With HONOR_NANS being false, the real appearance of
421 NaN would cause undefined behavior, though, so claiming that y (and x)
422 are UNDEFINED initially is correct. */
425 canonicalize_float_value (prop_value_t
*val
)
427 enum machine_mode mode
;
431 if (val
->lattice_val
!= CONSTANT
432 || TREE_CODE (val
->value
) != REAL_CST
)
435 d
= TREE_REAL_CST (val
->value
);
436 type
= TREE_TYPE (val
->value
);
437 mode
= TYPE_MODE (type
);
439 if (!HONOR_SIGNED_ZEROS (mode
)
440 && REAL_VALUE_MINUS_ZERO (d
))
442 val
->value
= build_real (type
, dconst0
);
446 if (!HONOR_NANS (mode
)
447 && REAL_VALUE_ISNAN (d
))
449 val
->lattice_val
= UNDEFINED
;
455 /* Set the value for variable VAR to NEW_VAL. Return true if the new
456 value is different from VAR's previous value. */
459 set_lattice_value (tree var
, prop_value_t new_val
)
461 prop_value_t
*old_val
= get_value (var
);
463 canonicalize_float_value (&new_val
);
465 /* Lattice transitions must always be monotonically increasing in
466 value. If *OLD_VAL and NEW_VAL are the same, return false to
467 inform the caller that this was a non-transition. */
469 gcc_assert (old_val
->lattice_val
< new_val
.lattice_val
470 || (old_val
->lattice_val
== new_val
.lattice_val
471 && ((!old_val
->value
&& !new_val
.value
)
472 || operand_equal_p (old_val
->value
, new_val
.value
, 0))));
474 if (old_val
->lattice_val
!= new_val
.lattice_val
)
476 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
478 dump_lattice_value (dump_file
, "Lattice value changed to ", new_val
);
479 fprintf (dump_file
, ". Adding SSA edges to worklist.\n");
484 gcc_assert (new_val
.lattice_val
!= UNDEFINED
);
492 /* Return the likely CCP lattice value for STMT.
494 If STMT has no operands, then return CONSTANT.
496 Else if undefinedness of operands of STMT cause its value to be
497 undefined, then return UNDEFINED.
499 Else if any operands of STMT are constants, then return CONSTANT.
501 Else return VARYING. */
504 likely_value (gimple stmt
)
506 bool has_constant_operand
, has_undefined_operand
, all_undefined_operands
;
511 enum gimple_code code
= gimple_code (stmt
);
513 /* This function appears to be called only for assignments, calls,
514 conditionals, and switches, due to the logic in visit_stmt. */
515 gcc_assert (code
== GIMPLE_ASSIGN
516 || code
== GIMPLE_CALL
517 || code
== GIMPLE_COND
518 || code
== GIMPLE_SWITCH
);
520 /* If the statement has volatile operands, it won't fold to a
522 if (gimple_has_volatile_ops (stmt
))
525 /* Arrive here for more complex cases. */
526 has_constant_operand
= false;
527 has_undefined_operand
= false;
528 all_undefined_operands
= true;
529 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, iter
, SSA_OP_USE
)
531 prop_value_t
*val
= get_value (use
);
533 if (val
->lattice_val
== UNDEFINED
)
534 has_undefined_operand
= true;
536 all_undefined_operands
= false;
538 if (val
->lattice_val
== CONSTANT
)
539 has_constant_operand
= true;
542 /* There may be constants in regular rhs operands. For calls we
543 have to ignore lhs, fndecl and static chain, otherwise only
545 for (i
= (is_gimple_call (stmt
) ? 2 : 0) + gimple_has_lhs (stmt
);
546 i
< gimple_num_ops (stmt
); ++i
)
548 tree op
= gimple_op (stmt
, i
);
549 if (!op
|| TREE_CODE (op
) == SSA_NAME
)
551 if (is_gimple_min_invariant (op
))
552 has_constant_operand
= true;
555 /* If the operation combines operands like COMPLEX_EXPR make sure to
556 not mark the result UNDEFINED if only one part of the result is
558 if (has_undefined_operand
&& all_undefined_operands
)
560 else if (code
== GIMPLE_ASSIGN
&& has_undefined_operand
)
562 switch (gimple_assign_rhs_code (stmt
))
564 /* Unary operators are handled with all_undefined_operands. */
567 case POINTER_PLUS_EXPR
:
568 /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected.
569 Not bitwise operators, one VARYING operand may specify the
570 result completely. Not logical operators for the same reason.
571 Not COMPLEX_EXPR as one VARYING operand makes the result partly
572 not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because
573 the undefined operand may be promoted. */
580 /* If there was an UNDEFINED operand but the result may be not UNDEFINED
581 fall back to VARYING even if there were CONSTANT operands. */
582 if (has_undefined_operand
)
585 /* We do not consider virtual operands here -- load from read-only
586 memory may have only VARYING virtual operands, but still be
588 if (has_constant_operand
589 || gimple_references_memory_p (stmt
))
595 /* Returns true if STMT cannot be constant. */
598 surely_varying_stmt_p (gimple stmt
)
600 /* If the statement has operands that we cannot handle, it cannot be
602 if (gimple_has_volatile_ops (stmt
))
605 /* If it is a call and does not return a value or is not a
606 builtin and not an indirect call, it is varying. */
607 if (is_gimple_call (stmt
))
610 if (!gimple_call_lhs (stmt
)
611 || ((fndecl
= gimple_call_fndecl (stmt
)) != NULL_TREE
612 && !DECL_BUILT_IN (fndecl
)))
616 /* Any other store operation is not interesting. */
617 else if (gimple_vdef (stmt
))
620 /* Anything other than assignments and conditional jumps are not
621 interesting for CCP. */
622 if (gimple_code (stmt
) != GIMPLE_ASSIGN
623 && gimple_code (stmt
) != GIMPLE_COND
624 && gimple_code (stmt
) != GIMPLE_SWITCH
625 && gimple_code (stmt
) != GIMPLE_CALL
)
631 /* Initialize local data structures for CCP. */
634 ccp_initialize (void)
638 const_val
= XCNEWVEC (prop_value_t
, num_ssa_names
);
640 /* Initialize simulation flags for PHI nodes and statements. */
643 gimple_stmt_iterator i
;
645 for (i
= gsi_start_bb (bb
); !gsi_end_p (i
); gsi_next (&i
))
647 gimple stmt
= gsi_stmt (i
);
648 bool is_varying
= surely_varying_stmt_p (stmt
);
655 /* If the statement will not produce a constant, mark
656 all its outputs VARYING. */
657 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_ALL_DEFS
)
658 set_value_varying (def
);
660 prop_set_simulate_again (stmt
, !is_varying
);
664 /* Now process PHI nodes. We never clear the simulate_again flag on
665 phi nodes, since we do not know which edges are executable yet,
666 except for phi nodes for virtual operands when we do not do store ccp. */
669 gimple_stmt_iterator i
;
671 for (i
= gsi_start_phis (bb
); !gsi_end_p (i
); gsi_next (&i
))
673 gimple phi
= gsi_stmt (i
);
675 if (!is_gimple_reg (gimple_phi_result (phi
)))
676 prop_set_simulate_again (phi
, false);
678 prop_set_simulate_again (phi
, true);
683 /* Debug count support. Reset the values of ssa names
684 VARYING when the total number ssa names analyzed is
685 beyond the debug count specified. */
691 for (i
= 0; i
< num_ssa_names
; i
++)
695 const_val
[i
].lattice_val
= VARYING
;
696 const_val
[i
].value
= NULL_TREE
;
702 /* Do final substitution of propagated values, cleanup the flowgraph and
703 free allocated storage.
705 Return TRUE when something was optimized. */
710 bool something_changed
;
713 /* Perform substitutions based on the known constant values. */
714 something_changed
= substitute_and_fold (const_val
, false);
718 return something_changed
;;
722 /* Compute the meet operator between *VAL1 and *VAL2. Store the result
725 any M UNDEFINED = any
726 any M VARYING = VARYING
727 Ci M Cj = Ci if (i == j)
728 Ci M Cj = VARYING if (i != j)
732 ccp_lattice_meet (prop_value_t
*val1
, prop_value_t
*val2
)
734 if (val1
->lattice_val
== UNDEFINED
)
736 /* UNDEFINED M any = any */
739 else if (val2
->lattice_val
== UNDEFINED
)
741 /* any M UNDEFINED = any
742 Nothing to do. VAL1 already contains the value we want. */
745 else if (val1
->lattice_val
== VARYING
746 || val2
->lattice_val
== VARYING
)
748 /* any M VARYING = VARYING. */
749 val1
->lattice_val
= VARYING
;
750 val1
->value
= NULL_TREE
;
752 else if (val1
->lattice_val
== CONSTANT
753 && val2
->lattice_val
== CONSTANT
754 && simple_cst_equal (val1
->value
, val2
->value
) == 1)
756 /* Ci M Cj = Ci if (i == j)
757 Ci M Cj = VARYING if (i != j)
759 If these two values come from memory stores, make sure that
760 they come from the same memory reference. */
761 val1
->lattice_val
= CONSTANT
;
762 val1
->value
= val1
->value
;
766 /* Any other combination is VARYING. */
767 val1
->lattice_val
= VARYING
;
768 val1
->value
= NULL_TREE
;
773 /* Loop through the PHI_NODE's parameters for BLOCK and compare their
774 lattice values to determine PHI_NODE's lattice value. The value of a
775 PHI node is determined calling ccp_lattice_meet with all the arguments
776 of the PHI node that are incoming via executable edges. */
778 static enum ssa_prop_result
779 ccp_visit_phi_node (gimple phi
)
782 prop_value_t
*old_val
, new_val
;
784 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
786 fprintf (dump_file
, "\nVisiting PHI node: ");
787 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
790 old_val
= get_value (gimple_phi_result (phi
));
791 switch (old_val
->lattice_val
)
794 return SSA_PROP_VARYING
;
801 new_val
.lattice_val
= UNDEFINED
;
802 new_val
.value
= NULL_TREE
;
809 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
811 /* Compute the meet operator over all the PHI arguments flowing
812 through executable edges. */
813 edge e
= gimple_phi_arg_edge (phi
, i
);
815 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
818 "\n Argument #%d (%d -> %d %sexecutable)\n",
819 i
, e
->src
->index
, e
->dest
->index
,
820 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
823 /* If the incoming edge is executable, Compute the meet operator for
824 the existing value of the PHI node and the current PHI argument. */
825 if (e
->flags
& EDGE_EXECUTABLE
)
827 tree arg
= gimple_phi_arg (phi
, i
)->def
;
828 prop_value_t arg_val
;
830 if (is_gimple_min_invariant (arg
))
832 arg_val
.lattice_val
= CONSTANT
;
836 arg_val
= *(get_value (arg
));
838 ccp_lattice_meet (&new_val
, &arg_val
);
840 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
842 fprintf (dump_file
, "\t");
843 print_generic_expr (dump_file
, arg
, dump_flags
);
844 dump_lattice_value (dump_file
, "\tValue: ", arg_val
);
845 fprintf (dump_file
, "\n");
848 if (new_val
.lattice_val
== VARYING
)
853 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
855 dump_lattice_value (dump_file
, "\n PHI node value: ", new_val
);
856 fprintf (dump_file
, "\n\n");
859 /* Make the transition to the new value. */
860 if (set_lattice_value (gimple_phi_result (phi
), new_val
))
862 if (new_val
.lattice_val
== VARYING
)
863 return SSA_PROP_VARYING
;
865 return SSA_PROP_INTERESTING
;
868 return SSA_PROP_NOT_INTERESTING
;
871 /* Return true if we may propagate the address expression ADDR into the
872 dereference DEREF and cancel them. */
875 may_propagate_address_into_dereference (tree addr
, tree deref
)
877 gcc_assert (INDIRECT_REF_P (deref
)
878 && TREE_CODE (addr
) == ADDR_EXPR
);
880 /* Don't propagate if ADDR's operand has incomplete type. */
881 if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_OPERAND (addr
, 0))))
884 /* If the address is invariant then we do not need to preserve restrict
885 qualifications. But we do need to preserve volatile qualifiers until
886 we can annotate the folded dereference itself properly. */
887 if (is_gimple_min_invariant (addr
)
888 && (!TREE_THIS_VOLATILE (deref
)
889 || TYPE_VOLATILE (TREE_TYPE (addr
))))
890 return useless_type_conversion_p (TREE_TYPE (deref
),
891 TREE_TYPE (TREE_OPERAND (addr
, 0)));
893 /* Else both the address substitution and the folding must result in
894 a valid useless type conversion sequence. */
895 return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref
, 0)),
897 && useless_type_conversion_p (TREE_TYPE (deref
),
898 TREE_TYPE (TREE_OPERAND (addr
, 0))));
901 /* CCP specific front-end to the non-destructive constant folding
904 Attempt to simplify the RHS of STMT knowing that one or more
905 operands are constants.
907 If simplification is possible, return the simplified RHS,
908 otherwise return the original RHS or NULL_TREE. */
911 ccp_fold (gimple stmt
)
913 switch (gimple_code (stmt
))
917 enum tree_code subcode
= gimple_assign_rhs_code (stmt
);
919 switch (get_gimple_rhs_class (subcode
))
921 case GIMPLE_SINGLE_RHS
:
923 tree rhs
= gimple_assign_rhs1 (stmt
);
924 enum tree_code_class kind
= TREE_CODE_CLASS (subcode
);
926 if (TREE_CODE (rhs
) == SSA_NAME
)
928 /* If the RHS is an SSA_NAME, return its known constant value,
930 return get_value (rhs
)->value
;
932 /* Handle propagating invariant addresses into address operations.
933 The folding we do here matches that in tree-ssa-forwprop.c. */
934 else if (TREE_CODE (rhs
) == ADDR_EXPR
)
937 base
= &TREE_OPERAND (rhs
, 0);
938 while (handled_component_p (*base
))
939 base
= &TREE_OPERAND (*base
, 0);
940 if (TREE_CODE (*base
) == INDIRECT_REF
941 && TREE_CODE (TREE_OPERAND (*base
, 0)) == SSA_NAME
)
943 prop_value_t
*val
= get_value (TREE_OPERAND (*base
, 0));
944 if (val
->lattice_val
== CONSTANT
945 && TREE_CODE (val
->value
) == ADDR_EXPR
946 && may_propagate_address_into_dereference
949 /* We need to return a new tree, not modify the IL
950 or share parts of it. So play some tricks to
951 avoid manually building it. */
952 tree ret
, save
= *base
;
953 *base
= TREE_OPERAND (val
->value
, 0);
954 ret
= unshare_expr (rhs
);
955 recompute_tree_invariant_for_addr_expr (ret
);
961 else if (TREE_CODE (rhs
) == CONSTRUCTOR
962 && TREE_CODE (TREE_TYPE (rhs
)) == VECTOR_TYPE
963 && (CONSTRUCTOR_NELTS (rhs
)
964 == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs
))))
970 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs
), i
, val
)
972 if (TREE_CODE (val
) == SSA_NAME
973 && get_value (val
)->lattice_val
== CONSTANT
)
974 val
= get_value (val
)->value
;
975 if (TREE_CODE (val
) == INTEGER_CST
976 || TREE_CODE (val
) == REAL_CST
977 || TREE_CODE (val
) == FIXED_CST
)
978 list
= tree_cons (NULL_TREE
, val
, list
);
983 return build_vector (TREE_TYPE (rhs
), nreverse (list
));
986 if (kind
== tcc_reference
)
988 if ((TREE_CODE (rhs
) == VIEW_CONVERT_EXPR
989 || TREE_CODE (rhs
) == REALPART_EXPR
990 || TREE_CODE (rhs
) == IMAGPART_EXPR
)
991 && TREE_CODE (TREE_OPERAND (rhs
, 0)) == SSA_NAME
)
993 prop_value_t
*val
= get_value (TREE_OPERAND (rhs
, 0));
994 if (val
->lattice_val
== CONSTANT
)
995 return fold_unary (TREE_CODE (rhs
),
996 TREE_TYPE (rhs
), val
->value
);
998 else if (TREE_CODE (rhs
) == INDIRECT_REF
999 && TREE_CODE (TREE_OPERAND (rhs
, 0)) == SSA_NAME
)
1001 prop_value_t
*val
= get_value (TREE_OPERAND (rhs
, 0));
1002 if (val
->lattice_val
== CONSTANT
1003 && TREE_CODE (val
->value
) == ADDR_EXPR
1004 && useless_type_conversion_p (TREE_TYPE (rhs
),
1005 TREE_TYPE (TREE_TYPE (val
->value
))))
1006 rhs
= TREE_OPERAND (val
->value
, 0);
1008 return fold_const_aggregate_ref (rhs
);
1010 else if (kind
== tcc_declaration
)
1011 return get_symbol_constant_value (rhs
);
1015 case GIMPLE_UNARY_RHS
:
1017 /* Handle unary operators that can appear in GIMPLE form.
1018 Note that we know the single operand must be a constant,
1019 so this should almost always return a simplified RHS. */
1020 tree lhs
= gimple_assign_lhs (stmt
);
1021 tree op0
= gimple_assign_rhs1 (stmt
);
1023 /* Simplify the operand down to a constant. */
1024 if (TREE_CODE (op0
) == SSA_NAME
)
1026 prop_value_t
*val
= get_value (op0
);
1027 if (val
->lattice_val
== CONSTANT
)
1028 op0
= get_value (op0
)->value
;
1031 /* Conversions are useless for CCP purposes if they are
1032 value-preserving. Thus the restrictions that
1033 useless_type_conversion_p places for pointer type conversions
1034 do not apply here. Substitution later will only substitute to
1036 if (CONVERT_EXPR_CODE_P (subcode
)
1037 && POINTER_TYPE_P (TREE_TYPE (lhs
))
1038 && POINTER_TYPE_P (TREE_TYPE (op0
))
1039 /* Do not allow differences in volatile qualification
1040 as this might get us confused as to whether a
1041 propagation destination statement is volatile
1042 or not. See PR36988. */
1043 && (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (lhs
)))
1044 == TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (op0
)))))
1047 /* Still try to generate a constant of correct type. */
1048 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
1050 && ((tem
= maybe_fold_offset_to_address
1051 (gimple_location (stmt
),
1052 op0
, integer_zero_node
, TREE_TYPE (lhs
)))
1058 return fold_unary_ignore_overflow (subcode
,
1059 gimple_expr_type (stmt
), op0
);
1062 case GIMPLE_BINARY_RHS
:
1064 /* Handle binary operators that can appear in GIMPLE form. */
1065 tree op0
= gimple_assign_rhs1 (stmt
);
1066 tree op1
= gimple_assign_rhs2 (stmt
);
1068 /* Simplify the operands down to constants when appropriate. */
1069 if (TREE_CODE (op0
) == SSA_NAME
)
1071 prop_value_t
*val
= get_value (op0
);
1072 if (val
->lattice_val
== CONSTANT
)
1076 if (TREE_CODE (op1
) == SSA_NAME
)
1078 prop_value_t
*val
= get_value (op1
);
1079 if (val
->lattice_val
== CONSTANT
)
1083 /* Fold &foo + CST into an invariant reference if possible. */
1084 if (gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
1085 && TREE_CODE (op0
) == ADDR_EXPR
1086 && TREE_CODE (op1
) == INTEGER_CST
)
1088 tree lhs
= gimple_assign_lhs (stmt
);
1089 tree tem
= maybe_fold_offset_to_address
1090 (gimple_location (stmt
), op0
, op1
, TREE_TYPE (lhs
));
1091 if (tem
!= NULL_TREE
)
1095 return fold_binary (subcode
, gimple_expr_type (stmt
), op0
, op1
);
1106 tree fn
= gimple_call_fn (stmt
);
1109 if (TREE_CODE (fn
) == SSA_NAME
)
1111 val
= get_value (fn
);
1112 if (val
->lattice_val
== CONSTANT
)
1115 if (TREE_CODE (fn
) == ADDR_EXPR
1116 && TREE_CODE (TREE_OPERAND (fn
, 0)) == FUNCTION_DECL
1117 && DECL_BUILT_IN (TREE_OPERAND (fn
, 0)))
1119 tree
*args
= XALLOCAVEC (tree
, gimple_call_num_args (stmt
));
1122 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
1124 args
[i
] = gimple_call_arg (stmt
, i
);
1125 if (TREE_CODE (args
[i
]) == SSA_NAME
)
1127 val
= get_value (args
[i
]);
1128 if (val
->lattice_val
== CONSTANT
)
1129 args
[i
] = val
->value
;
1132 call
= build_call_array (gimple_call_return_type (stmt
),
1133 fn
, gimple_call_num_args (stmt
), args
);
1134 retval
= fold_call_expr (call
, false);
1136 /* fold_call_expr wraps the result inside a NOP_EXPR. */
1137 STRIP_NOPS (retval
);
1145 /* Handle comparison operators that can appear in GIMPLE form. */
1146 tree op0
= gimple_cond_lhs (stmt
);
1147 tree op1
= gimple_cond_rhs (stmt
);
1148 enum tree_code code
= gimple_cond_code (stmt
);
1150 /* Simplify the operands down to constants when appropriate. */
1151 if (TREE_CODE (op0
) == SSA_NAME
)
1153 prop_value_t
*val
= get_value (op0
);
1154 if (val
->lattice_val
== CONSTANT
)
1158 if (TREE_CODE (op1
) == SSA_NAME
)
1160 prop_value_t
*val
= get_value (op1
);
1161 if (val
->lattice_val
== CONSTANT
)
1165 return fold_binary (code
, boolean_type_node
, op0
, op1
);
1170 tree rhs
= gimple_switch_index (stmt
);
1172 if (TREE_CODE (rhs
) == SSA_NAME
)
1174 /* If the RHS is an SSA_NAME, return its known constant value,
1176 return get_value (rhs
)->value
;
1188 /* Return the tree representing the element referenced by T if T is an
1189 ARRAY_REF or COMPONENT_REF into constant aggregates. Return
1190 NULL_TREE otherwise. */
1193 fold_const_aggregate_ref (tree t
)
1195 prop_value_t
*value
;
1196 tree base
, ctor
, idx
, field
;
1197 unsigned HOST_WIDE_INT cnt
;
1200 if (TREE_CODE_CLASS (TREE_CODE (t
)) == tcc_declaration
)
1201 return get_symbol_constant_value (t
);
1203 switch (TREE_CODE (t
))
1206 /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its
1207 DECL_INITIAL. If BASE is a nested reference into another
1208 ARRAY_REF or COMPONENT_REF, make a recursive call to resolve
1209 the inner reference. */
1210 base
= TREE_OPERAND (t
, 0);
1211 switch (TREE_CODE (base
))
1214 if (!TREE_READONLY (base
)
1215 || TREE_CODE (TREE_TYPE (base
)) != ARRAY_TYPE
1216 || !targetm
.binds_local_p (base
))
1219 ctor
= DECL_INITIAL (base
);
1224 ctor
= fold_const_aggregate_ref (base
);
1236 if (ctor
== NULL_TREE
1237 || (TREE_CODE (ctor
) != CONSTRUCTOR
1238 && TREE_CODE (ctor
) != STRING_CST
)
1239 || !TREE_STATIC (ctor
))
1242 /* Get the index. If we have an SSA_NAME, try to resolve it
1243 with the current lattice value for the SSA_NAME. */
1244 idx
= TREE_OPERAND (t
, 1);
1245 switch (TREE_CODE (idx
))
1248 if ((value
= get_value (idx
))
1249 && value
->lattice_val
== CONSTANT
1250 && TREE_CODE (value
->value
) == INTEGER_CST
)
1263 /* Fold read from constant string. */
1264 if (TREE_CODE (ctor
) == STRING_CST
)
1266 if ((TYPE_MODE (TREE_TYPE (t
))
1267 == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor
))))
1268 && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor
))))
1270 && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor
)))) == 1
1271 && compare_tree_int (idx
, TREE_STRING_LENGTH (ctor
)) < 0)
1272 return build_int_cst_type (TREE_TYPE (t
),
1273 (TREE_STRING_POINTER (ctor
)
1274 [TREE_INT_CST_LOW (idx
)]));
1278 /* Whoo-hoo! I'll fold ya baby. Yeah! */
1279 FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor
), cnt
, cfield
, cval
)
1280 if (tree_int_cst_equal (cfield
, idx
))
1282 STRIP_USELESS_TYPE_CONVERSION (cval
);
1283 if (TREE_CODE (cval
) == ADDR_EXPR
)
1285 tree base
= get_base_address (TREE_OPERAND (cval
, 0));
1286 if (base
&& TREE_CODE (base
) == VAR_DECL
)
1287 add_referenced_var (base
);
1294 /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its
1295 DECL_INITIAL. If BASE is a nested reference into another
1296 ARRAY_REF or COMPONENT_REF, make a recursive call to resolve
1297 the inner reference. */
1298 base
= TREE_OPERAND (t
, 0);
1299 switch (TREE_CODE (base
))
1302 if (!TREE_READONLY (base
)
1303 || TREE_CODE (TREE_TYPE (base
)) != RECORD_TYPE
1304 || !targetm
.binds_local_p (base
))
1307 ctor
= DECL_INITIAL (base
);
1312 ctor
= fold_const_aggregate_ref (base
);
1319 if (ctor
== NULL_TREE
1320 || TREE_CODE (ctor
) != CONSTRUCTOR
1321 || !TREE_STATIC (ctor
))
1324 field
= TREE_OPERAND (t
, 1);
1326 FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor
), cnt
, cfield
, cval
)
1328 /* FIXME: Handle bit-fields. */
1329 && ! DECL_BIT_FIELD (cfield
))
1331 STRIP_USELESS_TYPE_CONVERSION (cval
);
1332 if (TREE_CODE (cval
) == ADDR_EXPR
)
1334 tree base
= get_base_address (TREE_OPERAND (cval
, 0));
1335 if (base
&& TREE_CODE (base
) == VAR_DECL
)
1336 add_referenced_var (base
);
1345 tree c
= fold_const_aggregate_ref (TREE_OPERAND (t
, 0));
1346 if (c
&& TREE_CODE (c
) == COMPLEX_CST
)
1347 return fold_build1 (TREE_CODE (t
), TREE_TYPE (t
), c
);
1353 tree base
= TREE_OPERAND (t
, 0);
1354 if (TREE_CODE (base
) == SSA_NAME
1355 && (value
= get_value (base
))
1356 && value
->lattice_val
== CONSTANT
1357 && TREE_CODE (value
->value
) == ADDR_EXPR
1358 && useless_type_conversion_p (TREE_TYPE (t
),
1359 TREE_TYPE (TREE_TYPE (value
->value
))))
1360 return fold_const_aggregate_ref (TREE_OPERAND (value
->value
, 0));
1371 /* Evaluate statement STMT.
1372 Valid only for assignments, calls, conditionals, and switches. */
1375 evaluate_stmt (gimple stmt
)
1378 tree simplified
= NULL_TREE
;
1379 ccp_lattice_t likelyvalue
= likely_value (stmt
);
1382 fold_defer_overflow_warnings ();
1384 /* If the statement is likely to have a CONSTANT result, then try
1385 to fold the statement to determine the constant value. */
1386 /* FIXME. This is the only place that we call ccp_fold.
1387 Since likely_value never returns CONSTANT for calls, we will
1388 not attempt to fold them, including builtins that may profit. */
1389 if (likelyvalue
== CONSTANT
)
1390 simplified
= ccp_fold (stmt
);
1391 /* If the statement is likely to have a VARYING result, then do not
1392 bother folding the statement. */
1393 else if (likelyvalue
== VARYING
)
1395 enum gimple_code code
= gimple_code (stmt
);
1396 if (code
== GIMPLE_ASSIGN
)
1398 enum tree_code subcode
= gimple_assign_rhs_code (stmt
);
1400 /* Other cases cannot satisfy is_gimple_min_invariant
1402 if (get_gimple_rhs_class (subcode
) == GIMPLE_SINGLE_RHS
)
1403 simplified
= gimple_assign_rhs1 (stmt
);
1405 else if (code
== GIMPLE_SWITCH
)
1406 simplified
= gimple_switch_index (stmt
);
1408 /* These cannot satisfy is_gimple_min_invariant without folding. */
1409 gcc_assert (code
== GIMPLE_CALL
|| code
== GIMPLE_COND
);
1412 is_constant
= simplified
&& is_gimple_min_invariant (simplified
);
1414 fold_undefer_overflow_warnings (is_constant
, stmt
, 0);
1416 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1418 fprintf (dump_file
, "which is likely ");
1419 switch (likelyvalue
)
1422 fprintf (dump_file
, "CONSTANT");
1425 fprintf (dump_file
, "UNDEFINED");
1428 fprintf (dump_file
, "VARYING");
1432 fprintf (dump_file
, "\n");
1437 /* The statement produced a constant value. */
1438 val
.lattice_val
= CONSTANT
;
1439 val
.value
= simplified
;
1443 /* The statement produced a nonconstant value. If the statement
1444 had UNDEFINED operands, then the result of the statement
1445 should be UNDEFINED. Otherwise, the statement is VARYING. */
1446 if (likelyvalue
== UNDEFINED
)
1447 val
.lattice_val
= likelyvalue
;
1449 val
.lattice_val
= VARYING
;
1451 val
.value
= NULL_TREE
;
1457 /* Visit the assignment statement STMT. Set the value of its LHS to the
1458 value computed by the RHS and store LHS in *OUTPUT_P. If STMT
1459 creates virtual definitions, set the value of each new name to that
1460 of the RHS (if we can derive a constant out of the RHS).
1461 Value-returning call statements also perform an assignment, and
1462 are handled here. */
1464 static enum ssa_prop_result
1465 visit_assignment (gimple stmt
, tree
*output_p
)
1468 enum ssa_prop_result retval
;
1470 tree lhs
= gimple_get_lhs (stmt
);
1472 gcc_assert (gimple_code (stmt
) != GIMPLE_CALL
1473 || gimple_call_lhs (stmt
) != NULL_TREE
);
1475 if (gimple_assign_copy_p (stmt
))
1477 tree rhs
= gimple_assign_rhs1 (stmt
);
1479 if (TREE_CODE (rhs
) == SSA_NAME
)
1481 /* For a simple copy operation, we copy the lattice values. */
1482 prop_value_t
*nval
= get_value (rhs
);
1486 val
= evaluate_stmt (stmt
);
1489 /* Evaluate the statement, which could be
1490 either a GIMPLE_ASSIGN or a GIMPLE_CALL. */
1491 val
= evaluate_stmt (stmt
);
1493 retval
= SSA_PROP_NOT_INTERESTING
;
1495 /* Set the lattice value of the statement's output. */
1496 if (TREE_CODE (lhs
) == SSA_NAME
)
1498 /* If STMT is an assignment to an SSA_NAME, we only have one
1500 if (set_lattice_value (lhs
, val
))
1503 if (val
.lattice_val
== VARYING
)
1504 retval
= SSA_PROP_VARYING
;
1506 retval
= SSA_PROP_INTERESTING
;
1514 /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING
1515 if it can determine which edge will be taken. Otherwise, return
1516 SSA_PROP_VARYING. */
1518 static enum ssa_prop_result
1519 visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
1524 block
= gimple_bb (stmt
);
1525 val
= evaluate_stmt (stmt
);
1527 /* Find which edge out of the conditional block will be taken and add it
1528 to the worklist. If no single edge can be determined statically,
1529 return SSA_PROP_VARYING to feed all the outgoing edges to the
1530 propagation engine. */
1531 *taken_edge_p
= val
.value
? find_taken_edge (block
, val
.value
) : 0;
1533 return SSA_PROP_INTERESTING
;
1535 return SSA_PROP_VARYING
;
1539 /* Evaluate statement STMT. If the statement produces an output value and
1540 its evaluation changes the lattice value of its output, return
1541 SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the
1544 If STMT is a conditional branch and we can determine its truth
1545 value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying
1546 value, return SSA_PROP_VARYING. */
1548 static enum ssa_prop_result
1549 ccp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
1554 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1556 fprintf (dump_file
, "\nVisiting statement:\n");
1557 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
1560 switch (gimple_code (stmt
))
1563 /* If the statement is an assignment that produces a single
1564 output value, evaluate its RHS to see if the lattice value of
1565 its output has changed. */
1566 return visit_assignment (stmt
, output_p
);
1569 /* A value-returning call also performs an assignment. */
1570 if (gimple_call_lhs (stmt
) != NULL_TREE
)
1571 return visit_assignment (stmt
, output_p
);
1576 /* If STMT is a conditional branch, see if we can determine
1577 which branch will be taken. */
1578 /* FIXME. It appears that we should be able to optimize
1579 computed GOTOs here as well. */
1580 return visit_cond_stmt (stmt
, taken_edge_p
);
1586 /* Any other kind of statement is not interesting for constant
1587 propagation and, therefore, not worth simulating. */
1588 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1589 fprintf (dump_file
, "No interesting values produced. Marked VARYING.\n");
1591 /* Definitions made by statements other than assignments to
1592 SSA_NAMEs represent unknown modifications to their outputs.
1593 Mark them VARYING. */
1594 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_ALL_DEFS
)
1596 prop_value_t v
= { VARYING
, NULL_TREE
};
1597 set_lattice_value (def
, v
);
1600 return SSA_PROP_VARYING
;
1604 /* Main entry point for SSA Conditional Constant Propagation. */
1610 ssa_propagate (ccp_visit_stmt
, ccp_visit_phi_node
);
1611 if (ccp_finalize ())
1612 return (TODO_cleanup_cfg
| TODO_update_ssa
| TODO_remove_unused_locals
);
1621 return flag_tree_ccp
!= 0;
1625 struct gimple_opt_pass pass_ccp
=
1630 gate_ccp
, /* gate */
1631 do_ssa_ccp
, /* execute */
1634 0, /* static_pass_number */
1635 TV_TREE_CCP
, /* tv_id */
1636 PROP_cfg
| PROP_ssa
, /* properties_required */
1637 0, /* properties_provided */
1638 0, /* properties_destroyed */
1639 0, /* todo_flags_start */
1640 TODO_dump_func
| TODO_verify_ssa
1641 | TODO_verify_stmts
| TODO_ggc_collect
/* todo_flags_finish */
1646 /* A subroutine of fold_stmt. Attempts to fold *(A+O) to A[X].
1647 BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE
1648 is the desired result type.
1650 LOC is the location of the original expression. */
1653 maybe_fold_offset_to_array_ref (location_t loc
, tree base
, tree offset
,
1655 bool allow_negative_idx
)
1657 tree min_idx
, idx
, idx_type
, elt_offset
= integer_zero_node
;
1658 tree array_type
, elt_type
, elt_size
;
1661 /* If BASE is an ARRAY_REF, we can pick up another offset (this time
1662 measured in units of the size of elements type) from that ARRAY_REF).
1663 We can't do anything if either is variable.
1665 The case we handle here is *(&A[N]+O). */
1666 if (TREE_CODE (base
) == ARRAY_REF
)
1668 tree low_bound
= array_ref_low_bound (base
);
1670 elt_offset
= TREE_OPERAND (base
, 1);
1671 if (TREE_CODE (low_bound
) != INTEGER_CST
1672 || TREE_CODE (elt_offset
) != INTEGER_CST
)
1675 elt_offset
= int_const_binop (MINUS_EXPR
, elt_offset
, low_bound
, 0);
1676 base
= TREE_OPERAND (base
, 0);
1679 /* Ignore stupid user tricks of indexing non-array variables. */
1680 array_type
= TREE_TYPE (base
);
1681 if (TREE_CODE (array_type
) != ARRAY_TYPE
)
1683 elt_type
= TREE_TYPE (array_type
);
1684 if (!useless_type_conversion_p (orig_type
, elt_type
))
1687 /* Use signed size type for intermediate computation on the index. */
1688 idx_type
= signed_type_for (size_type_node
);
1690 /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the
1691 element type (so we can use the alignment if it's not constant).
1692 Otherwise, compute the offset as an index by using a division. If the
1693 division isn't exact, then don't do anything. */
1694 elt_size
= TYPE_SIZE_UNIT (elt_type
);
1697 if (integer_zerop (offset
))
1699 if (TREE_CODE (elt_size
) != INTEGER_CST
)
1700 elt_size
= size_int (TYPE_ALIGN (elt_type
));
1702 idx
= build_int_cst (idx_type
, 0);
1706 unsigned HOST_WIDE_INT lquo
, lrem
;
1707 HOST_WIDE_INT hquo
, hrem
;
1710 /* The final array offset should be signed, so we need
1711 to sign-extend the (possibly pointer) offset here
1712 and use signed division. */
1713 soffset
= double_int_sext (tree_to_double_int (offset
),
1714 TYPE_PRECISION (TREE_TYPE (offset
)));
1715 if (TREE_CODE (elt_size
) != INTEGER_CST
1716 || div_and_round_double (TRUNC_DIV_EXPR
, 0,
1717 soffset
.low
, soffset
.high
,
1718 TREE_INT_CST_LOW (elt_size
),
1719 TREE_INT_CST_HIGH (elt_size
),
1720 &lquo
, &hquo
, &lrem
, &hrem
)
1724 idx
= build_int_cst_wide (idx_type
, lquo
, hquo
);
1727 /* Assume the low bound is zero. If there is a domain type, get the
1728 low bound, if any, convert the index into that type, and add the
1730 min_idx
= build_int_cst (idx_type
, 0);
1731 domain_type
= TYPE_DOMAIN (array_type
);
1734 idx_type
= domain_type
;
1735 if (TYPE_MIN_VALUE (idx_type
))
1736 min_idx
= TYPE_MIN_VALUE (idx_type
);
1738 min_idx
= fold_convert (idx_type
, min_idx
);
1740 if (TREE_CODE (min_idx
) != INTEGER_CST
)
1743 elt_offset
= fold_convert (idx_type
, elt_offset
);
1746 if (!integer_zerop (min_idx
))
1747 idx
= int_const_binop (PLUS_EXPR
, idx
, min_idx
, 0);
1748 if (!integer_zerop (elt_offset
))
1749 idx
= int_const_binop (PLUS_EXPR
, idx
, elt_offset
, 0);
1751 /* Make sure to possibly truncate late after offsetting. */
1752 idx
= fold_convert (idx_type
, idx
);
1754 /* We don't want to construct access past array bounds. For example
1757 should not be simplified into (*c)[14] or tree-vrp will
1758 give false warnings. The same is true for
1759 struct A { long x; char d[0]; } *a;
1761 which should be not folded to &a->d[-8]. */
1763 && TYPE_MAX_VALUE (domain_type
)
1764 && TREE_CODE (TYPE_MAX_VALUE (domain_type
)) == INTEGER_CST
)
1766 tree up_bound
= TYPE_MAX_VALUE (domain_type
);
1768 if (tree_int_cst_lt (up_bound
, idx
)
1769 /* Accesses after the end of arrays of size 0 (gcc
1770 extension) and 1 are likely intentional ("struct
1772 && compare_tree_int (up_bound
, 1) > 0)
1776 && TYPE_MIN_VALUE (domain_type
))
1778 if (!allow_negative_idx
1779 && TREE_CODE (TYPE_MIN_VALUE (domain_type
)) == INTEGER_CST
1780 && tree_int_cst_lt (idx
, TYPE_MIN_VALUE (domain_type
)))
1783 else if (!allow_negative_idx
1784 && compare_tree_int (idx
, 0) < 0)
1788 tree t
= build4 (ARRAY_REF
, elt_type
, base
, idx
, NULL_TREE
, NULL_TREE
);
1789 SET_EXPR_LOCATION (t
, loc
);
1795 /* Attempt to fold *(S+O) to S.X.
1796 BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE
1797 is the desired result type.
1799 LOC is the location of the original expression. */
1802 maybe_fold_offset_to_component_ref (location_t loc
, tree record_type
,
1803 tree base
, tree offset
,
1804 tree orig_type
, bool base_is_ptr
)
1806 tree f
, t
, field_type
, tail_array_field
, field_offset
;
1810 if (TREE_CODE (record_type
) != RECORD_TYPE
1811 && TREE_CODE (record_type
) != UNION_TYPE
1812 && TREE_CODE (record_type
) != QUAL_UNION_TYPE
)
1815 /* Short-circuit silly cases. */
1816 if (useless_type_conversion_p (record_type
, orig_type
))
1819 tail_array_field
= NULL_TREE
;
1820 for (f
= TYPE_FIELDS (record_type
); f
; f
= TREE_CHAIN (f
))
1824 if (TREE_CODE (f
) != FIELD_DECL
)
1826 if (DECL_BIT_FIELD (f
))
1829 if (!DECL_FIELD_OFFSET (f
))
1831 field_offset
= byte_position (f
);
1832 if (TREE_CODE (field_offset
) != INTEGER_CST
)
1835 /* ??? Java creates "interesting" fields for representing base classes.
1836 They have no name, and have no context. With no context, we get into
1837 trouble with nonoverlapping_component_refs_p. Skip them. */
1838 if (!DECL_FIELD_CONTEXT (f
))
1841 /* The previous array field isn't at the end. */
1842 tail_array_field
= NULL_TREE
;
1844 /* Check to see if this offset overlaps with the field. */
1845 cmp
= tree_int_cst_compare (field_offset
, offset
);
1849 field_type
= TREE_TYPE (f
);
1851 /* Here we exactly match the offset being checked. If the types match,
1852 then we can return that field. */
1854 && useless_type_conversion_p (orig_type
, field_type
))
1857 base
= build1 (INDIRECT_REF
, record_type
, base
);
1858 t
= build3 (COMPONENT_REF
, field_type
, base
, f
, NULL_TREE
);
1862 /* Don't care about offsets into the middle of scalars. */
1863 if (!AGGREGATE_TYPE_P (field_type
))
1866 /* Check for array at the end of the struct. This is often
1867 used as for flexible array members. We should be able to
1868 turn this into an array access anyway. */
1869 if (TREE_CODE (field_type
) == ARRAY_TYPE
)
1870 tail_array_field
= f
;
1872 /* Check the end of the field against the offset. */
1873 if (!DECL_SIZE_UNIT (f
)
1874 || TREE_CODE (DECL_SIZE_UNIT (f
)) != INTEGER_CST
)
1876 t
= int_const_binop (MINUS_EXPR
, offset
, field_offset
, 1);
1877 if (!tree_int_cst_lt (t
, DECL_SIZE_UNIT (f
)))
1880 /* If we matched, then set offset to the displacement into
1883 new_base
= build1 (INDIRECT_REF
, record_type
, base
);
1886 protected_set_expr_location (new_base
, loc
);
1887 new_base
= build3 (COMPONENT_REF
, field_type
, new_base
, f
, NULL_TREE
);
1888 protected_set_expr_location (new_base
, loc
);
1890 /* Recurse to possibly find the match. */
1891 ret
= maybe_fold_offset_to_array_ref (loc
, new_base
, t
, orig_type
,
1892 f
== TYPE_FIELDS (record_type
));
1895 ret
= maybe_fold_offset_to_component_ref (loc
, field_type
, new_base
, t
,
1901 if (!tail_array_field
)
1904 f
= tail_array_field
;
1905 field_type
= TREE_TYPE (f
);
1906 offset
= int_const_binop (MINUS_EXPR
, offset
, byte_position (f
), 1);
1908 /* If we get here, we've got an aggregate field, and a possibly
1909 nonzero offset into them. Recurse and hope for a valid match. */
1912 base
= build1 (INDIRECT_REF
, record_type
, base
);
1913 SET_EXPR_LOCATION (base
, loc
);
1915 base
= build3 (COMPONENT_REF
, field_type
, base
, f
, NULL_TREE
);
1916 SET_EXPR_LOCATION (base
, loc
);
1918 t
= maybe_fold_offset_to_array_ref (loc
, base
, offset
, orig_type
,
1919 f
== TYPE_FIELDS (record_type
));
1922 return maybe_fold_offset_to_component_ref (loc
, field_type
, base
, offset
,
1926 /* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type
1927 or BASE[index] or by combination of those.
1929 LOC is the location of original expression.
1931 Before attempting the conversion strip off existing ADDR_EXPRs and
1932 handled component refs. */
1935 maybe_fold_offset_to_reference (location_t loc
, tree base
, tree offset
,
1940 bool base_is_ptr
= true;
1943 if (TREE_CODE (base
) == ADDR_EXPR
)
1945 base_is_ptr
= false;
1947 base
= TREE_OPERAND (base
, 0);
1949 /* Handle case where existing COMPONENT_REF pick e.g. wrong field of union,
1950 so it needs to be removed and new COMPONENT_REF constructed.
1951 The wrong COMPONENT_REF are often constructed by folding the
1952 (type *)&object within the expression (type *)&object+offset */
1953 if (handled_component_p (base
))
1955 HOST_WIDE_INT sub_offset
, size
, maxsize
;
1957 newbase
= get_ref_base_and_extent (base
, &sub_offset
,
1959 gcc_assert (newbase
);
1962 && !(sub_offset
& (BITS_PER_UNIT
- 1)))
1966 offset
= int_const_binop (PLUS_EXPR
, offset
,
1967 build_int_cst (TREE_TYPE (offset
),
1968 sub_offset
/ BITS_PER_UNIT
), 1);
1971 if (useless_type_conversion_p (orig_type
, TREE_TYPE (base
))
1972 && integer_zerop (offset
))
1974 type
= TREE_TYPE (base
);
1979 if (!POINTER_TYPE_P (TREE_TYPE (base
)))
1981 type
= TREE_TYPE (TREE_TYPE (base
));
1983 ret
= maybe_fold_offset_to_component_ref (loc
, type
, base
, offset
,
1984 orig_type
, base_is_ptr
);
1989 base
= build1 (INDIRECT_REF
, type
, base
);
1990 SET_EXPR_LOCATION (base
, loc
);
1992 ret
= maybe_fold_offset_to_array_ref (loc
,
1993 base
, offset
, orig_type
, true);
1998 /* Attempt to express (ORIG_TYPE)&BASE+OFFSET as &BASE->field_of_orig_type
1999 or &BASE[index] or by combination of those.
2001 LOC is the location of the original expression.
2003 Before attempting the conversion strip off existing component refs. */
2006 maybe_fold_offset_to_address (location_t loc
, tree addr
, tree offset
,
2011 gcc_assert (POINTER_TYPE_P (TREE_TYPE (addr
))
2012 && POINTER_TYPE_P (orig_type
));
2014 t
= maybe_fold_offset_to_reference (loc
, addr
, offset
,
2015 TREE_TYPE (orig_type
));
2021 /* For __builtin_object_size to function correctly we need to
2022 make sure not to fold address arithmetic so that we change
2023 reference from one array to another. This would happen for
2026 struct X { char s1[10]; char s2[10] } s;
2027 char *foo (void) { return &s.s2[-4]; }
2029 where we need to avoid generating &s.s1[6]. As the C and
2030 C++ frontends create different initial trees
2031 (char *) &s.s1 + -4 vs. &s.s1[-4] we have to do some
2032 sophisticated comparisons here. Note that checking for the
2033 condition after the fact is easier than trying to avoid doing
2036 if (TREE_CODE (orig
) == ADDR_EXPR
)
2037 orig
= TREE_OPERAND (orig
, 0);
2038 if ((TREE_CODE (orig
) == ARRAY_REF
2039 || (TREE_CODE (orig
) == COMPONENT_REF
2040 && TREE_CODE (TREE_TYPE (TREE_OPERAND (orig
, 1))) == ARRAY_TYPE
))
2041 && (TREE_CODE (t
) == ARRAY_REF
2042 || TREE_CODE (t
) == COMPONENT_REF
)
2043 && !operand_equal_p (TREE_CODE (orig
) == ARRAY_REF
2044 ? TREE_OPERAND (orig
, 0) : orig
,
2045 TREE_CODE (t
) == ARRAY_REF
2046 ? TREE_OPERAND (t
, 0) : t
, 0))
2049 ptr_type
= build_pointer_type (TREE_TYPE (t
));
2050 if (!useless_type_conversion_p (orig_type
, ptr_type
))
2052 t
= build_fold_addr_expr_with_type (t
, ptr_type
);
2053 protected_set_expr_location (t
, loc
);
2060 /* A subroutine of fold_stmt. Attempt to simplify *(BASE+OFFSET).
2061 Return the simplified expression, or NULL if nothing could be done. */
2064 maybe_fold_stmt_indirect (tree expr
, tree base
, tree offset
)
2067 bool volatile_p
= TREE_THIS_VOLATILE (expr
);
2068 location_t loc
= EXPR_LOCATION (expr
);
2070 /* We may well have constructed a double-nested PLUS_EXPR via multiple
2071 substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that
2072 are sometimes added. */
2074 STRIP_TYPE_NOPS (base
);
2075 TREE_OPERAND (expr
, 0) = base
;
2077 /* One possibility is that the address reduces to a string constant. */
2078 t
= fold_read_from_constant_string (expr
);
2082 /* Add in any offset from a POINTER_PLUS_EXPR. */
2083 if (TREE_CODE (base
) == POINTER_PLUS_EXPR
)
2087 offset2
= TREE_OPERAND (base
, 1);
2088 if (TREE_CODE (offset2
) != INTEGER_CST
)
2090 base
= TREE_OPERAND (base
, 0);
2092 offset
= fold_convert (sizetype
,
2093 int_const_binop (PLUS_EXPR
, offset
, offset2
, 1));
2096 if (TREE_CODE (base
) == ADDR_EXPR
)
2098 tree base_addr
= base
;
2100 /* Strip the ADDR_EXPR. */
2101 base
= TREE_OPERAND (base
, 0);
2103 /* Fold away CONST_DECL to its value, if the type is scalar. */
2104 if (TREE_CODE (base
) == CONST_DECL
2105 && is_gimple_min_invariant (DECL_INITIAL (base
)))
2106 return DECL_INITIAL (base
);
2108 /* Try folding *(&B+O) to B.X. */
2109 t
= maybe_fold_offset_to_reference (loc
, base_addr
, offset
,
2113 /* Preserve volatileness of the original expression.
2114 We can end up with a plain decl here which is shared
2115 and we shouldn't mess with its flags. */
2117 TREE_THIS_VOLATILE (t
) = volatile_p
;
2123 /* We can get here for out-of-range string constant accesses,
2124 such as "_"[3]. Bail out of the entire substitution search
2125 and arrange for the entire statement to be replaced by a
2126 call to __builtin_trap. In all likelihood this will all be
2127 constant-folded away, but in the meantime we can't leave with
2128 something that get_expr_operands can't understand. */
2132 if (TREE_CODE (t
) == ADDR_EXPR
2133 && TREE_CODE (TREE_OPERAND (t
, 0)) == STRING_CST
)
2135 /* FIXME: Except that this causes problems elsewhere with dead
2136 code not being deleted, and we die in the rtl expanders
2137 because we failed to remove some ssa_name. In the meantime,
2138 just return zero. */
2139 /* FIXME2: This condition should be signaled by
2140 fold_read_from_constant_string directly, rather than
2141 re-checking for it here. */
2142 return integer_zero_node
;
2145 /* Try folding *(B+O) to B->X. Still an improvement. */
2146 if (POINTER_TYPE_P (TREE_TYPE (base
)))
2148 t
= maybe_fold_offset_to_reference (loc
, base
, offset
,
2155 /* Otherwise we had an offset that we could not simplify. */
2160 /* A quaint feature extant in our address arithmetic is that there
2161 can be hidden type changes here. The type of the result need
2162 not be the same as the type of the input pointer.
2164 What we're after here is an expression of the form
2165 (T *)(&array + const)
2166 where array is OP0, const is OP1, RES_TYPE is T and
2167 the cast doesn't actually exist, but is implicit in the
2168 type of the POINTER_PLUS_EXPR. We'd like to turn this into
2170 which may be able to propagate further. */
2173 maybe_fold_stmt_addition (location_t loc
, tree res_type
, tree op0
, tree op1
)
2178 /* The first operand should be an ADDR_EXPR. */
2179 if (TREE_CODE (op0
) != ADDR_EXPR
)
2181 op0
= TREE_OPERAND (op0
, 0);
2183 /* It had better be a constant. */
2184 if (TREE_CODE (op1
) != INTEGER_CST
)
2186 /* Or op0 should now be A[0] and the non-constant offset defined
2187 via a multiplication by the array element size. */
2188 if (TREE_CODE (op0
) == ARRAY_REF
2189 && integer_zerop (TREE_OPERAND (op0
, 1))
2190 && TREE_CODE (op1
) == SSA_NAME
2191 && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (op0
)), 1))
2193 gimple offset_def
= SSA_NAME_DEF_STMT (op1
);
2194 if (!is_gimple_assign (offset_def
))
2197 if (gimple_assign_rhs_code (offset_def
) == MULT_EXPR
2198 && TREE_CODE (gimple_assign_rhs2 (offset_def
)) == INTEGER_CST
2199 && tree_int_cst_equal (gimple_assign_rhs2 (offset_def
),
2200 TYPE_SIZE_UNIT (TREE_TYPE (op0
))))
2201 return build1 (ADDR_EXPR
, res_type
,
2202 build4 (ARRAY_REF
, TREE_TYPE (op0
),
2203 TREE_OPERAND (op0
, 0),
2204 gimple_assign_rhs1 (offset_def
),
2205 TREE_OPERAND (op0
, 2),
2206 TREE_OPERAND (op0
, 3)));
2207 else if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (op0
)))
2208 && gimple_assign_rhs_code (offset_def
) != MULT_EXPR
)
2209 return build1 (ADDR_EXPR
, res_type
,
2210 build4 (ARRAY_REF
, TREE_TYPE (op0
),
2211 TREE_OPERAND (op0
, 0),
2213 TREE_OPERAND (op0
, 2),
2214 TREE_OPERAND (op0
, 3)));
2219 /* If the first operand is an ARRAY_REF, expand it so that we can fold
2220 the offset into it. */
2221 while (TREE_CODE (op0
) == ARRAY_REF
)
2223 tree array_obj
= TREE_OPERAND (op0
, 0);
2224 tree array_idx
= TREE_OPERAND (op0
, 1);
2225 tree elt_type
= TREE_TYPE (op0
);
2226 tree elt_size
= TYPE_SIZE_UNIT (elt_type
);
2229 if (TREE_CODE (array_idx
) != INTEGER_CST
)
2231 if (TREE_CODE (elt_size
) != INTEGER_CST
)
2234 /* Un-bias the index by the min index of the array type. */
2235 min_idx
= TYPE_DOMAIN (TREE_TYPE (array_obj
));
2238 min_idx
= TYPE_MIN_VALUE (min_idx
);
2241 if (TREE_CODE (min_idx
) != INTEGER_CST
)
2244 array_idx
= fold_convert (TREE_TYPE (min_idx
), array_idx
);
2245 if (!integer_zerop (min_idx
))
2246 array_idx
= int_const_binop (MINUS_EXPR
, array_idx
,
2251 /* Convert the index to a byte offset. */
2252 array_idx
= fold_convert (sizetype
, array_idx
);
2253 array_idx
= int_const_binop (MULT_EXPR
, array_idx
, elt_size
, 0);
2255 /* Update the operands for the next round, or for folding. */
2256 op1
= int_const_binop (PLUS_EXPR
,
2261 ptd_type
= TREE_TYPE (res_type
);
2262 /* If we want a pointer to void, reconstruct the reference from the
2263 array element type. A pointer to that can be trivially converted
2264 to void *. This happens as we fold (void *)(ptr p+ off). */
2265 if (VOID_TYPE_P (ptd_type
)
2266 && TREE_CODE (TREE_TYPE (op0
)) == ARRAY_TYPE
)
2267 ptd_type
= TREE_TYPE (TREE_TYPE (op0
));
2269 /* At which point we can try some of the same things as for indirects. */
2270 t
= maybe_fold_offset_to_array_ref (loc
, op0
, op1
, ptd_type
, true);
2272 t
= maybe_fold_offset_to_component_ref (loc
, TREE_TYPE (op0
), op0
, op1
,
2276 t
= build1 (ADDR_EXPR
, res_type
, t
);
2277 SET_EXPR_LOCATION (t
, loc
);
2283 /* Subroutine of fold_stmt. We perform several simplifications of the
2284 memory reference tree EXPR and make sure to re-gimplify them properly
2285 after propagation of constant addresses. IS_LHS is true if the
2286 reference is supposed to be an lvalue. */
2289 maybe_fold_reference (tree expr
, bool is_lhs
)
2293 if (TREE_CODE (expr
) == ARRAY_REF
2296 tree tem
= fold_read_from_constant_string (expr
);
2301 /* ??? We might want to open-code the relevant remaining cases
2302 to avoid using the generic fold. */
2303 if (handled_component_p (*t
)
2304 && CONSTANT_CLASS_P (TREE_OPERAND (*t
, 0)))
2306 tree tem
= fold (*t
);
2311 while (handled_component_p (*t
))
2312 t
= &TREE_OPERAND (*t
, 0);
2314 if (TREE_CODE (*t
) == INDIRECT_REF
)
2316 tree tem
= maybe_fold_stmt_indirect (*t
, TREE_OPERAND (*t
, 0),
2318 /* Avoid folding *"abc" = 5 into 'a' = 5. */
2319 if (is_lhs
&& tem
&& CONSTANT_CLASS_P (tem
))
2322 && TREE_CODE (TREE_OPERAND (*t
, 0)) == ADDR_EXPR
)
2323 /* If we had a good reason for propagating the address here,
2324 make sure we end up with valid gimple. See PR34989. */
2325 tem
= TREE_OPERAND (TREE_OPERAND (*t
, 0), 0);
2330 tem
= maybe_fold_reference (expr
, is_lhs
);
2341 /* Return the string length, maximum string length or maximum value of
2343 If ARG is an SSA name variable, follow its use-def chains. If LENGTH
2344 is not NULL and, for TYPE == 0, its value is not equal to the length
2345 we determine or if we are unable to determine the length or value,
2346 return false. VISITED is a bitmap of visited variables.
2347 TYPE is 0 if string length should be returned, 1 for maximum string
2348 length and 2 for maximum value ARG can have. */
2351 get_maxval_strlen (tree arg
, tree
*length
, bitmap visited
, int type
)
2356 if (TREE_CODE (arg
) != SSA_NAME
)
2358 if (TREE_CODE (arg
) == COND_EXPR
)
2359 return get_maxval_strlen (COND_EXPR_THEN (arg
), length
, visited
, type
)
2360 && get_maxval_strlen (COND_EXPR_ELSE (arg
), length
, visited
, type
);
2361 /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */
2362 else if (TREE_CODE (arg
) == ADDR_EXPR
2363 && TREE_CODE (TREE_OPERAND (arg
, 0)) == ARRAY_REF
2364 && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg
, 0), 1)))
2366 tree aop0
= TREE_OPERAND (TREE_OPERAND (arg
, 0), 0);
2367 if (TREE_CODE (aop0
) == INDIRECT_REF
2368 && TREE_CODE (TREE_OPERAND (aop0
, 0)) == SSA_NAME
)
2369 return get_maxval_strlen (TREE_OPERAND (aop0
, 0),
2370 length
, visited
, type
);
2376 if (TREE_CODE (val
) != INTEGER_CST
2377 || tree_int_cst_sgn (val
) < 0)
2381 val
= c_strlen (arg
, 1);
2389 if (TREE_CODE (*length
) != INTEGER_CST
2390 || TREE_CODE (val
) != INTEGER_CST
)
2393 if (tree_int_cst_lt (*length
, val
))
2397 else if (simple_cst_equal (val
, *length
) != 1)
2405 /* If we were already here, break the infinite cycle. */
2406 if (bitmap_bit_p (visited
, SSA_NAME_VERSION (arg
)))
2408 bitmap_set_bit (visited
, SSA_NAME_VERSION (arg
));
2411 def_stmt
= SSA_NAME_DEF_STMT (var
);
2413 switch (gimple_code (def_stmt
))
2416 /* The RHS of the statement defining VAR must either have a
2417 constant length or come from another SSA_NAME with a constant
2419 if (gimple_assign_single_p (def_stmt
)
2420 || gimple_assign_unary_nop_p (def_stmt
))
2422 tree rhs
= gimple_assign_rhs1 (def_stmt
);
2423 return get_maxval_strlen (rhs
, length
, visited
, type
);
2429 /* All the arguments of the PHI node must have the same constant
2433 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); i
++)
2435 tree arg
= gimple_phi_arg (def_stmt
, i
)->def
;
2437 /* If this PHI has itself as an argument, we cannot
2438 determine the string length of this argument. However,
2439 if we can find a constant string length for the other
2440 PHI args then we can still be sure that this is a
2441 constant string length. So be optimistic and just
2442 continue with the next argument. */
2443 if (arg
== gimple_phi_result (def_stmt
))
2446 if (!get_maxval_strlen (arg
, length
, visited
, type
))
2458 /* Fold builtin call in statement STMT. Returns a simplified tree.
2459 We may return a non-constant expression, including another call
2460 to a different function and with different arguments, e.g.,
2461 substituting memcpy for strcpy when the string length is known.
2462 Note that some builtins expand into inline code that may not
2463 be valid in GIMPLE. Callers must take care. */
2466 ccp_fold_builtin (gimple stmt
)
2468 tree result
, val
[3];
2475 gcc_assert (is_gimple_call (stmt
));
2477 ignore
= (gimple_call_lhs (stmt
) == NULL
);
2479 /* First try the generic builtin folder. If that succeeds, return the
2481 result
= fold_call_stmt (stmt
, ignore
);
2485 STRIP_NOPS (result
);
2489 /* Ignore MD builtins. */
2490 callee
= gimple_call_fndecl (stmt
);
2491 if (DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_MD
)
2494 /* If the builtin could not be folded, and it has no argument list,
2496 nargs
= gimple_call_num_args (stmt
);
2500 /* Limit the work only for builtins we know how to simplify. */
2501 switch (DECL_FUNCTION_CODE (callee
))
2503 case BUILT_IN_STRLEN
:
2504 case BUILT_IN_FPUTS
:
2505 case BUILT_IN_FPUTS_UNLOCKED
:
2509 case BUILT_IN_STRCPY
:
2510 case BUILT_IN_STRNCPY
:
2514 case BUILT_IN_MEMCPY_CHK
:
2515 case BUILT_IN_MEMPCPY_CHK
:
2516 case BUILT_IN_MEMMOVE_CHK
:
2517 case BUILT_IN_MEMSET_CHK
:
2518 case BUILT_IN_STRNCPY_CHK
:
2522 case BUILT_IN_STRCPY_CHK
:
2523 case BUILT_IN_STPCPY_CHK
:
2527 case BUILT_IN_SNPRINTF_CHK
:
2528 case BUILT_IN_VSNPRINTF_CHK
:
2536 if (arg_idx
>= nargs
)
2539 /* Try to use the dataflow information gathered by the CCP process. */
2540 visited
= BITMAP_ALLOC (NULL
);
2541 bitmap_clear (visited
);
2543 memset (val
, 0, sizeof (val
));
2544 a
= gimple_call_arg (stmt
, arg_idx
);
2545 if (!get_maxval_strlen (a
, &val
[arg_idx
], visited
, type
))
2546 val
[arg_idx
] = NULL_TREE
;
2548 BITMAP_FREE (visited
);
2551 switch (DECL_FUNCTION_CODE (callee
))
2553 case BUILT_IN_STRLEN
:
2554 if (val
[0] && nargs
== 1)
2557 fold_convert (TREE_TYPE (gimple_call_lhs (stmt
)), val
[0]);
2559 /* If the result is not a valid gimple value, or not a cast
2560 of a valid gimple value, then we can not use the result. */
2561 if (is_gimple_val (new_val
)
2562 || (is_gimple_cast (new_val
)
2563 && is_gimple_val (TREE_OPERAND (new_val
, 0))))
2568 case BUILT_IN_STRCPY
:
2569 if (val
[1] && is_gimple_val (val
[1]) && nargs
== 2)
2570 result
= fold_builtin_strcpy (callee
,
2571 gimple_call_arg (stmt
, 0),
2572 gimple_call_arg (stmt
, 1),
2576 case BUILT_IN_STRNCPY
:
2577 if (val
[1] && is_gimple_val (val
[1]) && nargs
== 3)
2578 result
= fold_builtin_strncpy (callee
,
2579 gimple_call_arg (stmt
, 0),
2580 gimple_call_arg (stmt
, 1),
2581 gimple_call_arg (stmt
, 2),
2585 case BUILT_IN_FPUTS
:
2587 result
= fold_builtin_fputs (gimple_call_arg (stmt
, 0),
2588 gimple_call_arg (stmt
, 1),
2589 ignore
, false, val
[0]);
2592 case BUILT_IN_FPUTS_UNLOCKED
:
2594 result
= fold_builtin_fputs (gimple_call_arg (stmt
, 0),
2595 gimple_call_arg (stmt
, 1),
2596 ignore
, true, val
[0]);
2599 case BUILT_IN_MEMCPY_CHK
:
2600 case BUILT_IN_MEMPCPY_CHK
:
2601 case BUILT_IN_MEMMOVE_CHK
:
2602 case BUILT_IN_MEMSET_CHK
:
2603 if (val
[2] && is_gimple_val (val
[2]) && nargs
== 4)
2604 result
= fold_builtin_memory_chk (callee
,
2605 gimple_call_arg (stmt
, 0),
2606 gimple_call_arg (stmt
, 1),
2607 gimple_call_arg (stmt
, 2),
2608 gimple_call_arg (stmt
, 3),
2610 DECL_FUNCTION_CODE (callee
));
2613 case BUILT_IN_STRCPY_CHK
:
2614 case BUILT_IN_STPCPY_CHK
:
2615 if (val
[1] && is_gimple_val (val
[1]) && nargs
== 3)
2616 result
= fold_builtin_stxcpy_chk (callee
,
2617 gimple_call_arg (stmt
, 0),
2618 gimple_call_arg (stmt
, 1),
2619 gimple_call_arg (stmt
, 2),
2621 DECL_FUNCTION_CODE (callee
));
2624 case BUILT_IN_STRNCPY_CHK
:
2625 if (val
[2] && is_gimple_val (val
[2]) && nargs
== 4)
2626 result
= fold_builtin_strncpy_chk (gimple_call_arg (stmt
, 0),
2627 gimple_call_arg (stmt
, 1),
2628 gimple_call_arg (stmt
, 2),
2629 gimple_call_arg (stmt
, 3),
2633 case BUILT_IN_SNPRINTF_CHK
:
2634 case BUILT_IN_VSNPRINTF_CHK
:
2635 if (val
[1] && is_gimple_val (val
[1]))
2636 result
= gimple_fold_builtin_snprintf_chk (stmt
, val
[1],
2637 DECL_FUNCTION_CODE (callee
));
2644 if (result
&& ignore
)
2645 result
= fold_ignored_result (result
);
2649 /* Attempt to fold an assignment statement pointed-to by SI. Returns a
2650 replacement rhs for the statement or NULL_TREE if no simplification
2651 could be made. It is assumed that the operands have been previously
2655 fold_gimple_assign (gimple_stmt_iterator
*si
)
2657 gimple stmt
= gsi_stmt (*si
);
2658 enum tree_code subcode
= gimple_assign_rhs_code (stmt
);
2660 tree result
= NULL_TREE
;
2662 switch (get_gimple_rhs_class (subcode
))
2664 case GIMPLE_SINGLE_RHS
:
2666 tree rhs
= gimple_assign_rhs1 (stmt
);
2668 /* Try to fold a conditional expression. */
2669 if (TREE_CODE (rhs
) == COND_EXPR
)
2671 tree op0
= COND_EXPR_COND (rhs
);
2675 if (COMPARISON_CLASS_P (op0
))
2677 fold_defer_overflow_warnings ();
2678 tem
= fold_binary (TREE_CODE (op0
), TREE_TYPE (op0
),
2679 TREE_OPERAND (op0
, 0),
2680 TREE_OPERAND (op0
, 1));
2681 /* This is actually a conditional expression, not a GIMPLE
2682 conditional statement, however, the valid_gimple_rhs_p
2683 test still applies. */
2684 set
= (tem
&& is_gimple_condexpr (tem
)
2685 && valid_gimple_rhs_p (tem
));
2686 fold_undefer_overflow_warnings (set
, stmt
, 0);
2688 else if (is_gimple_min_invariant (op0
))
2697 result
= fold_build3 (COND_EXPR
, TREE_TYPE (rhs
), tem
,
2698 COND_EXPR_THEN (rhs
), COND_EXPR_ELSE (rhs
));
2701 else if (TREE_CODE (rhs
) == TARGET_MEM_REF
)
2702 return maybe_fold_tmr (rhs
);
2704 else if (REFERENCE_CLASS_P (rhs
))
2705 return maybe_fold_reference (rhs
, false);
2707 else if (TREE_CODE (rhs
) == ADDR_EXPR
)
2709 tree tem
= maybe_fold_reference (TREE_OPERAND (rhs
, 0), true);
2711 result
= fold_convert (TREE_TYPE (rhs
),
2712 build_fold_addr_expr (tem
));
2715 else if (TREE_CODE (rhs
) == CONSTRUCTOR
2716 && TREE_CODE (TREE_TYPE (rhs
)) == VECTOR_TYPE
2717 && (CONSTRUCTOR_NELTS (rhs
)
2718 == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs
))))
2720 /* Fold a constant vector CONSTRUCTOR to VECTOR_CST. */
2724 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs
), i
, val
)
2725 if (TREE_CODE (val
) != INTEGER_CST
2726 && TREE_CODE (val
) != REAL_CST
2727 && TREE_CODE (val
) != FIXED_CST
)
2730 return build_vector_from_ctor (TREE_TYPE (rhs
),
2731 CONSTRUCTOR_ELTS (rhs
));
2734 /* If we couldn't fold the RHS, hand over to the generic
2736 if (result
== NULL_TREE
)
2737 result
= fold (rhs
);
2739 /* Strip away useless type conversions. Both the NON_LVALUE_EXPR
2740 that may have been added by fold, and "useless" type
2741 conversions that might now be apparent due to propagation. */
2742 STRIP_USELESS_TYPE_CONVERSION (result
);
2744 if (result
!= rhs
&& valid_gimple_rhs_p (result
))
2751 case GIMPLE_UNARY_RHS
:
2753 tree rhs
= gimple_assign_rhs1 (stmt
);
2755 result
= fold_unary (subcode
, gimple_expr_type (stmt
), rhs
);
2758 /* If the operation was a conversion do _not_ mark a
2759 resulting constant with TREE_OVERFLOW if the original
2760 constant was not. These conversions have implementation
2761 defined behavior and retaining the TREE_OVERFLOW flag
2762 here would confuse later passes such as VRP. */
2763 if (CONVERT_EXPR_CODE_P (subcode
)
2764 && TREE_CODE (result
) == INTEGER_CST
2765 && TREE_CODE (rhs
) == INTEGER_CST
)
2766 TREE_OVERFLOW (result
) = TREE_OVERFLOW (rhs
);
2768 STRIP_USELESS_TYPE_CONVERSION (result
);
2769 if (valid_gimple_rhs_p (result
))
2772 else if (CONVERT_EXPR_CODE_P (subcode
)
2773 && POINTER_TYPE_P (gimple_expr_type (stmt
))
2774 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
2776 tree type
= gimple_expr_type (stmt
);
2777 tree t
= maybe_fold_offset_to_address (gimple_location (stmt
),
2778 gimple_assign_rhs1 (stmt
),
2779 integer_zero_node
, type
);
2786 case GIMPLE_BINARY_RHS
:
2787 /* Try to fold pointer addition. */
2788 if (gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
)
2790 tree type
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2791 if (TREE_CODE (TREE_TYPE (type
)) == ARRAY_TYPE
)
2793 type
= build_pointer_type (TREE_TYPE (TREE_TYPE (type
)));
2794 if (!useless_type_conversion_p
2795 (TREE_TYPE (gimple_assign_lhs (stmt
)), type
))
2796 type
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2798 result
= maybe_fold_stmt_addition (gimple_location (stmt
),
2800 gimple_assign_rhs1 (stmt
),
2801 gimple_assign_rhs2 (stmt
));
2805 result
= fold_binary (subcode
,
2806 TREE_TYPE (gimple_assign_lhs (stmt
)),
2807 gimple_assign_rhs1 (stmt
),
2808 gimple_assign_rhs2 (stmt
));
2812 STRIP_USELESS_TYPE_CONVERSION (result
);
2813 if (valid_gimple_rhs_p (result
))
2816 /* Fold might have produced non-GIMPLE, so if we trust it blindly
2817 we lose canonicalization opportunities. Do not go again
2818 through fold here though, or the same non-GIMPLE will be
2820 if (commutative_tree_code (subcode
)
2821 && tree_swap_operands_p (gimple_assign_rhs1 (stmt
),
2822 gimple_assign_rhs2 (stmt
), false))
2823 return build2 (subcode
, TREE_TYPE (gimple_assign_lhs (stmt
)),
2824 gimple_assign_rhs2 (stmt
),
2825 gimple_assign_rhs1 (stmt
));
2829 case GIMPLE_INVALID_RHS
:
2836 /* Attempt to fold a conditional statement. Return true if any changes were
2837 made. We only attempt to fold the condition expression, and do not perform
2838 any transformation that would require alteration of the cfg. It is
2839 assumed that the operands have been previously folded. */
2842 fold_gimple_cond (gimple stmt
)
2844 tree result
= fold_binary (gimple_cond_code (stmt
),
2846 gimple_cond_lhs (stmt
),
2847 gimple_cond_rhs (stmt
));
2851 STRIP_USELESS_TYPE_CONVERSION (result
);
2852 if (is_gimple_condexpr (result
) && valid_gimple_rhs_p (result
))
2854 gimple_cond_set_condition_from_tree (stmt
, result
);
2863 /* Attempt to fold a call statement referenced by the statement iterator GSI.
2864 The statement may be replaced by another statement, e.g., if the call
2865 simplifies to a constant value. Return true if any changes were made.
2866 It is assumed that the operands have been previously folded. */
2869 fold_gimple_call (gimple_stmt_iterator
*gsi
)
2871 gimple stmt
= gsi_stmt (*gsi
);
2873 tree callee
= gimple_call_fndecl (stmt
);
2875 /* Check for builtins that CCP can handle using information not
2876 available in the generic fold routines. */
2877 if (callee
&& DECL_BUILT_IN (callee
))
2879 tree result
= ccp_fold_builtin (stmt
);
2882 return update_call_from_tree (gsi
, result
);
2886 /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve
2887 here are when we've propagated the address of a decl into the
2889 /* ??? Should perhaps do this in fold proper. However, doing it
2890 there requires that we create a new CALL_EXPR, and that requires
2891 copying EH region info to the new node. Easier to just do it
2892 here where we can just smash the call operand. */
2893 /* ??? Is there a good reason not to do this in fold_stmt_inplace? */
2894 callee
= gimple_call_fn (stmt
);
2895 if (TREE_CODE (callee
) == OBJ_TYPE_REF
2896 && lang_hooks
.fold_obj_type_ref
2897 && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee
)) == ADDR_EXPR
2898 && DECL_P (TREE_OPERAND
2899 (OBJ_TYPE_REF_OBJECT (callee
), 0)))
2903 /* ??? Caution: Broken ADDR_EXPR semantics means that
2904 looking at the type of the operand of the addr_expr
2905 can yield an array type. See silly exception in
2906 check_pointer_types_r. */
2907 t
= TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee
)));
2908 t
= lang_hooks
.fold_obj_type_ref (callee
, t
);
2911 gimple_call_set_fn (stmt
, t
);
2920 /* Worker for both fold_stmt and fold_stmt_inplace. The INPLACE argument
2921 distinguishes both cases. */
2924 fold_stmt_1 (gimple_stmt_iterator
*gsi
, bool inplace
)
2926 bool changed
= false;
2927 gimple stmt
= gsi_stmt (*gsi
);
2930 /* Fold the main computation performed by the statement. */
2931 switch (gimple_code (stmt
))
2935 unsigned old_num_ops
= gimple_num_ops (stmt
);
2936 tree new_rhs
= fold_gimple_assign (gsi
);
2937 if (new_rhs
!= NULL_TREE
2939 || get_gimple_rhs_num_ops (TREE_CODE (new_rhs
)) < old_num_ops
))
2941 gimple_assign_set_rhs_from_tree (gsi
, new_rhs
);
2948 changed
|= fold_gimple_cond (stmt
);
2952 /* Fold *& in call arguments. */
2953 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
2954 if (REFERENCE_CLASS_P (gimple_call_arg (stmt
, i
)))
2956 tree tmp
= maybe_fold_reference (gimple_call_arg (stmt
, i
), false);
2959 gimple_call_set_arg (stmt
, i
, tmp
);
2963 /* The entire statement may be replaced in this case. */
2965 changed
|= fold_gimple_call (gsi
);
2969 /* Fold *& in asm operands. */
2970 for (i
= 0; i
< gimple_asm_noutputs (stmt
); ++i
)
2972 tree link
= gimple_asm_output_op (stmt
, i
);
2973 tree op
= TREE_VALUE (link
);
2974 if (REFERENCE_CLASS_P (op
)
2975 && (op
= maybe_fold_reference (op
, true)) != NULL_TREE
)
2977 TREE_VALUE (link
) = op
;
2981 for (i
= 0; i
< gimple_asm_ninputs (stmt
); ++i
)
2983 tree link
= gimple_asm_input_op (stmt
, i
);
2984 tree op
= TREE_VALUE (link
);
2985 if (REFERENCE_CLASS_P (op
)
2986 && (op
= maybe_fold_reference (op
, false)) != NULL_TREE
)
2988 TREE_VALUE (link
) = op
;
2997 stmt
= gsi_stmt (*gsi
);
2999 /* Fold *& on the lhs. */
3000 if (gimple_has_lhs (stmt
))
3002 tree lhs
= gimple_get_lhs (stmt
);
3003 if (lhs
&& REFERENCE_CLASS_P (lhs
))
3005 tree new_lhs
= maybe_fold_reference (lhs
, true);
3008 gimple_set_lhs (stmt
, new_lhs
);
3017 /* Fold the statement pointed to by GSI. In some cases, this function may
3018 replace the whole statement with a new one. Returns true iff folding
3020 The statement pointed to by GSI should be in valid gimple form but may
3021 be in unfolded state as resulting from for example constant propagation
3022 which can produce *&x = 0. */
3025 fold_stmt (gimple_stmt_iterator
*gsi
)
3027 return fold_stmt_1 (gsi
, false);
3030 /* Perform the minimal folding on statement STMT. Only operations like
3031 *&x created by constant propagation are handled. The statement cannot
3032 be replaced with a new one. Return true if the statement was
3033 changed, false otherwise.
3034 The statement STMT should be in valid gimple form but may
3035 be in unfolded state as resulting from for example constant propagation
3036 which can produce *&x = 0. */
3039 fold_stmt_inplace (gimple stmt
)
3041 gimple_stmt_iterator gsi
= gsi_for_stmt (stmt
);
3042 bool changed
= fold_stmt_1 (&gsi
, true);
3043 gcc_assert (gsi_stmt (gsi
) == stmt
);
3047 /* Try to optimize out __builtin_stack_restore. Optimize it out
3048 if there is another __builtin_stack_restore in the same basic
3049 block and no calls or ASM_EXPRs are in between, or if this block's
3050 only outgoing edge is to EXIT_BLOCK and there are no calls or
3051 ASM_EXPRs after this __builtin_stack_restore. */
3054 optimize_stack_restore (gimple_stmt_iterator i
)
3057 gimple stmt
, stack_save
;
3058 gimple_stmt_iterator stack_save_gsi
;
3060 basic_block bb
= gsi_bb (i
);
3061 gimple call
= gsi_stmt (i
);
3063 if (gimple_code (call
) != GIMPLE_CALL
3064 || gimple_call_num_args (call
) != 1
3065 || TREE_CODE (gimple_call_arg (call
, 0)) != SSA_NAME
3066 || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call
, 0))))
3069 for (gsi_next (&i
); !gsi_end_p (i
); gsi_next (&i
))
3071 stmt
= gsi_stmt (i
);
3072 if (gimple_code (stmt
) == GIMPLE_ASM
)
3074 if (gimple_code (stmt
) != GIMPLE_CALL
)
3077 callee
= gimple_call_fndecl (stmt
);
3078 if (!callee
|| DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
)
3081 if (DECL_FUNCTION_CODE (callee
) == BUILT_IN_STACK_RESTORE
)
3086 && (! single_succ_p (bb
)
3087 || single_succ_edge (bb
)->dest
!= EXIT_BLOCK_PTR
))
3090 stack_save
= SSA_NAME_DEF_STMT (gimple_call_arg (call
, 0));
3091 if (gimple_code (stack_save
) != GIMPLE_CALL
3092 || gimple_call_lhs (stack_save
) != gimple_call_arg (call
, 0)
3093 || stmt_could_throw_p (stack_save
)
3094 || !has_single_use (gimple_call_arg (call
, 0)))
3097 callee
= gimple_call_fndecl (stack_save
);
3099 || DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
3100 || DECL_FUNCTION_CODE (callee
) != BUILT_IN_STACK_SAVE
3101 || gimple_call_num_args (stack_save
) != 0)
3104 stack_save_gsi
= gsi_for_stmt (stack_save
);
3105 rhs
= build_int_cst (TREE_TYPE (gimple_call_arg (call
, 0)), 0);
3106 if (!update_call_from_tree (&stack_save_gsi
, rhs
))
3109 /* No effect, so the statement will be deleted. */
3110 return integer_zero_node
;
3113 /* If va_list type is a simple pointer and nothing special is needed,
3114 optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0),
3115 __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple
3116 pointer assignment. */
3119 optimize_stdarg_builtin (gimple call
)
3121 tree callee
, lhs
, rhs
, cfun_va_list
;
3122 bool va_list_simple_ptr
;
3124 if (gimple_code (call
) != GIMPLE_CALL
)
3127 callee
= gimple_call_fndecl (call
);
3129 cfun_va_list
= targetm
.fn_abi_va_list (callee
);
3130 va_list_simple_ptr
= POINTER_TYPE_P (cfun_va_list
)
3131 && (TREE_TYPE (cfun_va_list
) == void_type_node
3132 || TREE_TYPE (cfun_va_list
) == char_type_node
);
3134 switch (DECL_FUNCTION_CODE (callee
))
3136 case BUILT_IN_VA_START
:
3137 if (!va_list_simple_ptr
3138 || targetm
.expand_builtin_va_start
!= NULL
3139 || built_in_decls
[BUILT_IN_NEXT_ARG
] == NULL
)
3142 if (gimple_call_num_args (call
) != 2)
3145 lhs
= gimple_call_arg (call
, 0);
3146 if (!POINTER_TYPE_P (TREE_TYPE (lhs
))
3147 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs
)))
3148 != TYPE_MAIN_VARIANT (cfun_va_list
))
3151 lhs
= build_fold_indirect_ref (lhs
);
3152 rhs
= build_call_expr (built_in_decls
[BUILT_IN_NEXT_ARG
],
3153 1, integer_zero_node
);
3154 rhs
= fold_convert (TREE_TYPE (lhs
), rhs
);
3155 return build2 (MODIFY_EXPR
, TREE_TYPE (lhs
), lhs
, rhs
);
3157 case BUILT_IN_VA_COPY
:
3158 if (!va_list_simple_ptr
)
3161 if (gimple_call_num_args (call
) != 2)
3164 lhs
= gimple_call_arg (call
, 0);
3165 if (!POINTER_TYPE_P (TREE_TYPE (lhs
))
3166 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs
)))
3167 != TYPE_MAIN_VARIANT (cfun_va_list
))
3170 lhs
= build_fold_indirect_ref (lhs
);
3171 rhs
= gimple_call_arg (call
, 1);
3172 if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs
))
3173 != TYPE_MAIN_VARIANT (cfun_va_list
))
3176 rhs
= fold_convert (TREE_TYPE (lhs
), rhs
);
3177 return build2 (MODIFY_EXPR
, TREE_TYPE (lhs
), lhs
, rhs
);
3179 case BUILT_IN_VA_END
:
3180 /* No effect, so the statement will be deleted. */
3181 return integer_zero_node
;
3188 /* Convert EXPR into a GIMPLE value suitable for substitution on the
3189 RHS of an assignment. Insert the necessary statements before
3190 iterator *SI_P. The statement at *SI_P, which must be a GIMPLE_CALL
3191 is replaced. If the call is expected to produces a result, then it
3192 is replaced by an assignment of the new RHS to the result variable.
3193 If the result is to be ignored, then the call is replaced by a
3197 gimplify_and_update_call_from_tree (gimple_stmt_iterator
*si_p
, tree expr
)
3200 tree tmp
= NULL_TREE
; /* Silence warning. */
3201 gimple stmt
, new_stmt
;
3202 gimple_stmt_iterator i
;
3203 gimple_seq stmts
= gimple_seq_alloc();
3204 struct gimplify_ctx gctx
;
3206 stmt
= gsi_stmt (*si_p
);
3208 gcc_assert (is_gimple_call (stmt
));
3210 lhs
= gimple_call_lhs (stmt
);
3212 push_gimplify_context (&gctx
);
3214 if (lhs
== NULL_TREE
)
3215 gimplify_and_add (expr
, &stmts
);
3217 tmp
= get_initialized_tmp_var (expr
, &stmts
, NULL
);
3219 pop_gimplify_context (NULL
);
3221 if (gimple_has_location (stmt
))
3222 annotate_all_with_location (stmts
, gimple_location (stmt
));
3224 /* The replacement can expose previously unreferenced variables. */
3225 for (i
= gsi_start (stmts
); !gsi_end_p (i
); gsi_next (&i
))
3227 new_stmt
= gsi_stmt (i
);
3228 find_new_referenced_vars (new_stmt
);
3229 gsi_insert_before (si_p
, new_stmt
, GSI_NEW_STMT
);
3230 mark_symbols_for_renaming (new_stmt
);
3234 if (lhs
== NULL_TREE
)
3236 new_stmt
= gimple_build_nop ();
3237 unlink_stmt_vdef (stmt
);
3238 release_defs (stmt
);
3242 new_stmt
= gimple_build_assign (lhs
, tmp
);
3243 gimple_set_vuse (new_stmt
, gimple_vuse (stmt
));
3244 gimple_set_vdef (new_stmt
, gimple_vdef (stmt
));
3245 move_ssa_defining_stmt_for_defs (new_stmt
, stmt
);
3248 gimple_set_location (new_stmt
, gimple_location (stmt
));
3249 gsi_replace (si_p
, new_stmt
, false);
3252 /* A simple pass that attempts to fold all builtin functions. This pass
3253 is run after we've propagated as many constants as we can. */
3256 execute_fold_all_builtins (void)
3258 bool cfg_changed
= false;
3260 unsigned int todoflags
= 0;
3264 gimple_stmt_iterator i
;
3265 for (i
= gsi_start_bb (bb
); !gsi_end_p (i
); )
3267 gimple stmt
, old_stmt
;
3268 tree callee
, result
;
3269 enum built_in_function fcode
;
3271 stmt
= gsi_stmt (i
);
3273 if (gimple_code (stmt
) != GIMPLE_CALL
)
3278 callee
= gimple_call_fndecl (stmt
);
3279 if (!callee
|| DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
)
3284 fcode
= DECL_FUNCTION_CODE (callee
);
3286 result
= ccp_fold_builtin (stmt
);
3289 gimple_remove_stmt_histograms (cfun
, stmt
);
3292 switch (DECL_FUNCTION_CODE (callee
))
3294 case BUILT_IN_CONSTANT_P
:
3295 /* Resolve __builtin_constant_p. If it hasn't been
3296 folded to integer_one_node by now, it's fairly
3297 certain that the value simply isn't constant. */
3298 result
= integer_zero_node
;
3301 case BUILT_IN_STACK_RESTORE
:
3302 result
= optimize_stack_restore (i
);
3308 case BUILT_IN_VA_START
:
3309 case BUILT_IN_VA_END
:
3310 case BUILT_IN_VA_COPY
:
3311 /* These shouldn't be folded before pass_stdarg. */
3312 result
= optimize_stdarg_builtin (stmt
);
3322 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3324 fprintf (dump_file
, "Simplified\n ");
3325 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3329 if (!update_call_from_tree (&i
, result
))
3331 gimplify_and_update_call_from_tree (&i
, result
);
3332 todoflags
|= TODO_update_address_taken
;
3335 stmt
= gsi_stmt (i
);
3338 if (maybe_clean_or_replace_eh_stmt (old_stmt
, stmt
)
3339 && gimple_purge_dead_eh_edges (bb
))
3342 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3344 fprintf (dump_file
, "to\n ");
3345 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
3346 fprintf (dump_file
, "\n");
3349 /* Retry the same statement if it changed into another
3350 builtin, there might be new opportunities now. */
3351 if (gimple_code (stmt
) != GIMPLE_CALL
)
3356 callee
= gimple_call_fndecl (stmt
);
3358 || DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
3359 || DECL_FUNCTION_CODE (callee
) == fcode
)
3364 /* Delete unreachable blocks. */
3366 todoflags
|= TODO_cleanup_cfg
;
3372 struct gimple_opt_pass pass_fold_builtins
=
3378 execute_fold_all_builtins
, /* execute */
3381 0, /* static_pass_number */
3382 TV_NONE
, /* tv_id */
3383 PROP_cfg
| PROP_ssa
, /* properties_required */
3384 0, /* properties_provided */
3385 0, /* properties_destroyed */
3386 0, /* todo_flags_start */
3389 | TODO_update_ssa
/* todo_flags_finish */