Line data Source code
1 : /* Support for fully folding sub-trees of an expression for C compiler.
2 : Copyright (C) 1992-2026 Free Software Foundation, Inc.
3 :
4 : This file is part of GCC.
5 :
6 : GCC is free software; you can redistribute it and/or modify it under
7 : the terms of the GNU General Public License as published by the Free
8 : Software Foundation; either version 3, or (at your option) any later
9 : version.
10 :
11 : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 : WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 : for more details.
15 :
16 : You should have received a copy of the GNU General Public License
17 : along with GCC; see the file COPYING3. If not see
18 : <http://www.gnu.org/licenses/>. */
19 :
20 : #include "config.h"
21 : #include "system.h"
22 : #include "coretypes.h"
23 : #include "target.h"
24 : #include "function.h"
25 : #include "bitmap.h"
26 : #include "c-tree.h"
27 : #include "intl.h"
28 : #include "gimplify.h"
29 :
30 : static tree c_fully_fold_internal (tree expr, bool, bool *, bool *, bool,
31 : bool);
32 :
33 : /* If DISABLE is true, stop issuing warnings. This is used when
34 : parsing code that we know will not be executed. This function may
35 : be called multiple times, and works as a stack. */
36 :
37 : static void
38 977005 : c_disable_warnings (bool disable)
39 : {
40 977005 : if (disable)
41 : {
42 68693 : ++c_inhibit_evaluation_warnings;
43 68693 : fold_defer_overflow_warnings ();
44 : }
45 977005 : }
46 :
47 : /* If ENABLE is true, reenable issuing warnings. */
48 :
49 : static void
50 977005 : c_enable_warnings (bool enable)
51 : {
52 977005 : if (enable)
53 : {
54 68693 : --c_inhibit_evaluation_warnings;
55 68693 : fold_undefer_and_ignore_overflow_warnings ();
56 : }
57 977005 : }
58 :
59 : /* Try to fold ARRAY_REF ary[index] if possible and not handled by
60 : normal fold, return NULL_TREE otherwise. */
61 :
62 : static tree
63 812 : c_fold_array_ref (tree type, tree ary, tree index)
64 : {
65 812 : if (TREE_CODE (ary) != STRING_CST
66 792 : || TREE_CODE (index) != INTEGER_CST
67 792 : || TREE_OVERFLOW (index)
68 791 : || TREE_CODE (TREE_TYPE (ary)) != ARRAY_TYPE
69 1603 : || !tree_fits_uhwi_p (index))
70 : return NULL_TREE;
71 :
72 790 : tree elem_type = TREE_TYPE (TREE_TYPE (ary));
73 790 : unsigned elem_nchars = (TYPE_PRECISION (elem_type)
74 790 : / TYPE_PRECISION (char_type_node));
75 790 : unsigned len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars;
76 790 : tree nelts_minus_one = array_type_nelts_minus_one (TREE_TYPE (ary));
77 790 : bool dummy1 = true, dummy2 = true;
78 790 : nelts_minus_one = c_fully_fold_internal (nelts_minus_one, true, &dummy1,
79 : &dummy2, false, false);
80 790 : unsigned HOST_WIDE_INT i = tree_to_uhwi (index);
81 790 : if (!tree_int_cst_le (index, nelts_minus_one)
82 789 : || i >= len
83 1579 : || i + elem_nchars > len)
84 : return NULL_TREE;
85 :
86 789 : if (elem_nchars == 1)
87 789 : return build_int_cst (type, TREE_STRING_POINTER (ary)[i]);
88 :
89 0 : const unsigned char *ptr
90 0 : = ((const unsigned char *)TREE_STRING_POINTER (ary) + i * elem_nchars);
91 0 : return native_interpret_expr (type, ptr, elem_nchars);
92 : }
93 :
94 : /* Fully fold EXPR, an expression that was not folded (beyond integer
95 : constant expressions and null pointer constants) when being built
96 : up. If IN_INIT, this is in a static initializer and certain
97 : changes are made to the folding done. Clear *MAYBE_CONST if
98 : MAYBE_CONST is not NULL and EXPR is definitely not a constant
99 : expression because it contains an evaluated operator (in C99) or an
100 : operator outside of sizeof returning an integer constant (in C90)
101 : not permitted in constant expressions, or because it contains an
102 : evaluated arithmetic overflow. (*MAYBE_CONST should typically be
103 : set to true by callers before calling this function.) Return the
104 : folded expression. Function arguments have already been folded
105 : before calling this function, as have the contents of SAVE_EXPR,
106 : TARGET_EXPR, BIND_EXPR, VA_ARG_EXPR, OBJ_TYPE_REF and
107 : C_MAYBE_CONST_EXPR. LVAL is true if it should be treated as an
108 : lvalue. */
109 :
110 : tree
111 269688560 : c_fully_fold (tree expr, bool in_init, bool *maybe_const, bool lval)
112 : {
113 269688560 : tree ret;
114 269688560 : tree eptype = NULL_TREE;
115 269688560 : bool dummy = true;
116 269688560 : bool maybe_const_itself = true;
117 269688560 : location_t loc = EXPR_LOCATION (expr);
118 :
119 269688560 : if (!maybe_const)
120 234177963 : maybe_const = &dummy;
121 269688560 : if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
122 : {
123 742 : eptype = TREE_TYPE (expr);
124 742 : expr = TREE_OPERAND (expr, 0);
125 : }
126 269688560 : ret = c_fully_fold_internal (expr, in_init, maybe_const,
127 : &maybe_const_itself, false, lval);
128 269688560 : if (eptype)
129 742 : ret = fold_convert_loc (loc, eptype, ret);
130 269688560 : *maybe_const &= maybe_const_itself;
131 269688560 : return ret;
132 : }
133 :
134 : /* Internal helper for c_fully_fold. EXPR and IN_INIT are as for
135 : c_fully_fold. *MAYBE_CONST_OPERANDS is cleared because of operands
136 : not permitted, while *MAYBE_CONST_ITSELF is cleared because of
137 : arithmetic overflow (for C90, *MAYBE_CONST_OPERANDS is carried from
138 : both evaluated and unevaluated subexpressions while
139 : *MAYBE_CONST_ITSELF is carried from only evaluated
140 : subexpressions). FOR_INT_CONST indicates if EXPR is an expression
141 : with integer constant operands, and if any of the operands doesn't
142 : get folded to an integer constant, don't fold the expression itself.
143 : LVAL indicates folding of lvalue, where we can't replace it with
144 : an rvalue. */
145 :
146 : static tree
147 485097205 : c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
148 : bool *maybe_const_itself, bool for_int_const, bool lval)
149 : {
150 485097205 : tree ret = expr;
151 485097205 : enum tree_code code = TREE_CODE (expr);
152 485097205 : enum tree_code_class kind = TREE_CODE_CLASS (code);
153 485097205 : location_t loc = EXPR_LOCATION (expr);
154 485097205 : tree op0, op1, op2, op3;
155 485097205 : tree orig_op0, orig_op1, orig_op2;
156 485097205 : bool op0_const = true, op1_const = true, op2_const = true;
157 485097205 : bool op0_const_self = true, op1_const_self = true, op2_const_self = true;
158 485097205 : bool nowarning = warning_suppressed_p (expr, OPT_Woverflow);
159 485097205 : bool unused_p;
160 485097205 : bool op0_lval = false;
161 485097205 : source_range old_range;
162 :
163 : /* Constants, declarations, statements, errors, and anything else not
164 : counted as an expression cannot usefully be folded further at this
165 : point. */
166 485097205 : if (!IS_EXPR_CODE_CLASS (kind) || kind == tcc_statement)
167 : {
168 : /* Except for variables which we can optimize to its initializer. */
169 228644647 : if (VAR_P (expr) && !lval && (optimize || in_init))
170 : {
171 14326762 : if (in_init)
172 466 : ret = decl_constant_value_1 (expr, true);
173 : else
174 : {
175 14326554 : ret = decl_constant_value (expr);
176 14326554 : if (ret != expr
177 14326554 : && (TYPE_MODE (TREE_TYPE (ret)) == BLKmode
178 15163 : || TREE_CODE (TREE_TYPE (ret)) == ARRAY_TYPE))
179 : return expr;
180 : }
181 : /* Avoid unwanted tree sharing between the initializer and current
182 : function's body where the tree can be modified e.g. by the
183 : gimplifier. */
184 14324493 : if (ret != expr && TREE_STATIC (expr))
185 5924 : ret = unshare_expr (ret);
186 14324493 : return ret;
187 : }
188 : return expr;
189 : }
190 :
191 256452558 : if (IS_EXPR_CODE_CLASS (kind))
192 256452558 : old_range = EXPR_LOCATION_RANGE (expr);
193 :
194 : /* Operands of variable-length expressions (function calls) have
195 : already been folded, as have __builtin_* function calls, and such
196 : expressions cannot occur in constant expressions. */
197 256452558 : if (kind == tcc_vl_exp)
198 : {
199 50124360 : *maybe_const_operands = false;
200 50124360 : ret = fold (expr);
201 50124360 : goto out;
202 : }
203 :
204 206328198 : if (code == C_MAYBE_CONST_EXPR)
205 : {
206 4527218 : tree pre = C_MAYBE_CONST_EXPR_PRE (expr);
207 4527218 : tree inner = C_MAYBE_CONST_EXPR_EXPR (expr);
208 4527218 : if (C_MAYBE_CONST_EXPR_NON_CONST (expr))
209 2169028 : *maybe_const_operands = false;
210 4527218 : if (C_MAYBE_CONST_EXPR_INT_OPERANDS (expr))
211 : {
212 1712 : *maybe_const_itself = false;
213 1712 : inner = c_fully_fold_internal (inner, in_init, maybe_const_operands,
214 : maybe_const_itself, true, lval);
215 : }
216 4527218 : if (pre && !in_init)
217 666 : ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr), pre, inner);
218 : else
219 : ret = inner;
220 4527218 : goto out;
221 : }
222 :
223 : /* Assignment, increment, decrement, function call and comma
224 : operators, and statement expressions, cannot occur in constant
225 : expressions if evaluated / outside of sizeof. (Function calls
226 : were handled above, though VA_ARG_EXPR is treated like a function
227 : call here, and statement expressions are handled through
228 : C_MAYBE_CONST_EXPR to avoid folding inside them.) */
229 201800980 : switch (code)
230 : {
231 4141817 : case MODIFY_EXPR:
232 4141817 : case PREDECREMENT_EXPR:
233 4141817 : case PREINCREMENT_EXPR:
234 4141817 : case POSTDECREMENT_EXPR:
235 4141817 : case POSTINCREMENT_EXPR:
236 4141817 : case COMPOUND_EXPR:
237 4141817 : *maybe_const_operands = false;
238 4141817 : break;
239 :
240 139589 : case VA_ARG_EXPR:
241 139589 : case TARGET_EXPR:
242 139589 : case BIND_EXPR:
243 139589 : case OBJ_TYPE_REF:
244 139589 : *maybe_const_operands = false;
245 139589 : ret = fold (expr);
246 139589 : goto out;
247 :
248 : default:
249 : break;
250 : }
251 :
252 : /* Fold individual tree codes as appropriate. */
253 201661391 : switch (code)
254 : {
255 918810 : case COMPOUND_LITERAL_EXPR:
256 : /* Any non-constancy will have been marked in a containing
257 : C_MAYBE_CONST_EXPR; there is no more folding to do here. */
258 918810 : goto out;
259 :
260 2810724 : case COMPONENT_REF:
261 2810724 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
262 2810724 : op1 = TREE_OPERAND (expr, 1);
263 2810724 : op2 = TREE_OPERAND (expr, 2);
264 2810724 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
265 : maybe_const_itself, for_int_const, lval);
266 5621448 : STRIP_TYPE_NOPS (op0);
267 2810724 : if (op0 != orig_op0)
268 10363 : ret = build3 (COMPONENT_REF, TREE_TYPE (expr), op0, op1, op2);
269 2810724 : if (ret != expr)
270 : {
271 10363 : TREE_READONLY (ret) = TREE_READONLY (expr);
272 10363 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
273 : }
274 2810724 : if (!lval)
275 2042103 : ret = fold (ret);
276 2810724 : goto out;
277 :
278 2918295 : case ARRAY_REF:
279 2918295 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
280 2918295 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
281 2918295 : op2 = TREE_OPERAND (expr, 2);
282 2918295 : op3 = TREE_OPERAND (expr, 3);
283 2918295 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
284 : maybe_const_itself, for_int_const, lval);
285 5836590 : STRIP_TYPE_NOPS (op0);
286 2918295 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
287 : maybe_const_itself, for_int_const, false);
288 5836590 : STRIP_TYPE_NOPS (op1);
289 : /* Fold "foo"[2] in initializers. */
290 2918295 : if (!lval && in_init)
291 : {
292 812 : ret = c_fold_array_ref (TREE_TYPE (expr), op0, op1);
293 812 : if (ret)
294 789 : goto out;
295 : ret = expr;
296 : }
297 2917506 : if (op0 != orig_op0 || op1 != orig_op1)
298 133791 : ret = build4 (ARRAY_REF, TREE_TYPE (expr), op0, op1, op2, op3);
299 2917506 : if (ret != expr)
300 : {
301 133791 : TREE_READONLY (ret) = TREE_READONLY (expr);
302 133791 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
303 133791 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
304 : }
305 2917506 : if (!lval)
306 2347011 : ret = fold (ret);
307 2917506 : goto out;
308 :
309 3882834 : case MODIFY_EXPR:
310 3882834 : case PREDECREMENT_EXPR:
311 3882834 : case PREINCREMENT_EXPR:
312 3882834 : case POSTDECREMENT_EXPR:
313 3882834 : case POSTINCREMENT_EXPR:
314 3882834 : op0_lval = true;
315 : /* FALLTHRU */
316 13598541 : case COMPOUND_EXPR:
317 13598541 : case PLUS_EXPR:
318 13598541 : case MINUS_EXPR:
319 13598541 : case MULT_EXPR:
320 13598541 : case POINTER_PLUS_EXPR:
321 13598541 : case POINTER_DIFF_EXPR:
322 13598541 : case TRUNC_DIV_EXPR:
323 13598541 : case CEIL_DIV_EXPR:
324 13598541 : case FLOOR_DIV_EXPR:
325 13598541 : case TRUNC_MOD_EXPR:
326 13598541 : case RDIV_EXPR:
327 13598541 : case EXACT_DIV_EXPR:
328 13598541 : case LSHIFT_EXPR:
329 13598541 : case RSHIFT_EXPR:
330 13598541 : case LROTATE_EXPR:
331 13598541 : case RROTATE_EXPR:
332 13598541 : case BIT_IOR_EXPR:
333 13598541 : case BIT_XOR_EXPR:
334 13598541 : case BIT_AND_EXPR:
335 13598541 : case LT_EXPR:
336 13598541 : case LE_EXPR:
337 13598541 : case GT_EXPR:
338 13598541 : case GE_EXPR:
339 13598541 : case EQ_EXPR:
340 13598541 : case NE_EXPR:
341 13598541 : case COMPLEX_EXPR:
342 13598541 : case TRUTH_AND_EXPR:
343 13598541 : case TRUTH_OR_EXPR:
344 13598541 : case TRUTH_XOR_EXPR:
345 13598541 : case UNORDERED_EXPR:
346 13598541 : case ORDERED_EXPR:
347 13598541 : case UNLT_EXPR:
348 13598541 : case UNLE_EXPR:
349 13598541 : case UNGT_EXPR:
350 13598541 : case UNGE_EXPR:
351 13598541 : case UNEQ_EXPR:
352 13598541 : case MEM_REF:
353 : /* Binary operations evaluating both arguments (increment and
354 : decrement are binary internally in GCC). */
355 13598541 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
356 13598541 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
357 13598541 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
358 : maybe_const_itself, for_int_const,
359 : op0_lval);
360 27197082 : STRIP_TYPE_NOPS (op0);
361 : /* The RHS of a MODIFY_EXPR was fully folded when building that
362 : expression for the sake of conversion warnings. */
363 13598541 : if (code != MODIFY_EXPR)
364 10654983 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
365 : maybe_const_itself, for_int_const, false);
366 13598592 : STRIP_TYPE_NOPS (op1);
367 :
368 13598541 : if (for_int_const && (TREE_CODE (op0) != INTEGER_CST
369 1272 : || TREE_CODE (op1) != INTEGER_CST))
370 271 : goto out;
371 :
372 13598270 : if (TREE_CODE_CLASS (code) == tcc_comparison
373 2459353 : && TREE_CODE (TREE_TYPE (op0)) == NULLPTR_TYPE
374 13598292 : && TREE_CODE (TREE_TYPE (op1)) == NULLPTR_TYPE)
375 : {
376 22 : switch (code)
377 : {
378 8 : case EQ_EXPR:
379 8 : ret = constant_boolean_node (true, TREE_TYPE (expr));
380 8 : break;
381 14 : case NE_EXPR:
382 14 : ret = constant_boolean_node (false, TREE_TYPE (expr));
383 14 : break;
384 0 : default:
385 0 : gcc_unreachable ();
386 : }
387 22 : ret = omit_two_operands_loc (loc, TREE_TYPE (expr), ret,
388 : op0, op1);
389 : }
390 13598248 : else if (op0 != orig_op0 || op1 != orig_op1 || in_init)
391 2544474 : ret = in_init
392 2546272 : ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
393 2541953 : : fold_build2_loc (loc, code, TREE_TYPE (expr), op0, op1);
394 : else
395 11051976 : ret = fold (expr);
396 266291 : if (TREE_OVERFLOW_P (ret)
397 23 : && !TREE_OVERFLOW_P (op0)
398 22 : && !(BINARY_CLASS_P (op0) && TREE_OVERFLOW_P (TREE_OPERAND (op0, 1)))
399 13598291 : && !TREE_OVERFLOW_P (op1))
400 20 : overflow_warning (EXPR_LOC_OR_LOC (expr, input_location), ret, expr);
401 13598270 : if (code == LSHIFT_EXPR
402 451065 : && TREE_CODE (orig_op0) != INTEGER_CST
403 366286 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
404 860 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
405 365746 : && TREE_CODE (op0) == INTEGER_CST
406 190 : && c_inhibit_evaluation_warnings == 0
407 83 : && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (orig_op0))
408 13598309 : && tree_int_cst_sgn (op0) < 0)
409 6 : warning_at (loc, OPT_Wshift_negative_value,
410 : "left shift of negative value");
411 13598270 : if ((code == LSHIFT_EXPR
412 : || code == RSHIFT_EXPR
413 : || code == LROTATE_EXPR
414 13598270 : || code == RROTATE_EXPR)
415 638809 : && TREE_CODE (orig_op1) != INTEGER_CST
416 145151 : && TREE_CODE (op1) == INTEGER_CST
417 519 : && TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
418 13598787 : && c_inhibit_evaluation_warnings == 0)
419 : {
420 327 : if (tree_int_cst_sgn (op1) < 0)
421 29 : warning_at (loc, OPT_Wshift_count_negative,
422 : (code == LSHIFT_EXPR
423 : ? G_("left shift count is negative")
424 : : G_("right shift count is negative")));
425 310 : else if ((TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
426 106 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE
427 12 : || TREE_CODE (TREE_TYPE (orig_op0)) == FIXED_POINT_TYPE)
428 298 : && compare_tree_int (op1,
429 298 : TYPE_PRECISION (TREE_TYPE (orig_op0)))
430 : >= 0
431 325 : && !warning_suppressed_p (expr, OPT_Wshift_count_overflow))
432 6 : warning_at (loc, OPT_Wshift_count_overflow,
433 : (code == LSHIFT_EXPR
434 : ? G_("left shift count >= width of type")
435 : : G_("right shift count >= width of type")));
436 306 : else if (TREE_CODE (TREE_TYPE (orig_op0)) == VECTOR_TYPE
437 318 : && compare_tree_int (op1,
438 12 : TYPE_PRECISION (TREE_TYPE (TREE_TYPE (orig_op0))))
439 : >= 0)
440 9 : warning_at (loc, OPT_Wshift_count_overflow,
441 : code == LSHIFT_EXPR
442 : ? G_("left shift count >= width of vector element")
443 : : G_("right shift count >= width of vector element"));
444 : }
445 13598270 : if (code == LSHIFT_EXPR
446 : /* If either OP0 has been folded to INTEGER_CST... */
447 451065 : && ((TREE_CODE (orig_op0) != INTEGER_CST
448 366286 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
449 860 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
450 365746 : && TREE_CODE (op0) == INTEGER_CST)
451 : /* ...or if OP1 has been folded to INTEGER_CST... */
452 450875 : || (TREE_CODE (orig_op1) != INTEGER_CST
453 113893 : && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
454 292 : || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE)
455 113631 : && TREE_CODE (op1) == INTEGER_CST))
456 13598676 : && c_inhibit_evaluation_warnings == 0)
457 : /* ...then maybe we can detect an overflow. */
458 218 : maybe_warn_shift_overflow (loc, op0, op1);
459 13598270 : if ((code == TRUNC_DIV_EXPR
460 : || code == CEIL_DIV_EXPR
461 13598270 : || code == FLOOR_DIV_EXPR
462 13598270 : || code == EXACT_DIV_EXPR
463 : || code == TRUNC_MOD_EXPR)
464 88898 : && TREE_CODE (orig_op1) != INTEGER_CST
465 11640 : && TREE_CODE (op1) == INTEGER_CST
466 89 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
467 0 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE
468 0 : || TREE_CODE (TREE_TYPE (orig_op0)) == FIXED_POINT_TYPE)
469 89 : && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
470 0 : || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE))
471 89 : warn_for_div_by_zero (loc, op1);
472 13598270 : if (code == MEM_REF
473 13598270 : && ret != expr
474 12335 : && TREE_CODE (ret) == MEM_REF)
475 : {
476 12335 : TREE_READONLY (ret) = TREE_READONLY (expr);
477 12335 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
478 12335 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
479 : }
480 13598270 : goto out;
481 :
482 52652132 : case ADDR_EXPR:
483 52652132 : op0_lval = true;
484 52652132 : goto unary;
485 94074497 : case REALPART_EXPR:
486 94074497 : case IMAGPART_EXPR:
487 94074497 : case VIEW_CONVERT_EXPR:
488 94074497 : op0_lval = lval;
489 : /* FALLTHRU */
490 180445052 : case INDIRECT_REF:
491 180445052 : case FIX_TRUNC_EXPR:
492 180445052 : case FLOAT_EXPR:
493 180445052 : CASE_CONVERT:
494 180445052 : case ADDR_SPACE_CONVERT_EXPR:
495 180445052 : case NON_LVALUE_EXPR:
496 180445052 : case NEGATE_EXPR:
497 180445052 : case BIT_NOT_EXPR:
498 180445052 : case TRUTH_NOT_EXPR:
499 180445052 : case CONJ_EXPR:
500 180445052 : case PAREN_EXPR:
501 180445052 : unary:
502 : /* Unary operations. */
503 180445052 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
504 180445052 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
505 : maybe_const_itself, for_int_const,
506 : op0_lval);
507 360890126 : STRIP_TYPE_NOPS (op0);
508 :
509 180445052 : if (for_int_const && TREE_CODE (op0) != INTEGER_CST)
510 14 : goto out;
511 :
512 : /* ??? Cope with user tricks that amount to offsetof. The middle-end is
513 : not prepared to deal with them if they occur in initializers. */
514 180445038 : if (op0 != orig_op0
515 180445038 : && code == ADDR_EXPR
516 517 : && (op1 = get_base_address (op0)) != NULL_TREE
517 517 : && INDIRECT_REF_P (op1)
518 180445201 : && TREE_CONSTANT (TREE_OPERAND (op1, 0)))
519 102 : ret = fold_offsetof (op0, TREE_TYPE (expr));
520 180444936 : else if (op0 != orig_op0 || in_init)
521 4175135 : ret = in_init
522 4175135 : ? fold_build1_initializer_loc (loc, code, TREE_TYPE (expr), op0)
523 1204897 : : fold_build1_loc (loc, code, TREE_TYPE (expr), op0);
524 : else
525 176269801 : ret = fold (expr);
526 180445038 : if (code == INDIRECT_REF
527 180445038 : && ret != expr
528 38947 : && INDIRECT_REF_P (ret))
529 : {
530 38849 : TREE_READONLY (ret) = TREE_READONLY (expr);
531 38849 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
532 38849 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
533 : }
534 180445038 : switch (code)
535 : {
536 : case FIX_TRUNC_EXPR:
537 : case FLOAT_EXPR:
538 : CASE_CONVERT:
539 : /* Don't warn about explicit conversions. We will already
540 : have warned about suspect implicit conversions. */
541 : break;
542 :
543 150818112 : default:
544 150818112 : if (TREE_OVERFLOW_P (ret) && !TREE_OVERFLOW_P (op0))
545 0 : overflow_warning (EXPR_LOCATION (expr), ret, op0);
546 : break;
547 : }
548 180445038 : goto out;
549 :
550 442041 : case TRUTH_ANDIF_EXPR:
551 442041 : case TRUTH_ORIF_EXPR:
552 : /* Binary operations not necessarily evaluating both
553 : arguments. */
554 442041 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
555 442041 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
556 442041 : op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
557 : for_int_const, false);
558 884082 : STRIP_TYPE_NOPS (op0);
559 :
560 884082 : unused_p = (op0 == (code == TRUTH_ANDIF_EXPR
561 442041 : ? truthvalue_false_node
562 : : truthvalue_true_node));
563 442041 : c_disable_warnings (unused_p);
564 442041 : op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
565 : for_int_const, false);
566 884082 : STRIP_TYPE_NOPS (op1);
567 442041 : c_enable_warnings (unused_p);
568 :
569 442041 : if (for_int_const
570 50 : && (TREE_CODE (op0) != INTEGER_CST
571 : /* Require OP1 be an INTEGER_CST only if it's evaluated. */
572 36 : || (!unused_p && TREE_CODE (op1) != INTEGER_CST)))
573 40 : goto out;
574 :
575 442001 : if (op0 != orig_op0 || op1 != orig_op1 || in_init)
576 432453 : ret = in_init
577 432453 : ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
578 432438 : : fold_build2_loc (loc, code, TREE_TYPE (expr), op0, op1);
579 : else
580 9548 : ret = fold (expr);
581 442001 : *maybe_const_operands &= op0_const;
582 442001 : *maybe_const_itself &= op0_const_self;
583 781716 : if (!(flag_isoc99
584 438494 : && op0_const
585 339715 : && op0_const_self
586 : && (code == TRUTH_ANDIF_EXPR
587 124859 : ? op0 == truthvalue_false_node
588 214856 : : op0 == truthvalue_true_node)))
589 432452 : *maybe_const_operands &= op1_const;
590 784473 : if (!(op0_const
591 342472 : && op0_const_self
592 : && (code == TRUTH_ANDIF_EXPR
593 125142 : ? op0 == truthvalue_false_node
594 217330 : : op0 == truthvalue_true_node)))
595 432436 : *maybe_const_itself &= op1_const_self;
596 442001 : goto out;
597 :
598 267482 : case COND_EXPR:
599 267482 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
600 267482 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
601 267482 : orig_op2 = op2 = TREE_OPERAND (expr, 2);
602 267482 : op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
603 : for_int_const, false);
604 :
605 534964 : STRIP_TYPE_NOPS (op0);
606 267482 : c_disable_warnings (op0 == truthvalue_false_node);
607 267482 : op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
608 : for_int_const, false);
609 534964 : STRIP_TYPE_NOPS (op1);
610 267482 : c_enable_warnings (op0 == truthvalue_false_node);
611 :
612 267482 : c_disable_warnings (op0 == truthvalue_true_node);
613 267482 : op2 = c_fully_fold_internal (op2, in_init, &op2_const, &op2_const_self,
614 : for_int_const, false);
615 534970 : STRIP_TYPE_NOPS (op2);
616 267482 : c_enable_warnings (op0 == truthvalue_true_node);
617 :
618 267482 : if (for_int_const
619 76 : && (TREE_CODE (op0) != INTEGER_CST
620 : /* Only the evaluated operand must be an INTEGER_CST. */
621 41 : || (op0 == truthvalue_true_node
622 14 : ? TREE_CODE (op1) != INTEGER_CST
623 27 : : TREE_CODE (op2) != INTEGER_CST)))
624 62 : goto out;
625 :
626 267420 : if (op0 != orig_op0 || op1 != orig_op1 || op2 != orig_op2)
627 210603 : ret = fold_build3_loc (loc, code, TREE_TYPE (expr), op0, op1, op2);
628 : else
629 56817 : ret = fold (expr);
630 267420 : *maybe_const_operands &= op0_const;
631 267420 : *maybe_const_itself &= op0_const_self;
632 267420 : if (!(flag_isoc99
633 266113 : && op0_const
634 190452 : && op0_const_self
635 190452 : && op0 == truthvalue_false_node))
636 252849 : *maybe_const_operands &= op1_const;
637 267420 : if (!(op0_const
638 191555 : && op0_const_self
639 191555 : && op0 == truthvalue_false_node))
640 252503 : *maybe_const_itself &= op1_const_self;
641 267420 : if (!(flag_isoc99
642 266113 : && op0_const
643 190452 : && op0_const_self
644 190452 : && op0 == truthvalue_true_node))
645 223733 : *maybe_const_operands &= op2_const;
646 267420 : if (!(op0_const
647 191555 : && op0_const_self
648 191555 : && op0 == truthvalue_true_node))
649 223619 : *maybe_const_itself &= op2_const_self;
650 267420 : goto out;
651 :
652 100938 : case VEC_COND_EXPR:
653 100938 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
654 100938 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
655 100938 : orig_op2 = op2 = TREE_OPERAND (expr, 2);
656 100938 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
657 : maybe_const_itself, for_int_const, false);
658 201876 : STRIP_TYPE_NOPS (op0);
659 100938 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
660 : maybe_const_itself, for_int_const, false);
661 201876 : STRIP_TYPE_NOPS (op1);
662 100938 : op2 = c_fully_fold_internal (op2, in_init, maybe_const_operands,
663 : maybe_const_itself, for_int_const, false);
664 201876 : STRIP_TYPE_NOPS (op2);
665 :
666 100938 : if (op0 != orig_op0 || op1 != orig_op1 || op2 != orig_op2)
667 558 : ret = fold_build3_loc (loc, code, TREE_TYPE (expr), op0, op1, op2);
668 : else
669 100380 : ret = fold (expr);
670 100938 : goto out;
671 :
672 0 : case EXCESS_PRECISION_EXPR:
673 : /* Each case where an operand with excess precision may be
674 : encountered must remove the EXCESS_PRECISION_EXPR around
675 : inner operands and possibly put one around the whole
676 : expression or possibly convert to the semantic type (which
677 : c_fully_fold does); we cannot tell at this stage which is
678 : appropriate in any particular case. */
679 0 : gcc_unreachable ();
680 :
681 149948 : case SAVE_EXPR:
682 : /* Make sure to fold the contents of a SAVE_EXPR exactly once. */
683 149948 : op0 = TREE_OPERAND (expr, 0);
684 149948 : if (!SAVE_EXPR_FOLDED_P (expr))
685 : {
686 70911 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
687 : maybe_const_itself, for_int_const,
688 : false);
689 70911 : TREE_OPERAND (expr, 0) = op0;
690 70911 : SAVE_EXPR_FOLDED_P (expr) = true;
691 : }
692 : /* Return the SAVE_EXPR operand if it is invariant. */
693 149948 : if (tree_invariant_p (op0))
694 3390 : ret = op0;
695 149948 : goto out;
696 :
697 9560 : default:
698 : /* Various codes may appear through folding built-in functions
699 : and their arguments. */
700 9560 : goto out;
701 : }
702 :
703 256452558 : out:
704 : /* Some folding may introduce NON_LVALUE_EXPRs; all lvalue checks
705 : have been done by this point, so remove them again. */
706 256452558 : nowarning |= warning_suppressed_p (ret, OPT_Woverflow);
707 256627114 : STRIP_TYPE_NOPS (ret);
708 256452558 : if (nowarning && !warning_suppressed_p (ret, OPT_Woverflow))
709 : {
710 12275 : if (!CAN_HAVE_LOCATION_P (ret))
711 804 : ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
712 12275 : suppress_warning (ret, OPT_Woverflow);
713 : }
714 256452558 : if (ret != expr)
715 : {
716 13362670 : protected_set_expr_location (ret, loc);
717 13362670 : if (IS_EXPR_CODE_CLASS (kind))
718 13362670 : set_source_range (ret, old_range.m_start, old_range.m_finish);
719 : }
720 : return ret;
721 : }
722 :
723 : /* Fold X for consideration by one of the warning functions when checking
724 : whether an expression has a constant value. */
725 :
726 : tree
727 128670829 : fold_for_warn (tree x)
728 : {
729 : /* The C front-end has already folded X appropriately. */
730 128670829 : return x;
731 : }
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