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1 : : /* Support for fully folding sub-trees of an expression for C compiler.
2 : : Copyright (C) 1992-2025 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 : 956543 : c_disable_warnings (bool disable)
39 : : {
40 : 956543 : if (disable)
41 : : {
42 : 68631 : ++c_inhibit_evaluation_warnings;
43 : 68631 : fold_defer_overflow_warnings ();
44 : : }
45 : 956543 : }
46 : :
47 : : /* If ENABLE is true, reenable issuing warnings. */
48 : :
49 : : static void
50 : 956543 : c_enable_warnings (bool enable)
51 : : {
52 : 956543 : if (enable)
53 : : {
54 : 68631 : --c_inhibit_evaluation_warnings;
55 : 68631 : fold_undefer_and_ignore_overflow_warnings ();
56 : : }
57 : 956543 : }
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 : 263315045 : c_fully_fold (tree expr, bool in_init, bool *maybe_const, bool lval)
112 : : {
113 : 263315045 : tree ret;
114 : 263315045 : tree eptype = NULL_TREE;
115 : 263315045 : bool dummy = true;
116 : 263315045 : bool maybe_const_itself = true;
117 : 263315045 : location_t loc = EXPR_LOCATION (expr);
118 : :
119 : 263315045 : if (!maybe_const)
120 : 228489152 : maybe_const = &dummy;
121 : 263315045 : if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
122 : : {
123 : 742 : eptype = TREE_TYPE (expr);
124 : 742 : expr = TREE_OPERAND (expr, 0);
125 : : }
126 : 263315045 : ret = c_fully_fold_internal (expr, in_init, maybe_const,
127 : : &maybe_const_itself, false, lval);
128 : 263315045 : if (eptype)
129 : 742 : ret = fold_convert_loc (loc, eptype, ret);
130 : 263315045 : *maybe_const &= maybe_const_itself;
131 : 263315045 : 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 : 473469437 : 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 : 473469437 : tree ret = expr;
151 : 473469437 : enum tree_code code = TREE_CODE (expr);
152 : 473469437 : enum tree_code_class kind = TREE_CODE_CLASS (code);
153 : 473469437 : location_t loc = EXPR_LOCATION (expr);
154 : 473469437 : tree op0, op1, op2, op3;
155 : 473469437 : tree orig_op0, orig_op1, orig_op2;
156 : 473469437 : bool op0_const = true, op1_const = true, op2_const = true;
157 : 473469437 : bool op0_const_self = true, op1_const_self = true, op2_const_self = true;
158 : 473469437 : bool nowarning = warning_suppressed_p (expr, OPT_Woverflow);
159 : 473469437 : bool unused_p;
160 : 473469437 : bool op0_lval = false;
161 : 473469437 : 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 : 473469437 : if (!IS_EXPR_CODE_CLASS (kind) || kind == tcc_statement)
167 : : {
168 : : /* Except for variables which we can optimize to its initializer. */
169 : 223321978 : if (VAR_P (expr) && !lval && (optimize || in_init))
170 : : {
171 : 13982118 : if (in_init)
172 : 466 : ret = decl_constant_value_1 (expr, true);
173 : : else
174 : : {
175 : 13981910 : ret = decl_constant_value (expr);
176 : 13981910 : if (ret != expr
177 : 13981910 : && (TYPE_MODE (TREE_TYPE (ret)) == BLKmode
178 : 14781 : || 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 : 13979852 : if (ret != expr && TREE_STATIC (expr))
185 : 5924 : ret = unshare_expr (ret);
186 : 13979852 : return ret;
187 : : }
188 : : return expr;
189 : : }
190 : :
191 : 250147459 : if (IS_EXPR_CODE_CLASS (kind))
192 : 250147459 : 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 : 250147459 : if (kind == tcc_vl_exp)
198 : : {
199 : 48879679 : *maybe_const_operands = false;
200 : 48879679 : ret = fold (expr);
201 : 48879679 : goto out;
202 : : }
203 : :
204 : 201267780 : if (code == C_MAYBE_CONST_EXPR)
205 : : {
206 : 4417061 : tree pre = C_MAYBE_CONST_EXPR_PRE (expr);
207 : 4417061 : tree inner = C_MAYBE_CONST_EXPR_EXPR (expr);
208 : 4417061 : if (C_MAYBE_CONST_EXPR_NON_CONST (expr))
209 : 2127419 : *maybe_const_operands = false;
210 : 4417061 : if (C_MAYBE_CONST_EXPR_INT_OPERANDS (expr))
211 : : {
212 : 1710 : *maybe_const_itself = false;
213 : 1710 : inner = c_fully_fold_internal (inner, in_init, maybe_const_operands,
214 : : maybe_const_itself, true, lval);
215 : : }
216 : 4417061 : if (pre && !in_init)
217 : 679 : ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr), pre, inner);
218 : : else
219 : : ret = inner;
220 : 4417061 : 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 : 196850719 : switch (code)
230 : : {
231 : 4064087 : case MODIFY_EXPR:
232 : 4064087 : case PREDECREMENT_EXPR:
233 : 4064087 : case PREINCREMENT_EXPR:
234 : 4064087 : case POSTDECREMENT_EXPR:
235 : 4064087 : case POSTINCREMENT_EXPR:
236 : 4064087 : case COMPOUND_EXPR:
237 : 4064087 : *maybe_const_operands = false;
238 : 4064087 : break;
239 : :
240 : 139337 : case VA_ARG_EXPR:
241 : 139337 : case TARGET_EXPR:
242 : 139337 : case BIND_EXPR:
243 : 139337 : case OBJ_TYPE_REF:
244 : 139337 : *maybe_const_operands = false;
245 : 139337 : ret = fold (expr);
246 : 139337 : goto out;
247 : :
248 : : default:
249 : : break;
250 : : }
251 : :
252 : : /* Fold individual tree codes as appropriate. */
253 : 196711382 : switch (code)
254 : : {
255 : 897746 : 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 : 897746 : goto out;
259 : :
260 : 2752750 : case COMPONENT_REF:
261 : 2752750 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
262 : 2752750 : op1 = TREE_OPERAND (expr, 1);
263 : 2752750 : op2 = TREE_OPERAND (expr, 2);
264 : 2752750 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
265 : : maybe_const_itself, for_int_const, lval);
266 : 5505500 : STRIP_TYPE_NOPS (op0);
267 : 2752750 : if (op0 != orig_op0)
268 : 10360 : ret = build3 (COMPONENT_REF, TREE_TYPE (expr), op0, op1, op2);
269 : 2752750 : if (ret != expr)
270 : : {
271 : 10360 : TREE_READONLY (ret) = TREE_READONLY (expr);
272 : 10360 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
273 : : }
274 : 2752750 : if (!lval)
275 : 1996944 : ret = fold (ret);
276 : 2752750 : goto out;
277 : :
278 : 2865979 : case ARRAY_REF:
279 : 2865979 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
280 : 2865979 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
281 : 2865979 : op2 = TREE_OPERAND (expr, 2);
282 : 2865979 : op3 = TREE_OPERAND (expr, 3);
283 : 2865979 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
284 : : maybe_const_itself, for_int_const, lval);
285 : 5731958 : STRIP_TYPE_NOPS (op0);
286 : 2865979 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
287 : : maybe_const_itself, for_int_const, false);
288 : 5731958 : STRIP_TYPE_NOPS (op1);
289 : : /* Fold "foo"[2] in initializers. */
290 : 2865979 : 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 : 2865190 : if (op0 != orig_op0 || op1 != orig_op1)
298 : 131383 : ret = build4 (ARRAY_REF, TREE_TYPE (expr), op0, op1, op2, op3);
299 : 2865190 : if (ret != expr)
300 : : {
301 : 131383 : TREE_READONLY (ret) = TREE_READONLY (expr);
302 : 131383 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
303 : 131383 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
304 : : }
305 : 2865190 : if (!lval)
306 : 2299194 : ret = fold (ret);
307 : 2865190 : goto out;
308 : :
309 : 3806162 : case MODIFY_EXPR:
310 : 3806162 : case PREDECREMENT_EXPR:
311 : 3806162 : case PREINCREMENT_EXPR:
312 : 3806162 : case POSTDECREMENT_EXPR:
313 : 3806162 : case POSTINCREMENT_EXPR:
314 : 3806162 : op0_lval = true;
315 : : /* FALLTHRU */
316 : 13293521 : case COMPOUND_EXPR:
317 : 13293521 : case PLUS_EXPR:
318 : 13293521 : case MINUS_EXPR:
319 : 13293521 : case MULT_EXPR:
320 : 13293521 : case POINTER_PLUS_EXPR:
321 : 13293521 : case POINTER_DIFF_EXPR:
322 : 13293521 : case TRUNC_DIV_EXPR:
323 : 13293521 : case CEIL_DIV_EXPR:
324 : 13293521 : case FLOOR_DIV_EXPR:
325 : 13293521 : case TRUNC_MOD_EXPR:
326 : 13293521 : case RDIV_EXPR:
327 : 13293521 : case EXACT_DIV_EXPR:
328 : 13293521 : case LSHIFT_EXPR:
329 : 13293521 : case RSHIFT_EXPR:
330 : 13293521 : case LROTATE_EXPR:
331 : 13293521 : case RROTATE_EXPR:
332 : 13293521 : case BIT_IOR_EXPR:
333 : 13293521 : case BIT_XOR_EXPR:
334 : 13293521 : case BIT_AND_EXPR:
335 : 13293521 : case LT_EXPR:
336 : 13293521 : case LE_EXPR:
337 : 13293521 : case GT_EXPR:
338 : 13293521 : case GE_EXPR:
339 : 13293521 : case EQ_EXPR:
340 : 13293521 : case NE_EXPR:
341 : 13293521 : case COMPLEX_EXPR:
342 : 13293521 : case TRUTH_AND_EXPR:
343 : 13293521 : case TRUTH_OR_EXPR:
344 : 13293521 : case TRUTH_XOR_EXPR:
345 : 13293521 : case UNORDERED_EXPR:
346 : 13293521 : case ORDERED_EXPR:
347 : 13293521 : case UNLT_EXPR:
348 : 13293521 : case UNLE_EXPR:
349 : 13293521 : case UNGT_EXPR:
350 : 13293521 : case UNGE_EXPR:
351 : 13293521 : case UNEQ_EXPR:
352 : 13293521 : case MEM_REF:
353 : : /* Binary operations evaluating both arguments (increment and
354 : : decrement are binary internally in GCC). */
355 : 13293521 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
356 : 13293521 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
357 : 13293521 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
358 : : maybe_const_itself, for_int_const,
359 : : op0_lval);
360 : 26587042 : 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 : 13293521 : if (code != MODIFY_EXPR)
364 : 10405891 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
365 : : maybe_const_itself, for_int_const, false);
366 : 13293572 : STRIP_TYPE_NOPS (op1);
367 : :
368 : 13293521 : if (for_int_const && (TREE_CODE (op0) != INTEGER_CST
369 : 1272 : || TREE_CODE (op1) != INTEGER_CST))
370 : 271 : goto out;
371 : :
372 : 13293250 : if (TREE_CODE_CLASS (code) == tcc_comparison
373 : 2406828 : && TREE_CODE (TREE_TYPE (op0)) == NULLPTR_TYPE
374 : 13293272 : && 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 : 13293228 : else if (op0 != orig_op0 || op1 != orig_op1 || in_init)
391 : 2490899 : ret = in_init
392 : 2492697 : ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
393 : 2488378 : : fold_build2_loc (loc, code, TREE_TYPE (expr), op0, op1);
394 : : else
395 : 10800531 : ret = fold (expr);
396 : 265947 : 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 : 13293271 : && !TREE_OVERFLOW_P (op1))
400 : 20 : overflow_warning (EXPR_LOC_OR_LOC (expr, input_location), ret, expr);
401 : 13293250 : if (code == LSHIFT_EXPR
402 : 437940 : && TREE_CODE (orig_op0) != INTEGER_CST
403 : 357904 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
404 : 845 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
405 : 357364 : && TREE_CODE (op0) == INTEGER_CST
406 : 190 : && c_inhibit_evaluation_warnings == 0
407 : 83 : && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (orig_op0))
408 : 13293289 : && tree_int_cst_sgn (op0) < 0)
409 : 6 : warning_at (loc, OPT_Wshift_negative_value,
410 : : "left shift of negative value");
411 : 13293250 : if ((code == LSHIFT_EXPR
412 : : || code == RSHIFT_EXPR
413 : : || code == LROTATE_EXPR
414 : 13293250 : || code == RROTATE_EXPR)
415 : 621210 : && TREE_CODE (orig_op1) != INTEGER_CST
416 : 139256 : && TREE_CODE (op1) == INTEGER_CST
417 : 519 : && TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
418 : 13293767 : && 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 : 13293250 : if (code == LSHIFT_EXPR
446 : : /* If either OP0 has been folded to INTEGER_CST... */
447 : 437940 : && ((TREE_CODE (orig_op0) != INTEGER_CST
448 : 357904 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
449 : 845 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
450 : 357364 : && TREE_CODE (op0) == INTEGER_CST)
451 : : /* ...or if OP1 has been folded to INTEGER_CST... */
452 : 437750 : || (TREE_CODE (orig_op1) != INTEGER_CST
453 : 108546 : && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
454 : 292 : || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE)
455 : 108284 : && TREE_CODE (op1) == INTEGER_CST))
456 : 13293656 : && c_inhibit_evaluation_warnings == 0)
457 : : /* ...then maybe we can detect an overflow. */
458 : 218 : maybe_warn_shift_overflow (loc, op0, op1);
459 : 13293250 : if ((code == TRUNC_DIV_EXPR
460 : : || code == CEIL_DIV_EXPR
461 : 13293250 : || code == FLOOR_DIV_EXPR
462 : 13293250 : || code == EXACT_DIV_EXPR
463 : : || code == TRUNC_MOD_EXPR)
464 : 85919 : && TREE_CODE (orig_op1) != INTEGER_CST
465 : 10601 : && TREE_CODE (op1) == INTEGER_CST
466 : 81 : && (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 : 81 : && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
470 : 0 : || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE))
471 : 81 : warn_for_div_by_zero (loc, op1);
472 : 13293250 : if (code == MEM_REF
473 : 13293250 : && ret != expr
474 : 12334 : && TREE_CODE (ret) == MEM_REF)
475 : : {
476 : 12334 : TREE_READONLY (ret) = TREE_READONLY (expr);
477 : 12334 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
478 : 12334 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
479 : : }
480 : 13293250 : goto out;
481 : :
482 : 51400709 : case ADDR_EXPR:
483 : 51400709 : op0_lval = true;
484 : 51400709 : goto unary;
485 : 91635909 : case REALPART_EXPR:
486 : 91635909 : case IMAGPART_EXPR:
487 : 91635909 : case VIEW_CONVERT_EXPR:
488 : 91635909 : op0_lval = lval;
489 : : /* FALLTHRU */
490 : 175948935 : case INDIRECT_REF:
491 : 175948935 : case FIX_TRUNC_EXPR:
492 : 175948935 : case FLOAT_EXPR:
493 : 175948935 : CASE_CONVERT:
494 : 175948935 : case ADDR_SPACE_CONVERT_EXPR:
495 : 175948935 : case NON_LVALUE_EXPR:
496 : 175948935 : case NEGATE_EXPR:
497 : 175948935 : case BIT_NOT_EXPR:
498 : 175948935 : case TRUTH_NOT_EXPR:
499 : 175948935 : case CONJ_EXPR:
500 : 175948935 : case PAREN_EXPR:
501 : 175948935 : unary:
502 : : /* Unary operations. */
503 : 175948935 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
504 : 175948935 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
505 : : maybe_const_itself, for_int_const,
506 : : op0_lval);
507 : 351897892 : STRIP_TYPE_NOPS (op0);
508 : :
509 : 175948935 : 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 : 175948921 : if (op0 != orig_op0
515 : 175948921 : && code == ADDR_EXPR
516 : 515 : && (op1 = get_base_address (op0)) != NULL_TREE
517 : 515 : && INDIRECT_REF_P (op1)
518 : 175949084 : && TREE_CONSTANT (TREE_OPERAND (op1, 0)))
519 : 102 : ret = fold_offsetof (op0, TREE_TYPE (expr));
520 : 175948819 : else if (op0 != orig_op0 || in_init)
521 : 4151080 : ret = in_init
522 : 4151080 : ? fold_build1_initializer_loc (loc, code, TREE_TYPE (expr), op0)
523 : 1180986 : : fold_build1_loc (loc, code, TREE_TYPE (expr), op0);
524 : : else
525 : 171797739 : ret = fold (expr);
526 : 175948921 : if (code == INDIRECT_REF
527 : 175948921 : && ret != expr
528 : 38416 : && INDIRECT_REF_P (ret))
529 : : {
530 : 38318 : TREE_READONLY (ret) = TREE_READONLY (expr);
531 : 38318 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
532 : 38318 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
533 : : }
534 : 175948921 : 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 : 147023552 : default:
544 : 147023552 : if (TREE_OVERFLOW_P (ret) && !TREE_OVERFLOW_P (op0))
545 : 0 : overflow_warning (EXPR_LOCATION (expr), ret, op0);
546 : : break;
547 : : }
548 : 175948921 : goto out;
549 : :
550 : 434443 : case TRUTH_ANDIF_EXPR:
551 : 434443 : case TRUTH_ORIF_EXPR:
552 : : /* Binary operations not necessarily evaluating both
553 : : arguments. */
554 : 434443 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
555 : 434443 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
556 : 434443 : op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
557 : : for_int_const, false);
558 : 868886 : STRIP_TYPE_NOPS (op0);
559 : :
560 : 868886 : unused_p = (op0 == (code == TRUTH_ANDIF_EXPR
561 : 434443 : ? truthvalue_false_node
562 : : : truthvalue_true_node));
563 : 434443 : c_disable_warnings (unused_p);
564 : 434443 : op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
565 : : for_int_const, false);
566 : 868886 : STRIP_TYPE_NOPS (op1);
567 : 434443 : c_enable_warnings (unused_p);
568 : :
569 : 434443 : 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 : 434403 : if (op0 != orig_op0 || op1 != orig_op1 || in_init)
576 : 424984 : ret = in_init
577 : 424984 : ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
578 : 424969 : : fold_build2_loc (loc, code, TREE_TYPE (expr), op0, op1);
579 : : else
580 : 9419 : ret = fold (expr);
581 : 434403 : *maybe_const_operands &= op0_const;
582 : 434403 : *maybe_const_itself &= op0_const_self;
583 : 767021 : if (!(flag_isoc99
584 : 430905 : && op0_const
585 : 332618 : && op0_const_self
586 : : && (code == TRUTH_ANDIF_EXPR
587 : 120394 : ? op0 == truthvalue_false_node
588 : 212224 : : op0 == truthvalue_true_node)))
589 : 424856 : *maybe_const_operands &= op1_const;
590 : 769769 : if (!(op0_const
591 : 335366 : && op0_const_self
592 : : && (code == TRUTH_ANDIF_EXPR
593 : 120672 : ? op0 == truthvalue_false_node
594 : 214694 : : op0 == truthvalue_true_node)))
595 : 424840 : *maybe_const_itself &= op1_const_self;
596 : 434403 : goto out;
597 : :
598 : 261050 : case COND_EXPR:
599 : 261050 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
600 : 261050 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
601 : 261050 : orig_op2 = op2 = TREE_OPERAND (expr, 2);
602 : 261050 : op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
603 : : for_int_const, false);
604 : :
605 : 522100 : STRIP_TYPE_NOPS (op0);
606 : 261050 : c_disable_warnings (op0 == truthvalue_false_node);
607 : 261050 : op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
608 : : for_int_const, false);
609 : 522100 : STRIP_TYPE_NOPS (op1);
610 : 261050 : c_enable_warnings (op0 == truthvalue_false_node);
611 : :
612 : 261050 : c_disable_warnings (op0 == truthvalue_true_node);
613 : 261050 : op2 = c_fully_fold_internal (op2, in_init, &op2_const, &op2_const_self,
614 : : for_int_const, false);
615 : 522106 : STRIP_TYPE_NOPS (op2);
616 : 261050 : c_enable_warnings (op0 == truthvalue_true_node);
617 : :
618 : 261050 : 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 : 260988 : if (op0 != orig_op0 || op1 != orig_op1 || op2 != orig_op2)
627 : 204349 : ret = fold_build3_loc (loc, code, TREE_TYPE (expr), op0, op1, op2);
628 : : else
629 : 56639 : ret = fold (expr);
630 : 260988 : *maybe_const_operands &= op0_const;
631 : 260988 : *maybe_const_itself &= op0_const_self;
632 : 260988 : if (!(flag_isoc99
633 : 259686 : && op0_const
634 : 184985 : && op0_const_self
635 : 184985 : && op0 == truthvalue_false_node))
636 : 246417 : *maybe_const_operands &= op1_const;
637 : 260988 : if (!(op0_const
638 : 186083 : && op0_const_self
639 : 186083 : && op0 == truthvalue_false_node))
640 : 246071 : *maybe_const_itself &= op1_const_self;
641 : 260988 : if (!(flag_isoc99
642 : 259686 : && op0_const
643 : 184985 : && op0_const_self
644 : 184985 : && op0 == truthvalue_true_node))
645 : 217361 : *maybe_const_operands &= op2_const;
646 : 260988 : if (!(op0_const
647 : 186083 : && op0_const_self
648 : 186083 : && op0 == truthvalue_true_node))
649 : 217247 : *maybe_const_itself &= op2_const_self;
650 : 260988 : goto out;
651 : :
652 : 98683 : case VEC_COND_EXPR:
653 : 98683 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
654 : 98683 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
655 : 98683 : orig_op2 = op2 = TREE_OPERAND (expr, 2);
656 : 98683 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
657 : : maybe_const_itself, for_int_const, false);
658 : 197366 : STRIP_TYPE_NOPS (op0);
659 : 98683 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
660 : : maybe_const_itself, for_int_const, false);
661 : 197366 : STRIP_TYPE_NOPS (op1);
662 : 98683 : op2 = c_fully_fold_internal (op2, in_init, maybe_const_operands,
663 : : maybe_const_itself, for_int_const, false);
664 : 197366 : STRIP_TYPE_NOPS (op2);
665 : :
666 : 98683 : if (op0 != orig_op0 || op1 != orig_op1 || op2 != orig_op2)
667 : 551 : ret = fold_build3_loc (loc, code, TREE_TYPE (expr), op0, op1, op2);
668 : : else
669 : 98132 : ret = fold (expr);
670 : 98683 : 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 : 149637 : case SAVE_EXPR:
682 : : /* Make sure to fold the contents of a SAVE_EXPR exactly once. */
683 : 149637 : op0 = TREE_OPERAND (expr, 0);
684 : 149637 : if (!SAVE_EXPR_FOLDED_P (expr))
685 : : {
686 : 70752 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
687 : : maybe_const_itself, for_int_const,
688 : : false);
689 : 70752 : TREE_OPERAND (expr, 0) = op0;
690 : 70752 : SAVE_EXPR_FOLDED_P (expr) = true;
691 : : }
692 : : /* Return the SAVE_EXPR operand if it is invariant. */
693 : 149637 : if (tree_invariant_p (op0))
694 : 3390 : ret = op0;
695 : 149637 : goto out;
696 : :
697 : 8638 : default:
698 : : /* Various codes may appear through folding built-in functions
699 : : and their arguments. */
700 : 8638 : goto out;
701 : : }
702 : :
703 : 250147459 : out:
704 : : /* Some folding may introduce NON_LVALUE_EXPRs; all lvalue checks
705 : : have been done by this point, so remove them again. */
706 : 250147459 : nowarning |= warning_suppressed_p (ret, OPT_Woverflow);
707 : 250317440 : STRIP_TYPE_NOPS (ret);
708 : 250147459 : if (nowarning && !warning_suppressed_p (ret, OPT_Woverflow))
709 : : {
710 : 12197 : if (!CAN_HAVE_LOCATION_P (ret))
711 : 804 : ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
712 : 12197 : suppress_warning (ret, OPT_Woverflow);
713 : : }
714 : 250147459 : if (ret != expr)
715 : : {
716 : 13137253 : protected_set_expr_location (ret, loc);
717 : 13137253 : if (IS_EXPR_CODE_CLASS (kind))
718 : 13137253 : 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 : 125510066 : fold_for_warn (tree x)
728 : : {
729 : : /* The C front-end has already folded X appropriately. */
730 : 125510066 : return x;
731 : : }
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