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 970156 : c_disable_warnings (bool disable)
39 : {
40 0 : if (disable)
41 : {
42 70545 : ++c_inhibit_evaluation_warnings;
43 : }
44 0 : }
45 :
46 : /* If ENABLE is true, re-enable issuing warnings. */
47 :
48 : static void
49 970156 : c_enable_warnings (bool enable)
50 : {
51 0 : if (enable)
52 : {
53 70545 : --c_inhibit_evaluation_warnings;
54 : }
55 0 : }
56 :
57 : /* Try to fold ARRAY_REF ary[index] if possible and not handled by
58 : normal fold, return NULL_TREE otherwise. */
59 :
60 : static tree
61 812 : c_fold_array_ref (tree type, tree ary, tree index)
62 : {
63 812 : if (TREE_CODE (ary) != STRING_CST
64 792 : || TREE_CODE (index) != INTEGER_CST
65 792 : || TREE_OVERFLOW (index)
66 791 : || TREE_CODE (TREE_TYPE (ary)) != ARRAY_TYPE
67 1603 : || !tree_fits_uhwi_p (index))
68 : return NULL_TREE;
69 :
70 790 : tree elem_type = TREE_TYPE (TREE_TYPE (ary));
71 790 : unsigned elem_nchars = (TYPE_PRECISION (elem_type)
72 790 : / TYPE_PRECISION (char_type_node));
73 790 : unsigned len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars;
74 790 : tree nelts_minus_one = array_type_nelts_minus_one (TREE_TYPE (ary));
75 790 : bool dummy1 = true, dummy2 = true;
76 790 : nelts_minus_one = c_fully_fold_internal (nelts_minus_one, true, &dummy1,
77 : &dummy2, false, false);
78 790 : unsigned HOST_WIDE_INT i = tree_to_uhwi (index);
79 790 : if (!tree_int_cst_le (index, nelts_minus_one)
80 789 : || i >= len
81 1579 : || i + elem_nchars > len)
82 : return NULL_TREE;
83 :
84 789 : if (elem_nchars == 1)
85 789 : return build_int_cst (type, TREE_STRING_POINTER (ary)[i]);
86 :
87 0 : const unsigned char *ptr
88 0 : = ((const unsigned char *)TREE_STRING_POINTER (ary) + i * elem_nchars);
89 0 : return native_interpret_expr (type, ptr, elem_nchars);
90 : }
91 :
92 : /* Fully fold EXPR, an expression that was not folded (beyond integer
93 : constant expressions and null pointer constants) when being built
94 : up. If IN_INIT, this is in a static initializer and certain
95 : changes are made to the folding done. Clear *MAYBE_CONST if
96 : MAYBE_CONST is not NULL and EXPR is definitely not a constant
97 : expression because it contains an evaluated operator (in C99) or an
98 : operator outside of sizeof returning an integer constant (in C90)
99 : not permitted in constant expressions, or because it contains an
100 : evaluated arithmetic overflow. (*MAYBE_CONST should typically be
101 : set to true by callers before calling this function.) Return the
102 : folded expression. Function arguments have already been folded
103 : before calling this function, as have the contents of SAVE_EXPR,
104 : TARGET_EXPR, BIND_EXPR, VA_ARG_EXPR, OBJ_TYPE_REF and
105 : C_MAYBE_CONST_EXPR. LVAL is true if it should be treated as an
106 : lvalue. */
107 :
108 : tree
109 270280504 : c_fully_fold (tree expr, bool in_init, bool *maybe_const, bool lval)
110 : {
111 270280504 : tree ret;
112 270280504 : tree eptype = NULL_TREE;
113 270280504 : bool dummy = true;
114 270280504 : bool maybe_const_itself = true;
115 270280504 : location_t loc = EXPR_LOCATION (expr);
116 :
117 270280504 : if (!maybe_const)
118 234693638 : maybe_const = &dummy;
119 270280504 : if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
120 : {
121 744 : eptype = TREE_TYPE (expr);
122 744 : expr = TREE_OPERAND (expr, 0);
123 : }
124 270280504 : ret = c_fully_fold_internal (expr, in_init, maybe_const,
125 : &maybe_const_itself, false, lval);
126 270280504 : if (eptype)
127 744 : ret = fold_convert_loc (loc, eptype, ret);
128 270280504 : *maybe_const &= maybe_const_itself;
129 270280504 : return ret;
130 : }
131 :
132 : /* Internal helper for c_fully_fold. EXPR and IN_INIT are as for
133 : c_fully_fold. *MAYBE_CONST_OPERANDS is cleared because of operands
134 : not permitted, while *MAYBE_CONST_ITSELF is cleared because of
135 : arithmetic overflow (for C90, *MAYBE_CONST_OPERANDS is carried from
136 : both evaluated and unevaluated subexpressions while
137 : *MAYBE_CONST_ITSELF is carried from only evaluated
138 : subexpressions). FOR_INT_CONST indicates if EXPR is an expression
139 : with integer constant operands, and if any of the operands doesn't
140 : get folded to an integer constant, don't fold the expression itself.
141 : LVAL indicates folding of lvalue, where we can't replace it with
142 : an rvalue. */
143 :
144 : static tree
145 486140509 : c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
146 : bool *maybe_const_itself, bool for_int_const, bool lval)
147 : {
148 486140509 : tree ret = expr;
149 486140509 : enum tree_code code = TREE_CODE (expr);
150 486140509 : enum tree_code_class kind = TREE_CODE_CLASS (code);
151 486140509 : location_t loc = EXPR_LOCATION (expr);
152 486140509 : tree op0, op1, op2, op3;
153 486140509 : tree orig_op0, orig_op1, orig_op2;
154 486140509 : bool op0_const = true, op1_const = true, op2_const = true;
155 486140509 : bool op0_const_self = true, op1_const_self = true, op2_const_self = true;
156 486140509 : bool nowarning = warning_suppressed_p (expr, OPT_Woverflow);
157 486140509 : bool unused_p;
158 486140509 : bool op0_lval = false;
159 486140509 : source_range old_range;
160 :
161 : /* Constants, declarations, statements, errors, and anything else not
162 : counted as an expression cannot usefully be folded further at this
163 : point. */
164 486140509 : if (!IS_EXPR_CODE_CLASS (kind) || kind == tcc_statement)
165 : {
166 : /* Except for variables which we can optimize to its initializer. */
167 229182331 : if (VAR_P (expr) && !lval && (optimize || in_init))
168 : {
169 14374435 : if (in_init)
170 466 : ret = decl_constant_value_1 (expr, true);
171 : else
172 : {
173 14374227 : ret = decl_constant_value (expr);
174 14374227 : if (ret != expr
175 14374227 : && (TYPE_MODE (TREE_TYPE (ret)) == BLKmode
176 15068 : || TREE_CODE (TREE_TYPE (ret)) == ARRAY_TYPE))
177 : return expr;
178 : }
179 : /* Avoid unwanted tree sharing between the initializer and current
180 : function's body where the tree can be modified e.g. by the
181 : gimplifier. */
182 14372164 : if (ret != expr && TREE_STATIC (expr))
183 5867 : ret = unshare_expr (ret);
184 14372164 : return ret;
185 : }
186 : return expr;
187 : }
188 :
189 256958178 : if (IS_EXPR_CODE_CLASS (kind))
190 256958178 : old_range = EXPR_LOCATION_RANGE (expr);
191 :
192 : /* Operands of variable-length expressions (function calls) have
193 : already been folded, as have __builtin_* function calls, and such
194 : expressions cannot occur in constant expressions. */
195 256958178 : if (kind == tcc_vl_exp)
196 : {
197 50209446 : *maybe_const_operands = false;
198 50209446 : ret = fold (expr);
199 50209446 : goto out;
200 : }
201 :
202 206748732 : if (code == C_MAYBE_CONST_EXPR)
203 : {
204 4551860 : tree pre = C_MAYBE_CONST_EXPR_PRE (expr);
205 4551860 : tree inner = C_MAYBE_CONST_EXPR_EXPR (expr);
206 4551860 : if (C_MAYBE_CONST_EXPR_NON_CONST (expr))
207 2172355 : *maybe_const_operands = false;
208 4551860 : if (C_MAYBE_CONST_EXPR_INT_OPERANDS (expr))
209 : {
210 1714 : *maybe_const_itself = false;
211 1714 : inner = c_fully_fold_internal (inner, in_init, maybe_const_operands,
212 : maybe_const_itself, true, lval);
213 : }
214 4551860 : if (pre && !in_init)
215 667 : ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr), pre, inner);
216 : else
217 : ret = inner;
218 4551860 : goto out;
219 : }
220 :
221 : /* Assignment, increment, decrement, function call and comma
222 : operators, and statement expressions, cannot occur in constant
223 : expressions if evaluated / outside of sizeof. (Function calls
224 : were handled above, though VA_ARG_EXPR is treated like a function
225 : call here, and statement expressions are handled through
226 : C_MAYBE_CONST_EXPR to avoid folding inside them.) */
227 202196872 : switch (code)
228 : {
229 4175741 : case MODIFY_EXPR:
230 4175741 : case PREDECREMENT_EXPR:
231 4175741 : case PREINCREMENT_EXPR:
232 4175741 : case POSTDECREMENT_EXPR:
233 4175741 : case POSTINCREMENT_EXPR:
234 4175741 : case COMPOUND_EXPR:
235 4175741 : *maybe_const_operands = false;
236 4175741 : break;
237 :
238 139654 : case VA_ARG_EXPR:
239 139654 : case TARGET_EXPR:
240 139654 : case BIND_EXPR:
241 139654 : case OBJ_TYPE_REF:
242 139654 : *maybe_const_operands = false;
243 139654 : ret = fold (expr);
244 139654 : goto out;
245 :
246 : default:
247 : break;
248 : }
249 :
250 : /* Fold individual tree codes as appropriate. */
251 202057218 : switch (code)
252 : {
253 919897 : case COMPOUND_LITERAL_EXPR:
254 : /* Any non-constancy will have been marked in a containing
255 : C_MAYBE_CONST_EXPR; there is no more folding to do here. */
256 919897 : goto out;
257 :
258 2822008 : case COMPONENT_REF:
259 2822008 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
260 2822008 : op1 = TREE_OPERAND (expr, 1);
261 2822008 : op2 = TREE_OPERAND (expr, 2);
262 2822008 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
263 : maybe_const_itself, for_int_const, lval);
264 5644016 : STRIP_TYPE_NOPS (op0);
265 2822008 : if (op0 != orig_op0)
266 10391 : ret = build3 (COMPONENT_REF, TREE_TYPE (expr), op0, op1, op2);
267 2822008 : if (ret != expr)
268 : {
269 10391 : TREE_READONLY (ret) = TREE_READONLY (expr);
270 10391 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
271 : }
272 2822008 : if (!lval)
273 2050377 : ret = fold (ret);
274 2822008 : goto out;
275 :
276 2929547 : case ARRAY_REF:
277 2929547 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
278 2929547 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
279 2929547 : op2 = TREE_OPERAND (expr, 2);
280 2929547 : op3 = TREE_OPERAND (expr, 3);
281 2929547 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
282 : maybe_const_itself, for_int_const, lval);
283 5859094 : STRIP_TYPE_NOPS (op0);
284 2929547 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
285 : maybe_const_itself, for_int_const, false);
286 5859094 : STRIP_TYPE_NOPS (op1);
287 : /* Fold "foo"[2] in initializers. */
288 2929547 : if (!lval && in_init)
289 : {
290 812 : ret = c_fold_array_ref (TREE_TYPE (expr), op0, op1);
291 812 : if (ret)
292 789 : goto out;
293 : ret = expr;
294 : }
295 2928758 : if (op0 != orig_op0 || op1 != orig_op1)
296 133900 : ret = build4 (ARRAY_REF, TREE_TYPE (expr), op0, op1, op2, op3);
297 2928758 : if (ret != expr)
298 : {
299 133900 : TREE_READONLY (ret) = TREE_READONLY (expr);
300 133900 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
301 133900 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
302 : }
303 2928758 : if (!lval)
304 2352158 : ret = fold (ret);
305 2928758 : goto out;
306 :
307 3913992 : case MODIFY_EXPR:
308 3913992 : case PREDECREMENT_EXPR:
309 3913992 : case PREINCREMENT_EXPR:
310 3913992 : case POSTDECREMENT_EXPR:
311 3913992 : case POSTINCREMENT_EXPR:
312 3913992 : op0_lval = true;
313 : /* FALLTHRU */
314 13671485 : case COMPOUND_EXPR:
315 13671485 : case PLUS_EXPR:
316 13671485 : case MINUS_EXPR:
317 13671485 : case MULT_EXPR:
318 13671485 : case POINTER_PLUS_EXPR:
319 13671485 : case POINTER_DIFF_EXPR:
320 13671485 : case TRUNC_DIV_EXPR:
321 13671485 : case CEIL_DIV_EXPR:
322 13671485 : case FLOOR_DIV_EXPR:
323 13671485 : case TRUNC_MOD_EXPR:
324 13671485 : case RDIV_EXPR:
325 13671485 : case EXACT_DIV_EXPR:
326 13671485 : case LSHIFT_EXPR:
327 13671485 : case RSHIFT_EXPR:
328 13671485 : case LROTATE_EXPR:
329 13671485 : case RROTATE_EXPR:
330 13671485 : case BIT_IOR_EXPR:
331 13671485 : case BIT_XOR_EXPR:
332 13671485 : case BIT_AND_EXPR:
333 13671485 : case LT_EXPR:
334 13671485 : case LE_EXPR:
335 13671485 : case GT_EXPR:
336 13671485 : case GE_EXPR:
337 13671485 : case EQ_EXPR:
338 13671485 : case NE_EXPR:
339 13671485 : case COMPLEX_EXPR:
340 13671485 : case TRUTH_AND_EXPR:
341 13671485 : case TRUTH_OR_EXPR:
342 13671485 : case TRUTH_XOR_EXPR:
343 13671485 : case UNORDERED_EXPR:
344 13671485 : case ORDERED_EXPR:
345 13671485 : case UNLT_EXPR:
346 13671485 : case UNLE_EXPR:
347 13671485 : case UNGT_EXPR:
348 13671485 : case UNGE_EXPR:
349 13671485 : case UNEQ_EXPR:
350 13671485 : case MEM_REF:
351 : /* Binary operations evaluating both arguments (increment and
352 : decrement are binary internally in GCC). */
353 13671485 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
354 13671485 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
355 13671485 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
356 : maybe_const_itself, for_int_const,
357 : op0_lval);
358 27342970 : STRIP_TYPE_NOPS (op0);
359 : /* The RHS of a MODIFY_EXPR was fully folded when building that
360 : expression for the sake of conversion warnings. */
361 13671485 : if (code != MODIFY_EXPR)
362 10706985 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
363 : maybe_const_itself, for_int_const, false);
364 13671543 : STRIP_TYPE_NOPS (op1);
365 :
366 13671485 : if (for_int_const && (TREE_CODE (op0) != INTEGER_CST
367 1252 : || TREE_CODE (op1) != INTEGER_CST))
368 245 : goto out;
369 :
370 13671240 : if (TREE_CODE_CLASS (code) == tcc_comparison
371 2479598 : && TREE_CODE (TREE_TYPE (op0)) == NULLPTR_TYPE
372 13671262 : && TREE_CODE (TREE_TYPE (op1)) == NULLPTR_TYPE)
373 : {
374 22 : switch (code)
375 : {
376 8 : case EQ_EXPR:
377 8 : ret = constant_boolean_node (true, TREE_TYPE (expr));
378 8 : break;
379 14 : case NE_EXPR:
380 14 : ret = constant_boolean_node (false, TREE_TYPE (expr));
381 14 : break;
382 0 : default:
383 0 : gcc_unreachable ();
384 : }
385 22 : ret = omit_two_operands_loc (loc, TREE_TYPE (expr), ret,
386 : op0, op1);
387 : }
388 13671218 : else if (op0 != orig_op0 || op1 != orig_op1 || in_init)
389 2563751 : ret = in_init
390 2565456 : ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
391 2561237 : : fold_build2_loc (loc, code, TREE_TYPE (expr), op0, op1);
392 : else
393 11105762 : ret = fold (expr);
394 268152 : if (TREE_OVERFLOW_P (ret)
395 22 : && !TREE_OVERFLOW_P (op0)
396 21 : && !(BINARY_CLASS_P (op0) && TREE_OVERFLOW_P (TREE_OPERAND (op0, 1)))
397 13671260 : && !TREE_OVERFLOW_P (op1))
398 19 : overflow_warning (EXPR_LOC_OR_LOC (expr, input_location), ret, expr);
399 13671240 : if (code == LSHIFT_EXPR
400 451591 : && TREE_CODE (orig_op0) != INTEGER_CST
401 366721 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
402 879 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
403 366180 : && TREE_CODE (op0) == INTEGER_CST
404 175 : && c_inhibit_evaluation_warnings == 0
405 76 : && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (orig_op0))
406 13671272 : && tree_int_cst_sgn (op0) < 0)
407 6 : warning_at (loc, OPT_Wshift_negative_value,
408 : "left shift of negative value");
409 13671240 : if ((code == LSHIFT_EXPR
410 : || code == RSHIFT_EXPR
411 : || code == LROTATE_EXPR
412 13671240 : || code == RROTATE_EXPR)
413 639890 : && TREE_CODE (orig_op1) != INTEGER_CST
414 145367 : && TREE_CODE (op1) == INTEGER_CST
415 521 : && TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
416 13671759 : && c_inhibit_evaluation_warnings == 0)
417 : {
418 329 : if (tree_int_cst_sgn (op1) < 0)
419 29 : warning_at (loc, OPT_Wshift_count_negative,
420 : (code == LSHIFT_EXPR
421 : ? G_("left shift count is negative")
422 : : G_("right shift count is negative")));
423 312 : else if ((TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
424 106 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE
425 12 : || TREE_CODE (TREE_TYPE (orig_op0)) == FIXED_POINT_TYPE)
426 300 : && compare_tree_int (op1,
427 300 : TYPE_PRECISION (TREE_TYPE (orig_op0)))
428 : >= 0
429 327 : && !warning_suppressed_p (expr, OPT_Wshift_count_overflow))
430 6 : warning_at (loc, OPT_Wshift_count_overflow,
431 : (code == LSHIFT_EXPR
432 : ? G_("left shift count >= width of type")
433 : : G_("right shift count >= width of type")));
434 308 : else if (TREE_CODE (TREE_TYPE (orig_op0)) == VECTOR_TYPE
435 320 : && compare_tree_int (op1,
436 12 : TYPE_PRECISION (TREE_TYPE (TREE_TYPE (orig_op0))))
437 : >= 0)
438 9 : warning_at (loc, OPT_Wshift_count_overflow,
439 : code == LSHIFT_EXPR
440 : ? G_("left shift count >= width of vector element")
441 : : G_("right shift count >= width of vector element"));
442 : }
443 13671240 : if (code == LSHIFT_EXPR
444 : /* If either OP0 has been folded to INTEGER_CST... */
445 451591 : && ((TREE_CODE (orig_op0) != INTEGER_CST
446 366721 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
447 879 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE)
448 366180 : && TREE_CODE (op0) == INTEGER_CST)
449 : /* ...or if OP1 has been folded to INTEGER_CST... */
450 451416 : || (TREE_CODE (orig_op1) != INTEGER_CST
451 114017 : && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
452 292 : || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE)
453 113755 : && TREE_CODE (op1) == INTEGER_CST))
454 13671631 : && c_inhibit_evaluation_warnings == 0)
455 : /* ...then maybe we can detect an overflow. */
456 211 : maybe_warn_shift_overflow (loc, op0, op1);
457 13671240 : if ((code == TRUNC_DIV_EXPR
458 : || code == CEIL_DIV_EXPR
459 13671240 : || code == FLOOR_DIV_EXPR
460 13671240 : || code == EXACT_DIV_EXPR
461 : || code == TRUNC_MOD_EXPR)
462 89035 : && TREE_CODE (orig_op1) != INTEGER_CST
463 11699 : && TREE_CODE (op1) == INTEGER_CST
464 90 : && (TREE_CODE (TREE_TYPE (orig_op0)) == INTEGER_TYPE
465 0 : || TREE_CODE (TREE_TYPE (orig_op0)) == BITINT_TYPE
466 0 : || TREE_CODE (TREE_TYPE (orig_op0)) == FIXED_POINT_TYPE)
467 90 : && (TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE
468 0 : || TREE_CODE (TREE_TYPE (orig_op1)) == BITINT_TYPE))
469 90 : warn_for_div_by_zero (loc, op1);
470 13671240 : if (code == MEM_REF
471 13671240 : && ret != expr
472 12335 : && TREE_CODE (ret) == MEM_REF)
473 : {
474 12335 : TREE_READONLY (ret) = TREE_READONLY (expr);
475 12335 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
476 12335 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
477 : }
478 13671240 : goto out;
479 :
480 52751369 : case ADDR_EXPR:
481 52751369 : op0_lval = true;
482 52751369 : goto unary;
483 94193485 : case REALPART_EXPR:
484 94193485 : case IMAGPART_EXPR:
485 94193485 : case VIEW_CONVERT_EXPR:
486 94193485 : op0_lval = lval;
487 : /* FALLTHRU */
488 180745826 : case INDIRECT_REF:
489 180745826 : case FIX_TRUNC_EXPR:
490 180745826 : case FLOAT_EXPR:
491 180745826 : CASE_CONVERT:
492 180745826 : case ADDR_SPACE_CONVERT_EXPR:
493 180745826 : case NON_LVALUE_EXPR:
494 180745826 : case NEGATE_EXPR:
495 180745826 : case BIT_NOT_EXPR:
496 180745826 : case TRUTH_NOT_EXPR:
497 180745826 : case CONJ_EXPR:
498 180745826 : case PAREN_EXPR:
499 180745826 : unary:
500 : /* Unary operations. */
501 180745826 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
502 180745826 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
503 : maybe_const_itself, for_int_const,
504 : op0_lval);
505 361491674 : STRIP_TYPE_NOPS (op0);
506 :
507 180745826 : if (for_int_const && TREE_CODE (op0) != INTEGER_CST)
508 14 : goto out;
509 :
510 : /* ??? Cope with user tricks that amount to offsetof. The middle-end is
511 : not prepared to deal with them if they occur in initializers. */
512 180745812 : if (op0 != orig_op0
513 180745812 : && code == ADDR_EXPR
514 517 : && (op1 = get_base_address (op0)) != NULL_TREE
515 517 : && INDIRECT_REF_P (op1)
516 180745975 : && TREE_CONSTANT (TREE_OPERAND (op1, 0)))
517 102 : ret = fold_offsetof (op0, TREE_TYPE (expr));
518 180745710 : else if (op0 != orig_op0 || in_init)
519 4178496 : ret = in_init
520 4178496 : ? fold_build1_initializer_loc (loc, code, TREE_TYPE (expr), op0)
521 1208278 : : fold_build1_loc (loc, code, TREE_TYPE (expr), op0);
522 : else
523 176567214 : ret = fold (expr);
524 180745812 : if (code == INDIRECT_REF
525 180745812 : && ret != expr
526 39105 : && INDIRECT_REF_P (ret))
527 : {
528 39007 : TREE_READONLY (ret) = TREE_READONLY (expr);
529 39007 : TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
530 39007 : TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
531 : }
532 180745812 : switch (code)
533 : {
534 : case FIX_TRUNC_EXPR:
535 : case FLOAT_EXPR:
536 : CASE_CONVERT:
537 : /* Don't warn about explicit conversions. We will already
538 : have warned about suspect implicit conversions. */
539 : break;
540 :
541 151055408 : default:
542 151055408 : if (TREE_OVERFLOW_P (ret) && !TREE_OVERFLOW_P (op0))
543 0 : overflow_warning (EXPR_LOCATION (expr), ret, op0);
544 : break;
545 : }
546 180745812 : goto out;
547 :
548 444672 : case TRUTH_ANDIF_EXPR:
549 444672 : case TRUTH_ORIF_EXPR:
550 : /* Binary operations not necessarily evaluating both
551 : arguments. */
552 444672 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
553 444672 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
554 444672 : op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
555 : for_int_const, false);
556 889344 : STRIP_TYPE_NOPS (op0);
557 :
558 889344 : unused_p = (op0 == (code == TRUTH_ANDIF_EXPR
559 444672 : ? truthvalue_false_node
560 : : truthvalue_true_node));
561 444672 : c_disable_warnings (unused_p);
562 444672 : op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
563 : for_int_const, false);
564 889344 : STRIP_TYPE_NOPS (op1);
565 444672 : c_enable_warnings (unused_p);
566 :
567 444672 : if (for_int_const
568 50 : && (TREE_CODE (op0) != INTEGER_CST
569 : /* Require OP1 be an INTEGER_CST only if it's evaluated. */
570 36 : || (!unused_p && TREE_CODE (op1) != INTEGER_CST)))
571 40 : goto out;
572 :
573 444632 : if (op0 != orig_op0 || op1 != orig_op1 || in_init)
574 435068 : ret = in_init
575 435068 : ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
576 435053 : : fold_build2_loc (loc, code, TREE_TYPE (expr), op0, op1);
577 : else
578 9564 : ret = fold (expr);
579 444632 : *maybe_const_operands &= op0_const;
580 444632 : *maybe_const_itself &= op0_const_self;
581 786841 : if (!(flag_isoc99
582 441122 : && op0_const
583 342209 : && op0_const_self
584 : && (code == TRUTH_ANDIF_EXPR
585 127126 : ? op0 == truthvalue_false_node
586 215083 : : op0 == truthvalue_true_node)))
587 433128 : *maybe_const_operands &= op1_const;
588 789600 : if (!(op0_const
589 344968 : && op0_const_self
590 : && (code == TRUTH_ANDIF_EXPR
591 127410 : ? op0 == truthvalue_false_node
592 217558 : : op0 == truthvalue_true_node)))
593 433112 : *maybe_const_itself &= op1_const_self;
594 444632 : goto out;
595 :
596 262742 : case COND_EXPR:
597 262742 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
598 262742 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
599 262742 : orig_op2 = op2 = TREE_OPERAND (expr, 2);
600 262742 : op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
601 : for_int_const, false);
602 :
603 525484 : STRIP_TYPE_NOPS (op0);
604 262742 : c_disable_warnings (op0 == truthvalue_false_node);
605 262742 : op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
606 : for_int_const, false);
607 525484 : STRIP_TYPE_NOPS (op1);
608 262742 : c_enable_warnings (op0 == truthvalue_false_node);
609 :
610 262742 : c_disable_warnings (op0 == truthvalue_true_node);
611 262742 : op2 = c_fully_fold_internal (op2, in_init, &op2_const, &op2_const_self,
612 : for_int_const, false);
613 525490 : STRIP_TYPE_NOPS (op2);
614 262742 : c_enable_warnings (op0 == truthvalue_true_node);
615 :
616 262783 : if (for_int_const
617 76 : && (TREE_CODE (op0) != INTEGER_CST
618 : /* Only the evaluated operand must be an INTEGER_CST. */
619 14 : || (op0 == truthvalue_true_node
620 14 : ? TREE_CODE (op1) != INTEGER_CST
621 27 : : TREE_CODE (op2) != INTEGER_CST)))
622 62 : goto out;
623 :
624 262680 : if (op0 != orig_op0 || op1 != orig_op1 || op2 != orig_op2)
625 206740 : ret = fold_build3_loc (loc, code, TREE_TYPE (expr), op0, op1, op2);
626 : else
627 55940 : ret = fold (expr);
628 262680 : *maybe_const_operands &= op0_const;
629 262680 : *maybe_const_itself &= op0_const_self;
630 262680 : if (!(flag_isoc99
631 261364 : && op0_const
632 187416 : && op0_const_self
633 187416 : && op0 == truthvalue_false_node))
634 248110 : *maybe_const_operands &= op1_const;
635 262680 : if (!(op0_const
636 188528 : && op0_const_self
637 188528 : && op0 == truthvalue_false_node))
638 247764 : *maybe_const_itself &= op1_const_self;
639 262680 : if (!(flag_isoc99
640 261364 : && op0_const
641 187416 : && op0_const_self
642 187416 : && op0 == truthvalue_true_node))
643 219096 : *maybe_const_operands &= op2_const;
644 262680 : if (!(op0_const
645 188528 : && op0_const_self
646 188528 : && op0 == truthvalue_true_node))
647 218981 : *maybe_const_itself &= op2_const_self;
648 262680 : goto out;
649 :
650 101102 : case VEC_COND_EXPR:
651 101102 : orig_op0 = op0 = TREE_OPERAND (expr, 0);
652 101102 : orig_op1 = op1 = TREE_OPERAND (expr, 1);
653 101102 : orig_op2 = op2 = TREE_OPERAND (expr, 2);
654 101102 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
655 : maybe_const_itself, for_int_const, false);
656 202204 : STRIP_TYPE_NOPS (op0);
657 101102 : op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
658 : maybe_const_itself, for_int_const, false);
659 202204 : STRIP_TYPE_NOPS (op1);
660 101102 : op2 = c_fully_fold_internal (op2, in_init, maybe_const_operands,
661 : maybe_const_itself, for_int_const, false);
662 202204 : STRIP_TYPE_NOPS (op2);
663 :
664 101102 : if (op0 != orig_op0 || op1 != orig_op1 || op2 != orig_op2)
665 581 : ret = fold_build3_loc (loc, code, TREE_TYPE (expr), op0, op1, op2);
666 : else
667 100521 : ret = fold (expr);
668 101102 : goto out;
669 :
670 0 : case EXCESS_PRECISION_EXPR:
671 : /* Each case where an operand with excess precision may be
672 : encountered must remove the EXCESS_PRECISION_EXPR around
673 : inner operands and possibly put one around the whole
674 : expression or possibly convert to the semantic type (which
675 : c_fully_fold does); we cannot tell at this stage which is
676 : appropriate in any particular case. */
677 0 : gcc_unreachable ();
678 :
679 150420 : case SAVE_EXPR:
680 : /* Make sure to fold the contents of a SAVE_EXPR exactly once. */
681 150420 : op0 = TREE_OPERAND (expr, 0);
682 150420 : if (!SAVE_EXPR_FOLDED_P (expr))
683 : {
684 71227 : op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
685 : maybe_const_itself, for_int_const,
686 : false);
687 71227 : TREE_OPERAND (expr, 0) = op0;
688 71227 : SAVE_EXPR_FOLDED_P (expr) = true;
689 : }
690 : /* Return the SAVE_EXPR operand if it is invariant. */
691 150420 : if (tree_invariant_p (op0))
692 3390 : ret = op0;
693 150420 : goto out;
694 :
695 9519 : default:
696 : /* Various codes may appear through folding built-in functions
697 : and their arguments. */
698 9519 : goto out;
699 : }
700 :
701 256958178 : out:
702 : /* Some folding may introduce NON_LVALUE_EXPRs; all lvalue checks
703 : have been done by this point, so remove them again. */
704 256958178 : nowarning |= warning_suppressed_p (ret, OPT_Woverflow);
705 257133455 : STRIP_TYPE_NOPS (ret);
706 256958178 : if (nowarning && !warning_suppressed_p (ret, OPT_Woverflow))
707 : {
708 12302 : if (!CAN_HAVE_LOCATION_P (ret))
709 804 : ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
710 12302 : suppress_warning (ret, OPT_Woverflow);
711 : }
712 256958178 : if (ret != expr)
713 : {
714 13409302 : protected_set_expr_location (ret, loc);
715 13409302 : if (IS_EXPR_CODE_CLASS (kind))
716 13409302 : set_source_range (ret, old_range.m_start, old_range.m_finish);
717 : }
718 : return ret;
719 : }
720 :
721 : /* Fold X for consideration by one of the warning functions when checking
722 : whether an expression has a constant value. */
723 :
724 : tree
725 128860232 : fold_for_warn (tree x)
726 : {
727 : /* The C front-end has already folded X appropriately. */
728 128860232 : return x;
729 : }
|
