]>
Commit | Line | Data |
---|---|---|
76e616db | 1 | /* Utility routines for data type conversion for GNU C. |
3c71940f JL |
2 | Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1997, |
3 | 1998 Free Software Foundation, Inc. | |
76e616db | 4 | |
1322177d | 5 | This file is part of GCC. |
76e616db | 6 | |
1322177d LB |
7 | GCC is free software; you can redistribute it and/or modify it under |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
76e616db | 11 | |
1322177d LB |
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
76e616db BK |
16 | |
17 | You should have received a copy of the GNU General Public License | |
1322177d LB |
18 | along with GCC; see the file COPYING. If not, write to the Free |
19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
20 | 02111-1307, USA. */ | |
76e616db BK |
21 | |
22 | ||
23 | /* These routines are somewhat language-independent utility function | |
0f41302f | 24 | intended to be called by the language-specific convert () functions. */ |
76e616db BK |
25 | |
26 | #include "config.h" | |
c5c76735 | 27 | #include "system.h" |
76e616db BK |
28 | #include "tree.h" |
29 | #include "flags.h" | |
30 | #include "convert.h" | |
10f0ad3d | 31 | #include "toplev.h" |
b0c48229 | 32 | #include "langhooks.h" |
76e616db | 33 | |
98c76e3c | 34 | /* Convert EXPR to some pointer or reference type TYPE. |
76e616db | 35 | |
98c76e3c | 36 | EXPR must be pointer, reference, integer, enumeral, or literal zero; |
0f41302f | 37 | in other cases error is called. */ |
76e616db BK |
38 | |
39 | tree | |
40 | convert_to_pointer (type, expr) | |
41 | tree type, expr; | |
42 | { | |
76e616db BK |
43 | if (integer_zerop (expr)) |
44 | { | |
76e616db BK |
45 | expr = build_int_2 (0, 0); |
46 | TREE_TYPE (expr) = type; | |
47 | return expr; | |
48 | } | |
49 | ||
f5963e61 | 50 | switch (TREE_CODE (TREE_TYPE (expr))) |
76e616db | 51 | { |
f5963e61 JL |
52 | case POINTER_TYPE: |
53 | case REFERENCE_TYPE: | |
54 | return build1 (NOP_EXPR, type, expr); | |
55 | ||
56 | case INTEGER_TYPE: | |
57 | case ENUMERAL_TYPE: | |
58 | case BOOLEAN_TYPE: | |
59 | case CHAR_TYPE: | |
60 | if (TYPE_PRECISION (TREE_TYPE (expr)) == POINTER_SIZE) | |
76e616db | 61 | return build1 (CONVERT_EXPR, type, expr); |
76e616db | 62 | |
f5963e61 JL |
63 | return |
64 | convert_to_pointer (type, | |
b0c48229 NB |
65 | convert ((*lang_hooks.types.type_for_size) |
66 | (POINTER_SIZE, 0), expr)); | |
76e616db | 67 | |
f5963e61 JL |
68 | default: |
69 | error ("cannot convert to a pointer type"); | |
70 | return convert_to_pointer (type, integer_zero_node); | |
71 | } | |
76e616db BK |
72 | } |
73 | ||
74 | /* Convert EXPR to some floating-point type TYPE. | |
75 | ||
76 | EXPR must be float, integer, or enumeral; | |
0f41302f | 77 | in other cases error is called. */ |
76e616db BK |
78 | |
79 | tree | |
80 | convert_to_real (type, expr) | |
81 | tree type, expr; | |
82 | { | |
f5963e61 JL |
83 | switch (TREE_CODE (TREE_TYPE (expr))) |
84 | { | |
85 | case REAL_TYPE: | |
86 | return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR, | |
87 | type, expr); | |
88 | ||
89 | case INTEGER_TYPE: | |
90 | case ENUMERAL_TYPE: | |
91 | case BOOLEAN_TYPE: | |
92 | case CHAR_TYPE: | |
93 | return build1 (FLOAT_EXPR, type, expr); | |
94 | ||
95 | case COMPLEX_TYPE: | |
96 | return convert (type, | |
97 | fold (build1 (REALPART_EXPR, | |
98 | TREE_TYPE (TREE_TYPE (expr)), expr))); | |
99 | ||
100 | case POINTER_TYPE: | |
101 | case REFERENCE_TYPE: | |
102 | error ("pointer value used where a floating point value was expected"); | |
103 | return convert_to_real (type, integer_zero_node); | |
104 | ||
105 | default: | |
106 | error ("aggregate value used where a float was expected"); | |
107 | return convert_to_real (type, integer_zero_node); | |
108 | } | |
76e616db BK |
109 | } |
110 | ||
111 | /* Convert EXPR to some integer (or enum) type TYPE. | |
112 | ||
0b4565c9 BS |
113 | EXPR must be pointer, integer, discrete (enum, char, or bool), float, or |
114 | vector; in other cases error is called. | |
76e616db BK |
115 | |
116 | The result of this is always supposed to be a newly created tree node | |
117 | not in use in any existing structure. */ | |
118 | ||
119 | tree | |
120 | convert_to_integer (type, expr) | |
121 | tree type, expr; | |
122 | { | |
f5963e61 JL |
123 | enum tree_code ex_form = TREE_CODE (expr); |
124 | tree intype = TREE_TYPE (expr); | |
770ae6cc RK |
125 | unsigned int inprec = TYPE_PRECISION (intype); |
126 | unsigned int outprec = TYPE_PRECISION (type); | |
76e616db | 127 | |
9c4cb3a3 MM |
128 | /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can |
129 | be. Consider `enum E = { a, b = (enum E) 3 };'. */ | |
d0f062fb | 130 | if (!COMPLETE_TYPE_P (type)) |
9c4cb3a3 MM |
131 | { |
132 | error ("conversion to incomplete type"); | |
133 | return error_mark_node; | |
134 | } | |
135 | ||
f5963e61 | 136 | switch (TREE_CODE (intype)) |
76e616db | 137 | { |
f5963e61 JL |
138 | case POINTER_TYPE: |
139 | case REFERENCE_TYPE: | |
76e616db BK |
140 | if (integer_zerop (expr)) |
141 | expr = integer_zero_node; | |
142 | else | |
b0c48229 NB |
143 | expr = fold (build1 (CONVERT_EXPR, (*lang_hooks.types.type_for_size) |
144 | (POINTER_SIZE, 0), expr)); | |
76e616db | 145 | |
f5963e61 | 146 | return convert_to_integer (type, expr); |
76e616db | 147 | |
f5963e61 JL |
148 | case INTEGER_TYPE: |
149 | case ENUMERAL_TYPE: | |
150 | case BOOLEAN_TYPE: | |
151 | case CHAR_TYPE: | |
152 | /* If this is a logical operation, which just returns 0 or 1, we can | |
153 | change the type of the expression. For some logical operations, | |
154 | we must also change the types of the operands to maintain type | |
c9529354 | 155 | correctness. */ |
76e616db | 156 | |
c9529354 | 157 | if (TREE_CODE_CLASS (ex_form) == '<') |
76e616db BK |
158 | { |
159 | TREE_TYPE (expr) = type; | |
160 | return expr; | |
161 | } | |
f5963e61 | 162 | |
c9529354 RK |
163 | else if (ex_form == TRUTH_AND_EXPR || ex_form == TRUTH_ANDIF_EXPR |
164 | || ex_form == TRUTH_OR_EXPR || ex_form == TRUTH_ORIF_EXPR | |
165 | || ex_form == TRUTH_XOR_EXPR) | |
166 | { | |
167 | TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0)); | |
168 | TREE_OPERAND (expr, 1) = convert (type, TREE_OPERAND (expr, 1)); | |
169 | TREE_TYPE (expr) = type; | |
170 | return expr; | |
171 | } | |
f5963e61 | 172 | |
c9529354 RK |
173 | else if (ex_form == TRUTH_NOT_EXPR) |
174 | { | |
175 | TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0)); | |
176 | TREE_TYPE (expr) = type; | |
177 | return expr; | |
178 | } | |
f5963e61 JL |
179 | |
180 | /* If we are widening the type, put in an explicit conversion. | |
181 | Similarly if we are not changing the width. After this, we know | |
182 | we are truncating EXPR. */ | |
183 | ||
76e616db BK |
184 | else if (outprec >= inprec) |
185 | return build1 (NOP_EXPR, type, expr); | |
186 | ||
1c013b45 RK |
187 | /* If TYPE is an enumeral type or a type with a precision less |
188 | than the number of bits in its mode, do the conversion to the | |
189 | type corresponding to its mode, then do a nop conversion | |
190 | to TYPE. */ | |
191 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
192 | || outprec != GET_MODE_BITSIZE (TYPE_MODE (type))) | |
193 | return build1 (NOP_EXPR, type, | |
b0c48229 NB |
194 | convert ((*lang_hooks.types.type_for_mode) |
195 | (TYPE_MODE (type), TREE_UNSIGNED (type)), | |
1c013b45 RK |
196 | expr)); |
197 | ||
ab29fdfc RK |
198 | /* Here detect when we can distribute the truncation down past some |
199 | arithmetic. For example, if adding two longs and converting to an | |
200 | int, we can equally well convert both to ints and then add. | |
201 | For the operations handled here, such truncation distribution | |
202 | is always safe. | |
203 | It is desirable in these cases: | |
204 | 1) when truncating down to full-word from a larger size | |
205 | 2) when truncating takes no work. | |
206 | 3) when at least one operand of the arithmetic has been extended | |
207 | (as by C's default conversions). In this case we need two conversions | |
208 | if we do the arithmetic as already requested, so we might as well | |
209 | truncate both and then combine. Perhaps that way we need only one. | |
210 | ||
211 | Note that in general we cannot do the arithmetic in a type | |
212 | shorter than the desired result of conversion, even if the operands | |
213 | are both extended from a shorter type, because they might overflow | |
214 | if combined in that type. The exceptions to this--the times when | |
215 | two narrow values can be combined in their narrow type even to | |
216 | make a wider result--are handled by "shorten" in build_binary_op. */ | |
76e616db BK |
217 | |
218 | switch (ex_form) | |
219 | { | |
220 | case RSHIFT_EXPR: | |
221 | /* We can pass truncation down through right shifting | |
222 | when the shift count is a nonpositive constant. */ | |
223 | if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST | |
ab29fdfc RK |
224 | && tree_int_cst_lt (TREE_OPERAND (expr, 1), |
225 | convert (TREE_TYPE (TREE_OPERAND (expr, 1)), | |
226 | integer_one_node))) | |
76e616db BK |
227 | goto trunc1; |
228 | break; | |
229 | ||
230 | case LSHIFT_EXPR: | |
231 | /* We can pass truncation down through left shifting | |
232 | when the shift count is a nonnegative constant. */ | |
233 | if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST | |
ab29fdfc | 234 | && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0 |
76e616db BK |
235 | && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST) |
236 | { | |
237 | /* If shift count is less than the width of the truncated type, | |
238 | really shift. */ | |
239 | if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type))) | |
240 | /* In this case, shifting is like multiplication. */ | |
241 | goto trunc1; | |
242 | else | |
d9a9c5a7 RK |
243 | { |
244 | /* If it is >= that width, result is zero. | |
245 | Handling this with trunc1 would give the wrong result: | |
246 | (int) ((long long) a << 32) is well defined (as 0) | |
247 | but (int) a << 32 is undefined and would get a | |
248 | warning. */ | |
249 | ||
250 | tree t = convert_to_integer (type, integer_zero_node); | |
251 | ||
252 | /* If the original expression had side-effects, we must | |
253 | preserve it. */ | |
254 | if (TREE_SIDE_EFFECTS (expr)) | |
255 | return build (COMPOUND_EXPR, type, expr, t); | |
256 | else | |
257 | return t; | |
258 | } | |
76e616db BK |
259 | } |
260 | break; | |
261 | ||
262 | case MAX_EXPR: | |
263 | case MIN_EXPR: | |
264 | case MULT_EXPR: | |
265 | { | |
266 | tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type); | |
267 | tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type); | |
268 | ||
269 | /* Don't distribute unless the output precision is at least as big | |
270 | as the actual inputs. Otherwise, the comparison of the | |
271 | truncated values will be wrong. */ | |
272 | if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0)) | |
273 | && outprec >= TYPE_PRECISION (TREE_TYPE (arg1)) | |
274 | /* If signedness of arg0 and arg1 don't match, | |
275 | we can't necessarily find a type to compare them in. */ | |
276 | && (TREE_UNSIGNED (TREE_TYPE (arg0)) | |
277 | == TREE_UNSIGNED (TREE_TYPE (arg1)))) | |
278 | goto trunc1; | |
279 | break; | |
280 | } | |
281 | ||
282 | case PLUS_EXPR: | |
283 | case MINUS_EXPR: | |
284 | case BIT_AND_EXPR: | |
285 | case BIT_IOR_EXPR: | |
286 | case BIT_XOR_EXPR: | |
287 | case BIT_ANDTC_EXPR: | |
288 | trunc1: | |
289 | { | |
290 | tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type); | |
291 | tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type); | |
292 | ||
293 | if (outprec >= BITS_PER_WORD | |
294 | || TRULY_NOOP_TRUNCATION (outprec, inprec) | |
295 | || inprec > TYPE_PRECISION (TREE_TYPE (arg0)) | |
296 | || inprec > TYPE_PRECISION (TREE_TYPE (arg1))) | |
297 | { | |
298 | /* Do the arithmetic in type TYPEX, | |
299 | then convert result to TYPE. */ | |
b3694847 | 300 | tree typex = type; |
76e616db BK |
301 | |
302 | /* Can't do arithmetic in enumeral types | |
303 | so use an integer type that will hold the values. */ | |
304 | if (TREE_CODE (typex) == ENUMERAL_TYPE) | |
b0c48229 NB |
305 | typex = (*lang_hooks.types.type_for_size) |
306 | (TYPE_PRECISION (typex), TREE_UNSIGNED (typex)); | |
76e616db BK |
307 | |
308 | /* But now perhaps TYPEX is as wide as INPREC. | |
309 | In that case, do nothing special here. | |
310 | (Otherwise would recurse infinitely in convert. */ | |
311 | if (TYPE_PRECISION (typex) != inprec) | |
312 | { | |
313 | /* Don't do unsigned arithmetic where signed was wanted, | |
314 | or vice versa. | |
3cc247a8 | 315 | Exception: if both of the original operands were |
76e616db BK |
316 | unsigned then can safely do the work as unsigned. |
317 | And we may need to do it as unsigned | |
318 | if we truncate to the original size. */ | |
ceef8ce4 NB |
319 | if (TREE_UNSIGNED (TREE_TYPE (expr)) |
320 | || (TREE_UNSIGNED (TREE_TYPE (arg0)) | |
321 | && TREE_UNSIGNED (TREE_TYPE (arg1)))) | |
322 | typex = (*lang_hooks.types.unsigned_type) (typex); | |
323 | else | |
324 | typex = (*lang_hooks.types.signed_type) (typex); | |
76e616db | 325 | return convert (type, |
95e78909 RK |
326 | fold (build (ex_form, typex, |
327 | convert (typex, arg0), | |
328 | convert (typex, arg1), | |
329 | 0))); | |
76e616db BK |
330 | } |
331 | } | |
332 | } | |
333 | break; | |
334 | ||
335 | case NEGATE_EXPR: | |
336 | case BIT_NOT_EXPR: | |
d283912a RS |
337 | /* This is not correct for ABS_EXPR, |
338 | since we must test the sign before truncation. */ | |
76e616db | 339 | { |
b3694847 | 340 | tree typex = type; |
76e616db BK |
341 | |
342 | /* Can't do arithmetic in enumeral types | |
343 | so use an integer type that will hold the values. */ | |
344 | if (TREE_CODE (typex) == ENUMERAL_TYPE) | |
b0c48229 NB |
345 | typex = (*lang_hooks.types.type_for_size) |
346 | (TYPE_PRECISION (typex), TREE_UNSIGNED (typex)); | |
76e616db BK |
347 | |
348 | /* But now perhaps TYPEX is as wide as INPREC. | |
349 | In that case, do nothing special here. | |
350 | (Otherwise would recurse infinitely in convert. */ | |
351 | if (TYPE_PRECISION (typex) != inprec) | |
352 | { | |
353 | /* Don't do unsigned arithmetic where signed was wanted, | |
354 | or vice versa. */ | |
ceef8ce4 NB |
355 | if (TREE_UNSIGNED (TREE_TYPE (expr))) |
356 | typex = (*lang_hooks.types.unsigned_type) (typex); | |
357 | else | |
358 | typex = (*lang_hooks.types.signed_type) (typex); | |
76e616db | 359 | return convert (type, |
95e78909 RK |
360 | fold (build1 (ex_form, typex, |
361 | convert (typex, | |
362 | TREE_OPERAND (expr, 0))))); | |
76e616db BK |
363 | } |
364 | } | |
365 | ||
366 | case NOP_EXPR: | |
367 | /* If truncating after truncating, might as well do all at once. | |
368 | If truncating after extending, we may get rid of wasted work. */ | |
369 | return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type)); | |
370 | ||
371 | case COND_EXPR: | |
f5963e61 JL |
372 | /* It is sometimes worthwhile to push the narrowing down through |
373 | the conditional and never loses. */ | |
374 | return fold (build (COND_EXPR, type, TREE_OPERAND (expr, 0), | |
375 | convert (type, TREE_OPERAND (expr, 1)), | |
376 | convert (type, TREE_OPERAND (expr, 2)))); | |
76e616db | 377 | |
31031edd JL |
378 | default: |
379 | break; | |
76e616db BK |
380 | } |
381 | ||
382 | return build1 (NOP_EXPR, type, expr); | |
76e616db | 383 | |
f5963e61 JL |
384 | case REAL_TYPE: |
385 | return build1 (FIX_TRUNC_EXPR, type, expr); | |
76e616db | 386 | |
f5963e61 JL |
387 | case COMPLEX_TYPE: |
388 | return convert (type, | |
389 | fold (build1 (REALPART_EXPR, | |
390 | TREE_TYPE (TREE_TYPE (expr)), expr))); | |
0b127821 | 391 | |
0b4565c9 BS |
392 | case VECTOR_TYPE: |
393 | if (GET_MODE_SIZE (TYPE_MODE (type)) | |
394 | != GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))) | |
395 | { | |
396 | error ("can't convert between vector values of different size"); | |
397 | return error_mark_node; | |
398 | } | |
399 | return build1 (NOP_EXPR, type, expr); | |
400 | ||
f5963e61 JL |
401 | default: |
402 | error ("aggregate value used where an integer was expected"); | |
403 | return convert (type, integer_zero_node); | |
404 | } | |
76e616db | 405 | } |
0b127821 RS |
406 | |
407 | /* Convert EXPR to the complex type TYPE in the usual ways. */ | |
408 | ||
409 | tree | |
410 | convert_to_complex (type, expr) | |
411 | tree type, expr; | |
412 | { | |
0b127821 RS |
413 | tree subtype = TREE_TYPE (type); |
414 | ||
f5963e61 | 415 | switch (TREE_CODE (TREE_TYPE (expr))) |
0b127821 | 416 | { |
f5963e61 JL |
417 | case REAL_TYPE: |
418 | case INTEGER_TYPE: | |
419 | case ENUMERAL_TYPE: | |
420 | case BOOLEAN_TYPE: | |
421 | case CHAR_TYPE: | |
422 | return build (COMPLEX_EXPR, type, convert (subtype, expr), | |
0b127821 | 423 | convert (subtype, integer_zero_node)); |
0b127821 | 424 | |
f5963e61 JL |
425 | case COMPLEX_TYPE: |
426 | { | |
427 | tree elt_type = TREE_TYPE (TREE_TYPE (expr)); | |
428 | ||
429 | if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype)) | |
430 | return expr; | |
431 | else if (TREE_CODE (expr) == COMPLEX_EXPR) | |
0b127821 RS |
432 | return fold (build (COMPLEX_EXPR, |
433 | type, | |
f5963e61 JL |
434 | convert (subtype, TREE_OPERAND (expr, 0)), |
435 | convert (subtype, TREE_OPERAND (expr, 1)))); | |
436 | else | |
437 | { | |
438 | expr = save_expr (expr); | |
439 | return | |
440 | fold (build (COMPLEX_EXPR, | |
441 | type, convert (subtype, | |
442 | fold (build1 (REALPART_EXPR, | |
443 | TREE_TYPE (TREE_TYPE (expr)), | |
444 | expr))), | |
445 | convert (subtype, | |
446 | fold (build1 (IMAGPART_EXPR, | |
447 | TREE_TYPE (TREE_TYPE (expr)), | |
448 | expr))))); | |
449 | } | |
450 | } | |
0b127821 | 451 | |
f5963e61 JL |
452 | case POINTER_TYPE: |
453 | case REFERENCE_TYPE: | |
454 | error ("pointer value used where a complex was expected"); | |
455 | return convert_to_complex (type, integer_zero_node); | |
456 | ||
457 | default: | |
458 | error ("aggregate value used where a complex was expected"); | |
459 | return convert_to_complex (type, integer_zero_node); | |
460 | } | |
0b127821 | 461 | } |
0b4565c9 BS |
462 | |
463 | /* Convert EXPR to the vector type TYPE in the usual ways. */ | |
464 | ||
465 | tree | |
466 | convert_to_vector (type, expr) | |
467 | tree type, expr; | |
468 | { | |
0b4565c9 BS |
469 | switch (TREE_CODE (TREE_TYPE (expr))) |
470 | { | |
471 | case INTEGER_TYPE: | |
472 | case VECTOR_TYPE: | |
473 | if (GET_MODE_SIZE (TYPE_MODE (type)) | |
474 | != GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))) | |
475 | { | |
476 | error ("can't convert between vector values of different size"); | |
477 | return error_mark_node; | |
478 | } | |
479 | return build1 (NOP_EXPR, type, expr); | |
480 | ||
481 | default: | |
482 | error ("can't convert value to a vector"); | |
483 | return convert_to_vector (type, integer_zero_node); | |
484 | } | |
485 | } |