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76e616db | 1 | /* Utility routines for data type conversion for GNU C. |
1c013b45 | 2 | Copyright (C) 1987, 88, 91, 92, 94, 1995 Free Software Foundation, Inc. |
76e616db BK |
3 | |
4 | This file is part of GNU C. | |
5 | ||
6 | GNU CC is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU CC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GNU CC; see the file COPYING. If not, write to | |
940d9d63 RK |
18 | the Free Software Foundation, 59 Temple Place - Suite 330, |
19 | Boston, MA 02111-1307, USA. */ | |
76e616db BK |
20 | |
21 | ||
22 | /* These routines are somewhat language-independent utility function | |
23 | intended to be called by the language-specific convert () functions. */ | |
24 | ||
25 | #include "config.h" | |
26 | #include "tree.h" | |
27 | #include "flags.h" | |
28 | #include "convert.h" | |
29 | ||
98c76e3c | 30 | /* Convert EXPR to some pointer or reference type TYPE. |
76e616db | 31 | |
98c76e3c | 32 | EXPR must be pointer, reference, integer, enumeral, or literal zero; |
76e616db BK |
33 | in other cases error is called. */ |
34 | ||
35 | tree | |
36 | convert_to_pointer (type, expr) | |
37 | tree type, expr; | |
38 | { | |
39 | register tree intype = TREE_TYPE (expr); | |
40 | register enum tree_code form = TREE_CODE (intype); | |
41 | ||
42 | if (integer_zerop (expr)) | |
43 | { | |
76e616db BK |
44 | expr = build_int_2 (0, 0); |
45 | TREE_TYPE (expr) = type; | |
46 | return expr; | |
47 | } | |
48 | ||
98c76e3c | 49 | if (form == POINTER_TYPE || form == REFERENCE_TYPE) |
76e616db BK |
50 | return build1 (NOP_EXPR, type, expr); |
51 | ||
52 | ||
53 | if (form == INTEGER_TYPE || form == ENUMERAL_TYPE) | |
54 | { | |
55 | if (type_precision (intype) == POINTER_SIZE) | |
56 | return build1 (CONVERT_EXPR, type, expr); | |
57 | expr = convert (type_for_size (POINTER_SIZE, 0), expr); | |
502d58a6 SC |
58 | /* Modes may be different but sizes should be the same. */ |
59 | if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
60 | != GET_MODE_SIZE (TYPE_MODE (type))) | |
76e616db BK |
61 | /* There is supposed to be some integral type |
62 | that is the same width as a pointer. */ | |
63 | abort (); | |
64 | return convert_to_pointer (type, expr); | |
65 | } | |
66 | ||
67 | error ("cannot convert to a pointer type"); | |
68 | ||
fb2f4828 RK |
69 | expr = build_int_2 (0, 0); |
70 | TREE_TYPE (expr) = type; | |
71 | return expr; | |
76e616db BK |
72 | } |
73 | ||
74 | /* Convert EXPR to some floating-point type TYPE. | |
75 | ||
76 | EXPR must be float, integer, or enumeral; | |
77 | in other cases error is called. */ | |
78 | ||
79 | tree | |
80 | convert_to_real (type, expr) | |
81 | tree type, expr; | |
82 | { | |
83 | register enum tree_code form = TREE_CODE (TREE_TYPE (expr)); | |
84 | ||
85 | if (form == REAL_TYPE) | |
86 | return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR, | |
87 | type, expr); | |
88 | ||
b722f2b8 | 89 | if (INTEGRAL_TYPE_P (TREE_TYPE (expr))) |
76e616db BK |
90 | return build1 (FLOAT_EXPR, type, expr); |
91 | ||
0b127821 RS |
92 | if (form == COMPLEX_TYPE) |
93 | return convert (type, fold (build1 (REALPART_EXPR, | |
94 | TREE_TYPE (TREE_TYPE (expr)), expr))); | |
95 | ||
98c76e3c | 96 | if (form == POINTER_TYPE || form == REFERENCE_TYPE) |
76e616db BK |
97 | error ("pointer value used where a floating point value was expected"); |
98 | else | |
99 | error ("aggregate value used where a float was expected"); | |
100 | ||
101 | { | |
102 | register tree tem = make_node (REAL_CST); | |
103 | TREE_TYPE (tem) = type; | |
d7889764 | 104 | TREE_REAL_CST (tem) = REAL_VALUE_ATOF ("0.0", TYPE_MODE (type)); |
76e616db BK |
105 | return tem; |
106 | } | |
107 | } | |
108 | ||
109 | /* Convert EXPR to some integer (or enum) type TYPE. | |
110 | ||
111 | EXPR must be pointer, integer, discrete (enum, char, or bool), or float; | |
112 | in other cases error is called. | |
113 | ||
114 | The result of this is always supposed to be a newly created tree node | |
115 | not in use in any existing structure. */ | |
116 | ||
117 | tree | |
118 | convert_to_integer (type, expr) | |
119 | tree type, expr; | |
120 | { | |
121 | register tree intype = TREE_TYPE (expr); | |
122 | register enum tree_code form = TREE_CODE (intype); | |
123 | ||
98c76e3c | 124 | if (form == POINTER_TYPE || form == REFERENCE_TYPE) |
76e616db BK |
125 | { |
126 | if (integer_zerop (expr)) | |
127 | expr = integer_zero_node; | |
128 | else | |
129 | expr = fold (build1 (CONVERT_EXPR, | |
130 | type_for_size (POINTER_SIZE, 0), expr)); | |
131 | intype = TREE_TYPE (expr); | |
132 | form = TREE_CODE (intype); | |
133 | if (intype == type) | |
134 | return expr; | |
135 | } | |
136 | ||
137 | if (form == INTEGER_TYPE || form == ENUMERAL_TYPE | |
138 | || form == BOOLEAN_TYPE || form == CHAR_TYPE) | |
139 | { | |
140 | register unsigned outprec = TYPE_PRECISION (type); | |
141 | register unsigned inprec = TYPE_PRECISION (intype); | |
142 | register enum tree_code ex_form = TREE_CODE (expr); | |
143 | ||
144 | /* If we are widening the type, put in an explicit conversion. | |
145 | Similarly if we are not changing the width. However, if this is | |
146 | a logical operation that just returns 0 or 1, we can change the | |
c9529354 RK |
147 | type of the expression. For logical operations, we must |
148 | also change the types of the operands to maintain type | |
149 | correctness. */ | |
76e616db | 150 | |
c9529354 | 151 | if (TREE_CODE_CLASS (ex_form) == '<') |
76e616db BK |
152 | { |
153 | TREE_TYPE (expr) = type; | |
154 | return expr; | |
155 | } | |
c9529354 RK |
156 | else if (ex_form == TRUTH_AND_EXPR || ex_form == TRUTH_ANDIF_EXPR |
157 | || ex_form == TRUTH_OR_EXPR || ex_form == TRUTH_ORIF_EXPR | |
158 | || ex_form == TRUTH_XOR_EXPR) | |
159 | { | |
160 | TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0)); | |
161 | TREE_OPERAND (expr, 1) = convert (type, TREE_OPERAND (expr, 1)); | |
162 | TREE_TYPE (expr) = type; | |
163 | return expr; | |
164 | } | |
165 | else if (ex_form == TRUTH_NOT_EXPR) | |
166 | { | |
167 | TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0)); | |
168 | TREE_TYPE (expr) = type; | |
169 | return expr; | |
170 | } | |
76e616db BK |
171 | else if (outprec >= inprec) |
172 | return build1 (NOP_EXPR, type, expr); | |
173 | ||
1c013b45 RK |
174 | /* If TYPE is an enumeral type or a type with a precision less |
175 | than the number of bits in its mode, do the conversion to the | |
176 | type corresponding to its mode, then do a nop conversion | |
177 | to TYPE. */ | |
178 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
179 | || outprec != GET_MODE_BITSIZE (TYPE_MODE (type))) | |
180 | return build1 (NOP_EXPR, type, | |
181 | convert (type_for_mode (TYPE_MODE (type), | |
182 | TREE_UNSIGNED (type)), | |
183 | expr)); | |
184 | ||
ab29fdfc RK |
185 | /* Here detect when we can distribute the truncation down past some |
186 | arithmetic. For example, if adding two longs and converting to an | |
187 | int, we can equally well convert both to ints and then add. | |
188 | For the operations handled here, such truncation distribution | |
189 | is always safe. | |
190 | It is desirable in these cases: | |
191 | 1) when truncating down to full-word from a larger size | |
192 | 2) when truncating takes no work. | |
193 | 3) when at least one operand of the arithmetic has been extended | |
194 | (as by C's default conversions). In this case we need two conversions | |
195 | if we do the arithmetic as already requested, so we might as well | |
196 | truncate both and then combine. Perhaps that way we need only one. | |
197 | ||
198 | Note that in general we cannot do the arithmetic in a type | |
199 | shorter than the desired result of conversion, even if the operands | |
200 | are both extended from a shorter type, because they might overflow | |
201 | if combined in that type. The exceptions to this--the times when | |
202 | two narrow values can be combined in their narrow type even to | |
203 | make a wider result--are handled by "shorten" in build_binary_op. */ | |
76e616db BK |
204 | |
205 | switch (ex_form) | |
206 | { | |
207 | case RSHIFT_EXPR: | |
208 | /* We can pass truncation down through right shifting | |
209 | when the shift count is a nonpositive constant. */ | |
210 | if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST | |
ab29fdfc RK |
211 | && tree_int_cst_lt (TREE_OPERAND (expr, 1), |
212 | convert (TREE_TYPE (TREE_OPERAND (expr, 1)), | |
213 | integer_one_node))) | |
76e616db BK |
214 | goto trunc1; |
215 | break; | |
216 | ||
217 | case LSHIFT_EXPR: | |
218 | /* We can pass truncation down through left shifting | |
219 | when the shift count is a nonnegative constant. */ | |
220 | if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST | |
ab29fdfc | 221 | && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0 |
76e616db BK |
222 | && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST) |
223 | { | |
224 | /* If shift count is less than the width of the truncated type, | |
225 | really shift. */ | |
226 | if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type))) | |
227 | /* In this case, shifting is like multiplication. */ | |
228 | goto trunc1; | |
229 | else | |
d9a9c5a7 RK |
230 | { |
231 | /* If it is >= that width, result is zero. | |
232 | Handling this with trunc1 would give the wrong result: | |
233 | (int) ((long long) a << 32) is well defined (as 0) | |
234 | but (int) a << 32 is undefined and would get a | |
235 | warning. */ | |
236 | ||
237 | tree t = convert_to_integer (type, integer_zero_node); | |
238 | ||
239 | /* If the original expression had side-effects, we must | |
240 | preserve it. */ | |
241 | if (TREE_SIDE_EFFECTS (expr)) | |
242 | return build (COMPOUND_EXPR, type, expr, t); | |
243 | else | |
244 | return t; | |
245 | } | |
76e616db BK |
246 | } |
247 | break; | |
248 | ||
249 | case MAX_EXPR: | |
250 | case MIN_EXPR: | |
251 | case MULT_EXPR: | |
252 | { | |
253 | tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type); | |
254 | tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type); | |
255 | ||
256 | /* Don't distribute unless the output precision is at least as big | |
257 | as the actual inputs. Otherwise, the comparison of the | |
258 | truncated values will be wrong. */ | |
259 | if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0)) | |
260 | && outprec >= TYPE_PRECISION (TREE_TYPE (arg1)) | |
261 | /* If signedness of arg0 and arg1 don't match, | |
262 | we can't necessarily find a type to compare them in. */ | |
263 | && (TREE_UNSIGNED (TREE_TYPE (arg0)) | |
264 | == TREE_UNSIGNED (TREE_TYPE (arg1)))) | |
265 | goto trunc1; | |
266 | break; | |
267 | } | |
268 | ||
269 | case PLUS_EXPR: | |
270 | case MINUS_EXPR: | |
271 | case BIT_AND_EXPR: | |
272 | case BIT_IOR_EXPR: | |
273 | case BIT_XOR_EXPR: | |
274 | case BIT_ANDTC_EXPR: | |
275 | trunc1: | |
276 | { | |
277 | tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type); | |
278 | tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type); | |
279 | ||
280 | if (outprec >= BITS_PER_WORD | |
281 | || TRULY_NOOP_TRUNCATION (outprec, inprec) | |
282 | || inprec > TYPE_PRECISION (TREE_TYPE (arg0)) | |
283 | || inprec > TYPE_PRECISION (TREE_TYPE (arg1))) | |
284 | { | |
285 | /* Do the arithmetic in type TYPEX, | |
286 | then convert result to TYPE. */ | |
287 | register tree typex = type; | |
288 | ||
289 | /* Can't do arithmetic in enumeral types | |
290 | so use an integer type that will hold the values. */ | |
291 | if (TREE_CODE (typex) == ENUMERAL_TYPE) | |
292 | typex = type_for_size (TYPE_PRECISION (typex), | |
293 | TREE_UNSIGNED (typex)); | |
294 | ||
295 | /* But now perhaps TYPEX is as wide as INPREC. | |
296 | In that case, do nothing special here. | |
297 | (Otherwise would recurse infinitely in convert. */ | |
298 | if (TYPE_PRECISION (typex) != inprec) | |
299 | { | |
300 | /* Don't do unsigned arithmetic where signed was wanted, | |
301 | or vice versa. | |
302 | Exception: if either of the original operands were | |
303 | unsigned then can safely do the work as unsigned. | |
304 | And we may need to do it as unsigned | |
305 | if we truncate to the original size. */ | |
306 | typex = ((TREE_UNSIGNED (TREE_TYPE (expr)) | |
307 | || TREE_UNSIGNED (TREE_TYPE (arg0)) | |
308 | || TREE_UNSIGNED (TREE_TYPE (arg1))) | |
309 | ? unsigned_type (typex) : signed_type (typex)); | |
310 | return convert (type, | |
95e78909 RK |
311 | fold (build (ex_form, typex, |
312 | convert (typex, arg0), | |
313 | convert (typex, arg1), | |
314 | 0))); | |
76e616db BK |
315 | } |
316 | } | |
317 | } | |
318 | break; | |
319 | ||
320 | case NEGATE_EXPR: | |
321 | case BIT_NOT_EXPR: | |
d283912a RS |
322 | /* This is not correct for ABS_EXPR, |
323 | since we must test the sign before truncation. */ | |
76e616db BK |
324 | { |
325 | register tree typex = type; | |
326 | ||
327 | /* Can't do arithmetic in enumeral types | |
328 | so use an integer type that will hold the values. */ | |
329 | if (TREE_CODE (typex) == ENUMERAL_TYPE) | |
330 | typex = type_for_size (TYPE_PRECISION (typex), | |
331 | TREE_UNSIGNED (typex)); | |
332 | ||
333 | /* But now perhaps TYPEX is as wide as INPREC. | |
334 | In that case, do nothing special here. | |
335 | (Otherwise would recurse infinitely in convert. */ | |
336 | if (TYPE_PRECISION (typex) != inprec) | |
337 | { | |
338 | /* Don't do unsigned arithmetic where signed was wanted, | |
339 | or vice versa. */ | |
340 | typex = (TREE_UNSIGNED (TREE_TYPE (expr)) | |
341 | ? unsigned_type (typex) : signed_type (typex)); | |
342 | return convert (type, | |
95e78909 RK |
343 | fold (build1 (ex_form, typex, |
344 | convert (typex, | |
345 | TREE_OPERAND (expr, 0))))); | |
76e616db BK |
346 | } |
347 | } | |
348 | ||
349 | case NOP_EXPR: | |
350 | /* If truncating after truncating, might as well do all at once. | |
351 | If truncating after extending, we may get rid of wasted work. */ | |
352 | return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type)); | |
353 | ||
354 | case COND_EXPR: | |
355 | /* Can treat the two alternative values like the operands | |
356 | of an arithmetic expression. */ | |
357 | { | |
358 | tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type); | |
359 | tree arg2 = get_unwidened (TREE_OPERAND (expr, 2), type); | |
360 | ||
361 | if (outprec >= BITS_PER_WORD | |
362 | || TRULY_NOOP_TRUNCATION (outprec, inprec) | |
363 | || inprec > TYPE_PRECISION (TREE_TYPE (arg1)) | |
364 | || inprec > TYPE_PRECISION (TREE_TYPE (arg2))) | |
365 | { | |
366 | /* Do the arithmetic in type TYPEX, | |
367 | then convert result to TYPE. */ | |
368 | register tree typex = type; | |
369 | ||
370 | /* Can't do arithmetic in enumeral types | |
371 | so use an integer type that will hold the values. */ | |
372 | if (TREE_CODE (typex) == ENUMERAL_TYPE) | |
373 | typex = type_for_size (TYPE_PRECISION (typex), | |
374 | TREE_UNSIGNED (typex)); | |
375 | ||
376 | /* But now perhaps TYPEX is as wide as INPREC. | |
377 | In that case, do nothing special here. | |
378 | (Otherwise would recurse infinitely in convert. */ | |
379 | if (TYPE_PRECISION (typex) != inprec) | |
380 | { | |
381 | /* Don't do unsigned arithmetic where signed was wanted, | |
382 | or vice versa. */ | |
383 | typex = (TREE_UNSIGNED (TREE_TYPE (expr)) | |
384 | ? unsigned_type (typex) : signed_type (typex)); | |
385 | return convert (type, | |
386 | fold (build (COND_EXPR, typex, | |
387 | TREE_OPERAND (expr, 0), | |
388 | convert (typex, arg1), | |
389 | convert (typex, arg2)))); | |
390 | } | |
391 | else | |
392 | /* It is sometimes worthwhile | |
393 | to push the narrowing down through the conditional. */ | |
394 | return fold (build (COND_EXPR, type, | |
395 | TREE_OPERAND (expr, 0), | |
396 | convert (type, TREE_OPERAND (expr, 1)), | |
397 | convert (type, TREE_OPERAND (expr, 2)))); | |
398 | } | |
399 | } | |
400 | ||
401 | } | |
402 | ||
403 | return build1 (NOP_EXPR, type, expr); | |
404 | } | |
405 | ||
406 | if (form == REAL_TYPE) | |
407 | return build1 (FIX_TRUNC_EXPR, type, expr); | |
408 | ||
0b127821 RS |
409 | if (form == COMPLEX_TYPE) |
410 | return convert (type, fold (build1 (REALPART_EXPR, | |
411 | TREE_TYPE (TREE_TYPE (expr)), expr))); | |
412 | ||
76e616db BK |
413 | error ("aggregate value used where an integer was expected"); |
414 | ||
415 | { | |
416 | register tree tem = build_int_2 (0, 0); | |
417 | TREE_TYPE (tem) = type; | |
418 | return tem; | |
419 | } | |
420 | } | |
0b127821 RS |
421 | |
422 | /* Convert EXPR to the complex type TYPE in the usual ways. */ | |
423 | ||
424 | tree | |
425 | convert_to_complex (type, expr) | |
426 | tree type, expr; | |
427 | { | |
428 | register enum tree_code form = TREE_CODE (TREE_TYPE (expr)); | |
429 | tree subtype = TREE_TYPE (type); | |
430 | ||
431 | if (form == REAL_TYPE || form == INTEGER_TYPE || form == ENUMERAL_TYPE) | |
432 | { | |
433 | expr = convert (subtype, expr); | |
434 | return build (COMPLEX_EXPR, type, expr, | |
435 | convert (subtype, integer_zero_node)); | |
436 | } | |
437 | ||
438 | if (form == COMPLEX_TYPE) | |
439 | { | |
07150665 | 440 | tree elt_type = TREE_TYPE (TREE_TYPE (expr)); |
d847907d | 441 | if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype)) |
0b127821 RS |
442 | return expr; |
443 | else if (TREE_CODE (expr) == COMPLEX_EXPR) | |
444 | return fold (build (COMPLEX_EXPR, | |
445 | type, | |
446 | convert (subtype, TREE_OPERAND (expr, 0)), | |
447 | convert (subtype, TREE_OPERAND (expr, 1)))); | |
448 | else | |
449 | { | |
450 | expr = save_expr (expr); | |
451 | return fold (build (COMPLEX_EXPR, | |
452 | type, | |
453 | convert (subtype, | |
95e78909 RK |
454 | fold (build1 (REALPART_EXPR, |
455 | TREE_TYPE (TREE_TYPE (expr)), | |
456 | expr))), | |
0b127821 | 457 | convert (subtype, |
95e78909 RK |
458 | fold (build1 (IMAGPART_EXPR, |
459 | TREE_TYPE (TREE_TYPE (expr)), | |
460 | expr))))); | |
0b127821 RS |
461 | } |
462 | } | |
463 | ||
98c76e3c | 464 | if (form == POINTER_TYPE || form == REFERENCE_TYPE) |
0b127821 RS |
465 | error ("pointer value used where a complex was expected"); |
466 | else | |
467 | error ("aggregate value used where a complex was expected"); | |
468 | ||
469 | return build (COMPLEX_EXPR, type, | |
470 | convert (subtype, integer_zero_node), | |
471 | convert (subtype, integer_zero_node)); | |
472 | } |