]>
Commit | Line | Data |
---|---|---|
947ed59a | 1 | /* IR-agnostic target query functions relating to optabs |
2 | Copyright (C) 1987-2015 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 | ||
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "target.h" | |
25 | #include "insn-codes.h" | |
26 | #include "optabs-query.h" | |
27 | #include "optabs-libfuncs.h" | |
28 | #include "insn-config.h" | |
29 | #include "rtl.h" | |
30 | #include "recog.h" | |
31 | ||
32 | struct target_optabs default_target_optabs; | |
33 | struct target_optabs *this_fn_optabs = &default_target_optabs; | |
34 | #if SWITCHABLE_TARGET | |
35 | struct target_optabs *this_target_optabs = &default_target_optabs; | |
36 | #endif | |
37 | ||
38 | /* Enumerates the possible types of structure operand to an | |
39 | extraction_insn. */ | |
40 | enum extraction_type { ET_unaligned_mem, ET_reg }; | |
41 | ||
42 | /* Check whether insv, extv or extzv pattern ICODE can be used for an | |
43 | insertion or extraction of type TYPE on a structure of mode MODE. | |
44 | Return true if so and fill in *INSN accordingly. STRUCT_OP is the | |
45 | operand number of the structure (the first sign_extract or zero_extract | |
46 | operand) and FIELD_OP is the operand number of the field (the other | |
47 | side of the set from the sign_extract or zero_extract). */ | |
48 | ||
49 | static bool | |
50 | get_traditional_extraction_insn (extraction_insn *insn, | |
51 | enum extraction_type type, | |
52 | machine_mode mode, | |
53 | enum insn_code icode, | |
54 | int struct_op, int field_op) | |
55 | { | |
56 | const struct insn_data_d *data = &insn_data[icode]; | |
57 | ||
58 | machine_mode struct_mode = data->operand[struct_op].mode; | |
59 | if (struct_mode == VOIDmode) | |
60 | struct_mode = word_mode; | |
61 | if (mode != struct_mode) | |
62 | return false; | |
63 | ||
64 | machine_mode field_mode = data->operand[field_op].mode; | |
65 | if (field_mode == VOIDmode) | |
66 | field_mode = word_mode; | |
67 | ||
68 | machine_mode pos_mode = data->operand[struct_op + 2].mode; | |
69 | if (pos_mode == VOIDmode) | |
70 | pos_mode = word_mode; | |
71 | ||
72 | insn->icode = icode; | |
73 | insn->field_mode = field_mode; | |
74 | insn->struct_mode = (type == ET_unaligned_mem ? byte_mode : struct_mode); | |
75 | insn->pos_mode = pos_mode; | |
76 | return true; | |
77 | } | |
78 | ||
79 | /* Return true if an optab exists to perform an insertion or extraction | |
80 | of type TYPE in mode MODE. Describe the instruction in *INSN if so. | |
81 | ||
82 | REG_OPTAB is the optab to use for register structures and | |
83 | MISALIGN_OPTAB is the optab to use for misaligned memory structures. | |
84 | POS_OP is the operand number of the bit position. */ | |
85 | ||
86 | static bool | |
87 | get_optab_extraction_insn (struct extraction_insn *insn, | |
88 | enum extraction_type type, | |
89 | machine_mode mode, direct_optab reg_optab, | |
90 | direct_optab misalign_optab, int pos_op) | |
91 | { | |
92 | direct_optab optab = (type == ET_unaligned_mem ? misalign_optab : reg_optab); | |
93 | enum insn_code icode = direct_optab_handler (optab, mode); | |
94 | if (icode == CODE_FOR_nothing) | |
95 | return false; | |
96 | ||
97 | const struct insn_data_d *data = &insn_data[icode]; | |
98 | ||
99 | insn->icode = icode; | |
100 | insn->field_mode = mode; | |
101 | insn->struct_mode = (type == ET_unaligned_mem ? BLKmode : mode); | |
102 | insn->pos_mode = data->operand[pos_op].mode; | |
103 | if (insn->pos_mode == VOIDmode) | |
104 | insn->pos_mode = word_mode; | |
105 | return true; | |
106 | } | |
107 | ||
108 | /* Return true if an instruction exists to perform an insertion or | |
109 | extraction (PATTERN says which) of type TYPE in mode MODE. | |
110 | Describe the instruction in *INSN if so. */ | |
111 | ||
112 | static bool | |
113 | get_extraction_insn (extraction_insn *insn, | |
114 | enum extraction_pattern pattern, | |
115 | enum extraction_type type, | |
116 | machine_mode mode) | |
117 | { | |
118 | switch (pattern) | |
119 | { | |
120 | case EP_insv: | |
121 | if (targetm.have_insv () | |
122 | && get_traditional_extraction_insn (insn, type, mode, | |
123 | targetm.code_for_insv, 0, 3)) | |
124 | return true; | |
125 | return get_optab_extraction_insn (insn, type, mode, insv_optab, | |
126 | insvmisalign_optab, 2); | |
127 | ||
128 | case EP_extv: | |
129 | if (targetm.have_extv () | |
130 | && get_traditional_extraction_insn (insn, type, mode, | |
131 | targetm.code_for_extv, 1, 0)) | |
132 | return true; | |
133 | return get_optab_extraction_insn (insn, type, mode, extv_optab, | |
134 | extvmisalign_optab, 3); | |
135 | ||
136 | case EP_extzv: | |
137 | if (targetm.have_extzv () | |
138 | && get_traditional_extraction_insn (insn, type, mode, | |
139 | targetm.code_for_extzv, 1, 0)) | |
140 | return true; | |
141 | return get_optab_extraction_insn (insn, type, mode, extzv_optab, | |
142 | extzvmisalign_optab, 3); | |
143 | ||
144 | default: | |
145 | gcc_unreachable (); | |
146 | } | |
147 | } | |
148 | ||
149 | /* Return true if an instruction exists to access a field of mode | |
150 | FIELDMODE in a structure that has STRUCT_BITS significant bits. | |
151 | Describe the "best" such instruction in *INSN if so. PATTERN and | |
152 | TYPE describe the type of insertion or extraction we want to perform. | |
153 | ||
154 | For an insertion, the number of significant structure bits includes | |
155 | all bits of the target. For an extraction, it need only include the | |
156 | most significant bit of the field. Larger widths are acceptable | |
157 | in both cases. */ | |
158 | ||
159 | static bool | |
160 | get_best_extraction_insn (extraction_insn *insn, | |
161 | enum extraction_pattern pattern, | |
162 | enum extraction_type type, | |
163 | unsigned HOST_WIDE_INT struct_bits, | |
164 | machine_mode field_mode) | |
165 | { | |
166 | machine_mode mode = smallest_mode_for_size (struct_bits, MODE_INT); | |
167 | while (mode != VOIDmode) | |
168 | { | |
169 | if (get_extraction_insn (insn, pattern, type, mode)) | |
170 | { | |
171 | while (mode != VOIDmode | |
172 | && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (field_mode) | |
173 | && !TRULY_NOOP_TRUNCATION_MODES_P (insn->field_mode, | |
174 | field_mode)) | |
175 | { | |
176 | get_extraction_insn (insn, pattern, type, mode); | |
177 | mode = GET_MODE_WIDER_MODE (mode); | |
178 | } | |
179 | return true; | |
180 | } | |
181 | mode = GET_MODE_WIDER_MODE (mode); | |
182 | } | |
183 | return false; | |
184 | } | |
185 | ||
186 | /* Return true if an instruction exists to access a field of mode | |
187 | FIELDMODE in a register structure that has STRUCT_BITS significant bits. | |
188 | Describe the "best" such instruction in *INSN if so. PATTERN describes | |
189 | the type of insertion or extraction we want to perform. | |
190 | ||
191 | For an insertion, the number of significant structure bits includes | |
192 | all bits of the target. For an extraction, it need only include the | |
193 | most significant bit of the field. Larger widths are acceptable | |
194 | in both cases. */ | |
195 | ||
196 | bool | |
197 | get_best_reg_extraction_insn (extraction_insn *insn, | |
198 | enum extraction_pattern pattern, | |
199 | unsigned HOST_WIDE_INT struct_bits, | |
200 | machine_mode field_mode) | |
201 | { | |
202 | return get_best_extraction_insn (insn, pattern, ET_reg, struct_bits, | |
203 | field_mode); | |
204 | } | |
205 | ||
206 | /* Return true if an instruction exists to access a field of BITSIZE | |
207 | bits starting BITNUM bits into a memory structure. Describe the | |
208 | "best" such instruction in *INSN if so. PATTERN describes the type | |
209 | of insertion or extraction we want to perform and FIELDMODE is the | |
210 | natural mode of the extracted field. | |
211 | ||
212 | The instructions considered here only access bytes that overlap | |
213 | the bitfield; they do not touch any surrounding bytes. */ | |
214 | ||
215 | bool | |
216 | get_best_mem_extraction_insn (extraction_insn *insn, | |
217 | enum extraction_pattern pattern, | |
218 | HOST_WIDE_INT bitsize, HOST_WIDE_INT bitnum, | |
219 | machine_mode field_mode) | |
220 | { | |
221 | unsigned HOST_WIDE_INT struct_bits = (bitnum % BITS_PER_UNIT | |
222 | + bitsize | |
223 | + BITS_PER_UNIT - 1); | |
224 | struct_bits -= struct_bits % BITS_PER_UNIT; | |
225 | return get_best_extraction_insn (insn, pattern, ET_unaligned_mem, | |
226 | struct_bits, field_mode); | |
227 | } | |
228 | ||
229 | /* Return the insn code used to extend FROM_MODE to TO_MODE. | |
230 | UNSIGNEDP specifies zero-extension instead of sign-extension. If | |
231 | no such operation exists, CODE_FOR_nothing will be returned. */ | |
232 | ||
233 | enum insn_code | |
234 | can_extend_p (machine_mode to_mode, machine_mode from_mode, | |
235 | int unsignedp) | |
236 | { | |
237 | if (unsignedp < 0 && targetm.have_ptr_extend ()) | |
238 | return targetm.code_for_ptr_extend; | |
239 | ||
240 | convert_optab tab = unsignedp ? zext_optab : sext_optab; | |
241 | return convert_optab_handler (tab, to_mode, from_mode); | |
242 | } | |
243 | ||
244 | /* Return the insn code to convert fixed-point mode FIXMODE to floating-point | |
245 | mode FLTMODE, or CODE_FOR_nothing if no such instruction exists. | |
246 | UNSIGNEDP specifies whether FIXMODE is unsigned. */ | |
247 | ||
248 | enum insn_code | |
249 | can_float_p (machine_mode fltmode, machine_mode fixmode, | |
250 | int unsignedp) | |
251 | { | |
252 | convert_optab tab = unsignedp ? ufloat_optab : sfloat_optab; | |
253 | return convert_optab_handler (tab, fltmode, fixmode); | |
254 | } | |
255 | ||
256 | /* Return the insn code to convert floating-point mode FLTMODE to fixed-point | |
257 | mode FIXMODE, or CODE_FOR_nothing if no such instruction exists. | |
258 | UNSIGNEDP specifies whether FIXMODE is unsigned. | |
259 | ||
260 | On a successful return, set *TRUNCP_PTR to true if it is necessary to | |
261 | output an explicit FTRUNC before the instruction. */ | |
262 | ||
263 | enum insn_code | |
264 | can_fix_p (machine_mode fixmode, machine_mode fltmode, | |
265 | int unsignedp, bool *truncp_ptr) | |
266 | { | |
267 | convert_optab tab; | |
268 | enum insn_code icode; | |
269 | ||
270 | tab = unsignedp ? ufixtrunc_optab : sfixtrunc_optab; | |
271 | icode = convert_optab_handler (tab, fixmode, fltmode); | |
272 | if (icode != CODE_FOR_nothing) | |
273 | { | |
274 | *truncp_ptr = false; | |
275 | return icode; | |
276 | } | |
277 | ||
278 | /* FIXME: This requires a port to define both FIX and FTRUNC pattern | |
279 | for this to work. We need to rework the fix* and ftrunc* patterns | |
280 | and documentation. */ | |
281 | tab = unsignedp ? ufix_optab : sfix_optab; | |
282 | icode = convert_optab_handler (tab, fixmode, fltmode); | |
283 | if (icode != CODE_FOR_nothing | |
284 | && optab_handler (ftrunc_optab, fltmode) != CODE_FOR_nothing) | |
285 | { | |
286 | *truncp_ptr = true; | |
287 | return icode; | |
288 | } | |
289 | ||
290 | return CODE_FOR_nothing; | |
291 | } | |
292 | ||
293 | /* Return nonzero if a conditional move of mode MODE is supported. | |
294 | ||
295 | This function is for combine so it can tell whether an insn that looks | |
296 | like a conditional move is actually supported by the hardware. If we | |
297 | guess wrong we lose a bit on optimization, but that's it. */ | |
298 | /* ??? sparc64 supports conditionally moving integers values based on fp | |
299 | comparisons, and vice versa. How do we handle them? */ | |
300 | ||
301 | bool | |
302 | can_conditionally_move_p (machine_mode mode) | |
303 | { | |
304 | return direct_optab_handler (movcc_optab, mode) != CODE_FOR_nothing; | |
305 | } | |
306 | ||
307 | /* Return true if VEC_PERM_EXPR of arbitrary input vectors can be | |
308 | expanded using SIMD extensions of the CPU. SEL may be NULL, which | |
309 | stands for an unknown constant. Note that additional permutations | |
310 | representing whole-vector shifts may also be handled via the vec_shr | |
311 | optab, but only where the second input vector is entirely constant | |
312 | zeroes; this case is not dealt with here. */ | |
313 | ||
314 | bool | |
315 | can_vec_perm_p (machine_mode mode, bool variable, | |
316 | const unsigned char *sel) | |
317 | { | |
318 | machine_mode qimode; | |
319 | ||
320 | /* If the target doesn't implement a vector mode for the vector type, | |
321 | then no operations are supported. */ | |
322 | if (!VECTOR_MODE_P (mode)) | |
323 | return false; | |
324 | ||
325 | if (!variable) | |
326 | { | |
327 | if (direct_optab_handler (vec_perm_const_optab, mode) != CODE_FOR_nothing | |
328 | && (sel == NULL | |
329 | || targetm.vectorize.vec_perm_const_ok == NULL | |
330 | || targetm.vectorize.vec_perm_const_ok (mode, sel))) | |
331 | return true; | |
332 | } | |
333 | ||
334 | if (direct_optab_handler (vec_perm_optab, mode) != CODE_FOR_nothing) | |
335 | return true; | |
336 | ||
337 | /* We allow fallback to a QI vector mode, and adjust the mask. */ | |
338 | if (GET_MODE_INNER (mode) == QImode) | |
339 | return false; | |
340 | qimode = mode_for_vector (QImode, GET_MODE_SIZE (mode)); | |
341 | if (!VECTOR_MODE_P (qimode)) | |
342 | return false; | |
343 | ||
344 | /* ??? For completeness, we ought to check the QImode version of | |
345 | vec_perm_const_optab. But all users of this implicit lowering | |
346 | feature implement the variable vec_perm_optab. */ | |
347 | if (direct_optab_handler (vec_perm_optab, qimode) == CODE_FOR_nothing) | |
348 | return false; | |
349 | ||
350 | /* In order to support the lowering of variable permutations, | |
351 | we need to support shifts and adds. */ | |
352 | if (variable) | |
353 | { | |
354 | if (GET_MODE_UNIT_SIZE (mode) > 2 | |
355 | && optab_handler (ashl_optab, mode) == CODE_FOR_nothing | |
356 | && optab_handler (vashl_optab, mode) == CODE_FOR_nothing) | |
357 | return false; | |
358 | if (optab_handler (add_optab, qimode) == CODE_FOR_nothing) | |
359 | return false; | |
360 | } | |
361 | ||
362 | return true; | |
363 | } | |
364 | ||
365 | /* Like optab_handler, but for widening_operations that have a | |
366 | TO_MODE and a FROM_MODE. */ | |
367 | ||
368 | enum insn_code | |
369 | widening_optab_handler (optab op, machine_mode to_mode, | |
370 | machine_mode from_mode) | |
371 | { | |
372 | unsigned scode = (op << 16) | to_mode; | |
373 | if (to_mode != from_mode && from_mode != VOIDmode) | |
374 | { | |
375 | /* ??? Why does find_widening_optab_handler_and_mode attempt to | |
376 | widen things that can't be widened? E.g. add_optab... */ | |
377 | if (op > LAST_CONV_OPTAB) | |
378 | return CODE_FOR_nothing; | |
379 | scode |= from_mode << 8; | |
380 | } | |
381 | return raw_optab_handler (scode); | |
382 | } | |
383 | ||
384 | /* Find a widening optab even if it doesn't widen as much as we want. | |
385 | E.g. if from_mode is HImode, and to_mode is DImode, and there is no | |
386 | direct HI->SI insn, then return SI->DI, if that exists. | |
387 | If PERMIT_NON_WIDENING is non-zero then this can be used with | |
388 | non-widening optabs also. */ | |
389 | ||
390 | enum insn_code | |
391 | find_widening_optab_handler_and_mode (optab op, machine_mode to_mode, | |
392 | machine_mode from_mode, | |
393 | int permit_non_widening, | |
394 | machine_mode *found_mode) | |
395 | { | |
396 | for (; (permit_non_widening || from_mode != to_mode) | |
397 | && GET_MODE_SIZE (from_mode) <= GET_MODE_SIZE (to_mode) | |
398 | && from_mode != VOIDmode; | |
399 | from_mode = GET_MODE_WIDER_MODE (from_mode)) | |
400 | { | |
401 | enum insn_code handler = widening_optab_handler (op, to_mode, | |
402 | from_mode); | |
403 | ||
404 | if (handler != CODE_FOR_nothing) | |
405 | { | |
406 | if (found_mode) | |
407 | *found_mode = from_mode; | |
408 | return handler; | |
409 | } | |
410 | } | |
411 | ||
412 | return CODE_FOR_nothing; | |
413 | } | |
414 | ||
415 | /* Return non-zero if a highpart multiply is supported of can be synthisized. | |
416 | For the benefit of expand_mult_highpart, the return value is 1 for direct, | |
417 | 2 for even/odd widening, and 3 for hi/lo widening. */ | |
418 | ||
419 | int | |
420 | can_mult_highpart_p (machine_mode mode, bool uns_p) | |
421 | { | |
422 | optab op; | |
423 | unsigned char *sel; | |
424 | unsigned i, nunits; | |
425 | ||
426 | op = uns_p ? umul_highpart_optab : smul_highpart_optab; | |
427 | if (optab_handler (op, mode) != CODE_FOR_nothing) | |
428 | return 1; | |
429 | ||
430 | /* If the mode is an integral vector, synth from widening operations. */ | |
431 | if (GET_MODE_CLASS (mode) != MODE_VECTOR_INT) | |
432 | return 0; | |
433 | ||
434 | nunits = GET_MODE_NUNITS (mode); | |
435 | sel = XALLOCAVEC (unsigned char, nunits); | |
436 | ||
437 | op = uns_p ? vec_widen_umult_even_optab : vec_widen_smult_even_optab; | |
438 | if (optab_handler (op, mode) != CODE_FOR_nothing) | |
439 | { | |
440 | op = uns_p ? vec_widen_umult_odd_optab : vec_widen_smult_odd_optab; | |
441 | if (optab_handler (op, mode) != CODE_FOR_nothing) | |
442 | { | |
443 | for (i = 0; i < nunits; ++i) | |
444 | sel[i] = !BYTES_BIG_ENDIAN + (i & ~1) + ((i & 1) ? nunits : 0); | |
445 | if (can_vec_perm_p (mode, false, sel)) | |
446 | return 2; | |
447 | } | |
448 | } | |
449 | ||
450 | op = uns_p ? vec_widen_umult_hi_optab : vec_widen_smult_hi_optab; | |
451 | if (optab_handler (op, mode) != CODE_FOR_nothing) | |
452 | { | |
453 | op = uns_p ? vec_widen_umult_lo_optab : vec_widen_smult_lo_optab; | |
454 | if (optab_handler (op, mode) != CODE_FOR_nothing) | |
455 | { | |
456 | for (i = 0; i < nunits; ++i) | |
457 | sel[i] = 2 * i + (BYTES_BIG_ENDIAN ? 0 : 1); | |
458 | if (can_vec_perm_p (mode, false, sel)) | |
459 | return 3; | |
460 | } | |
461 | } | |
462 | ||
463 | return 0; | |
464 | } | |
465 | ||
466 | /* Return true if target supports vector masked load/store for mode. */ | |
467 | ||
468 | bool | |
469 | can_vec_mask_load_store_p (machine_mode mode, bool is_load) | |
470 | { | |
471 | optab op = is_load ? maskload_optab : maskstore_optab; | |
472 | machine_mode vmode; | |
473 | unsigned int vector_sizes; | |
474 | ||
475 | /* If mode is vector mode, check it directly. */ | |
476 | if (VECTOR_MODE_P (mode)) | |
477 | return optab_handler (op, mode) != CODE_FOR_nothing; | |
478 | ||
479 | /* Otherwise, return true if there is some vector mode with | |
480 | the mask load/store supported. */ | |
481 | ||
482 | /* See if there is any chance the mask load or store might be | |
483 | vectorized. If not, punt. */ | |
484 | vmode = targetm.vectorize.preferred_simd_mode (mode); | |
485 | if (!VECTOR_MODE_P (vmode)) | |
486 | return false; | |
487 | ||
488 | if (optab_handler (op, vmode) != CODE_FOR_nothing) | |
489 | return true; | |
490 | ||
491 | vector_sizes = targetm.vectorize.autovectorize_vector_sizes (); | |
492 | while (vector_sizes != 0) | |
493 | { | |
494 | unsigned int cur = 1 << floor_log2 (vector_sizes); | |
495 | vector_sizes &= ~cur; | |
496 | if (cur <= GET_MODE_SIZE (mode)) | |
497 | continue; | |
498 | vmode = mode_for_vector (mode, cur / GET_MODE_SIZE (mode)); | |
499 | if (VECTOR_MODE_P (vmode) | |
500 | && optab_handler (op, vmode) != CODE_FOR_nothing) | |
501 | return true; | |
502 | } | |
503 | return false; | |
504 | } | |
505 | ||
506 | /* Return true if there is a compare_and_swap pattern. */ | |
507 | ||
508 | bool | |
509 | can_compare_and_swap_p (machine_mode mode, bool allow_libcall) | |
510 | { | |
511 | enum insn_code icode; | |
512 | ||
513 | /* Check for __atomic_compare_and_swap. */ | |
514 | icode = direct_optab_handler (atomic_compare_and_swap_optab, mode); | |
515 | if (icode != CODE_FOR_nothing) | |
516 | return true; | |
517 | ||
518 | /* Check for __sync_compare_and_swap. */ | |
519 | icode = optab_handler (sync_compare_and_swap_optab, mode); | |
520 | if (icode != CODE_FOR_nothing) | |
521 | return true; | |
522 | if (allow_libcall && optab_libfunc (sync_compare_and_swap_optab, mode)) | |
523 | return true; | |
524 | ||
525 | /* No inline compare and swap. */ | |
526 | return false; | |
527 | } | |
528 | ||
529 | /* Return true if an atomic exchange can be performed. */ | |
530 | ||
531 | bool | |
532 | can_atomic_exchange_p (machine_mode mode, bool allow_libcall) | |
533 | { | |
534 | enum insn_code icode; | |
535 | ||
536 | /* Check for __atomic_exchange. */ | |
537 | icode = direct_optab_handler (atomic_exchange_optab, mode); | |
538 | if (icode != CODE_FOR_nothing) | |
539 | return true; | |
540 | ||
541 | /* Don't check __sync_test_and_set, as on some platforms that | |
542 | has reduced functionality. Targets that really do support | |
543 | a proper exchange should simply be updated to the __atomics. */ | |
544 | ||
545 | return can_compare_and_swap_p (mode, allow_libcall); | |
546 | } | |
547 | ||
548 | /* Determine whether "1 << x" is relatively cheap in word_mode. */ | |
549 | ||
550 | bool | |
551 | lshift_cheap_p (bool speed_p) | |
552 | { | |
553 | /* FIXME: This should be made target dependent via this "this_target" | |
554 | mechanism, similar to e.g. can_copy_init_p in gcse.c. */ | |
555 | static bool init[2] = { false, false }; | |
556 | static bool cheap[2] = { true, true }; | |
557 | ||
558 | /* If the targer has no lshift in word_mode, the operation will most | |
559 | probably not be cheap. ??? Does GCC even work for such targets? */ | |
560 | if (optab_handler (ashl_optab, word_mode) == CODE_FOR_nothing) | |
561 | return false; | |
562 | ||
563 | if (!init[speed_p]) | |
564 | { | |
565 | rtx reg = gen_raw_REG (word_mode, 10000); | |
566 | int cost = set_src_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), | |
567 | word_mode, speed_p); | |
568 | cheap[speed_p] = cost < COSTS_N_INSNS (3); | |
569 | init[speed_p] = true; | |
570 | } | |
571 | ||
572 | return cheap[speed_p]; | |
573 | } |