xref: /openbmc/qemu/tcg/optimize.c (revision 2e1cacfb)
1 /*
2  * Optimizations for Tiny Code Generator for QEMU
3  *
4  * Copyright (c) 2010 Samsung Electronics.
5  * Contributed by Kirill Batuzov <batuzovk@ispras.ru>
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a copy
8  * of this software and associated documentation files (the "Software"), to deal
9  * in the Software without restriction, including without limitation the rights
10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11  * copies of the Software, and to permit persons to whom the Software is
12  * furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in
15  * all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23  * THE SOFTWARE.
24  */
25 
26 #include "qemu/osdep.h"
27 #include "qemu/int128.h"
28 #include "qemu/interval-tree.h"
29 #include "tcg/tcg-op-common.h"
30 #include "tcg-internal.h"
31 
32 #define CASE_OP_32_64(x)                        \
33         glue(glue(case INDEX_op_, x), _i32):    \
34         glue(glue(case INDEX_op_, x), _i64)
35 
36 #define CASE_OP_32_64_VEC(x)                    \
37         glue(glue(case INDEX_op_, x), _i32):    \
38         glue(glue(case INDEX_op_, x), _i64):    \
39         glue(glue(case INDEX_op_, x), _vec)
40 
41 typedef struct MemCopyInfo {
42     IntervalTreeNode itree;
43     QSIMPLEQ_ENTRY (MemCopyInfo) next;
44     TCGTemp *ts;
45     TCGType type;
46 } MemCopyInfo;
47 
48 typedef struct TempOptInfo {
49     bool is_const;
50     TCGTemp *prev_copy;
51     TCGTemp *next_copy;
52     QSIMPLEQ_HEAD(, MemCopyInfo) mem_copy;
53     uint64_t val;
54     uint64_t z_mask;  /* mask bit is 0 if and only if value bit is 0 */
55     uint64_t s_mask;  /* a left-aligned mask of clrsb(value) bits. */
56 } TempOptInfo;
57 
58 typedef struct OptContext {
59     TCGContext *tcg;
60     TCGOp *prev_mb;
61     TCGTempSet temps_used;
62 
63     IntervalTreeRoot mem_copy;
64     QSIMPLEQ_HEAD(, MemCopyInfo) mem_free;
65 
66     /* In flight values from optimization. */
67     uint64_t a_mask;  /* mask bit is 0 iff value identical to first input */
68     uint64_t z_mask;  /* mask bit is 0 iff value bit is 0 */
69     uint64_t s_mask;  /* mask of clrsb(value) bits */
70     TCGType type;
71 } OptContext;
72 
73 /* Calculate the smask for a specific value. */
74 static uint64_t smask_from_value(uint64_t value)
75 {
76     int rep = clrsb64(value);
77     return ~(~0ull >> rep);
78 }
79 
80 /*
81  * Calculate the smask for a given set of known-zeros.
82  * If there are lots of zeros on the left, we can consider the remainder
83  * an unsigned field, and thus the corresponding signed field is one bit
84  * larger.
85  */
86 static uint64_t smask_from_zmask(uint64_t zmask)
87 {
88     /*
89      * Only the 0 bits are significant for zmask, thus the msb itself
90      * must be zero, else we have no sign information.
91      */
92     int rep = clz64(zmask);
93     if (rep == 0) {
94         return 0;
95     }
96     rep -= 1;
97     return ~(~0ull >> rep);
98 }
99 
100 /*
101  * Recreate a properly left-aligned smask after manipulation.
102  * Some bit-shuffling, particularly shifts and rotates, may
103  * retain sign bits on the left, but may scatter disconnected
104  * sign bits on the right.  Retain only what remains to the left.
105  */
106 static uint64_t smask_from_smask(int64_t smask)
107 {
108     /* Only the 1 bits are significant for smask */
109     return smask_from_zmask(~smask);
110 }
111 
112 static inline TempOptInfo *ts_info(TCGTemp *ts)
113 {
114     return ts->state_ptr;
115 }
116 
117 static inline TempOptInfo *arg_info(TCGArg arg)
118 {
119     return ts_info(arg_temp(arg));
120 }
121 
122 static inline bool ts_is_const(TCGTemp *ts)
123 {
124     return ts_info(ts)->is_const;
125 }
126 
127 static inline bool ts_is_const_val(TCGTemp *ts, uint64_t val)
128 {
129     TempOptInfo *ti = ts_info(ts);
130     return ti->is_const && ti->val == val;
131 }
132 
133 static inline bool arg_is_const(TCGArg arg)
134 {
135     return ts_is_const(arg_temp(arg));
136 }
137 
138 static inline bool arg_is_const_val(TCGArg arg, uint64_t val)
139 {
140     return ts_is_const_val(arg_temp(arg), val);
141 }
142 
143 static inline bool ts_is_copy(TCGTemp *ts)
144 {
145     return ts_info(ts)->next_copy != ts;
146 }
147 
148 static TCGTemp *cmp_better_copy(TCGTemp *a, TCGTemp *b)
149 {
150     return a->kind < b->kind ? b : a;
151 }
152 
153 /* Initialize and activate a temporary.  */
154 static void init_ts_info(OptContext *ctx, TCGTemp *ts)
155 {
156     size_t idx = temp_idx(ts);
157     TempOptInfo *ti;
158 
159     if (test_bit(idx, ctx->temps_used.l)) {
160         return;
161     }
162     set_bit(idx, ctx->temps_used.l);
163 
164     ti = ts->state_ptr;
165     if (ti == NULL) {
166         ti = tcg_malloc(sizeof(TempOptInfo));
167         ts->state_ptr = ti;
168     }
169 
170     ti->next_copy = ts;
171     ti->prev_copy = ts;
172     QSIMPLEQ_INIT(&ti->mem_copy);
173     if (ts->kind == TEMP_CONST) {
174         ti->is_const = true;
175         ti->val = ts->val;
176         ti->z_mask = ts->val;
177         ti->s_mask = smask_from_value(ts->val);
178     } else {
179         ti->is_const = false;
180         ti->z_mask = -1;
181         ti->s_mask = 0;
182     }
183 }
184 
185 static MemCopyInfo *mem_copy_first(OptContext *ctx, intptr_t s, intptr_t l)
186 {
187     IntervalTreeNode *r = interval_tree_iter_first(&ctx->mem_copy, s, l);
188     return r ? container_of(r, MemCopyInfo, itree) : NULL;
189 }
190 
191 static MemCopyInfo *mem_copy_next(MemCopyInfo *mem, intptr_t s, intptr_t l)
192 {
193     IntervalTreeNode *r = interval_tree_iter_next(&mem->itree, s, l);
194     return r ? container_of(r, MemCopyInfo, itree) : NULL;
195 }
196 
197 static void remove_mem_copy(OptContext *ctx, MemCopyInfo *mc)
198 {
199     TCGTemp *ts = mc->ts;
200     TempOptInfo *ti = ts_info(ts);
201 
202     interval_tree_remove(&mc->itree, &ctx->mem_copy);
203     QSIMPLEQ_REMOVE(&ti->mem_copy, mc, MemCopyInfo, next);
204     QSIMPLEQ_INSERT_TAIL(&ctx->mem_free, mc, next);
205 }
206 
207 static void remove_mem_copy_in(OptContext *ctx, intptr_t s, intptr_t l)
208 {
209     while (true) {
210         MemCopyInfo *mc = mem_copy_first(ctx, s, l);
211         if (!mc) {
212             break;
213         }
214         remove_mem_copy(ctx, mc);
215     }
216 }
217 
218 static void remove_mem_copy_all(OptContext *ctx)
219 {
220     remove_mem_copy_in(ctx, 0, -1);
221     tcg_debug_assert(interval_tree_is_empty(&ctx->mem_copy));
222 }
223 
224 static TCGTemp *find_better_copy(TCGTemp *ts)
225 {
226     TCGTemp *i, *ret;
227 
228     /* If this is already readonly, we can't do better. */
229     if (temp_readonly(ts)) {
230         return ts;
231     }
232 
233     ret = ts;
234     for (i = ts_info(ts)->next_copy; i != ts; i = ts_info(i)->next_copy) {
235         ret = cmp_better_copy(ret, i);
236     }
237     return ret;
238 }
239 
240 static void move_mem_copies(TCGTemp *dst_ts, TCGTemp *src_ts)
241 {
242     TempOptInfo *si = ts_info(src_ts);
243     TempOptInfo *di = ts_info(dst_ts);
244     MemCopyInfo *mc;
245 
246     QSIMPLEQ_FOREACH(mc, &si->mem_copy, next) {
247         tcg_debug_assert(mc->ts == src_ts);
248         mc->ts = dst_ts;
249     }
250     QSIMPLEQ_CONCAT(&di->mem_copy, &si->mem_copy);
251 }
252 
253 /* Reset TEMP's state, possibly removing the temp for the list of copies.  */
254 static void reset_ts(OptContext *ctx, TCGTemp *ts)
255 {
256     TempOptInfo *ti = ts_info(ts);
257     TCGTemp *pts = ti->prev_copy;
258     TCGTemp *nts = ti->next_copy;
259     TempOptInfo *pi = ts_info(pts);
260     TempOptInfo *ni = ts_info(nts);
261 
262     ni->prev_copy = ti->prev_copy;
263     pi->next_copy = ti->next_copy;
264     ti->next_copy = ts;
265     ti->prev_copy = ts;
266     ti->is_const = false;
267     ti->z_mask = -1;
268     ti->s_mask = 0;
269 
270     if (!QSIMPLEQ_EMPTY(&ti->mem_copy)) {
271         if (ts == nts) {
272             /* Last temp copy being removed, the mem copies die. */
273             MemCopyInfo *mc;
274             QSIMPLEQ_FOREACH(mc, &ti->mem_copy, next) {
275                 interval_tree_remove(&mc->itree, &ctx->mem_copy);
276             }
277             QSIMPLEQ_CONCAT(&ctx->mem_free, &ti->mem_copy);
278         } else {
279             move_mem_copies(find_better_copy(nts), ts);
280         }
281     }
282 }
283 
284 static void reset_temp(OptContext *ctx, TCGArg arg)
285 {
286     reset_ts(ctx, arg_temp(arg));
287 }
288 
289 static void record_mem_copy(OptContext *ctx, TCGType type,
290                             TCGTemp *ts, intptr_t start, intptr_t last)
291 {
292     MemCopyInfo *mc;
293     TempOptInfo *ti;
294 
295     mc = QSIMPLEQ_FIRST(&ctx->mem_free);
296     if (mc) {
297         QSIMPLEQ_REMOVE_HEAD(&ctx->mem_free, next);
298     } else {
299         mc = tcg_malloc(sizeof(*mc));
300     }
301 
302     memset(mc, 0, sizeof(*mc));
303     mc->itree.start = start;
304     mc->itree.last = last;
305     mc->type = type;
306     interval_tree_insert(&mc->itree, &ctx->mem_copy);
307 
308     ts = find_better_copy(ts);
309     ti = ts_info(ts);
310     mc->ts = ts;
311     QSIMPLEQ_INSERT_TAIL(&ti->mem_copy, mc, next);
312 }
313 
314 static bool ts_are_copies(TCGTemp *ts1, TCGTemp *ts2)
315 {
316     TCGTemp *i;
317 
318     if (ts1 == ts2) {
319         return true;
320     }
321 
322     if (!ts_is_copy(ts1) || !ts_is_copy(ts2)) {
323         return false;
324     }
325 
326     for (i = ts_info(ts1)->next_copy; i != ts1; i = ts_info(i)->next_copy) {
327         if (i == ts2) {
328             return true;
329         }
330     }
331 
332     return false;
333 }
334 
335 static bool args_are_copies(TCGArg arg1, TCGArg arg2)
336 {
337     return ts_are_copies(arg_temp(arg1), arg_temp(arg2));
338 }
339 
340 static TCGTemp *find_mem_copy_for(OptContext *ctx, TCGType type, intptr_t s)
341 {
342     MemCopyInfo *mc;
343 
344     for (mc = mem_copy_first(ctx, s, s); mc; mc = mem_copy_next(mc, s, s)) {
345         if (mc->itree.start == s && mc->type == type) {
346             return find_better_copy(mc->ts);
347         }
348     }
349     return NULL;
350 }
351 
352 static TCGArg arg_new_constant(OptContext *ctx, uint64_t val)
353 {
354     TCGType type = ctx->type;
355     TCGTemp *ts;
356 
357     if (type == TCG_TYPE_I32) {
358         val = (int32_t)val;
359     }
360 
361     ts = tcg_constant_internal(type, val);
362     init_ts_info(ctx, ts);
363 
364     return temp_arg(ts);
365 }
366 
367 static TCGArg arg_new_temp(OptContext *ctx)
368 {
369     TCGTemp *ts = tcg_temp_new_internal(ctx->type, TEMP_EBB);
370     init_ts_info(ctx, ts);
371     return temp_arg(ts);
372 }
373 
374 static bool tcg_opt_gen_mov(OptContext *ctx, TCGOp *op, TCGArg dst, TCGArg src)
375 {
376     TCGTemp *dst_ts = arg_temp(dst);
377     TCGTemp *src_ts = arg_temp(src);
378     TempOptInfo *di;
379     TempOptInfo *si;
380     TCGOpcode new_op;
381 
382     if (ts_are_copies(dst_ts, src_ts)) {
383         tcg_op_remove(ctx->tcg, op);
384         return true;
385     }
386 
387     reset_ts(ctx, dst_ts);
388     di = ts_info(dst_ts);
389     si = ts_info(src_ts);
390 
391     switch (ctx->type) {
392     case TCG_TYPE_I32:
393         new_op = INDEX_op_mov_i32;
394         break;
395     case TCG_TYPE_I64:
396         new_op = INDEX_op_mov_i64;
397         break;
398     case TCG_TYPE_V64:
399     case TCG_TYPE_V128:
400     case TCG_TYPE_V256:
401         /* TCGOP_VECL and TCGOP_VECE remain unchanged.  */
402         new_op = INDEX_op_mov_vec;
403         break;
404     default:
405         g_assert_not_reached();
406     }
407     op->opc = new_op;
408     op->args[0] = dst;
409     op->args[1] = src;
410 
411     di->z_mask = si->z_mask;
412     di->s_mask = si->s_mask;
413 
414     if (src_ts->type == dst_ts->type) {
415         TempOptInfo *ni = ts_info(si->next_copy);
416 
417         di->next_copy = si->next_copy;
418         di->prev_copy = src_ts;
419         ni->prev_copy = dst_ts;
420         si->next_copy = dst_ts;
421         di->is_const = si->is_const;
422         di->val = si->val;
423 
424         if (!QSIMPLEQ_EMPTY(&si->mem_copy)
425             && cmp_better_copy(src_ts, dst_ts) == dst_ts) {
426             move_mem_copies(dst_ts, src_ts);
427         }
428     }
429     return true;
430 }
431 
432 static bool tcg_opt_gen_movi(OptContext *ctx, TCGOp *op,
433                              TCGArg dst, uint64_t val)
434 {
435     /* Convert movi to mov with constant temp. */
436     return tcg_opt_gen_mov(ctx, op, dst, arg_new_constant(ctx, val));
437 }
438 
439 static uint64_t do_constant_folding_2(TCGOpcode op, uint64_t x, uint64_t y)
440 {
441     uint64_t l64, h64;
442 
443     switch (op) {
444     CASE_OP_32_64(add):
445         return x + y;
446 
447     CASE_OP_32_64(sub):
448         return x - y;
449 
450     CASE_OP_32_64(mul):
451         return x * y;
452 
453     CASE_OP_32_64_VEC(and):
454         return x & y;
455 
456     CASE_OP_32_64_VEC(or):
457         return x | y;
458 
459     CASE_OP_32_64_VEC(xor):
460         return x ^ y;
461 
462     case INDEX_op_shl_i32:
463         return (uint32_t)x << (y & 31);
464 
465     case INDEX_op_shl_i64:
466         return (uint64_t)x << (y & 63);
467 
468     case INDEX_op_shr_i32:
469         return (uint32_t)x >> (y & 31);
470 
471     case INDEX_op_shr_i64:
472         return (uint64_t)x >> (y & 63);
473 
474     case INDEX_op_sar_i32:
475         return (int32_t)x >> (y & 31);
476 
477     case INDEX_op_sar_i64:
478         return (int64_t)x >> (y & 63);
479 
480     case INDEX_op_rotr_i32:
481         return ror32(x, y & 31);
482 
483     case INDEX_op_rotr_i64:
484         return ror64(x, y & 63);
485 
486     case INDEX_op_rotl_i32:
487         return rol32(x, y & 31);
488 
489     case INDEX_op_rotl_i64:
490         return rol64(x, y & 63);
491 
492     CASE_OP_32_64_VEC(not):
493         return ~x;
494 
495     CASE_OP_32_64(neg):
496         return -x;
497 
498     CASE_OP_32_64_VEC(andc):
499         return x & ~y;
500 
501     CASE_OP_32_64_VEC(orc):
502         return x | ~y;
503 
504     CASE_OP_32_64_VEC(eqv):
505         return ~(x ^ y);
506 
507     CASE_OP_32_64_VEC(nand):
508         return ~(x & y);
509 
510     CASE_OP_32_64_VEC(nor):
511         return ~(x | y);
512 
513     case INDEX_op_clz_i32:
514         return (uint32_t)x ? clz32(x) : y;
515 
516     case INDEX_op_clz_i64:
517         return x ? clz64(x) : y;
518 
519     case INDEX_op_ctz_i32:
520         return (uint32_t)x ? ctz32(x) : y;
521 
522     case INDEX_op_ctz_i64:
523         return x ? ctz64(x) : y;
524 
525     case INDEX_op_ctpop_i32:
526         return ctpop32(x);
527 
528     case INDEX_op_ctpop_i64:
529         return ctpop64(x);
530 
531     CASE_OP_32_64(ext8s):
532         return (int8_t)x;
533 
534     CASE_OP_32_64(ext16s):
535         return (int16_t)x;
536 
537     CASE_OP_32_64(ext8u):
538         return (uint8_t)x;
539 
540     CASE_OP_32_64(ext16u):
541         return (uint16_t)x;
542 
543     CASE_OP_32_64(bswap16):
544         x = bswap16(x);
545         return y & TCG_BSWAP_OS ? (int16_t)x : x;
546 
547     CASE_OP_32_64(bswap32):
548         x = bswap32(x);
549         return y & TCG_BSWAP_OS ? (int32_t)x : x;
550 
551     case INDEX_op_bswap64_i64:
552         return bswap64(x);
553 
554     case INDEX_op_ext_i32_i64:
555     case INDEX_op_ext32s_i64:
556         return (int32_t)x;
557 
558     case INDEX_op_extu_i32_i64:
559     case INDEX_op_extrl_i64_i32:
560     case INDEX_op_ext32u_i64:
561         return (uint32_t)x;
562 
563     case INDEX_op_extrh_i64_i32:
564         return (uint64_t)x >> 32;
565 
566     case INDEX_op_muluh_i32:
567         return ((uint64_t)(uint32_t)x * (uint32_t)y) >> 32;
568     case INDEX_op_mulsh_i32:
569         return ((int64_t)(int32_t)x * (int32_t)y) >> 32;
570 
571     case INDEX_op_muluh_i64:
572         mulu64(&l64, &h64, x, y);
573         return h64;
574     case INDEX_op_mulsh_i64:
575         muls64(&l64, &h64, x, y);
576         return h64;
577 
578     case INDEX_op_div_i32:
579         /* Avoid crashing on divide by zero, otherwise undefined.  */
580         return (int32_t)x / ((int32_t)y ? : 1);
581     case INDEX_op_divu_i32:
582         return (uint32_t)x / ((uint32_t)y ? : 1);
583     case INDEX_op_div_i64:
584         return (int64_t)x / ((int64_t)y ? : 1);
585     case INDEX_op_divu_i64:
586         return (uint64_t)x / ((uint64_t)y ? : 1);
587 
588     case INDEX_op_rem_i32:
589         return (int32_t)x % ((int32_t)y ? : 1);
590     case INDEX_op_remu_i32:
591         return (uint32_t)x % ((uint32_t)y ? : 1);
592     case INDEX_op_rem_i64:
593         return (int64_t)x % ((int64_t)y ? : 1);
594     case INDEX_op_remu_i64:
595         return (uint64_t)x % ((uint64_t)y ? : 1);
596 
597     default:
598         g_assert_not_reached();
599     }
600 }
601 
602 static uint64_t do_constant_folding(TCGOpcode op, TCGType type,
603                                     uint64_t x, uint64_t y)
604 {
605     uint64_t res = do_constant_folding_2(op, x, y);
606     if (type == TCG_TYPE_I32) {
607         res = (int32_t)res;
608     }
609     return res;
610 }
611 
612 static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c)
613 {
614     switch (c) {
615     case TCG_COND_EQ:
616         return x == y;
617     case TCG_COND_NE:
618         return x != y;
619     case TCG_COND_LT:
620         return (int32_t)x < (int32_t)y;
621     case TCG_COND_GE:
622         return (int32_t)x >= (int32_t)y;
623     case TCG_COND_LE:
624         return (int32_t)x <= (int32_t)y;
625     case TCG_COND_GT:
626         return (int32_t)x > (int32_t)y;
627     case TCG_COND_LTU:
628         return x < y;
629     case TCG_COND_GEU:
630         return x >= y;
631     case TCG_COND_LEU:
632         return x <= y;
633     case TCG_COND_GTU:
634         return x > y;
635     case TCG_COND_TSTEQ:
636         return (x & y) == 0;
637     case TCG_COND_TSTNE:
638         return (x & y) != 0;
639     case TCG_COND_ALWAYS:
640     case TCG_COND_NEVER:
641         break;
642     }
643     g_assert_not_reached();
644 }
645 
646 static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c)
647 {
648     switch (c) {
649     case TCG_COND_EQ:
650         return x == y;
651     case TCG_COND_NE:
652         return x != y;
653     case TCG_COND_LT:
654         return (int64_t)x < (int64_t)y;
655     case TCG_COND_GE:
656         return (int64_t)x >= (int64_t)y;
657     case TCG_COND_LE:
658         return (int64_t)x <= (int64_t)y;
659     case TCG_COND_GT:
660         return (int64_t)x > (int64_t)y;
661     case TCG_COND_LTU:
662         return x < y;
663     case TCG_COND_GEU:
664         return x >= y;
665     case TCG_COND_LEU:
666         return x <= y;
667     case TCG_COND_GTU:
668         return x > y;
669     case TCG_COND_TSTEQ:
670         return (x & y) == 0;
671     case TCG_COND_TSTNE:
672         return (x & y) != 0;
673     case TCG_COND_ALWAYS:
674     case TCG_COND_NEVER:
675         break;
676     }
677     g_assert_not_reached();
678 }
679 
680 static int do_constant_folding_cond_eq(TCGCond c)
681 {
682     switch (c) {
683     case TCG_COND_GT:
684     case TCG_COND_LTU:
685     case TCG_COND_LT:
686     case TCG_COND_GTU:
687     case TCG_COND_NE:
688         return 0;
689     case TCG_COND_GE:
690     case TCG_COND_GEU:
691     case TCG_COND_LE:
692     case TCG_COND_LEU:
693     case TCG_COND_EQ:
694         return 1;
695     case TCG_COND_TSTEQ:
696     case TCG_COND_TSTNE:
697         return -1;
698     case TCG_COND_ALWAYS:
699     case TCG_COND_NEVER:
700         break;
701     }
702     g_assert_not_reached();
703 }
704 
705 /*
706  * Return -1 if the condition can't be simplified,
707  * and the result of the condition (0 or 1) if it can.
708  */
709 static int do_constant_folding_cond(TCGType type, TCGArg x,
710                                     TCGArg y, TCGCond c)
711 {
712     if (arg_is_const(x) && arg_is_const(y)) {
713         uint64_t xv = arg_info(x)->val;
714         uint64_t yv = arg_info(y)->val;
715 
716         switch (type) {
717         case TCG_TYPE_I32:
718             return do_constant_folding_cond_32(xv, yv, c);
719         case TCG_TYPE_I64:
720             return do_constant_folding_cond_64(xv, yv, c);
721         default:
722             /* Only scalar comparisons are optimizable */
723             return -1;
724         }
725     } else if (args_are_copies(x, y)) {
726         return do_constant_folding_cond_eq(c);
727     } else if (arg_is_const_val(y, 0)) {
728         switch (c) {
729         case TCG_COND_LTU:
730         case TCG_COND_TSTNE:
731             return 0;
732         case TCG_COND_GEU:
733         case TCG_COND_TSTEQ:
734             return 1;
735         default:
736             return -1;
737         }
738     }
739     return -1;
740 }
741 
742 /**
743  * swap_commutative:
744  * @dest: TCGArg of the destination argument, or NO_DEST.
745  * @p1: first paired argument
746  * @p2: second paired argument
747  *
748  * If *@p1 is a constant and *@p2 is not, swap.
749  * If *@p2 matches @dest, swap.
750  * Return true if a swap was performed.
751  */
752 
753 #define NO_DEST  temp_arg(NULL)
754 
755 static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
756 {
757     TCGArg a1 = *p1, a2 = *p2;
758     int sum = 0;
759     sum += arg_is_const(a1);
760     sum -= arg_is_const(a2);
761 
762     /* Prefer the constant in second argument, and then the form
763        op a, a, b, which is better handled on non-RISC hosts. */
764     if (sum > 0 || (sum == 0 && dest == a2)) {
765         *p1 = a2;
766         *p2 = a1;
767         return true;
768     }
769     return false;
770 }
771 
772 static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
773 {
774     int sum = 0;
775     sum += arg_is_const(p1[0]);
776     sum += arg_is_const(p1[1]);
777     sum -= arg_is_const(p2[0]);
778     sum -= arg_is_const(p2[1]);
779     if (sum > 0) {
780         TCGArg t;
781         t = p1[0], p1[0] = p2[0], p2[0] = t;
782         t = p1[1], p1[1] = p2[1], p2[1] = t;
783         return true;
784     }
785     return false;
786 }
787 
788 /*
789  * Return -1 if the condition can't be simplified,
790  * and the result of the condition (0 or 1) if it can.
791  */
792 static int do_constant_folding_cond1(OptContext *ctx, TCGOp *op, TCGArg dest,
793                                      TCGArg *p1, TCGArg *p2, TCGArg *pcond)
794 {
795     TCGCond cond;
796     bool swap;
797     int r;
798 
799     swap = swap_commutative(dest, p1, p2);
800     cond = *pcond;
801     if (swap) {
802         *pcond = cond = tcg_swap_cond(cond);
803     }
804 
805     r = do_constant_folding_cond(ctx->type, *p1, *p2, cond);
806     if (r >= 0) {
807         return r;
808     }
809     if (!is_tst_cond(cond)) {
810         return -1;
811     }
812 
813     /*
814      * TSTNE x,x -> NE x,0
815      * TSTNE x,-1 -> NE x,0
816      */
817     if (args_are_copies(*p1, *p2) || arg_is_const_val(*p2, -1)) {
818         *p2 = arg_new_constant(ctx, 0);
819         *pcond = tcg_tst_eqne_cond(cond);
820         return -1;
821     }
822 
823     /* TSTNE x,sign -> LT x,0 */
824     if (arg_is_const_val(*p2, (ctx->type == TCG_TYPE_I32
825                                ? INT32_MIN : INT64_MIN))) {
826         *p2 = arg_new_constant(ctx, 0);
827         *pcond = tcg_tst_ltge_cond(cond);
828         return -1;
829     }
830 
831     /* Expand to AND with a temporary if no backend support. */
832     if (!TCG_TARGET_HAS_tst) {
833         TCGOpcode and_opc = (ctx->type == TCG_TYPE_I32
834                              ? INDEX_op_and_i32 : INDEX_op_and_i64);
835         TCGOp *op2 = tcg_op_insert_before(ctx->tcg, op, and_opc, 3);
836         TCGArg tmp = arg_new_temp(ctx);
837 
838         op2->args[0] = tmp;
839         op2->args[1] = *p1;
840         op2->args[2] = *p2;
841 
842         *p1 = tmp;
843         *p2 = arg_new_constant(ctx, 0);
844         *pcond = tcg_tst_eqne_cond(cond);
845     }
846     return -1;
847 }
848 
849 static int do_constant_folding_cond2(OptContext *ctx, TCGOp *op, TCGArg *args)
850 {
851     TCGArg al, ah, bl, bh;
852     TCGCond c;
853     bool swap;
854     int r;
855 
856     swap = swap_commutative2(args, args + 2);
857     c = args[4];
858     if (swap) {
859         args[4] = c = tcg_swap_cond(c);
860     }
861 
862     al = args[0];
863     ah = args[1];
864     bl = args[2];
865     bh = args[3];
866 
867     if (arg_is_const(bl) && arg_is_const(bh)) {
868         tcg_target_ulong blv = arg_info(bl)->val;
869         tcg_target_ulong bhv = arg_info(bh)->val;
870         uint64_t b = deposit64(blv, 32, 32, bhv);
871 
872         if (arg_is_const(al) && arg_is_const(ah)) {
873             tcg_target_ulong alv = arg_info(al)->val;
874             tcg_target_ulong ahv = arg_info(ah)->val;
875             uint64_t a = deposit64(alv, 32, 32, ahv);
876 
877             r = do_constant_folding_cond_64(a, b, c);
878             if (r >= 0) {
879                 return r;
880             }
881         }
882 
883         if (b == 0) {
884             switch (c) {
885             case TCG_COND_LTU:
886             case TCG_COND_TSTNE:
887                 return 0;
888             case TCG_COND_GEU:
889             case TCG_COND_TSTEQ:
890                 return 1;
891             default:
892                 break;
893             }
894         }
895 
896         /* TSTNE x,-1 -> NE x,0 */
897         if (b == -1 && is_tst_cond(c)) {
898             args[3] = args[2] = arg_new_constant(ctx, 0);
899             args[4] = tcg_tst_eqne_cond(c);
900             return -1;
901         }
902 
903         /* TSTNE x,sign -> LT x,0 */
904         if (b == INT64_MIN && is_tst_cond(c)) {
905             /* bl must be 0, so copy that to bh */
906             args[3] = bl;
907             args[4] = tcg_tst_ltge_cond(c);
908             return -1;
909         }
910     }
911 
912     if (args_are_copies(al, bl) && args_are_copies(ah, bh)) {
913         r = do_constant_folding_cond_eq(c);
914         if (r >= 0) {
915             return r;
916         }
917 
918         /* TSTNE x,x -> NE x,0 */
919         if (is_tst_cond(c)) {
920             args[3] = args[2] = arg_new_constant(ctx, 0);
921             args[4] = tcg_tst_eqne_cond(c);
922             return -1;
923         }
924     }
925 
926     /* Expand to AND with a temporary if no backend support. */
927     if (!TCG_TARGET_HAS_tst && is_tst_cond(c)) {
928         TCGOp *op1 = tcg_op_insert_before(ctx->tcg, op, INDEX_op_and_i32, 3);
929         TCGOp *op2 = tcg_op_insert_before(ctx->tcg, op, INDEX_op_and_i32, 3);
930         TCGArg t1 = arg_new_temp(ctx);
931         TCGArg t2 = arg_new_temp(ctx);
932 
933         op1->args[0] = t1;
934         op1->args[1] = al;
935         op1->args[2] = bl;
936         op2->args[0] = t2;
937         op2->args[1] = ah;
938         op2->args[2] = bh;
939 
940         args[0] = t1;
941         args[1] = t2;
942         args[3] = args[2] = arg_new_constant(ctx, 0);
943         args[4] = tcg_tst_eqne_cond(c);
944     }
945     return -1;
946 }
947 
948 static void init_arguments(OptContext *ctx, TCGOp *op, int nb_args)
949 {
950     for (int i = 0; i < nb_args; i++) {
951         TCGTemp *ts = arg_temp(op->args[i]);
952         init_ts_info(ctx, ts);
953     }
954 }
955 
956 static void copy_propagate(OptContext *ctx, TCGOp *op,
957                            int nb_oargs, int nb_iargs)
958 {
959     for (int i = nb_oargs; i < nb_oargs + nb_iargs; i++) {
960         TCGTemp *ts = arg_temp(op->args[i]);
961         if (ts_is_copy(ts)) {
962             op->args[i] = temp_arg(find_better_copy(ts));
963         }
964     }
965 }
966 
967 static void finish_folding(OptContext *ctx, TCGOp *op)
968 {
969     const TCGOpDef *def = &tcg_op_defs[op->opc];
970     int i, nb_oargs;
971 
972     /*
973      * We only optimize extended basic blocks.  If the opcode ends a BB
974      * and is not a conditional branch, reset all temp data.
975      */
976     if (def->flags & TCG_OPF_BB_END) {
977         ctx->prev_mb = NULL;
978         if (!(def->flags & TCG_OPF_COND_BRANCH)) {
979             memset(&ctx->temps_used, 0, sizeof(ctx->temps_used));
980             remove_mem_copy_all(ctx);
981         }
982         return;
983     }
984 
985     nb_oargs = def->nb_oargs;
986     for (i = 0; i < nb_oargs; i++) {
987         TCGTemp *ts = arg_temp(op->args[i]);
988         reset_ts(ctx, ts);
989         /*
990          * Save the corresponding known-zero/sign bits mask for the
991          * first output argument (only one supported so far).
992          */
993         if (i == 0) {
994             ts_info(ts)->z_mask = ctx->z_mask;
995             ts_info(ts)->s_mask = ctx->s_mask;
996         }
997     }
998 }
999 
1000 /*
1001  * The fold_* functions return true when processing is complete,
1002  * usually by folding the operation to a constant or to a copy,
1003  * and calling tcg_opt_gen_{mov,movi}.  They may do other things,
1004  * like collect information about the value produced, for use in
1005  * optimizing a subsequent operation.
1006  *
1007  * These first fold_* functions are all helpers, used by other
1008  * folders for more specific operations.
1009  */
1010 
1011 static bool fold_const1(OptContext *ctx, TCGOp *op)
1012 {
1013     if (arg_is_const(op->args[1])) {
1014         uint64_t t;
1015 
1016         t = arg_info(op->args[1])->val;
1017         t = do_constant_folding(op->opc, ctx->type, t, 0);
1018         return tcg_opt_gen_movi(ctx, op, op->args[0], t);
1019     }
1020     return false;
1021 }
1022 
1023 static bool fold_const2(OptContext *ctx, TCGOp *op)
1024 {
1025     if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1026         uint64_t t1 = arg_info(op->args[1])->val;
1027         uint64_t t2 = arg_info(op->args[2])->val;
1028 
1029         t1 = do_constant_folding(op->opc, ctx->type, t1, t2);
1030         return tcg_opt_gen_movi(ctx, op, op->args[0], t1);
1031     }
1032     return false;
1033 }
1034 
1035 static bool fold_commutative(OptContext *ctx, TCGOp *op)
1036 {
1037     swap_commutative(op->args[0], &op->args[1], &op->args[2]);
1038     return false;
1039 }
1040 
1041 static bool fold_const2_commutative(OptContext *ctx, TCGOp *op)
1042 {
1043     swap_commutative(op->args[0], &op->args[1], &op->args[2]);
1044     return fold_const2(ctx, op);
1045 }
1046 
1047 static bool fold_masks(OptContext *ctx, TCGOp *op)
1048 {
1049     uint64_t a_mask = ctx->a_mask;
1050     uint64_t z_mask = ctx->z_mask;
1051     uint64_t s_mask = ctx->s_mask;
1052 
1053     /*
1054      * 32-bit ops generate 32-bit results, which for the purpose of
1055      * simplifying tcg are sign-extended.  Certainly that's how we
1056      * represent our constants elsewhere.  Note that the bits will
1057      * be reset properly for a 64-bit value when encountering the
1058      * type changing opcodes.
1059      */
1060     if (ctx->type == TCG_TYPE_I32) {
1061         a_mask = (int32_t)a_mask;
1062         z_mask = (int32_t)z_mask;
1063         s_mask |= MAKE_64BIT_MASK(32, 32);
1064         ctx->z_mask = z_mask;
1065         ctx->s_mask = s_mask;
1066     }
1067 
1068     if (z_mask == 0) {
1069         return tcg_opt_gen_movi(ctx, op, op->args[0], 0);
1070     }
1071     if (a_mask == 0) {
1072         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
1073     }
1074     return false;
1075 }
1076 
1077 /*
1078  * Convert @op to NOT, if NOT is supported by the host.
1079  * Return true f the conversion is successful, which will still
1080  * indicate that the processing is complete.
1081  */
1082 static bool fold_not(OptContext *ctx, TCGOp *op);
1083 static bool fold_to_not(OptContext *ctx, TCGOp *op, int idx)
1084 {
1085     TCGOpcode not_op;
1086     bool have_not;
1087 
1088     switch (ctx->type) {
1089     case TCG_TYPE_I32:
1090         not_op = INDEX_op_not_i32;
1091         have_not = TCG_TARGET_HAS_not_i32;
1092         break;
1093     case TCG_TYPE_I64:
1094         not_op = INDEX_op_not_i64;
1095         have_not = TCG_TARGET_HAS_not_i64;
1096         break;
1097     case TCG_TYPE_V64:
1098     case TCG_TYPE_V128:
1099     case TCG_TYPE_V256:
1100         not_op = INDEX_op_not_vec;
1101         have_not = TCG_TARGET_HAS_not_vec;
1102         break;
1103     default:
1104         g_assert_not_reached();
1105     }
1106     if (have_not) {
1107         op->opc = not_op;
1108         op->args[1] = op->args[idx];
1109         return fold_not(ctx, op);
1110     }
1111     return false;
1112 }
1113 
1114 /* If the binary operation has first argument @i, fold to @i. */
1115 static bool fold_ix_to_i(OptContext *ctx, TCGOp *op, uint64_t i)
1116 {
1117     if (arg_is_const_val(op->args[1], i)) {
1118         return tcg_opt_gen_movi(ctx, op, op->args[0], i);
1119     }
1120     return false;
1121 }
1122 
1123 /* If the binary operation has first argument @i, fold to NOT. */
1124 static bool fold_ix_to_not(OptContext *ctx, TCGOp *op, uint64_t i)
1125 {
1126     if (arg_is_const_val(op->args[1], i)) {
1127         return fold_to_not(ctx, op, 2);
1128     }
1129     return false;
1130 }
1131 
1132 /* If the binary operation has second argument @i, fold to @i. */
1133 static bool fold_xi_to_i(OptContext *ctx, TCGOp *op, uint64_t i)
1134 {
1135     if (arg_is_const_val(op->args[2], i)) {
1136         return tcg_opt_gen_movi(ctx, op, op->args[0], i);
1137     }
1138     return false;
1139 }
1140 
1141 /* If the binary operation has second argument @i, fold to identity. */
1142 static bool fold_xi_to_x(OptContext *ctx, TCGOp *op, uint64_t i)
1143 {
1144     if (arg_is_const_val(op->args[2], i)) {
1145         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
1146     }
1147     return false;
1148 }
1149 
1150 /* If the binary operation has second argument @i, fold to NOT. */
1151 static bool fold_xi_to_not(OptContext *ctx, TCGOp *op, uint64_t i)
1152 {
1153     if (arg_is_const_val(op->args[2], i)) {
1154         return fold_to_not(ctx, op, 1);
1155     }
1156     return false;
1157 }
1158 
1159 /* If the binary operation has both arguments equal, fold to @i. */
1160 static bool fold_xx_to_i(OptContext *ctx, TCGOp *op, uint64_t i)
1161 {
1162     if (args_are_copies(op->args[1], op->args[2])) {
1163         return tcg_opt_gen_movi(ctx, op, op->args[0], i);
1164     }
1165     return false;
1166 }
1167 
1168 /* If the binary operation has both arguments equal, fold to identity. */
1169 static bool fold_xx_to_x(OptContext *ctx, TCGOp *op)
1170 {
1171     if (args_are_copies(op->args[1], op->args[2])) {
1172         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
1173     }
1174     return false;
1175 }
1176 
1177 /*
1178  * These outermost fold_<op> functions are sorted alphabetically.
1179  *
1180  * The ordering of the transformations should be:
1181  *   1) those that produce a constant
1182  *   2) those that produce a copy
1183  *   3) those that produce information about the result value.
1184  */
1185 
1186 static bool fold_add(OptContext *ctx, TCGOp *op)
1187 {
1188     if (fold_const2_commutative(ctx, op) ||
1189         fold_xi_to_x(ctx, op, 0)) {
1190         return true;
1191     }
1192     return false;
1193 }
1194 
1195 /* We cannot as yet do_constant_folding with vectors. */
1196 static bool fold_add_vec(OptContext *ctx, TCGOp *op)
1197 {
1198     if (fold_commutative(ctx, op) ||
1199         fold_xi_to_x(ctx, op, 0)) {
1200         return true;
1201     }
1202     return false;
1203 }
1204 
1205 static bool fold_addsub2(OptContext *ctx, TCGOp *op, bool add)
1206 {
1207     bool a_const = arg_is_const(op->args[2]) && arg_is_const(op->args[3]);
1208     bool b_const = arg_is_const(op->args[4]) && arg_is_const(op->args[5]);
1209 
1210     if (a_const && b_const) {
1211         uint64_t al = arg_info(op->args[2])->val;
1212         uint64_t ah = arg_info(op->args[3])->val;
1213         uint64_t bl = arg_info(op->args[4])->val;
1214         uint64_t bh = arg_info(op->args[5])->val;
1215         TCGArg rl, rh;
1216         TCGOp *op2;
1217 
1218         if (ctx->type == TCG_TYPE_I32) {
1219             uint64_t a = deposit64(al, 32, 32, ah);
1220             uint64_t b = deposit64(bl, 32, 32, bh);
1221 
1222             if (add) {
1223                 a += b;
1224             } else {
1225                 a -= b;
1226             }
1227 
1228             al = sextract64(a, 0, 32);
1229             ah = sextract64(a, 32, 32);
1230         } else {
1231             Int128 a = int128_make128(al, ah);
1232             Int128 b = int128_make128(bl, bh);
1233 
1234             if (add) {
1235                 a = int128_add(a, b);
1236             } else {
1237                 a = int128_sub(a, b);
1238             }
1239 
1240             al = int128_getlo(a);
1241             ah = int128_gethi(a);
1242         }
1243 
1244         rl = op->args[0];
1245         rh = op->args[1];
1246 
1247         /* The proper opcode is supplied by tcg_opt_gen_mov. */
1248         op2 = tcg_op_insert_before(ctx->tcg, op, 0, 2);
1249 
1250         tcg_opt_gen_movi(ctx, op, rl, al);
1251         tcg_opt_gen_movi(ctx, op2, rh, ah);
1252         return true;
1253     }
1254 
1255     /* Fold sub2 r,x,i to add2 r,x,-i */
1256     if (!add && b_const) {
1257         uint64_t bl = arg_info(op->args[4])->val;
1258         uint64_t bh = arg_info(op->args[5])->val;
1259 
1260         /* Negate the two parts without assembling and disassembling. */
1261         bl = -bl;
1262         bh = ~bh + !bl;
1263 
1264         op->opc = (ctx->type == TCG_TYPE_I32
1265                    ? INDEX_op_add2_i32 : INDEX_op_add2_i64);
1266         op->args[4] = arg_new_constant(ctx, bl);
1267         op->args[5] = arg_new_constant(ctx, bh);
1268     }
1269     return false;
1270 }
1271 
1272 static bool fold_add2(OptContext *ctx, TCGOp *op)
1273 {
1274     /* Note that the high and low parts may be independently swapped. */
1275     swap_commutative(op->args[0], &op->args[2], &op->args[4]);
1276     swap_commutative(op->args[1], &op->args[3], &op->args[5]);
1277 
1278     return fold_addsub2(ctx, op, true);
1279 }
1280 
1281 static bool fold_and(OptContext *ctx, TCGOp *op)
1282 {
1283     uint64_t z1, z2;
1284 
1285     if (fold_const2_commutative(ctx, op) ||
1286         fold_xi_to_i(ctx, op, 0) ||
1287         fold_xi_to_x(ctx, op, -1) ||
1288         fold_xx_to_x(ctx, op)) {
1289         return true;
1290     }
1291 
1292     z1 = arg_info(op->args[1])->z_mask;
1293     z2 = arg_info(op->args[2])->z_mask;
1294     ctx->z_mask = z1 & z2;
1295 
1296     /*
1297      * Sign repetitions are perforce all identical, whether they are 1 or 0.
1298      * Bitwise operations preserve the relative quantity of the repetitions.
1299      */
1300     ctx->s_mask = arg_info(op->args[1])->s_mask
1301                 & arg_info(op->args[2])->s_mask;
1302 
1303     /*
1304      * Known-zeros does not imply known-ones.  Therefore unless
1305      * arg2 is constant, we can't infer affected bits from it.
1306      */
1307     if (arg_is_const(op->args[2])) {
1308         ctx->a_mask = z1 & ~z2;
1309     }
1310 
1311     return fold_masks(ctx, op);
1312 }
1313 
1314 static bool fold_andc(OptContext *ctx, TCGOp *op)
1315 {
1316     uint64_t z1;
1317 
1318     if (fold_const2(ctx, op) ||
1319         fold_xx_to_i(ctx, op, 0) ||
1320         fold_xi_to_x(ctx, op, 0) ||
1321         fold_ix_to_not(ctx, op, -1)) {
1322         return true;
1323     }
1324 
1325     z1 = arg_info(op->args[1])->z_mask;
1326 
1327     /*
1328      * Known-zeros does not imply known-ones.  Therefore unless
1329      * arg2 is constant, we can't infer anything from it.
1330      */
1331     if (arg_is_const(op->args[2])) {
1332         uint64_t z2 = ~arg_info(op->args[2])->z_mask;
1333         ctx->a_mask = z1 & ~z2;
1334         z1 &= z2;
1335     }
1336     ctx->z_mask = z1;
1337 
1338     ctx->s_mask = arg_info(op->args[1])->s_mask
1339                 & arg_info(op->args[2])->s_mask;
1340     return fold_masks(ctx, op);
1341 }
1342 
1343 static bool fold_brcond(OptContext *ctx, TCGOp *op)
1344 {
1345     int i = do_constant_folding_cond1(ctx, op, NO_DEST, &op->args[0],
1346                                       &op->args[1], &op->args[2]);
1347     if (i == 0) {
1348         tcg_op_remove(ctx->tcg, op);
1349         return true;
1350     }
1351     if (i > 0) {
1352         op->opc = INDEX_op_br;
1353         op->args[0] = op->args[3];
1354     }
1355     return false;
1356 }
1357 
1358 static bool fold_brcond2(OptContext *ctx, TCGOp *op)
1359 {
1360     TCGCond cond;
1361     TCGArg label;
1362     int i, inv = 0;
1363 
1364     i = do_constant_folding_cond2(ctx, op, &op->args[0]);
1365     cond = op->args[4];
1366     label = op->args[5];
1367     if (i >= 0) {
1368         goto do_brcond_const;
1369     }
1370 
1371     switch (cond) {
1372     case TCG_COND_LT:
1373     case TCG_COND_GE:
1374         /*
1375          * Simplify LT/GE comparisons vs zero to a single compare
1376          * vs the high word of the input.
1377          */
1378         if (arg_is_const_val(op->args[2], 0) &&
1379             arg_is_const_val(op->args[3], 0)) {
1380             goto do_brcond_high;
1381         }
1382         break;
1383 
1384     case TCG_COND_NE:
1385         inv = 1;
1386         QEMU_FALLTHROUGH;
1387     case TCG_COND_EQ:
1388         /*
1389          * Simplify EQ/NE comparisons where one of the pairs
1390          * can be simplified.
1391          */
1392         i = do_constant_folding_cond(TCG_TYPE_I32, op->args[0],
1393                                      op->args[2], cond);
1394         switch (i ^ inv) {
1395         case 0:
1396             goto do_brcond_const;
1397         case 1:
1398             goto do_brcond_high;
1399         }
1400 
1401         i = do_constant_folding_cond(TCG_TYPE_I32, op->args[1],
1402                                      op->args[3], cond);
1403         switch (i ^ inv) {
1404         case 0:
1405             goto do_brcond_const;
1406         case 1:
1407             goto do_brcond_low;
1408         }
1409         break;
1410 
1411     case TCG_COND_TSTEQ:
1412     case TCG_COND_TSTNE:
1413         if (arg_is_const_val(op->args[2], 0)) {
1414             goto do_brcond_high;
1415         }
1416         if (arg_is_const_val(op->args[3], 0)) {
1417             goto do_brcond_low;
1418         }
1419         break;
1420 
1421     default:
1422         break;
1423 
1424     do_brcond_low:
1425         op->opc = INDEX_op_brcond_i32;
1426         op->args[1] = op->args[2];
1427         op->args[2] = cond;
1428         op->args[3] = label;
1429         return fold_brcond(ctx, op);
1430 
1431     do_brcond_high:
1432         op->opc = INDEX_op_brcond_i32;
1433         op->args[0] = op->args[1];
1434         op->args[1] = op->args[3];
1435         op->args[2] = cond;
1436         op->args[3] = label;
1437         return fold_brcond(ctx, op);
1438 
1439     do_brcond_const:
1440         if (i == 0) {
1441             tcg_op_remove(ctx->tcg, op);
1442             return true;
1443         }
1444         op->opc = INDEX_op_br;
1445         op->args[0] = label;
1446         break;
1447     }
1448     return false;
1449 }
1450 
1451 static bool fold_bswap(OptContext *ctx, TCGOp *op)
1452 {
1453     uint64_t z_mask, s_mask, sign;
1454 
1455     if (arg_is_const(op->args[1])) {
1456         uint64_t t = arg_info(op->args[1])->val;
1457 
1458         t = do_constant_folding(op->opc, ctx->type, t, op->args[2]);
1459         return tcg_opt_gen_movi(ctx, op, op->args[0], t);
1460     }
1461 
1462     z_mask = arg_info(op->args[1])->z_mask;
1463 
1464     switch (op->opc) {
1465     case INDEX_op_bswap16_i32:
1466     case INDEX_op_bswap16_i64:
1467         z_mask = bswap16(z_mask);
1468         sign = INT16_MIN;
1469         break;
1470     case INDEX_op_bswap32_i32:
1471     case INDEX_op_bswap32_i64:
1472         z_mask = bswap32(z_mask);
1473         sign = INT32_MIN;
1474         break;
1475     case INDEX_op_bswap64_i64:
1476         z_mask = bswap64(z_mask);
1477         sign = INT64_MIN;
1478         break;
1479     default:
1480         g_assert_not_reached();
1481     }
1482     s_mask = smask_from_zmask(z_mask);
1483 
1484     switch (op->args[2] & (TCG_BSWAP_OZ | TCG_BSWAP_OS)) {
1485     case TCG_BSWAP_OZ:
1486         break;
1487     case TCG_BSWAP_OS:
1488         /* If the sign bit may be 1, force all the bits above to 1. */
1489         if (z_mask & sign) {
1490             z_mask |= sign;
1491             s_mask = sign << 1;
1492         }
1493         break;
1494     default:
1495         /* The high bits are undefined: force all bits above the sign to 1. */
1496         z_mask |= sign << 1;
1497         s_mask = 0;
1498         break;
1499     }
1500     ctx->z_mask = z_mask;
1501     ctx->s_mask = s_mask;
1502 
1503     return fold_masks(ctx, op);
1504 }
1505 
1506 static bool fold_call(OptContext *ctx, TCGOp *op)
1507 {
1508     TCGContext *s = ctx->tcg;
1509     int nb_oargs = TCGOP_CALLO(op);
1510     int nb_iargs = TCGOP_CALLI(op);
1511     int flags, i;
1512 
1513     init_arguments(ctx, op, nb_oargs + nb_iargs);
1514     copy_propagate(ctx, op, nb_oargs, nb_iargs);
1515 
1516     /* If the function reads or writes globals, reset temp data. */
1517     flags = tcg_call_flags(op);
1518     if (!(flags & (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) {
1519         int nb_globals = s->nb_globals;
1520 
1521         for (i = 0; i < nb_globals; i++) {
1522             if (test_bit(i, ctx->temps_used.l)) {
1523                 reset_ts(ctx, &ctx->tcg->temps[i]);
1524             }
1525         }
1526     }
1527 
1528     /* If the function has side effects, reset mem data. */
1529     if (!(flags & TCG_CALL_NO_SIDE_EFFECTS)) {
1530         remove_mem_copy_all(ctx);
1531     }
1532 
1533     /* Reset temp data for outputs. */
1534     for (i = 0; i < nb_oargs; i++) {
1535         reset_temp(ctx, op->args[i]);
1536     }
1537 
1538     /* Stop optimizing MB across calls. */
1539     ctx->prev_mb = NULL;
1540     return true;
1541 }
1542 
1543 static bool fold_count_zeros(OptContext *ctx, TCGOp *op)
1544 {
1545     uint64_t z_mask;
1546 
1547     if (arg_is_const(op->args[1])) {
1548         uint64_t t = arg_info(op->args[1])->val;
1549 
1550         if (t != 0) {
1551             t = do_constant_folding(op->opc, ctx->type, t, 0);
1552             return tcg_opt_gen_movi(ctx, op, op->args[0], t);
1553         }
1554         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[2]);
1555     }
1556 
1557     switch (ctx->type) {
1558     case TCG_TYPE_I32:
1559         z_mask = 31;
1560         break;
1561     case TCG_TYPE_I64:
1562         z_mask = 63;
1563         break;
1564     default:
1565         g_assert_not_reached();
1566     }
1567     ctx->z_mask = arg_info(op->args[2])->z_mask | z_mask;
1568     ctx->s_mask = smask_from_zmask(ctx->z_mask);
1569     return false;
1570 }
1571 
1572 static bool fold_ctpop(OptContext *ctx, TCGOp *op)
1573 {
1574     if (fold_const1(ctx, op)) {
1575         return true;
1576     }
1577 
1578     switch (ctx->type) {
1579     case TCG_TYPE_I32:
1580         ctx->z_mask = 32 | 31;
1581         break;
1582     case TCG_TYPE_I64:
1583         ctx->z_mask = 64 | 63;
1584         break;
1585     default:
1586         g_assert_not_reached();
1587     }
1588     ctx->s_mask = smask_from_zmask(ctx->z_mask);
1589     return false;
1590 }
1591 
1592 static bool fold_deposit(OptContext *ctx, TCGOp *op)
1593 {
1594     TCGOpcode and_opc;
1595 
1596     if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1597         uint64_t t1 = arg_info(op->args[1])->val;
1598         uint64_t t2 = arg_info(op->args[2])->val;
1599 
1600         t1 = deposit64(t1, op->args[3], op->args[4], t2);
1601         return tcg_opt_gen_movi(ctx, op, op->args[0], t1);
1602     }
1603 
1604     switch (ctx->type) {
1605     case TCG_TYPE_I32:
1606         and_opc = INDEX_op_and_i32;
1607         break;
1608     case TCG_TYPE_I64:
1609         and_opc = INDEX_op_and_i64;
1610         break;
1611     default:
1612         g_assert_not_reached();
1613     }
1614 
1615     /* Inserting a value into zero at offset 0. */
1616     if (arg_is_const_val(op->args[1], 0) && op->args[3] == 0) {
1617         uint64_t mask = MAKE_64BIT_MASK(0, op->args[4]);
1618 
1619         op->opc = and_opc;
1620         op->args[1] = op->args[2];
1621         op->args[2] = arg_new_constant(ctx, mask);
1622         ctx->z_mask = mask & arg_info(op->args[1])->z_mask;
1623         return false;
1624     }
1625 
1626     /* Inserting zero into a value. */
1627     if (arg_is_const_val(op->args[2], 0)) {
1628         uint64_t mask = deposit64(-1, op->args[3], op->args[4], 0);
1629 
1630         op->opc = and_opc;
1631         op->args[2] = arg_new_constant(ctx, mask);
1632         ctx->z_mask = mask & arg_info(op->args[1])->z_mask;
1633         return false;
1634     }
1635 
1636     ctx->z_mask = deposit64(arg_info(op->args[1])->z_mask,
1637                             op->args[3], op->args[4],
1638                             arg_info(op->args[2])->z_mask);
1639     return false;
1640 }
1641 
1642 static bool fold_divide(OptContext *ctx, TCGOp *op)
1643 {
1644     if (fold_const2(ctx, op) ||
1645         fold_xi_to_x(ctx, op, 1)) {
1646         return true;
1647     }
1648     return false;
1649 }
1650 
1651 static bool fold_dup(OptContext *ctx, TCGOp *op)
1652 {
1653     if (arg_is_const(op->args[1])) {
1654         uint64_t t = arg_info(op->args[1])->val;
1655         t = dup_const(TCGOP_VECE(op), t);
1656         return tcg_opt_gen_movi(ctx, op, op->args[0], t);
1657     }
1658     return false;
1659 }
1660 
1661 static bool fold_dup2(OptContext *ctx, TCGOp *op)
1662 {
1663     if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1664         uint64_t t = deposit64(arg_info(op->args[1])->val, 32, 32,
1665                                arg_info(op->args[2])->val);
1666         return tcg_opt_gen_movi(ctx, op, op->args[0], t);
1667     }
1668 
1669     if (args_are_copies(op->args[1], op->args[2])) {
1670         op->opc = INDEX_op_dup_vec;
1671         TCGOP_VECE(op) = MO_32;
1672     }
1673     return false;
1674 }
1675 
1676 static bool fold_eqv(OptContext *ctx, TCGOp *op)
1677 {
1678     if (fold_const2_commutative(ctx, op) ||
1679         fold_xi_to_x(ctx, op, -1) ||
1680         fold_xi_to_not(ctx, op, 0)) {
1681         return true;
1682     }
1683 
1684     ctx->s_mask = arg_info(op->args[1])->s_mask
1685                 & arg_info(op->args[2])->s_mask;
1686     return false;
1687 }
1688 
1689 static bool fold_extract(OptContext *ctx, TCGOp *op)
1690 {
1691     uint64_t z_mask_old, z_mask;
1692     int pos = op->args[2];
1693     int len = op->args[3];
1694 
1695     if (arg_is_const(op->args[1])) {
1696         uint64_t t;
1697 
1698         t = arg_info(op->args[1])->val;
1699         t = extract64(t, pos, len);
1700         return tcg_opt_gen_movi(ctx, op, op->args[0], t);
1701     }
1702 
1703     z_mask_old = arg_info(op->args[1])->z_mask;
1704     z_mask = extract64(z_mask_old, pos, len);
1705     if (pos == 0) {
1706         ctx->a_mask = z_mask_old ^ z_mask;
1707     }
1708     ctx->z_mask = z_mask;
1709     ctx->s_mask = smask_from_zmask(z_mask);
1710 
1711     return fold_masks(ctx, op);
1712 }
1713 
1714 static bool fold_extract2(OptContext *ctx, TCGOp *op)
1715 {
1716     if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1717         uint64_t v1 = arg_info(op->args[1])->val;
1718         uint64_t v2 = arg_info(op->args[2])->val;
1719         int shr = op->args[3];
1720 
1721         if (op->opc == INDEX_op_extract2_i64) {
1722             v1 >>= shr;
1723             v2 <<= 64 - shr;
1724         } else {
1725             v1 = (uint32_t)v1 >> shr;
1726             v2 = (uint64_t)((int32_t)v2 << (32 - shr));
1727         }
1728         return tcg_opt_gen_movi(ctx, op, op->args[0], v1 | v2);
1729     }
1730     return false;
1731 }
1732 
1733 static bool fold_exts(OptContext *ctx, TCGOp *op)
1734 {
1735     uint64_t s_mask_old, s_mask, z_mask, sign;
1736     bool type_change = false;
1737 
1738     if (fold_const1(ctx, op)) {
1739         return true;
1740     }
1741 
1742     z_mask = arg_info(op->args[1])->z_mask;
1743     s_mask = arg_info(op->args[1])->s_mask;
1744     s_mask_old = s_mask;
1745 
1746     switch (op->opc) {
1747     CASE_OP_32_64(ext8s):
1748         sign = INT8_MIN;
1749         z_mask = (uint8_t)z_mask;
1750         break;
1751     CASE_OP_32_64(ext16s):
1752         sign = INT16_MIN;
1753         z_mask = (uint16_t)z_mask;
1754         break;
1755     case INDEX_op_ext_i32_i64:
1756         type_change = true;
1757         QEMU_FALLTHROUGH;
1758     case INDEX_op_ext32s_i64:
1759         sign = INT32_MIN;
1760         z_mask = (uint32_t)z_mask;
1761         break;
1762     default:
1763         g_assert_not_reached();
1764     }
1765 
1766     if (z_mask & sign) {
1767         z_mask |= sign;
1768     }
1769     s_mask |= sign << 1;
1770 
1771     ctx->z_mask = z_mask;
1772     ctx->s_mask = s_mask;
1773     if (!type_change) {
1774         ctx->a_mask = s_mask & ~s_mask_old;
1775     }
1776 
1777     return fold_masks(ctx, op);
1778 }
1779 
1780 static bool fold_extu(OptContext *ctx, TCGOp *op)
1781 {
1782     uint64_t z_mask_old, z_mask;
1783     bool type_change = false;
1784 
1785     if (fold_const1(ctx, op)) {
1786         return true;
1787     }
1788 
1789     z_mask_old = z_mask = arg_info(op->args[1])->z_mask;
1790 
1791     switch (op->opc) {
1792     CASE_OP_32_64(ext8u):
1793         z_mask = (uint8_t)z_mask;
1794         break;
1795     CASE_OP_32_64(ext16u):
1796         z_mask = (uint16_t)z_mask;
1797         break;
1798     case INDEX_op_extrl_i64_i32:
1799     case INDEX_op_extu_i32_i64:
1800         type_change = true;
1801         QEMU_FALLTHROUGH;
1802     case INDEX_op_ext32u_i64:
1803         z_mask = (uint32_t)z_mask;
1804         break;
1805     case INDEX_op_extrh_i64_i32:
1806         type_change = true;
1807         z_mask >>= 32;
1808         break;
1809     default:
1810         g_assert_not_reached();
1811     }
1812 
1813     ctx->z_mask = z_mask;
1814     ctx->s_mask = smask_from_zmask(z_mask);
1815     if (!type_change) {
1816         ctx->a_mask = z_mask_old ^ z_mask;
1817     }
1818     return fold_masks(ctx, op);
1819 }
1820 
1821 static bool fold_mb(OptContext *ctx, TCGOp *op)
1822 {
1823     /* Eliminate duplicate and redundant fence instructions.  */
1824     if (ctx->prev_mb) {
1825         /*
1826          * Merge two barriers of the same type into one,
1827          * or a weaker barrier into a stronger one,
1828          * or two weaker barriers into a stronger one.
1829          *   mb X; mb Y => mb X|Y
1830          *   mb; strl => mb; st
1831          *   ldaq; mb => ld; mb
1832          *   ldaq; strl => ld; mb; st
1833          * Other combinations are also merged into a strong
1834          * barrier.  This is stricter than specified but for
1835          * the purposes of TCG is better than not optimizing.
1836          */
1837         ctx->prev_mb->args[0] |= op->args[0];
1838         tcg_op_remove(ctx->tcg, op);
1839     } else {
1840         ctx->prev_mb = op;
1841     }
1842     return true;
1843 }
1844 
1845 static bool fold_mov(OptContext *ctx, TCGOp *op)
1846 {
1847     return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
1848 }
1849 
1850 static bool fold_movcond(OptContext *ctx, TCGOp *op)
1851 {
1852     int i;
1853 
1854     /* If true and false values are the same, eliminate the cmp. */
1855     if (args_are_copies(op->args[3], op->args[4])) {
1856         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[3]);
1857     }
1858 
1859     /*
1860      * Canonicalize the "false" input reg to match the destination reg so
1861      * that the tcg backend can implement a "move if true" operation.
1862      */
1863     if (swap_commutative(op->args[0], &op->args[4], &op->args[3])) {
1864         op->args[5] = tcg_invert_cond(op->args[5]);
1865     }
1866 
1867     i = do_constant_folding_cond1(ctx, op, NO_DEST, &op->args[1],
1868                                   &op->args[2], &op->args[5]);
1869     if (i >= 0) {
1870         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[4 - i]);
1871     }
1872 
1873     ctx->z_mask = arg_info(op->args[3])->z_mask
1874                 | arg_info(op->args[4])->z_mask;
1875     ctx->s_mask = arg_info(op->args[3])->s_mask
1876                 & arg_info(op->args[4])->s_mask;
1877 
1878     if (arg_is_const(op->args[3]) && arg_is_const(op->args[4])) {
1879         uint64_t tv = arg_info(op->args[3])->val;
1880         uint64_t fv = arg_info(op->args[4])->val;
1881         TCGOpcode opc, negopc = 0;
1882         TCGCond cond = op->args[5];
1883 
1884         switch (ctx->type) {
1885         case TCG_TYPE_I32:
1886             opc = INDEX_op_setcond_i32;
1887             if (TCG_TARGET_HAS_negsetcond_i32) {
1888                 negopc = INDEX_op_negsetcond_i32;
1889             }
1890             tv = (int32_t)tv;
1891             fv = (int32_t)fv;
1892             break;
1893         case TCG_TYPE_I64:
1894             opc = INDEX_op_setcond_i64;
1895             if (TCG_TARGET_HAS_negsetcond_i64) {
1896                 negopc = INDEX_op_negsetcond_i64;
1897             }
1898             break;
1899         default:
1900             g_assert_not_reached();
1901         }
1902 
1903         if (tv == 1 && fv == 0) {
1904             op->opc = opc;
1905             op->args[3] = cond;
1906         } else if (fv == 1 && tv == 0) {
1907             op->opc = opc;
1908             op->args[3] = tcg_invert_cond(cond);
1909         } else if (negopc) {
1910             if (tv == -1 && fv == 0) {
1911                 op->opc = negopc;
1912                 op->args[3] = cond;
1913             } else if (fv == -1 && tv == 0) {
1914                 op->opc = negopc;
1915                 op->args[3] = tcg_invert_cond(cond);
1916             }
1917         }
1918     }
1919     return false;
1920 }
1921 
1922 static bool fold_mul(OptContext *ctx, TCGOp *op)
1923 {
1924     if (fold_const2(ctx, op) ||
1925         fold_xi_to_i(ctx, op, 0) ||
1926         fold_xi_to_x(ctx, op, 1)) {
1927         return true;
1928     }
1929     return false;
1930 }
1931 
1932 static bool fold_mul_highpart(OptContext *ctx, TCGOp *op)
1933 {
1934     if (fold_const2_commutative(ctx, op) ||
1935         fold_xi_to_i(ctx, op, 0)) {
1936         return true;
1937     }
1938     return false;
1939 }
1940 
1941 static bool fold_multiply2(OptContext *ctx, TCGOp *op)
1942 {
1943     swap_commutative(op->args[0], &op->args[2], &op->args[3]);
1944 
1945     if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])) {
1946         uint64_t a = arg_info(op->args[2])->val;
1947         uint64_t b = arg_info(op->args[3])->val;
1948         uint64_t h, l;
1949         TCGArg rl, rh;
1950         TCGOp *op2;
1951 
1952         switch (op->opc) {
1953         case INDEX_op_mulu2_i32:
1954             l = (uint64_t)(uint32_t)a * (uint32_t)b;
1955             h = (int32_t)(l >> 32);
1956             l = (int32_t)l;
1957             break;
1958         case INDEX_op_muls2_i32:
1959             l = (int64_t)(int32_t)a * (int32_t)b;
1960             h = l >> 32;
1961             l = (int32_t)l;
1962             break;
1963         case INDEX_op_mulu2_i64:
1964             mulu64(&l, &h, a, b);
1965             break;
1966         case INDEX_op_muls2_i64:
1967             muls64(&l, &h, a, b);
1968             break;
1969         default:
1970             g_assert_not_reached();
1971         }
1972 
1973         rl = op->args[0];
1974         rh = op->args[1];
1975 
1976         /* The proper opcode is supplied by tcg_opt_gen_mov. */
1977         op2 = tcg_op_insert_before(ctx->tcg, op, 0, 2);
1978 
1979         tcg_opt_gen_movi(ctx, op, rl, l);
1980         tcg_opt_gen_movi(ctx, op2, rh, h);
1981         return true;
1982     }
1983     return false;
1984 }
1985 
1986 static bool fold_nand(OptContext *ctx, TCGOp *op)
1987 {
1988     if (fold_const2_commutative(ctx, op) ||
1989         fold_xi_to_not(ctx, op, -1)) {
1990         return true;
1991     }
1992 
1993     ctx->s_mask = arg_info(op->args[1])->s_mask
1994                 & arg_info(op->args[2])->s_mask;
1995     return false;
1996 }
1997 
1998 static bool fold_neg_no_const(OptContext *ctx, TCGOp *op)
1999 {
2000     /* Set to 1 all bits to the left of the rightmost.  */
2001     uint64_t z_mask = arg_info(op->args[1])->z_mask;
2002     ctx->z_mask = -(z_mask & -z_mask);
2003 
2004     /*
2005      * Because of fold_sub_to_neg, we want to always return true,
2006      * via finish_folding.
2007      */
2008     finish_folding(ctx, op);
2009     return true;
2010 }
2011 
2012 static bool fold_neg(OptContext *ctx, TCGOp *op)
2013 {
2014     return fold_const1(ctx, op) || fold_neg_no_const(ctx, op);
2015 }
2016 
2017 static bool fold_nor(OptContext *ctx, TCGOp *op)
2018 {
2019     if (fold_const2_commutative(ctx, op) ||
2020         fold_xi_to_not(ctx, op, 0)) {
2021         return true;
2022     }
2023 
2024     ctx->s_mask = arg_info(op->args[1])->s_mask
2025                 & arg_info(op->args[2])->s_mask;
2026     return false;
2027 }
2028 
2029 static bool fold_not(OptContext *ctx, TCGOp *op)
2030 {
2031     if (fold_const1(ctx, op)) {
2032         return true;
2033     }
2034 
2035     ctx->s_mask = arg_info(op->args[1])->s_mask;
2036 
2037     /* Because of fold_to_not, we want to always return true, via finish. */
2038     finish_folding(ctx, op);
2039     return true;
2040 }
2041 
2042 static bool fold_or(OptContext *ctx, TCGOp *op)
2043 {
2044     if (fold_const2_commutative(ctx, op) ||
2045         fold_xi_to_x(ctx, op, 0) ||
2046         fold_xx_to_x(ctx, op)) {
2047         return true;
2048     }
2049 
2050     ctx->z_mask = arg_info(op->args[1])->z_mask
2051                 | arg_info(op->args[2])->z_mask;
2052     ctx->s_mask = arg_info(op->args[1])->s_mask
2053                 & arg_info(op->args[2])->s_mask;
2054     return fold_masks(ctx, op);
2055 }
2056 
2057 static bool fold_orc(OptContext *ctx, TCGOp *op)
2058 {
2059     if (fold_const2(ctx, op) ||
2060         fold_xx_to_i(ctx, op, -1) ||
2061         fold_xi_to_x(ctx, op, -1) ||
2062         fold_ix_to_not(ctx, op, 0)) {
2063         return true;
2064     }
2065 
2066     ctx->s_mask = arg_info(op->args[1])->s_mask
2067                 & arg_info(op->args[2])->s_mask;
2068     return false;
2069 }
2070 
2071 static bool fold_qemu_ld(OptContext *ctx, TCGOp *op)
2072 {
2073     const TCGOpDef *def = &tcg_op_defs[op->opc];
2074     MemOpIdx oi = op->args[def->nb_oargs + def->nb_iargs];
2075     MemOp mop = get_memop(oi);
2076     int width = 8 * memop_size(mop);
2077 
2078     if (width < 64) {
2079         ctx->s_mask = MAKE_64BIT_MASK(width, 64 - width);
2080         if (!(mop & MO_SIGN)) {
2081             ctx->z_mask = MAKE_64BIT_MASK(0, width);
2082             ctx->s_mask <<= 1;
2083         }
2084     }
2085 
2086     /* Opcodes that touch guest memory stop the mb optimization.  */
2087     ctx->prev_mb = NULL;
2088     return false;
2089 }
2090 
2091 static bool fold_qemu_st(OptContext *ctx, TCGOp *op)
2092 {
2093     /* Opcodes that touch guest memory stop the mb optimization.  */
2094     ctx->prev_mb = NULL;
2095     return false;
2096 }
2097 
2098 static bool fold_remainder(OptContext *ctx, TCGOp *op)
2099 {
2100     if (fold_const2(ctx, op) ||
2101         fold_xx_to_i(ctx, op, 0)) {
2102         return true;
2103     }
2104     return false;
2105 }
2106 
2107 static bool fold_setcond_zmask(OptContext *ctx, TCGOp *op, bool neg)
2108 {
2109     uint64_t a_zmask, b_val;
2110     TCGCond cond;
2111 
2112     if (!arg_is_const(op->args[2])) {
2113         return false;
2114     }
2115 
2116     a_zmask = arg_info(op->args[1])->z_mask;
2117     b_val = arg_info(op->args[2])->val;
2118     cond = op->args[3];
2119 
2120     if (ctx->type == TCG_TYPE_I32) {
2121         a_zmask = (uint32_t)a_zmask;
2122         b_val = (uint32_t)b_val;
2123     }
2124 
2125     /*
2126      * A with only low bits set vs B with high bits set means that A < B.
2127      */
2128     if (a_zmask < b_val) {
2129         bool inv = false;
2130 
2131         switch (cond) {
2132         case TCG_COND_NE:
2133         case TCG_COND_LEU:
2134         case TCG_COND_LTU:
2135             inv = true;
2136             /* fall through */
2137         case TCG_COND_GTU:
2138         case TCG_COND_GEU:
2139         case TCG_COND_EQ:
2140             return tcg_opt_gen_movi(ctx, op, op->args[0], neg ? -inv : inv);
2141         default:
2142             break;
2143         }
2144     }
2145 
2146     /*
2147      * A with only lsb set is already boolean.
2148      */
2149     if (a_zmask <= 1) {
2150         bool convert = false;
2151         bool inv = false;
2152 
2153         switch (cond) {
2154         case TCG_COND_EQ:
2155             inv = true;
2156             /* fall through */
2157         case TCG_COND_NE:
2158             convert = (b_val == 0);
2159             break;
2160         case TCG_COND_LTU:
2161         case TCG_COND_TSTEQ:
2162             inv = true;
2163             /* fall through */
2164         case TCG_COND_GEU:
2165         case TCG_COND_TSTNE:
2166             convert = (b_val == 1);
2167             break;
2168         default:
2169             break;
2170         }
2171         if (convert) {
2172             TCGOpcode add_opc, xor_opc, neg_opc;
2173 
2174             if (!inv && !neg) {
2175                 return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
2176             }
2177 
2178             switch (ctx->type) {
2179             case TCG_TYPE_I32:
2180                 add_opc = INDEX_op_add_i32;
2181                 neg_opc = INDEX_op_neg_i32;
2182                 xor_opc = INDEX_op_xor_i32;
2183                 break;
2184             case TCG_TYPE_I64:
2185                 add_opc = INDEX_op_add_i64;
2186                 neg_opc = INDEX_op_neg_i64;
2187                 xor_opc = INDEX_op_xor_i64;
2188                 break;
2189             default:
2190                 g_assert_not_reached();
2191             }
2192 
2193             if (!inv) {
2194                 op->opc = neg_opc;
2195             } else if (neg) {
2196                 op->opc = add_opc;
2197                 op->args[2] = arg_new_constant(ctx, -1);
2198             } else {
2199                 op->opc = xor_opc;
2200                 op->args[2] = arg_new_constant(ctx, 1);
2201             }
2202             return false;
2203         }
2204     }
2205 
2206     return false;
2207 }
2208 
2209 static void fold_setcond_tst_pow2(OptContext *ctx, TCGOp *op, bool neg)
2210 {
2211     TCGOpcode and_opc, sub_opc, xor_opc, neg_opc, shr_opc;
2212     TCGOpcode uext_opc = 0, sext_opc = 0;
2213     TCGCond cond = op->args[3];
2214     TCGArg ret, src1, src2;
2215     TCGOp *op2;
2216     uint64_t val;
2217     int sh;
2218     bool inv;
2219 
2220     if (!is_tst_cond(cond) || !arg_is_const(op->args[2])) {
2221         return;
2222     }
2223 
2224     src2 = op->args[2];
2225     val = arg_info(src2)->val;
2226     if (!is_power_of_2(val)) {
2227         return;
2228     }
2229     sh = ctz64(val);
2230 
2231     switch (ctx->type) {
2232     case TCG_TYPE_I32:
2233         and_opc = INDEX_op_and_i32;
2234         sub_opc = INDEX_op_sub_i32;
2235         xor_opc = INDEX_op_xor_i32;
2236         shr_opc = INDEX_op_shr_i32;
2237         neg_opc = INDEX_op_neg_i32;
2238         if (TCG_TARGET_extract_i32_valid(sh, 1)) {
2239             uext_opc = TCG_TARGET_HAS_extract_i32 ? INDEX_op_extract_i32 : 0;
2240             sext_opc = TCG_TARGET_HAS_sextract_i32 ? INDEX_op_sextract_i32 : 0;
2241         }
2242         break;
2243     case TCG_TYPE_I64:
2244         and_opc = INDEX_op_and_i64;
2245         sub_opc = INDEX_op_sub_i64;
2246         xor_opc = INDEX_op_xor_i64;
2247         shr_opc = INDEX_op_shr_i64;
2248         neg_opc = INDEX_op_neg_i64;
2249         if (TCG_TARGET_extract_i64_valid(sh, 1)) {
2250             uext_opc = TCG_TARGET_HAS_extract_i64 ? INDEX_op_extract_i64 : 0;
2251             sext_opc = TCG_TARGET_HAS_sextract_i64 ? INDEX_op_sextract_i64 : 0;
2252         }
2253         break;
2254     default:
2255         g_assert_not_reached();
2256     }
2257 
2258     ret = op->args[0];
2259     src1 = op->args[1];
2260     inv = cond == TCG_COND_TSTEQ;
2261 
2262     if (sh && sext_opc && neg && !inv) {
2263         op->opc = sext_opc;
2264         op->args[1] = src1;
2265         op->args[2] = sh;
2266         op->args[3] = 1;
2267         return;
2268     } else if (sh && uext_opc) {
2269         op->opc = uext_opc;
2270         op->args[1] = src1;
2271         op->args[2] = sh;
2272         op->args[3] = 1;
2273     } else {
2274         if (sh) {
2275             op2 = tcg_op_insert_before(ctx->tcg, op, shr_opc, 3);
2276             op2->args[0] = ret;
2277             op2->args[1] = src1;
2278             op2->args[2] = arg_new_constant(ctx, sh);
2279             src1 = ret;
2280         }
2281         op->opc = and_opc;
2282         op->args[1] = src1;
2283         op->args[2] = arg_new_constant(ctx, 1);
2284     }
2285 
2286     if (neg && inv) {
2287         op2 = tcg_op_insert_after(ctx->tcg, op, sub_opc, 3);
2288         op2->args[0] = ret;
2289         op2->args[1] = ret;
2290         op2->args[2] = arg_new_constant(ctx, 1);
2291     } else if (inv) {
2292         op2 = tcg_op_insert_after(ctx->tcg, op, xor_opc, 3);
2293         op2->args[0] = ret;
2294         op2->args[1] = ret;
2295         op2->args[2] = arg_new_constant(ctx, 1);
2296     } else if (neg) {
2297         op2 = tcg_op_insert_after(ctx->tcg, op, neg_opc, 2);
2298         op2->args[0] = ret;
2299         op2->args[1] = ret;
2300     }
2301 }
2302 
2303 static bool fold_setcond(OptContext *ctx, TCGOp *op)
2304 {
2305     int i = do_constant_folding_cond1(ctx, op, op->args[0], &op->args[1],
2306                                       &op->args[2], &op->args[3]);
2307     if (i >= 0) {
2308         return tcg_opt_gen_movi(ctx, op, op->args[0], i);
2309     }
2310 
2311     if (fold_setcond_zmask(ctx, op, false)) {
2312         return true;
2313     }
2314     fold_setcond_tst_pow2(ctx, op, false);
2315 
2316     ctx->z_mask = 1;
2317     ctx->s_mask = smask_from_zmask(1);
2318     return false;
2319 }
2320 
2321 static bool fold_negsetcond(OptContext *ctx, TCGOp *op)
2322 {
2323     int i = do_constant_folding_cond1(ctx, op, op->args[0], &op->args[1],
2324                                       &op->args[2], &op->args[3]);
2325     if (i >= 0) {
2326         return tcg_opt_gen_movi(ctx, op, op->args[0], -i);
2327     }
2328 
2329     if (fold_setcond_zmask(ctx, op, true)) {
2330         return true;
2331     }
2332     fold_setcond_tst_pow2(ctx, op, true);
2333 
2334     /* Value is {0,-1} so all bits are repetitions of the sign. */
2335     ctx->s_mask = -1;
2336     return false;
2337 }
2338 
2339 static bool fold_setcond2(OptContext *ctx, TCGOp *op)
2340 {
2341     TCGCond cond;
2342     int i, inv = 0;
2343 
2344     i = do_constant_folding_cond2(ctx, op, &op->args[1]);
2345     cond = op->args[5];
2346     if (i >= 0) {
2347         goto do_setcond_const;
2348     }
2349 
2350     switch (cond) {
2351     case TCG_COND_LT:
2352     case TCG_COND_GE:
2353         /*
2354          * Simplify LT/GE comparisons vs zero to a single compare
2355          * vs the high word of the input.
2356          */
2357         if (arg_is_const_val(op->args[3], 0) &&
2358             arg_is_const_val(op->args[4], 0)) {
2359             goto do_setcond_high;
2360         }
2361         break;
2362 
2363     case TCG_COND_NE:
2364         inv = 1;
2365         QEMU_FALLTHROUGH;
2366     case TCG_COND_EQ:
2367         /*
2368          * Simplify EQ/NE comparisons where one of the pairs
2369          * can be simplified.
2370          */
2371         i = do_constant_folding_cond(TCG_TYPE_I32, op->args[1],
2372                                      op->args[3], cond);
2373         switch (i ^ inv) {
2374         case 0:
2375             goto do_setcond_const;
2376         case 1:
2377             goto do_setcond_high;
2378         }
2379 
2380         i = do_constant_folding_cond(TCG_TYPE_I32, op->args[2],
2381                                      op->args[4], cond);
2382         switch (i ^ inv) {
2383         case 0:
2384             goto do_setcond_const;
2385         case 1:
2386             goto do_setcond_low;
2387         }
2388         break;
2389 
2390     case TCG_COND_TSTEQ:
2391     case TCG_COND_TSTNE:
2392         if (arg_is_const_val(op->args[3], 0)) {
2393             goto do_setcond_high;
2394         }
2395         if (arg_is_const_val(op->args[4], 0)) {
2396             goto do_setcond_low;
2397         }
2398         break;
2399 
2400     default:
2401         break;
2402 
2403     do_setcond_low:
2404         op->args[2] = op->args[3];
2405         op->args[3] = cond;
2406         op->opc = INDEX_op_setcond_i32;
2407         return fold_setcond(ctx, op);
2408 
2409     do_setcond_high:
2410         op->args[1] = op->args[2];
2411         op->args[2] = op->args[4];
2412         op->args[3] = cond;
2413         op->opc = INDEX_op_setcond_i32;
2414         return fold_setcond(ctx, op);
2415     }
2416 
2417     ctx->z_mask = 1;
2418     ctx->s_mask = smask_from_zmask(1);
2419     return false;
2420 
2421  do_setcond_const:
2422     return tcg_opt_gen_movi(ctx, op, op->args[0], i);
2423 }
2424 
2425 static bool fold_cmp_vec(OptContext *ctx, TCGOp *op)
2426 {
2427     /* Canonicalize the comparison to put immediate second. */
2428     if (swap_commutative(NO_DEST, &op->args[1], &op->args[2])) {
2429         op->args[3] = tcg_swap_cond(op->args[3]);
2430     }
2431     return false;
2432 }
2433 
2434 static bool fold_cmpsel_vec(OptContext *ctx, TCGOp *op)
2435 {
2436     /* If true and false values are the same, eliminate the cmp. */
2437     if (args_are_copies(op->args[3], op->args[4])) {
2438         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[3]);
2439     }
2440 
2441     /* Canonicalize the comparison to put immediate second. */
2442     if (swap_commutative(NO_DEST, &op->args[1], &op->args[2])) {
2443         op->args[5] = tcg_swap_cond(op->args[5]);
2444     }
2445     /*
2446      * Canonicalize the "false" input reg to match the destination,
2447      * so that the tcg backend can implement "move if true".
2448      */
2449     if (swap_commutative(op->args[0], &op->args[4], &op->args[3])) {
2450         op->args[5] = tcg_invert_cond(op->args[5]);
2451     }
2452     return false;
2453 }
2454 
2455 static bool fold_sextract(OptContext *ctx, TCGOp *op)
2456 {
2457     uint64_t z_mask, s_mask, s_mask_old;
2458     int pos = op->args[2];
2459     int len = op->args[3];
2460 
2461     if (arg_is_const(op->args[1])) {
2462         uint64_t t;
2463 
2464         t = arg_info(op->args[1])->val;
2465         t = sextract64(t, pos, len);
2466         return tcg_opt_gen_movi(ctx, op, op->args[0], t);
2467     }
2468 
2469     z_mask = arg_info(op->args[1])->z_mask;
2470     z_mask = sextract64(z_mask, pos, len);
2471     ctx->z_mask = z_mask;
2472 
2473     s_mask_old = arg_info(op->args[1])->s_mask;
2474     s_mask = sextract64(s_mask_old, pos, len);
2475     s_mask |= MAKE_64BIT_MASK(len, 64 - len);
2476     ctx->s_mask = s_mask;
2477 
2478     if (pos == 0) {
2479         ctx->a_mask = s_mask & ~s_mask_old;
2480     }
2481 
2482     return fold_masks(ctx, op);
2483 }
2484 
2485 static bool fold_shift(OptContext *ctx, TCGOp *op)
2486 {
2487     uint64_t s_mask, z_mask, sign;
2488 
2489     if (fold_const2(ctx, op) ||
2490         fold_ix_to_i(ctx, op, 0) ||
2491         fold_xi_to_x(ctx, op, 0)) {
2492         return true;
2493     }
2494 
2495     s_mask = arg_info(op->args[1])->s_mask;
2496     z_mask = arg_info(op->args[1])->z_mask;
2497 
2498     if (arg_is_const(op->args[2])) {
2499         int sh = arg_info(op->args[2])->val;
2500 
2501         ctx->z_mask = do_constant_folding(op->opc, ctx->type, z_mask, sh);
2502 
2503         s_mask = do_constant_folding(op->opc, ctx->type, s_mask, sh);
2504         ctx->s_mask = smask_from_smask(s_mask);
2505 
2506         return fold_masks(ctx, op);
2507     }
2508 
2509     switch (op->opc) {
2510     CASE_OP_32_64(sar):
2511         /*
2512          * Arithmetic right shift will not reduce the number of
2513          * input sign repetitions.
2514          */
2515         ctx->s_mask = s_mask;
2516         break;
2517     CASE_OP_32_64(shr):
2518         /*
2519          * If the sign bit is known zero, then logical right shift
2520          * will not reduced the number of input sign repetitions.
2521          */
2522         sign = (s_mask & -s_mask) >> 1;
2523         if (sign && !(z_mask & sign)) {
2524             ctx->s_mask = s_mask;
2525         }
2526         break;
2527     default:
2528         break;
2529     }
2530 
2531     return false;
2532 }
2533 
2534 static bool fold_sub_to_neg(OptContext *ctx, TCGOp *op)
2535 {
2536     TCGOpcode neg_op;
2537     bool have_neg;
2538 
2539     if (!arg_is_const(op->args[1]) || arg_info(op->args[1])->val != 0) {
2540         return false;
2541     }
2542 
2543     switch (ctx->type) {
2544     case TCG_TYPE_I32:
2545         neg_op = INDEX_op_neg_i32;
2546         have_neg = true;
2547         break;
2548     case TCG_TYPE_I64:
2549         neg_op = INDEX_op_neg_i64;
2550         have_neg = true;
2551         break;
2552     case TCG_TYPE_V64:
2553     case TCG_TYPE_V128:
2554     case TCG_TYPE_V256:
2555         neg_op = INDEX_op_neg_vec;
2556         have_neg = (TCG_TARGET_HAS_neg_vec &&
2557                     tcg_can_emit_vec_op(neg_op, ctx->type, TCGOP_VECE(op)) > 0);
2558         break;
2559     default:
2560         g_assert_not_reached();
2561     }
2562     if (have_neg) {
2563         op->opc = neg_op;
2564         op->args[1] = op->args[2];
2565         return fold_neg_no_const(ctx, op);
2566     }
2567     return false;
2568 }
2569 
2570 /* We cannot as yet do_constant_folding with vectors. */
2571 static bool fold_sub_vec(OptContext *ctx, TCGOp *op)
2572 {
2573     if (fold_xx_to_i(ctx, op, 0) ||
2574         fold_xi_to_x(ctx, op, 0) ||
2575         fold_sub_to_neg(ctx, op)) {
2576         return true;
2577     }
2578     return false;
2579 }
2580 
2581 static bool fold_sub(OptContext *ctx, TCGOp *op)
2582 {
2583     if (fold_const2(ctx, op) || fold_sub_vec(ctx, op)) {
2584         return true;
2585     }
2586 
2587     /* Fold sub r,x,i to add r,x,-i */
2588     if (arg_is_const(op->args[2])) {
2589         uint64_t val = arg_info(op->args[2])->val;
2590 
2591         op->opc = (ctx->type == TCG_TYPE_I32
2592                    ? INDEX_op_add_i32 : INDEX_op_add_i64);
2593         op->args[2] = arg_new_constant(ctx, -val);
2594     }
2595     return false;
2596 }
2597 
2598 static bool fold_sub2(OptContext *ctx, TCGOp *op)
2599 {
2600     return fold_addsub2(ctx, op, false);
2601 }
2602 
2603 static bool fold_tcg_ld(OptContext *ctx, TCGOp *op)
2604 {
2605     /* We can't do any folding with a load, but we can record bits. */
2606     switch (op->opc) {
2607     CASE_OP_32_64(ld8s):
2608         ctx->s_mask = MAKE_64BIT_MASK(8, 56);
2609         break;
2610     CASE_OP_32_64(ld8u):
2611         ctx->z_mask = MAKE_64BIT_MASK(0, 8);
2612         ctx->s_mask = MAKE_64BIT_MASK(9, 55);
2613         break;
2614     CASE_OP_32_64(ld16s):
2615         ctx->s_mask = MAKE_64BIT_MASK(16, 48);
2616         break;
2617     CASE_OP_32_64(ld16u):
2618         ctx->z_mask = MAKE_64BIT_MASK(0, 16);
2619         ctx->s_mask = MAKE_64BIT_MASK(17, 47);
2620         break;
2621     case INDEX_op_ld32s_i64:
2622         ctx->s_mask = MAKE_64BIT_MASK(32, 32);
2623         break;
2624     case INDEX_op_ld32u_i64:
2625         ctx->z_mask = MAKE_64BIT_MASK(0, 32);
2626         ctx->s_mask = MAKE_64BIT_MASK(33, 31);
2627         break;
2628     default:
2629         g_assert_not_reached();
2630     }
2631     return false;
2632 }
2633 
2634 static bool fold_tcg_ld_memcopy(OptContext *ctx, TCGOp *op)
2635 {
2636     TCGTemp *dst, *src;
2637     intptr_t ofs;
2638     TCGType type;
2639 
2640     if (op->args[1] != tcgv_ptr_arg(tcg_env)) {
2641         return false;
2642     }
2643 
2644     type = ctx->type;
2645     ofs = op->args[2];
2646     dst = arg_temp(op->args[0]);
2647     src = find_mem_copy_for(ctx, type, ofs);
2648     if (src && src->base_type == type) {
2649         return tcg_opt_gen_mov(ctx, op, temp_arg(dst), temp_arg(src));
2650     }
2651 
2652     reset_ts(ctx, dst);
2653     record_mem_copy(ctx, type, dst, ofs, ofs + tcg_type_size(type) - 1);
2654     return true;
2655 }
2656 
2657 static bool fold_tcg_st(OptContext *ctx, TCGOp *op)
2658 {
2659     intptr_t ofs = op->args[2];
2660     intptr_t lm1;
2661 
2662     if (op->args[1] != tcgv_ptr_arg(tcg_env)) {
2663         remove_mem_copy_all(ctx);
2664         return false;
2665     }
2666 
2667     switch (op->opc) {
2668     CASE_OP_32_64(st8):
2669         lm1 = 0;
2670         break;
2671     CASE_OP_32_64(st16):
2672         lm1 = 1;
2673         break;
2674     case INDEX_op_st32_i64:
2675     case INDEX_op_st_i32:
2676         lm1 = 3;
2677         break;
2678     case INDEX_op_st_i64:
2679         lm1 = 7;
2680         break;
2681     case INDEX_op_st_vec:
2682         lm1 = tcg_type_size(ctx->type) - 1;
2683         break;
2684     default:
2685         g_assert_not_reached();
2686     }
2687     remove_mem_copy_in(ctx, ofs, ofs + lm1);
2688     return false;
2689 }
2690 
2691 static bool fold_tcg_st_memcopy(OptContext *ctx, TCGOp *op)
2692 {
2693     TCGTemp *src;
2694     intptr_t ofs, last;
2695     TCGType type;
2696 
2697     if (op->args[1] != tcgv_ptr_arg(tcg_env)) {
2698         fold_tcg_st(ctx, op);
2699         return false;
2700     }
2701 
2702     src = arg_temp(op->args[0]);
2703     ofs = op->args[2];
2704     type = ctx->type;
2705 
2706     /*
2707      * Eliminate duplicate stores of a constant.
2708      * This happens frequently when the target ISA zero-extends.
2709      */
2710     if (ts_is_const(src)) {
2711         TCGTemp *prev = find_mem_copy_for(ctx, type, ofs);
2712         if (src == prev) {
2713             tcg_op_remove(ctx->tcg, op);
2714             return true;
2715         }
2716     }
2717 
2718     last = ofs + tcg_type_size(type) - 1;
2719     remove_mem_copy_in(ctx, ofs, last);
2720     record_mem_copy(ctx, type, src, ofs, last);
2721     return false;
2722 }
2723 
2724 static bool fold_xor(OptContext *ctx, TCGOp *op)
2725 {
2726     if (fold_const2_commutative(ctx, op) ||
2727         fold_xx_to_i(ctx, op, 0) ||
2728         fold_xi_to_x(ctx, op, 0) ||
2729         fold_xi_to_not(ctx, op, -1)) {
2730         return true;
2731     }
2732 
2733     ctx->z_mask = arg_info(op->args[1])->z_mask
2734                 | arg_info(op->args[2])->z_mask;
2735     ctx->s_mask = arg_info(op->args[1])->s_mask
2736                 & arg_info(op->args[2])->s_mask;
2737     return fold_masks(ctx, op);
2738 }
2739 
2740 static bool fold_bitsel_vec(OptContext *ctx, TCGOp *op)
2741 {
2742     /* If true and false values are the same, eliminate the cmp. */
2743     if (args_are_copies(op->args[2], op->args[3])) {
2744         return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[2]);
2745     }
2746 
2747     if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])) {
2748         uint64_t tv = arg_info(op->args[2])->val;
2749         uint64_t fv = arg_info(op->args[3])->val;
2750 
2751         if (tv == -1 && fv == 0) {
2752             return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
2753         }
2754         if (tv == 0 && fv == -1) {
2755             if (TCG_TARGET_HAS_not_vec) {
2756                 op->opc = INDEX_op_not_vec;
2757                 return fold_not(ctx, op);
2758             } else {
2759                 op->opc = INDEX_op_xor_vec;
2760                 op->args[2] = arg_new_constant(ctx, -1);
2761                 return fold_xor(ctx, op);
2762             }
2763         }
2764     }
2765     if (arg_is_const(op->args[2])) {
2766         uint64_t tv = arg_info(op->args[2])->val;
2767         if (tv == -1) {
2768             op->opc = INDEX_op_or_vec;
2769             op->args[2] = op->args[3];
2770             return fold_or(ctx, op);
2771         }
2772         if (tv == 0 && TCG_TARGET_HAS_andc_vec) {
2773             op->opc = INDEX_op_andc_vec;
2774             op->args[2] = op->args[1];
2775             op->args[1] = op->args[3];
2776             return fold_andc(ctx, op);
2777         }
2778     }
2779     if (arg_is_const(op->args[3])) {
2780         uint64_t fv = arg_info(op->args[3])->val;
2781         if (fv == 0) {
2782             op->opc = INDEX_op_and_vec;
2783             return fold_and(ctx, op);
2784         }
2785         if (fv == -1 && TCG_TARGET_HAS_orc_vec) {
2786             op->opc = INDEX_op_orc_vec;
2787             op->args[2] = op->args[1];
2788             op->args[1] = op->args[3];
2789             return fold_orc(ctx, op);
2790         }
2791     }
2792     return false;
2793 }
2794 
2795 /* Propagate constants and copies, fold constant expressions. */
2796 void tcg_optimize(TCGContext *s)
2797 {
2798     int nb_temps, i;
2799     TCGOp *op, *op_next;
2800     OptContext ctx = { .tcg = s };
2801 
2802     QSIMPLEQ_INIT(&ctx.mem_free);
2803 
2804     /* Array VALS has an element for each temp.
2805        If this temp holds a constant then its value is kept in VALS' element.
2806        If this temp is a copy of other ones then the other copies are
2807        available through the doubly linked circular list. */
2808 
2809     nb_temps = s->nb_temps;
2810     for (i = 0; i < nb_temps; ++i) {
2811         s->temps[i].state_ptr = NULL;
2812     }
2813 
2814     QTAILQ_FOREACH_SAFE(op, &s->ops, link, op_next) {
2815         TCGOpcode opc = op->opc;
2816         const TCGOpDef *def;
2817         bool done = false;
2818 
2819         /* Calls are special. */
2820         if (opc == INDEX_op_call) {
2821             fold_call(&ctx, op);
2822             continue;
2823         }
2824 
2825         def = &tcg_op_defs[opc];
2826         init_arguments(&ctx, op, def->nb_oargs + def->nb_iargs);
2827         copy_propagate(&ctx, op, def->nb_oargs, def->nb_iargs);
2828 
2829         /* Pre-compute the type of the operation. */
2830         if (def->flags & TCG_OPF_VECTOR) {
2831             ctx.type = TCG_TYPE_V64 + TCGOP_VECL(op);
2832         } else if (def->flags & TCG_OPF_64BIT) {
2833             ctx.type = TCG_TYPE_I64;
2834         } else {
2835             ctx.type = TCG_TYPE_I32;
2836         }
2837 
2838         /* Assume all bits affected, no bits known zero, no sign reps. */
2839         ctx.a_mask = -1;
2840         ctx.z_mask = -1;
2841         ctx.s_mask = 0;
2842 
2843         /*
2844          * Process each opcode.
2845          * Sorted alphabetically by opcode as much as possible.
2846          */
2847         switch (opc) {
2848         CASE_OP_32_64(add):
2849             done = fold_add(&ctx, op);
2850             break;
2851         case INDEX_op_add_vec:
2852             done = fold_add_vec(&ctx, op);
2853             break;
2854         CASE_OP_32_64(add2):
2855             done = fold_add2(&ctx, op);
2856             break;
2857         CASE_OP_32_64_VEC(and):
2858             done = fold_and(&ctx, op);
2859             break;
2860         CASE_OP_32_64_VEC(andc):
2861             done = fold_andc(&ctx, op);
2862             break;
2863         CASE_OP_32_64(brcond):
2864             done = fold_brcond(&ctx, op);
2865             break;
2866         case INDEX_op_brcond2_i32:
2867             done = fold_brcond2(&ctx, op);
2868             break;
2869         CASE_OP_32_64(bswap16):
2870         CASE_OP_32_64(bswap32):
2871         case INDEX_op_bswap64_i64:
2872             done = fold_bswap(&ctx, op);
2873             break;
2874         CASE_OP_32_64(clz):
2875         CASE_OP_32_64(ctz):
2876             done = fold_count_zeros(&ctx, op);
2877             break;
2878         CASE_OP_32_64(ctpop):
2879             done = fold_ctpop(&ctx, op);
2880             break;
2881         CASE_OP_32_64(deposit):
2882             done = fold_deposit(&ctx, op);
2883             break;
2884         CASE_OP_32_64(div):
2885         CASE_OP_32_64(divu):
2886             done = fold_divide(&ctx, op);
2887             break;
2888         case INDEX_op_dup_vec:
2889             done = fold_dup(&ctx, op);
2890             break;
2891         case INDEX_op_dup2_vec:
2892             done = fold_dup2(&ctx, op);
2893             break;
2894         CASE_OP_32_64_VEC(eqv):
2895             done = fold_eqv(&ctx, op);
2896             break;
2897         CASE_OP_32_64(extract):
2898             done = fold_extract(&ctx, op);
2899             break;
2900         CASE_OP_32_64(extract2):
2901             done = fold_extract2(&ctx, op);
2902             break;
2903         CASE_OP_32_64(ext8s):
2904         CASE_OP_32_64(ext16s):
2905         case INDEX_op_ext32s_i64:
2906         case INDEX_op_ext_i32_i64:
2907             done = fold_exts(&ctx, op);
2908             break;
2909         CASE_OP_32_64(ext8u):
2910         CASE_OP_32_64(ext16u):
2911         case INDEX_op_ext32u_i64:
2912         case INDEX_op_extu_i32_i64:
2913         case INDEX_op_extrl_i64_i32:
2914         case INDEX_op_extrh_i64_i32:
2915             done = fold_extu(&ctx, op);
2916             break;
2917         CASE_OP_32_64(ld8s):
2918         CASE_OP_32_64(ld8u):
2919         CASE_OP_32_64(ld16s):
2920         CASE_OP_32_64(ld16u):
2921         case INDEX_op_ld32s_i64:
2922         case INDEX_op_ld32u_i64:
2923             done = fold_tcg_ld(&ctx, op);
2924             break;
2925         case INDEX_op_ld_i32:
2926         case INDEX_op_ld_i64:
2927         case INDEX_op_ld_vec:
2928             done = fold_tcg_ld_memcopy(&ctx, op);
2929             break;
2930         CASE_OP_32_64(st8):
2931         CASE_OP_32_64(st16):
2932         case INDEX_op_st32_i64:
2933             done = fold_tcg_st(&ctx, op);
2934             break;
2935         case INDEX_op_st_i32:
2936         case INDEX_op_st_i64:
2937         case INDEX_op_st_vec:
2938             done = fold_tcg_st_memcopy(&ctx, op);
2939             break;
2940         case INDEX_op_mb:
2941             done = fold_mb(&ctx, op);
2942             break;
2943         CASE_OP_32_64_VEC(mov):
2944             done = fold_mov(&ctx, op);
2945             break;
2946         CASE_OP_32_64(movcond):
2947             done = fold_movcond(&ctx, op);
2948             break;
2949         CASE_OP_32_64(mul):
2950             done = fold_mul(&ctx, op);
2951             break;
2952         CASE_OP_32_64(mulsh):
2953         CASE_OP_32_64(muluh):
2954             done = fold_mul_highpart(&ctx, op);
2955             break;
2956         CASE_OP_32_64(muls2):
2957         CASE_OP_32_64(mulu2):
2958             done = fold_multiply2(&ctx, op);
2959             break;
2960         CASE_OP_32_64_VEC(nand):
2961             done = fold_nand(&ctx, op);
2962             break;
2963         CASE_OP_32_64(neg):
2964             done = fold_neg(&ctx, op);
2965             break;
2966         CASE_OP_32_64_VEC(nor):
2967             done = fold_nor(&ctx, op);
2968             break;
2969         CASE_OP_32_64_VEC(not):
2970             done = fold_not(&ctx, op);
2971             break;
2972         CASE_OP_32_64_VEC(or):
2973             done = fold_or(&ctx, op);
2974             break;
2975         CASE_OP_32_64_VEC(orc):
2976             done = fold_orc(&ctx, op);
2977             break;
2978         case INDEX_op_qemu_ld_a32_i32:
2979         case INDEX_op_qemu_ld_a64_i32:
2980         case INDEX_op_qemu_ld_a32_i64:
2981         case INDEX_op_qemu_ld_a64_i64:
2982         case INDEX_op_qemu_ld_a32_i128:
2983         case INDEX_op_qemu_ld_a64_i128:
2984             done = fold_qemu_ld(&ctx, op);
2985             break;
2986         case INDEX_op_qemu_st8_a32_i32:
2987         case INDEX_op_qemu_st8_a64_i32:
2988         case INDEX_op_qemu_st_a32_i32:
2989         case INDEX_op_qemu_st_a64_i32:
2990         case INDEX_op_qemu_st_a32_i64:
2991         case INDEX_op_qemu_st_a64_i64:
2992         case INDEX_op_qemu_st_a32_i128:
2993         case INDEX_op_qemu_st_a64_i128:
2994             done = fold_qemu_st(&ctx, op);
2995             break;
2996         CASE_OP_32_64(rem):
2997         CASE_OP_32_64(remu):
2998             done = fold_remainder(&ctx, op);
2999             break;
3000         CASE_OP_32_64(rotl):
3001         CASE_OP_32_64(rotr):
3002         CASE_OP_32_64(sar):
3003         CASE_OP_32_64(shl):
3004         CASE_OP_32_64(shr):
3005             done = fold_shift(&ctx, op);
3006             break;
3007         CASE_OP_32_64(setcond):
3008             done = fold_setcond(&ctx, op);
3009             break;
3010         CASE_OP_32_64(negsetcond):
3011             done = fold_negsetcond(&ctx, op);
3012             break;
3013         case INDEX_op_setcond2_i32:
3014             done = fold_setcond2(&ctx, op);
3015             break;
3016         case INDEX_op_cmp_vec:
3017             done = fold_cmp_vec(&ctx, op);
3018             break;
3019         case INDEX_op_cmpsel_vec:
3020             done = fold_cmpsel_vec(&ctx, op);
3021             break;
3022         case INDEX_op_bitsel_vec:
3023             done = fold_bitsel_vec(&ctx, op);
3024             break;
3025         CASE_OP_32_64(sextract):
3026             done = fold_sextract(&ctx, op);
3027             break;
3028         CASE_OP_32_64(sub):
3029             done = fold_sub(&ctx, op);
3030             break;
3031         case INDEX_op_sub_vec:
3032             done = fold_sub_vec(&ctx, op);
3033             break;
3034         CASE_OP_32_64(sub2):
3035             done = fold_sub2(&ctx, op);
3036             break;
3037         CASE_OP_32_64_VEC(xor):
3038             done = fold_xor(&ctx, op);
3039             break;
3040         default:
3041             break;
3042         }
3043 
3044         if (!done) {
3045             finish_folding(&ctx, op);
3046         }
3047     }
3048 }
3049