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Merge pull request #1861 from saper/home-override
[mono-project.git] / mono / mini / ssa.c
blob8f804b85c93ee73019f43f97f19fb3b6e6aca8a4
1 /*
2 * ssa.c: Static single assign form support for the JIT compiler.
3 *
4 * Author:
5 * Dietmar Maurer (dietmar@ximian.com)
6 *
7 * (C) 2003 Ximian, Inc.
8 * Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
9 */
10 #include <config.h>
11 #include <string.h>
12 #include <mono/metadata/debug-helpers.h>
13 #include <mono/metadata/mempool.h>
14 #include <mono/metadata/mempool-internals.h>
15
16 #ifndef DISABLE_JIT
17
18 #include "mini.h"
19 #ifdef HAVE_ALLOCA_H
20 #include <alloca.h>
21 #endif
22
23 #define CREATE_PRUNED_SSA
24
25 //#define DEBUG_SSA 1
26
27 #define NEW_PHI(cfg,dest,val) do { \
28 MONO_INST_NEW ((cfg), (dest), OP_PHI); \
29 (dest)->inst_c0 = (val); \
30 } while (0)
31
32 typedef struct {
33 MonoBasicBlock *bb;
34 MonoInst *inst;
35 } MonoVarUsageInfo;
36
37 static void
38 unlink_target (MonoBasicBlock *bb, MonoBasicBlock *target)
39 {
40 int i;
41
42 for (i = 0; i < bb->out_count; i++) {
43 if (bb->out_bb [i] == target) {
44 bb->out_bb [i] = bb->out_bb [--bb->out_count];
45 break;
46 }
47 }
48 for (i = 0; i < target->in_count; i++) {
49 if (target->in_bb [i] == bb) {
50 target->in_bb [i] = target->in_bb [--target->in_count];
51 break;
52
53 }
54 }
55 }
56
57 static void
58 unlink_unused_bblocks (MonoCompile *cfg)
59 {
60 int i, j;
61 MonoBasicBlock *bb;
62
63 g_assert (cfg->comp_done & MONO_COMP_REACHABILITY);
64
65 if (G_UNLIKELY (cfg->verbose_level > 1))
66 printf ("\nUNLINK UNUSED BBLOCKS:\n");
67
68 for (bb = cfg->bb_entry; bb && bb->next_bb;) {
69 if (!(bb->next_bb->flags & BB_REACHABLE)) {
70 bb->next_bb = bb->next_bb->next_bb;
71 } else
72 bb = bb->next_bb;
73 }
74
75 for (i = 1; i < cfg->num_bblocks; i++) {
76 bb = cfg->bblocks [i];
77
78 if (!(bb->flags & BB_REACHABLE)) {
79 for (j = 0; j < bb->in_count; j++) {
80 unlink_target (bb->in_bb [j], bb);
81 }
82 for (j = 0; j < bb->out_count; j++) {
83 unlink_target (bb, bb->out_bb [j]);
84 }
85 if (G_UNLIKELY (cfg->verbose_level > 1))
86 printf ("\tUnlinked BB%d\n", bb->block_num);
87 }
88
89 }
90 }
91
92 /**
93 * remove_bb_from_phis:
94 *
95 * Remove BB from the PHI statements in TARGET.
96 */
97 static void
98 remove_bb_from_phis (MonoCompile *cfg, MonoBasicBlock *bb, MonoBasicBlock *target)
99 {
100 MonoInst *ins;
101 int i, j;
102
103 for (i = 0; i < target->in_count; i++) {
104 if (target->in_bb [i] == bb) {
105 break;
106 }
107 }
108 g_assert (i < target->in_count);
109
110 for (ins = target->code; ins; ins = ins->next) {
111 if (MONO_IS_PHI (ins)) {
112 for (j = i; j < ins->inst_phi_args [0] - 1; ++j)
113 ins->inst_phi_args [j + 1] = ins->inst_phi_args [j + 2];
114 ins->inst_phi_args [0] --;
115 }
116 else
117 break;
118 }
119 }
120
121 static inline int
122 op_phi_to_move (int opcode)
123 {
124 switch (opcode) {
125 case OP_PHI:
126 return OP_MOVE;
127 case OP_FPHI:
128 return OP_FMOVE;
129 case OP_VPHI:
130 return OP_VMOVE;
131 case OP_XPHI:
132 return OP_XMOVE;
133 default:
134 g_assert_not_reached ();
135 }
136
137 return -1;
138 }
139
140 static inline void
141 record_use (MonoCompile *cfg, MonoInst *var, MonoBasicBlock *bb, MonoInst *ins)
142 {
143 MonoMethodVar *info;
144 MonoVarUsageInfo *ui = mono_mempool_alloc (cfg->mempool, sizeof (MonoVarUsageInfo));
145
146 info = MONO_VARINFO (cfg, var->inst_c0);
147
148 ui->bb = bb;
149 ui->inst = ins;
150 info->uses = g_list_prepend_mempool (cfg->mempool, info->uses, ui);
151 }
152
153 typedef struct {
154 MonoInst *var;
155 int idx;
156 } RenameInfo;
157
158 /**
159 * mono_ssa_rename_vars:
160 *
161 * Implement renaming of SSA variables. Also compute def-use information in parallel.
162 * @stack_history points to an area of memory which can be used for storing changes
163 * made to the stack, so they can be reverted later.
164 */
165 static void
166 mono_ssa_rename_vars (MonoCompile *cfg, int max_vars, MonoBasicBlock *bb, gboolean *originals_used, MonoInst **stack, guint32 *lvreg_stack, gboolean *lvreg_defined, RenameInfo *stack_history, int stack_history_size)
167 {
168 MonoInst *ins, *new_var;
169 int i, j, idx;
170 GSList *tmp;
171 int stack_history_len = 0;
172
173 if (cfg->verbose_level >= 4)
174 printf ("\nRENAME VARS BLOCK %d:\n", bb->block_num);
175
176 /* First pass: Create new vars */
177 for (ins = bb->code; ins; ins = ins->next) {
178 const char *spec = INS_INFO (ins->opcode);
179 int num_sregs;
180 int sregs [MONO_MAX_SRC_REGS];
181
182 #ifdef DEBUG_SSA
183 printf ("\tProcessing "); mono_print_ins (ins);
184 #endif
185 if (ins->opcode == OP_NOP)
186 continue;
187
188 /* SREGs */
189 num_sregs = mono_inst_get_src_registers (ins, sregs);
190 for (i = 0; i < num_sregs; ++i) {
191 if (spec [MONO_INST_SRC1 + i] != ' ') {
192 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
193 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
194 int idx = var->inst_c0;
195 if (stack [idx]) {
196 if (var->opcode != OP_ARG)
197 g_assert (stack [idx]);
198 sregs [i] = stack [idx]->dreg;
199 record_use (cfg, stack [idx], bb, ins);
200 }
201 else
202 record_use (cfg, var, bb, ins);
203 }
204 else if (G_UNLIKELY (!var && lvreg_stack [sregs [i]]))
205 sregs [i] = lvreg_stack [sregs [i]];
206 }
207 }
208 mono_inst_set_src_registers (ins, sregs);
209
210 if (MONO_IS_STORE_MEMBASE (ins)) {
211 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
212 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
213 int idx = var->inst_c0;
214 if (stack [idx]) {
215 if (var->opcode != OP_ARG)
216 g_assert (stack [idx]);
217 ins->dreg = stack [idx]->dreg;
218 record_use (cfg, stack [idx], bb, ins);
219 }
220 else
221 record_use (cfg, var, bb, ins);
222 }
223 else if (G_UNLIKELY (!var && lvreg_stack [ins->dreg]))
224 ins->dreg = lvreg_stack [ins->dreg];
225 }
226
227 /* DREG */
228 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
229 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
230 MonoMethodVar *info;
231
232 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
233 idx = var->inst_c0;
234 g_assert (idx < max_vars);
235
236 if (var->opcode == OP_ARG)
237 originals_used [idx] = TRUE;
238
239 /* FIXME: */
240 g_assert (stack_history_len < stack_history_size);
241 stack_history [stack_history_len].var = stack [idx];
242 stack_history [stack_history_len].idx = idx;
243 stack_history_len ++;
244
245 if (originals_used [idx]) {
246 new_var = mono_compile_create_var (cfg, var->inst_vtype, OP_LOCAL);
247 new_var->flags = var->flags;
248 MONO_VARINFO (cfg, new_var->inst_c0)->reg = idx;
249
250 if (cfg->verbose_level >= 4)
251 printf (" R%d -> R%d\n", var->dreg, new_var->dreg);
252
253 stack [idx] = new_var;
254
255 ins->dreg = new_var->dreg;
256 var = new_var;
257 }
258 else {
259 stack [idx] = var;
260 originals_used [idx] = TRUE;
261 }
262
263 info = MONO_VARINFO (cfg, var->inst_c0);
264 info->def = ins;
265 info->def_bb = bb;
266 }
267 else if (G_UNLIKELY (!var && lvreg_defined [ins->dreg] && (ins->dreg >= MONO_MAX_IREGS))) {
268 /* Perform renaming for local vregs */
269 lvreg_stack [ins->dreg] = vreg_is_ref (cfg, ins->dreg) ? mono_alloc_ireg_ref (cfg) : mono_alloc_preg (cfg);
270 ins->dreg = lvreg_stack [ins->dreg];
271 }
272 else
273 lvreg_defined [ins->dreg] = TRUE;
274 }
275
276 #ifdef DEBUG_SSA
277 printf ("\tAfter processing "); mono_print_ins (ins);
278 #endif
279
280 }
281
282 /* Rename PHI arguments in succeeding bblocks */
283 for (i = 0; i < bb->out_count; i++) {
284 MonoBasicBlock *n = bb->out_bb [i];
285
286 for (j = 0; j < n->in_count; j++)
287 if (n->in_bb [j] == bb)
288 break;
289
290 for (ins = n->code; ins; ins = ins->next) {
291 if (MONO_IS_PHI (ins)) {
292 idx = ins->inst_c0;
293 if (stack [idx])
294 new_var = stack [idx];
295 else
296 new_var = cfg->varinfo [idx];
297 #ifdef DEBUG_SSA
298 printf ("FOUND PHI %d (%d, %d)\n", idx, j, new_var->inst_c0);
299 #endif
300 ins->inst_phi_args [j + 1] = new_var->dreg;
301 record_use (cfg, new_var, n, ins);
302 if (G_UNLIKELY (cfg->verbose_level >= 4))
303 printf ("\tAdd PHI R%d <- R%d to BB%d\n", ins->dreg, new_var->dreg, n->block_num);
304 }
305 else
306 /* The phi nodes are at the beginning of the bblock */
307 break;
308 }
309 }
310
311 if (bb->dominated) {
312 for (tmp = bb->dominated; tmp; tmp = tmp->next) {
313 mono_ssa_rename_vars (cfg, max_vars, (MonoBasicBlock *)tmp->data, originals_used, stack, lvreg_stack, lvreg_defined, stack_history + stack_history_len, stack_history_size - stack_history_len);
314 }
315 }
316
317 /* Restore stack */
318 for (i = stack_history_len - 1; i >= 0; i--) {
319 stack [stack_history [i].idx] = stack_history [i].var;
320 }
321
322 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
323 }
324
325 void
326 mono_ssa_compute (MonoCompile *cfg)
327 {
328 int i, j, idx, bitsize;
329 MonoBitSet *set;
330 MonoMethodVar *vinfo = g_new0 (MonoMethodVar, cfg->num_varinfo);
331 MonoInst *ins, **stack;
332 guint8 *buf, *buf_start;
333 RenameInfo *stack_history;
334 int stack_history_size;
335 gboolean *originals;
336 guint32 *lvreg_stack;
337 gboolean *lvreg_defined;
338
339 g_assert (!(cfg->comp_done & MONO_COMP_SSA));
340
341 g_assert (!cfg->disable_ssa);
342
343 if (cfg->verbose_level >= 4)
344 printf ("\nCOMPUTE SSA %d (R%d-)\n\n", cfg->num_varinfo, cfg->next_vreg);
345
346 #ifdef CREATE_PRUNED_SSA
347 /* we need liveness for pruned SSA */
348 if (!(cfg->comp_done & MONO_COMP_LIVENESS))
349 mono_analyze_liveness (cfg);
350 #endif
351
352 mono_compile_dominator_info (cfg, MONO_COMP_DOM | MONO_COMP_IDOM | MONO_COMP_DFRONTIER);
353
354 bitsize = mono_bitset_alloc_size (cfg->num_bblocks, 0);
355 buf = buf_start = g_malloc0 (mono_bitset_alloc_size (cfg->num_bblocks, 0) * cfg->num_varinfo);
356
357 for (i = 0; i < cfg->num_varinfo; ++i) {
358 vinfo [i].def_in = mono_bitset_mem_new (buf, cfg->num_bblocks, 0);
359 buf += bitsize;
360 vinfo [i].idx = i;
361 /* implicit reference at start */
362 if (cfg->varinfo [i]->opcode == OP_ARG)
363 mono_bitset_set_fast (vinfo [i].def_in, 0);
364 }
365
366 for (i = 0; i < cfg->num_bblocks; ++i) {
367 MONO_BB_FOR_EACH_INS (cfg->bblocks [i], ins) {
368 if (ins->opcode == OP_NOP)
369 continue;
370
371 if (!MONO_IS_STORE_MEMBASE (ins) && get_vreg_to_inst (cfg, ins->dreg)) {
372 mono_bitset_set_fast (vinfo [get_vreg_to_inst (cfg, ins->dreg)->inst_c0].def_in, i);
373 }
374 }
375 }
376
377 /* insert phi functions */
378 for (i = 0; i < cfg->num_varinfo; ++i) {
379 MonoInst *var = cfg->varinfo [i];
380
381 #if SIZEOF_REGISTER == 4
382 if (var->type == STACK_I8 && !COMPILE_LLVM (cfg))
383 continue;
384 #endif
385 if (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))
386 continue;
387
388 /* Most variables have only one definition */
389 if (mono_bitset_count (vinfo [i].def_in) <= 1)
390 continue;
391
392 set = mono_compile_iterated_dfrontier (cfg, vinfo [i].def_in);
393
394 if (cfg->verbose_level >= 4) {
395 if (mono_bitset_count (set) > 0) {
396 printf ("\tR%d needs PHI functions in ", var->dreg);
397 mono_blockset_print (cfg, set, "", -1);
398 }
399 }
400
401 mono_bitset_foreach_bit (set, idx, cfg->num_bblocks) {
402 MonoBasicBlock *bb = cfg->bblocks [idx];
403
404 /* fixme: create pruned SSA? we would need liveness information for that */
405
406 if (bb == cfg->bb_exit && !COMPILE_LLVM (cfg))
407 continue;
408
409 if ((cfg->comp_done & MONO_COMP_LIVENESS) && !mono_bitset_test_fast (bb->live_in_set, i)) {
410 //printf ("%d is not live in BB%d %s\n", i, bb->block_num, mono_method_full_name (cfg->method, TRUE));
411 continue;
412 }
413
414 NEW_PHI (cfg, ins, i);
415
416 switch (var->type) {
417 case STACK_I4:
418 case STACK_I8:
419 case STACK_PTR:
420 case STACK_MP:
421 case STACK_OBJ:
422 ins->opcode = OP_PHI;
423 break;
424 case STACK_R8:
425 ins->opcode = OP_FPHI;
426 break;
427 case STACK_VTYPE:
428 ins->opcode = MONO_CLASS_IS_SIMD (cfg, var->klass) ? OP_XPHI : OP_VPHI;
429 break;
430 }
431
432 if (var->inst_vtype->byref)
433 ins->klass = mono_defaults.int_class;
434 else
435 ins->klass = var->klass;
436
437 ins->inst_phi_args = mono_mempool_alloc0 (cfg->mempool, sizeof (int) * (cfg->bblocks [idx]->in_count + 1));
438 ins->inst_phi_args [0] = cfg->bblocks [idx]->in_count;
439
440 /* For debugging */
441 for (j = 0; j < cfg->bblocks [idx]->in_count; ++j)
442 ins->inst_phi_args [j + 1] = -1;
443
444 ins->dreg = cfg->varinfo [i]->dreg;
445
446 mono_bblock_insert_before_ins (bb, bb->code, ins);
447
448 #ifdef DEBUG_SSA
449 printf ("ADD PHI BB%d %s\n", cfg->bblocks [idx]->block_num, mono_method_full_name (cfg->method, TRUE));
450 #endif
451 }
452 }
453
454 /* free the stuff */
455 g_free (vinfo);
456 g_free (buf_start);
457
458 /* Renaming phase */
459
460 stack = alloca (sizeof (MonoInst *) * cfg->num_varinfo);
461 memset (stack, 0, sizeof (MonoInst *) * cfg->num_varinfo);
462
463 lvreg_stack = g_new0 (guint32, cfg->next_vreg);
464 lvreg_defined = g_new0 (gboolean, cfg->next_vreg);
465 stack_history_size = 10240;
466 stack_history = g_new (RenameInfo, stack_history_size);
467 originals = g_new0 (gboolean, cfg->num_varinfo);
468 mono_ssa_rename_vars (cfg, cfg->num_varinfo, cfg->bb_entry, originals, stack, lvreg_stack, lvreg_defined, stack_history, stack_history_size);
469 g_free (stack_history);
470 g_free (originals);
471 g_free (lvreg_stack);
472 g_free (lvreg_defined);
473
474 if (cfg->verbose_level >= 4)
475 printf ("\nEND COMPUTE SSA.\n\n");
476
477 cfg->comp_done |= MONO_COMP_SSA;
478 }
479
480 void
481 mono_ssa_remove (MonoCompile *cfg)
482 {
483 MonoInst *ins, *var, *move;
484 int bbindex, i, j, first;
485
486 g_assert (cfg->comp_done & MONO_COMP_SSA);
487
488 for (i = 0; i < cfg->num_bblocks; ++i) {
489 MonoBasicBlock *bb = cfg->bblocks [i];
490
491 if (cfg->verbose_level >= 4)
492 printf ("\nREMOVE SSA %d:\n", bb->block_num);
493
494 for (ins = bb->code; ins; ins = ins->next) {
495 if (MONO_IS_PHI (ins)) {
496 g_assert (ins->inst_phi_args [0] == bb->in_count);
497 var = get_vreg_to_inst (cfg, ins->dreg);
498
499 /* Check for PHI nodes where all the inputs are the same */
500 first = ins->inst_phi_args [1];
501
502 for (j = 1; j < bb->in_count; ++j)
503 if (first != ins->inst_phi_args [j + 1])
504 break;
505
506 if ((bb->in_count > 1) && (j == bb->in_count)) {
507 ins->opcode = op_phi_to_move (ins->opcode);
508 if (ins->opcode == OP_VMOVE)
509 g_assert (ins->klass);
510 ins->sreg1 = first;
511 } else {
512 for (j = 0; j < bb->in_count; j++) {
513 MonoBasicBlock *pred = bb->in_bb [j];
514 int sreg = ins->inst_phi_args [j + 1];
515
516 if (cfg->verbose_level >= 4)
517 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
518 if (var->dreg != sreg) {
519 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
520 if (move->opcode == OP_VMOVE) {
521 g_assert (ins->klass);
522 move->klass = ins->klass;
523 }
524 move->dreg = var->dreg;
525 move->sreg1 = sreg;
526 mono_add_ins_to_end (pred, move);
527 }
528 }
529
530 NULLIFY_INS (ins);
531 }
532 }
533 }
534 }
535
536 if (cfg->verbose_level >= 4) {
537 for (i = 0; i < cfg->num_bblocks; ++i) {
538 MonoBasicBlock *bb = cfg->bblocks [i];
539
540 mono_print_bb (bb, "AFTER REMOVE SSA:");
541 }
542 }
543
544 /*
545 * Removal of SSA form introduces many copies. To avoid this, we tyry to coalesce
546 * the variables if possible. Since the newly introduced SSA variables don't
547 * have overlapping live ranges (because we don't do agressive optimization), we
548 * can coalesce them into the original variable.
549 */
550
551 for (bbindex = 0; bbindex < cfg->num_bblocks; ++bbindex) {
552 MonoBasicBlock *bb = cfg->bblocks [bbindex];
553
554 for (ins = bb->code; ins; ins = ins->next) {
555 const char *spec = INS_INFO (ins->opcode);
556 int num_sregs;
557 int sregs [MONO_MAX_SRC_REGS];
558
559 if (ins->opcode == OP_NOP)
560 continue;
561
562 if (spec [MONO_INST_DEST] != ' ') {
563 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
564
565 if (var) {
566 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
567
568 /*
569 * The third condition avoids coalescing with variables eliminated
570 * during deadce.
571 */
572 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
573 printf ("COALESCE: R%d -> R%d\n", ins->dreg, cfg->varinfo [vmv->reg]->dreg);
574 ins->dreg = cfg->varinfo [vmv->reg]->dreg;
575 }
576 }
577 }
578
579 num_sregs = mono_inst_get_src_registers (ins, sregs);
580 for (i = 0; i < num_sregs; ++i) {
581 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
582
583 if (var) {
584 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
585
586 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
587 printf ("COALESCE: R%d -> R%d\n", sregs [i], cfg->varinfo [vmv->reg]->dreg);
588 sregs [i] = cfg->varinfo [vmv->reg]->dreg;
589 }
590 }
591 }
592 mono_inst_set_src_registers (ins, sregs);
593 }
594 }
595
596 for (i = 0; i < cfg->num_varinfo; ++i) {
597 MONO_VARINFO (cfg, i)->reg = -1;
598 }
599
600 if (cfg->comp_done & MONO_COMP_REACHABILITY)
601 unlink_unused_bblocks (cfg);
602
603 cfg->comp_done &= ~MONO_COMP_LIVENESS;
604
605 cfg->comp_done &= ~MONO_COMP_SSA;
606 }
607
608 static void
609 mono_ssa_create_def_use (MonoCompile *cfg)
610 {
611 MonoBasicBlock *bb;
612 MonoInst *ins;
613 int i;
614
615 g_assert (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE));
616
617 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
618 for (ins = bb->code; ins; ins = ins->next) {
619 const char *spec = INS_INFO (ins->opcode);
620 MonoMethodVar *info;
621 int num_sregs;
622 int sregs [MONO_MAX_SRC_REGS];
623
624 if (ins->opcode == OP_NOP)
625 continue;
626
627 /* SREGs */
628 num_sregs = mono_inst_get_src_registers (ins, sregs);
629 for (i = 0; i < num_sregs; ++i) {
630 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
631 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
632 record_use (cfg, var, bb, ins);
633 }
634
635 if (MONO_IS_STORE_MEMBASE (ins)) {
636 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
637 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
638 record_use (cfg, var, bb, ins);
639 }
640
641 if (MONO_IS_PHI (ins)) {
642 for (i = ins->inst_phi_args [0]; i > 0; i--) {
643 g_assert (ins->inst_phi_args [i] != -1);
644 record_use (cfg, get_vreg_to_inst (cfg, ins->inst_phi_args [i]), bb, ins);
645 }
646 }
647
648 /* DREG */
649 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
650 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
651
652 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
653 info = MONO_VARINFO (cfg, var->inst_c0);
654 info->def = ins;
655 info->def_bb = bb;
656 }
657 }
658 }
659 }
660
661 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
662 }
663
664 static void
665 mono_ssa_copyprop (MonoCompile *cfg)
666 {
667 int i, index;
668 GList *l;
669
670 g_assert ((cfg->comp_done & MONO_COMP_SSA_DEF_USE));
671
672 for (index = 0; index < cfg->num_varinfo; ++index) {
673 MonoInst *var = cfg->varinfo [index];
674 MonoMethodVar *info = MONO_VARINFO (cfg, index);
675
676 if (info->def && (MONO_IS_MOVE (info->def))) {
677 MonoInst *var2 = get_vreg_to_inst (cfg, info->def->sreg1);
678
679 if (var2 && !(var2->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)) && MONO_VARINFO (cfg, var2->inst_c0)->def && (!MONO_IS_PHI (MONO_VARINFO (cfg, var2->inst_c0)->def))) {
680 /* Rewrite all uses of var to be uses of var2 */
681 int dreg = var->dreg;
682 int sreg1 = var2->dreg;
683
684 l = info->uses;
685 while (l) {
686 MonoVarUsageInfo *u = (MonoVarUsageInfo*)l->data;
687 MonoInst *ins = u->inst;
688 GList *next = l->next;
689 int num_sregs;
690 int sregs [MONO_MAX_SRC_REGS];
691
692 num_sregs = mono_inst_get_src_registers (ins, sregs);
693 for (i = 0; i < num_sregs; ++i) {
694 if (sregs [i] == dreg)
695 break;
696 }
697 if (i < num_sregs) {
698 g_assert (sregs [i] == dreg);
699 sregs [i] = sreg1;
700 mono_inst_set_src_registers (ins, sregs);
701 } else if (MONO_IS_STORE_MEMBASE (ins) && ins->dreg == dreg) {
702 ins->dreg = sreg1;
703 } else if (MONO_IS_PHI (ins)) {
704 for (i = ins->inst_phi_args [0]; i > 0; i--) {
705 int sreg = ins->inst_phi_args [i];
706 if (sreg == var->dreg)
707 break;
708 }
709 g_assert (i > 0);
710 ins->inst_phi_args [i] = sreg1;
711 }
712 else
713 g_assert_not_reached ();
714
715 record_use (cfg, var2, u->bb, ins);
716
717 l = next;
718 }
719
720 info->uses = NULL;
721 }
722 }
723 }
724
725 if (cfg->verbose_level >= 4) {
726 MonoBasicBlock *bb;
727
728 for (bb = cfg->bb_entry; bb; bb = bb->next_bb)
729 mono_print_bb (bb, "AFTER SSA COPYPROP");
730 }
731 }
732
733 static int
734 evaluate_ins (MonoCompile *cfg, MonoInst *ins, MonoInst **res, MonoInst **carray)
735 {
736 MonoInst *args [MONO_MAX_SRC_REGS];
737 int rs [MONO_MAX_SRC_REGS];
738 MonoInst *c0;
739 gboolean const_args = TRUE;
740 const char *spec = INS_INFO (ins->opcode);
741 int num_sregs, i;
742 int sregs [MONO_MAX_SRC_REGS];
743
744 /* Short-circuit this */
745 if (ins->opcode == OP_ICONST) {
746 *res = ins;
747 return 1;
748 }
749
750 if (ins->opcode == OP_NOP)
751 return 2;
752
753 num_sregs = mono_inst_get_src_registers (ins, sregs);
754 for (i = 0; i < MONO_MAX_SRC_REGS; ++i)
755 args [i] = NULL;
756 for (i = 0; i < num_sregs; ++i) {
757 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
758
759 rs [i] = 2;
760 args [i] = carray [sregs [i]];
761 if (args [i])
762 rs [i] = 1;
763 else if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
764 rs [i] = MONO_VARINFO (cfg, var->inst_c0)->cpstate;
765 if (rs [i] != 1)
766 const_args = FALSE;
767 }
768
769 c0 = NULL;
770
771 if (num_sregs > 0 && const_args) {
772 g_assert (num_sregs <= 2);
773 if ((spec [MONO_INST_DEST] != ' ') && carray [ins->dreg]) {
774 // Cached value
775 *res = carray [ins->dreg];
776 return 1;
777 }
778 c0 = mono_constant_fold_ins (cfg, ins, args [0], args [1], FALSE);
779 if (c0) {
780 if (G_UNLIKELY (cfg->verbose_level > 1)) {
781 printf ("\t cfold -> ");
782 mono_print_ins (c0);
783 }
784 *res = c0;
785 return 1;
786 }
787 else
788 /* Can't cfold this ins */
789 return 2;
790 }
791
792 if (num_sregs == 0)
793 return 2;
794 for (i = 0; i < num_sregs; ++i) {
795 if (rs [i] == 2)
796 return 2;
797 }
798 return 0;
799 }
800
801 static inline void
802 change_varstate (MonoCompile *cfg, GList **cvars, MonoMethodVar *info, int state, MonoInst *c0, MonoInst **carray)
803 {
804 if (info->cpstate >= state)
805 return;
806
807 info->cpstate = state;
808
809 if (G_UNLIKELY (cfg->verbose_level > 1))
810 printf ("\tState of R%d set to %d\n", cfg->varinfo [info->idx]->dreg, info->cpstate);
811
812 if (state == 1)
813 g_assert (c0);
814
815 carray [cfg->varinfo [info->idx]->dreg] = c0;
816
817 if (!g_list_find (*cvars, info)) {
818 *cvars = g_list_prepend (*cvars, info);
819 }
820 }
821
822 static inline void
823 add_cprop_bb (MonoCompile *cfg, MonoBasicBlock *bb, GList **bblist)
824 {
825 if (G_UNLIKELY (cfg->verbose_level > 1))
826 printf ("\tAdd BB%d to worklist\n", bb->block_num);
827
828 if (!(bb->flags & BB_REACHABLE)) {
829 bb->flags |= BB_REACHABLE;
830 *bblist = g_list_prepend (*bblist, bb);
831 }
832 }
833
834 static void
835 visit_inst (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, GList **cvars, GList **bblist, MonoInst **carray)
836 {
837 const char *spec = INS_INFO (ins->opcode);
838
839 if (ins->opcode == OP_NOP)
840 return;
841
842 if (cfg->verbose_level > 1)
843 mono_print_ins (ins);
844
845 /* FIXME: Support longs/floats */
846 /* FIXME: Work on vregs as well */
847
848 if (MONO_IS_PHI (ins)) {
849 MonoMethodVar *info = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, ins->dreg)->inst_c0);
850 MonoInst *c0 = NULL;
851 int j;
852
853 for (j = 1; j <= ins->inst_phi_args [0]; j++) {
854 MonoInst *var = get_vreg_to_inst (cfg, ins->inst_phi_args [j]);
855 MonoMethodVar *mv = MONO_VARINFO (cfg, var->inst_c0);
856 MonoInst *src = mv->def;
857
858 if (mv->def_bb && !(mv->def_bb->flags & BB_REACHABLE))
859 continue;
860
861 if (!mv->def || !src || mv->cpstate == 2) {
862 change_varstate (cfg, cvars, info, 2, NULL, carray);
863 break;
864 }
865
866 if (mv->cpstate == 0)
867 continue;
868
869 g_assert (carray [var->dreg]);
870
871 if (!c0)
872 c0 = carray [var->dreg];
873
874 /* FIXME: */
875 if (c0->opcode != OP_ICONST) {
876 change_varstate (cfg, cvars, info, 2, NULL, carray);
877 break;
878 }
879
880 if (carray [var->dreg]->inst_c0 != c0->inst_c0) {
881 change_varstate (cfg, cvars, info, 2, NULL, carray);
882 break;
883 }
884 }
885
886 if (c0 && info->cpstate < 1) {
887 change_varstate (cfg, cvars, info, 1, c0, carray);
888
889 g_assert (c0->opcode == OP_ICONST);
890 }
891 }
892 else if (!MONO_IS_STORE_MEMBASE (ins) && ((spec [MONO_INST_SRC1] != ' ') || (spec [MONO_INST_SRC2] != ' ') || (spec [MONO_INST_DEST] != ' '))) {
893 MonoInst *var, *c0;
894 int state;
895
896 if (spec [MONO_INST_DEST] != ' ')
897 var = get_vreg_to_inst (cfg, ins->dreg);
898 else
899 var = NULL;
900
901 c0 = NULL;
902 state = evaluate_ins (cfg, ins, &c0, carray);
903
904 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
905 MonoMethodVar *info = MONO_VARINFO (cfg, var->inst_c0);
906
907 if (info->cpstate < 2) {
908 if (state == 1)
909 change_varstate (cfg, cvars, info, 1, c0, carray);
910 else if (state == 2)
911 change_varstate (cfg, cvars, info, 2, NULL, carray);
912 }
913 }
914 else if (!var && (ins->dreg != -1)) {
915 /*
916 * We don't record def-use information for local vregs since it would be
917 * expensive. Instead, we depend on the fact that all uses of the vreg are in
918 * the same bblock, so they will be examined after the definition.
919 * FIXME: This isn't true if the ins is visited through an SSA edge.
920 */
921 if (c0) {
922 carray [ins->dreg] = c0;
923 } else {
924 if (carray [ins->dreg]) {
925 /*
926 * The state of the vreg changed from constant to non-constant
927 * -> need to rescan the whole bblock.
928 */
929 carray [ins->dreg] = NULL;
930 /* FIXME: Speed this up */
931
932 if (!g_list_find (*bblist, bb))
933 *bblist = g_list_prepend (*bblist, bb);
934 }
935 }
936 }
937
938 if (MONO_IS_JUMP_TABLE (ins)) {
939 int i;
940 MonoJumpInfoBBTable *table = MONO_JUMP_TABLE_FROM_INS (ins);
941
942 if (!ins->next || ins->next->opcode != OP_PADD) {
943 /* The PADD was optimized away */
944 /* FIXME: handle this as well */
945 for (i = 0; i < table->table_size; i++)
946 if (table->table [i])
947 add_cprop_bb (cfg, table->table [i], bblist);
948 return;
949 }
950
951 g_assert (ins->next->opcode == OP_PADD);
952 g_assert (ins->next->sreg1 == ins->dreg);
953
954 if (carray [ins->next->sreg2]) {
955 #if SIZEOF_REGISTER == 8
956 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
957 #else
958 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
959 #endif
960 if ((idx < 0) || (idx >= table->table_size))
961 /* Out-of-range, no branch is executed */
962 return;
963 else
964 if (table->table [idx])
965 add_cprop_bb (cfg, table->table [idx], bblist);
966 }
967 else {
968 for (i = 0; i < table->table_size; i++)
969 if (table->table [i])
970 add_cprop_bb (cfg, table->table [i], bblist);
971 }
972 }
973
974 if (ins->opcode == OP_SWITCH) {
975 int i;
976 MonoJumpInfoBBTable *table = ins->inst_p0;
977
978 for (i = 0; i < table->table_size; i++)
979 if (table->table [i])
980 add_cprop_bb (cfg, table->table [i], bblist);
981 }
982
983 /* Handle COMPARE+BRCOND pairs */
984 if (ins->next && MONO_IS_COND_BRANCH_OP (ins->next)) {
985 if (c0) {
986 g_assert (c0->opcode == OP_ICONST);
987
988 if (c0->inst_c0)
989 ins->next->flags |= MONO_INST_CFOLD_TAKEN;
990 else
991 ins->next->flags |= MONO_INST_CFOLD_NOT_TAKEN;
992 }
993 else {
994 ins->next->flags &= ~(MONO_INST_CFOLD_TAKEN | MONO_INST_CFOLD_NOT_TAKEN);
995 }
996
997 visit_inst (cfg, bb, ins->next, cvars, bblist, carray);
998 }
999 } else if (ins->opcode == OP_BR) {
1000 add_cprop_bb (cfg, ins->inst_target_bb, bblist);
1001 } else if (MONO_IS_COND_BRANCH_OP (ins)) {
1002 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1003 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1004 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1005 if (ins->inst_false_bb)
1006 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1007 } else {
1008 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1009 if (ins->inst_false_bb)
1010 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1011 }
1012 }
1013 }
1014
1015 /**
1016 * fold_ins:
1017 *
1018 * Replace INS with its constant value, if it exists
1019 */
1020 static void
1021 fold_ins (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, MonoInst **carray)
1022 {
1023 const char *spec = INS_INFO (ins->opcode);
1024 int opcode2;
1025 int num_sregs = mono_inst_get_num_src_registers (ins);
1026
1027 if ((ins->opcode != OP_NOP) && (ins->dreg != -1) && !MONO_IS_STORE_MEMBASE (ins)) {
1028 if (carray [ins->dreg] && (spec [MONO_INST_DEST] == 'i') && (ins->dreg >= MONO_MAX_IREGS)) {
1029 /* Perform constant folding */
1030 /* FIXME: */
1031 g_assert (carray [ins->dreg]->opcode == OP_ICONST);
1032 ins->opcode = OP_ICONST;
1033 ins->inst_c0 = carray [ins->dreg]->inst_c0;
1034 MONO_INST_NULLIFY_SREGS (ins);
1035 } else if (num_sregs == 2 && carray [ins->sreg2]) {
1036 /* Perform op->op_imm conversion */
1037 opcode2 = mono_op_to_op_imm (ins->opcode);
1038 if (opcode2 != -1) {
1039 ins->opcode = opcode2;
1040 ins->inst_imm = carray [ins->sreg2]->inst_c0;
1041 ins->sreg2 = -1;
1042
1043 if ((opcode2 == OP_VOIDCALL) || (opcode2 == OP_CALL) || (opcode2 == OP_LCALL) || (opcode2 == OP_FCALL))
1044 ((MonoCallInst*)ins)->fptr = (gpointer)ins->inst_imm;
1045 }
1046 } else {
1047 /* FIXME: Handle 3 op insns */
1048 }
1049
1050 if (MONO_IS_JUMP_TABLE (ins)) {
1051 int i;
1052 MonoJumpInfoBBTable *table = MONO_JUMP_TABLE_FROM_INS (ins);
1053
1054 if (!ins->next || ins->next->opcode != OP_PADD) {
1055 /* The PADD was optimized away */
1056 /* FIXME: handle this as well */
1057 return;
1058 }
1059
1060 g_assert (ins->next->opcode == OP_PADD);
1061 g_assert (ins->next->sreg1 == ins->dreg);
1062 g_assert (ins->next->next->opcode == OP_LOAD_MEMBASE);
1063
1064 if (carray [ins->next->sreg2]) {
1065 /* Convert to a simple branch */
1066 #if SIZEOF_REGISTER == 8
1067 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1068 #else
1069 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1070 #endif
1071
1072 if (!((idx >= 0) && (idx < table->table_size))) {
1073 /* Out of range, eliminate the whole switch */
1074 for (i = 0; i < table->table_size; ++i) {
1075 remove_bb_from_phis (cfg, bb, table->table [i]);
1076 mono_unlink_bblock (cfg, bb, table->table [i]);
1077 }
1078
1079 NULLIFY_INS (ins);
1080 NULLIFY_INS (ins->next);
1081 NULLIFY_INS (ins->next->next);
1082 if (ins->next->next->next)
1083 NULLIFY_INS (ins->next->next->next);
1084
1085 return;
1086 }
1087
1088 if (!ins->next->next->next || ins->next->next->next->opcode != OP_BR_REG) {
1089 /* A one-way switch which got optimized away */
1090 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1091 printf ("\tNo cfold on ");
1092 mono_print_ins (ins);
1093 }
1094 return;
1095 }
1096
1097 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1098 printf ("\tcfold on ");
1099 mono_print_ins (ins);
1100 }
1101
1102 /* Unlink target bblocks */
1103 for (i = 0; i < table->table_size; ++i) {
1104 if (table->table [i] != table->table [idx]) {
1105 remove_bb_from_phis (cfg, bb, table->table [i]);
1106 mono_unlink_bblock (cfg, bb, table->table [i]);
1107 }
1108 }
1109
1110 /* Change the OP_BR_REG to a simple branch */
1111 ins->next->next->next->opcode = OP_BR;
1112 ins->next->next->next->inst_target_bb = table->table [idx];
1113 ins->next->next->next->sreg1 = -1;
1114
1115 /* Nullify the other instructions */
1116 NULLIFY_INS (ins);
1117 NULLIFY_INS (ins->next);
1118 NULLIFY_INS (ins->next->next);
1119 }
1120 }
1121 }
1122 else if (MONO_IS_COND_BRANCH_OP (ins)) {
1123 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1124 remove_bb_from_phis (cfg, bb, ins->inst_false_bb);
1125 mono_unlink_bblock (cfg, bb, ins->inst_false_bb);
1126 ins->opcode = OP_BR;
1127 ins->inst_target_bb = ins->inst_true_bb;
1128 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1129 remove_bb_from_phis (cfg, bb, ins->inst_true_bb);
1130 mono_unlink_bblock (cfg, bb, ins->inst_true_bb);
1131 ins->opcode = OP_BR;
1132 ins->inst_target_bb = ins->inst_false_bb;
1133 }
1134 }
1135 }
1136
1137 void
1138 mono_ssa_cprop (MonoCompile *cfg)
1139 {
1140 MonoInst **carray;
1141 MonoBasicBlock *bb;
1142 GList *bblock_list, *cvars;
1143 GList *tmp;
1144 int i;
1145 //printf ("SIMPLE OPTS BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
1146
1147 carray = g_new0 (MonoInst*, cfg->next_vreg);
1148
1149 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1150 mono_ssa_create_def_use (cfg);
1151
1152 bblock_list = g_list_prepend (NULL, cfg->bb_entry);
1153 cfg->bb_entry->flags |= BB_REACHABLE;
1154
1155 memset (carray, 0, sizeof (MonoInst *) * cfg->num_varinfo);
1156
1157 for (i = 0; i < cfg->num_varinfo; i++) {
1158 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1159 if (!info->def)
1160 info->cpstate = 2;
1161 }
1162
1163 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1164 /*
1165 * FIXME: This should be bb->flags & BB_FLAG_EXCEPTION_HANDLER, but
1166 * that would still allow unreachable try's to be removed.
1167 */
1168 if (bb->region)
1169 add_cprop_bb (cfg, bb, &bblock_list);
1170 }
1171
1172 cvars = NULL;
1173
1174 while (bblock_list) {
1175 MonoInst *inst;
1176
1177 bb = (MonoBasicBlock *)bblock_list->data;
1178
1179 bblock_list = g_list_delete_link (bblock_list, bblock_list);
1180
1181 g_assert (bb->flags & BB_REACHABLE);
1182
1183 /*
1184 * Some bblocks are linked to 2 others even through they fall through to the
1185 * next bblock.
1186 */
1187 if (!(bb->last_ins && MONO_IS_BRANCH_OP (bb->last_ins))) {
1188 for (i = 0; i < bb->out_count; ++i)
1189 add_cprop_bb (cfg, bb->out_bb [i], &bblock_list);
1190 }
1191
1192 if (cfg->verbose_level > 1)
1193 printf ("\nSSA CONSPROP BB%d:\n", bb->block_num);
1194
1195 for (inst = bb->code; inst; inst = inst->next) {
1196 visit_inst (cfg, bb, inst, &cvars, &bblock_list, carray);
1197 }
1198
1199 while (cvars) {
1200 MonoMethodVar *info = (MonoMethodVar *)cvars->data;
1201 cvars = g_list_delete_link (cvars, cvars);
1202
1203 for (tmp = info->uses; tmp; tmp = tmp->next) {
1204 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1205 if (!(ui->bb->flags & BB_REACHABLE))
1206 continue;
1207 visit_inst (cfg, ui->bb, ui->inst, &cvars, &bblock_list, carray);
1208 }
1209 }
1210 }
1211
1212 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1213 MonoInst *inst;
1214 for (inst = bb->code; inst; inst = inst->next) {
1215 fold_ins (cfg, bb, inst, carray);
1216 }
1217 }
1218
1219 g_free (carray);
1220
1221 cfg->comp_done |= MONO_COMP_REACHABILITY;
1222
1223 /* fixme: we should update usage infos during cprop, instead of computing it again */
1224 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1225 for (i = 0; i < cfg->num_varinfo; i++) {
1226 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1227 info->def = NULL;
1228 info->uses = NULL;
1229 }
1230 }
1231
1232 static inline void
1233 add_to_dce_worklist (MonoCompile *cfg, MonoMethodVar *var, MonoMethodVar *use, GList **wl)
1234 {
1235 GList *tmp;
1236
1237 *wl = g_list_prepend_mempool (cfg->mempool, *wl, use);
1238
1239 for (tmp = use->uses; tmp; tmp = tmp->next) {
1240 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1241 if (ui->inst == var->def) {
1242 /* from the mempool */
1243 use->uses = g_list_remove_link (use->uses, tmp);
1244 break;
1245 }
1246 }
1247 }
1248
1249 void
1250 mono_ssa_deadce (MonoCompile *cfg)
1251 {
1252 int i;
1253 GList *work_list;
1254
1255 g_assert (cfg->comp_done & MONO_COMP_SSA);
1256
1257 //printf ("DEADCE %s\n", mono_method_full_name (cfg->method, TRUE));
1258
1259 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1260 mono_ssa_create_def_use (cfg);
1261
1262 mono_ssa_copyprop (cfg);
1263
1264 work_list = NULL;
1265 for (i = 0; i < cfg->num_varinfo; i++) {
1266 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1267 work_list = g_list_prepend_mempool (cfg->mempool, work_list, info);
1268 }
1269
1270 while (work_list) {
1271 MonoMethodVar *info = (MonoMethodVar *)work_list->data;
1272 work_list = g_list_remove_link (work_list, work_list);
1273
1274 /*
1275 * The second part of the condition happens often when PHI nodes have their dreg
1276 * as one of their arguments due to the fact that we use the original vars.
1277 */
1278 if (info->def && (!info->uses || ((info->uses->next == NULL) && (((MonoVarUsageInfo*)info->uses->data)->inst == info->def)))) {
1279 MonoInst *def = info->def;
1280
1281 /* Eliminating FMOVE could screw up the fp stack */
1282 if (MONO_IS_MOVE (def) && (!MONO_ARCH_USE_FPSTACK || (def->opcode != OP_FMOVE))) {
1283 MonoInst *src_var = get_vreg_to_inst (cfg, def->sreg1);
1284 if (src_var && !(src_var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1285 add_to_dce_worklist (cfg, info, MONO_VARINFO (cfg, src_var->inst_c0), &work_list);
1286 NULLIFY_INS (def);
1287 info->reg = -1;
1288 } else if ((def->opcode == OP_ICONST) || (def->opcode == OP_I8CONST) || MONO_IS_ZERO (def)) {
1289 NULLIFY_INS (def);
1290 info->reg = -1;
1291 } else if (MONO_IS_PHI (def)) {
1292 int j;
1293 for (j = def->inst_phi_args [0]; j > 0; j--) {
1294 MonoMethodVar *u = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, def->inst_phi_args [j])->inst_c0);
1295 add_to_dce_worklist (cfg, info, u, &work_list);
1296 }
1297 NULLIFY_INS (def);
1298 info->reg = -1;
1299 }
1300 else if (def->opcode == OP_NOP) {
1301 }
1302 //else
1303 //mono_print_ins (def);
1304 }
1305
1306 }
1307 }
1308
1309 #if 0
1310 void
1311 mono_ssa_strength_reduction (MonoCompile *cfg)
1312 {
1313 MonoBasicBlock *bb;
1314 int i;
1315
1316 g_assert (cfg->comp_done & MONO_COMP_SSA);
1317 g_assert (cfg->comp_done & MONO_COMP_LOOPS);
1318 g_assert (cfg->comp_done & MONO_COMP_SSA_DEF_USE);
1319
1320 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1321 GList *lp = bb->loop_blocks;
1322
1323 if (lp) {
1324 MonoBasicBlock *h = (MonoBasicBlock *)lp->data;
1325
1326 /* we only consider loops with 2 in bblocks */
1327 if (!h->in_count == 2)
1328 continue;
1329
1330 for (i = 0; i < cfg->num_varinfo; i++) {
1331 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1332
1333 if (info->def && info->def->ssa_op == MONO_SSA_STORE &&
1334 info->def->inst_i0->opcode == OP_LOCAL && g_list_find (lp, info->def_bb)) {
1335 MonoInst *v = info->def->inst_i1;
1336
1337
1338 printf ("FOUND %d in %s\n", info->idx, mono_method_full_name (cfg->method, TRUE));
1339 }
1340 }
1341 }
1342 }
1343 }
1344 #endif
1345
1346 void
1347 mono_ssa_loop_invariant_code_motion (MonoCompile *cfg)
1348 {
1349 MonoBasicBlock *bb, *h, *idom;
1350 MonoInst *ins, *n, *tins;
1351 int i;
1352
1353 g_assert (cfg->comp_done & MONO_COMP_SSA);
1354 if (!(cfg->comp_done & MONO_COMP_LOOPS) || !(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1355 return;
1356
1357 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1358 GList *lp = bb->loop_blocks;
1359
1360 if (!lp)
1361 continue;
1362 h = (MonoBasicBlock *)lp->data;
1363 if (bb != h)
1364 continue;
1365 MONO_BB_FOR_EACH_INS_SAFE (bb, n, ins) {
1366 gboolean is_class_init = FALSE;
1367
1368 /*
1369 * Try to move instructions out of loop headers into the preceeding bblock.
1370 */
1371 if (ins->opcode == OP_VOIDCALL) {
1372 MonoCallInst *call = (MonoCallInst*)ins;
1373
1374 if (call->fptr_is_patch) {
1375 MonoJumpInfo *ji = (MonoJumpInfo*)call->fptr;
1376
1377 if (ji->type == MONO_PATCH_INFO_CLASS_INIT)
1378 is_class_init = TRUE;
1379 }
1380 }
1381 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS || ins->opcode == OP_AOTCONST || is_class_init) {
1382 gboolean skip;
1383 int sreg;
1384
1385 idom = h->idom;
1386 /*
1387 * h->nesting is needed to work around:
1388 * http://llvm.org/bugs/show_bug.cgi?id=17868
1389 */
1390 if (!(idom && idom->last_ins && idom->last_ins->opcode == OP_BR && idom->last_ins->inst_target_bb == h && h->nesting == 1)) {
1391 continue;
1392 }
1393
1394 /*
1395 * Make sure there are no instructions with side effects before ins.
1396 */
1397 skip = FALSE;
1398 MONO_BB_FOR_EACH_INS (bb, tins) {
1399 if (tins == ins)
1400 break;
1401 if (!MONO_INS_HAS_NO_SIDE_EFFECT (tins)) {
1402 skip = TRUE;
1403 break;
1404 }
1405 }
1406 if (skip) {
1407 /*
1408 printf ("%s\n", mono_method_full_name (cfg->method, TRUE));
1409 mono_print_ins (tins);
1410 */
1411 continue;
1412 }
1413
1414 /* Make sure we don't move the instruction before the def of its sreg */
1415 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS)
1416 sreg = ins->sreg1;
1417 else
1418 sreg = -1;
1419 if (sreg != -1) {
1420 MonoInst *tins, *var;
1421
1422 skip = FALSE;
1423 for (tins = ins->prev; tins; tins = tins->prev) {
1424 const char *spec = INS_INFO (tins->opcode);
1425
1426 if (tins->opcode == OP_MOVE && tins->dreg == sreg) {
1427 sreg = tins->sreg1;
1428 } if (spec [MONO_INST_DEST] != ' ' && tins->dreg == sreg) {
1429 skip = TRUE;
1430 break;
1431 }
1432 }
1433 if (skip)
1434 continue;
1435 var = get_vreg_to_inst (cfg, sreg);
1436 if (var && (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1437 continue;
1438 ins->sreg1 = sreg;
1439 }
1440
1441 if (cfg->verbose_level > 1) {
1442 printf ("licm in BB%d on ", bb->block_num);
1443 mono_print_ins (ins);
1444 }
1445 //{ static int count = 0; count ++; printf ("%d\n", count); }
1446 MONO_REMOVE_INS (bb, ins);
1447 mono_bblock_insert_before_ins (idom, idom->last_ins, ins);
1448 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN)
1449 idom->has_array_access = TRUE;
1450 }
1451 }
1452 }
1453
1454 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1455 for (i = 0; i < cfg->num_varinfo; i++) {
1456 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1457 info->def = NULL;
1458 info->uses = NULL;
1459 }
1460 }
1461
1462 #endif /* DISABLE_JIT */
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