2 * ssa.c: Static single assign form support for the JIT compiler.
5 * Dietmar Maurer (dietmar@ximian.com)
7 * (C) 2003 Ximian, Inc.
10 #include <mono/metadata/debug-helpers.h>
11 #include <mono/metadata/mempool.h>
12 #include <mono/metadata/mempool-internals.h>
20 #define USE_ORIGINAL_VARS
21 #define CREATE_PRUNED_SSA
25 #define NEW_PHI(cfg,dest,val) do { \
26 (dest) = mono_mempool_alloc0 ((cfg)->mempool, sizeof (MonoInst)); \
27 (dest)->opcode = OP_PHI; \
28 (dest)->inst_c0 = (val); \
31 #define NEW_ICONST(cfg,dest,val) do { \
32 (dest) = mono_mempool_alloc0 ((cfg)->mempool, sizeof (MonoInst)); \
33 (dest)->opcode = OP_ICONST; \
34 (dest)->inst_c0 = (val); \
35 (dest)->type = STACK_I4; \
39 unlink_target (MonoBasicBlock *bb, MonoBasicBlock *target)
43 for (i = 0; i < bb->out_count; i++) {
44 if (bb->out_bb [i] == target) {
45 bb->out_bb [i] = bb->out_bb [--bb->out_count];
49 for (i = 0; i < target->in_count; i++) {
50 if (target->in_bb [i] == bb) {
51 target->in_bb [i] = target->in_bb [--target->in_count];
59 unlink_unused_bblocks (MonoCompile *cfg)
64 g_assert (cfg->comp_done & MONO_COMP_REACHABILITY);
66 for (bb = cfg->bb_entry; bb && bb->next_bb;) {
67 if (!(bb->next_bb->flags & BB_REACHABLE)) {
68 bb->next_bb = bb->next_bb->next_bb;
73 for (i = 1; i < cfg->num_bblocks; i++) {
74 bb = cfg->bblocks [i];
76 if (!(bb->flags & BB_REACHABLE)) {
77 for (j = 0; j < bb->in_count; j++) {
78 unlink_target (bb->in_bb [j], bb);
80 for (j = 0; j < bb->out_count; j++) {
81 unlink_target (bb, bb->out_bb [j]);
91 replace_usage (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *inst, MonoInst **stack)
98 arity = mono_burg_arity [inst->opcode];
100 if ((inst->ssa_op == MONO_SSA_LOAD || inst->ssa_op == MONO_SSA_ADDRESS_TAKEN) &&
101 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG)) {
103 int idx = inst->inst_i0->inst_c0;
106 new_var = stack [idx];
108 new_var = cfg->varinfo [idx];
110 if ((new_var->opcode != OP_ARG) && (new_var->opcode != OP_LOCAL)) {
111 /* uninitialized variable ? */
112 g_warning ("using uninitialized variables %d in BB%d (%s)", idx, bb->block_num,
113 mono_method_full_name (cfg->method, TRUE));
114 //g_assert_not_reached ();
118 printf ("REPLACE BB%d %d %d\n", bb->block_num, idx, new_var->inst_c0);
120 inst->inst_i0 = new_var;
124 if (inst->ssa_op != MONO_SSA_STORE)
125 replace_usage (cfg, bb, inst->inst_left, stack);
127 replace_usage (cfg, bb, inst->inst_right, stack);
135 extends_live (MonoInst *inst)
142 arity = mono_burg_arity [inst->opcode];
144 if (inst->ssa_op == MONO_SSA_LOAD &&
145 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG)) {
149 if (inst->ssa_op != MONO_SSA_STORE)
150 if (extends_live (inst->inst_left))
153 if (extends_live (inst->inst_right))
162 replace_usage_new (MonoCompile *cfg, MonoInst *inst, int varnum, MonoInst *rep)
169 arity = mono_burg_arity [inst->opcode];
171 if ((inst->ssa_op == MONO_SSA_LOAD) &&
172 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG) &&
173 inst->inst_i0->inst_c0 == varnum && rep->type == inst->type) {
178 if (inst->ssa_op != MONO_SSA_STORE)
179 if (replace_usage_new (cfg, inst->inst_left, varnum, rep))
182 if (replace_usage_new (cfg, inst->inst_right, varnum, rep))
193 mono_ssa_rename_vars (MonoCompile *cfg, int max_vars, MonoBasicBlock *bb, MonoInst **stack)
195 MonoInst *inst, *new_var;
198 MonoInst **new_stack;
201 printf ("RENAME VARS BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
204 MONO_BB_FOR_EACH_INS (bb, inst) {
205 if (inst->opcode != OP_PHI)
206 replace_usage (cfg, bb, inst, stack);
208 if (inst->ssa_op == MONO_SSA_STORE &&
209 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG)) {
210 idx = inst->inst_i0->inst_c0;
211 g_assert (idx < max_vars);
213 if ((!stack [idx]) && (bb == cfg->bb_init) && (inst->inst_i0->opcode != OP_ARG)) {
214 new_var = cfg->varinfo [idx];
216 new_var = mono_compile_create_var (cfg, inst->inst_i0->inst_vtype, inst->inst_i0->opcode);
217 new_var->flags = inst->inst_i0->flags;
220 printf ("DEF %d %d\n", idx, new_var->inst_c0);
222 inst->inst_i0 = new_var;
224 #ifdef USE_ORIGINAL_VARS
225 MONO_VARINFO (cfg, new_var->inst_c0)->reg = idx;
228 stack [idx] = new_var;
232 for (i = 0; i < bb->out_count; i++) {
233 MonoBasicBlock *n = bb->out_bb [i];
235 for (j = 0; j < n->in_count; j++)
236 if (n->in_bb [j] == bb)
239 MONO_BB_FOR_EACH_INS (n, inst) {
240 if (inst->ssa_op == MONO_SSA_STORE && inst->inst_i1->opcode == OP_PHI) {
241 idx = inst->inst_i1->inst_c0;
243 new_var = stack [idx];
245 new_var = cfg->varinfo [idx];
247 printf ("FOUND PHI %d (%d, %d)\n", idx, j, new_var->inst_c0);
249 inst->inst_i1->inst_phi_args [j + 1] = new_var->inst_c0;
256 new_stack = g_new (MonoInst*, max_vars);
257 for (tmp = bb->dominated; tmp; tmp = tmp->next) {
258 memcpy (new_stack, stack, sizeof (MonoInst *) * max_vars);
259 mono_ssa_rename_vars (cfg, max_vars, (MonoBasicBlock *)tmp->data, new_stack);
266 mono_ssa_compute (MonoCompile *cfg)
270 MonoMethodVar *vinfo = g_new0 (MonoMethodVar, cfg->num_varinfo);
271 MonoInst *inst, *store, **stack;
273 g_assert (!(cfg->comp_done & MONO_COMP_SSA));
275 /* we dont support methods containing exception clauses */
276 g_assert (mono_method_get_header (cfg->method)->num_clauses == 0);
277 g_assert (!cfg->disable_ssa);
279 //printf ("COMPUTS SSA %s %d\n", mono_method_full_name (cfg->method, TRUE), cfg->num_varinfo);
281 #ifdef CREATE_PRUNED_SSA
282 /* we need liveness for pruned SSA */
283 if (!(cfg->comp_done & MONO_COMP_LIVENESS))
284 mono_analyze_liveness (cfg);
287 mono_compile_dominator_info (cfg, MONO_COMP_DOM | MONO_COMP_IDOM | MONO_COMP_DFRONTIER);
289 for (i = 0; i < cfg->num_varinfo; ++i) {
290 vinfo [i].def_in = mono_bitset_new (cfg->num_bblocks, 0);
292 /* implizit reference at start */
293 mono_bitset_set (vinfo [i].def_in, 0);
295 for (i = 0; i < cfg->num_bblocks; ++i) {
296 MONO_BB_FOR_EACH_INS (cfg->bblocks [i], inst) {
297 if (inst->ssa_op == MONO_SSA_STORE) {
298 idx = inst->inst_i0->inst_c0;
299 g_assert (idx < cfg->num_varinfo);
300 mono_bitset_set (vinfo [idx].def_in, i);
305 /* insert phi functions */
306 for (i = 0; i < cfg->num_varinfo; ++i) {
307 set = mono_compile_iterated_dfrontier (cfg, vinfo [i].def_in);
308 mono_bitset_foreach_bit (set, idx, cfg->num_bblocks) {
309 MonoBasicBlock *bb = cfg->bblocks [idx];
311 /* fixme: create pruned SSA? we would need liveness information for that */
313 if (bb == cfg->bb_exit)
316 if ((cfg->comp_done & MONO_COMP_LIVENESS) && !mono_bitset_test_fast (bb->live_in_set, i)) {
317 //printf ("%d is not live in BB%d %s\n", i, bb->block_num, mono_method_full_name (cfg->method, TRUE));
321 NEW_PHI (cfg, inst, i);
323 inst->inst_phi_args = mono_mempool_alloc0 (cfg->mempool, sizeof (int) * (cfg->bblocks [idx]->in_count + 1));
324 inst->inst_phi_args [0] = cfg->bblocks [idx]->in_count;
326 store = mono_mempool_alloc0 ((cfg)->mempool, sizeof (MonoInst));
327 if (!cfg->varinfo [i]->inst_vtype->type)
328 g_assert_not_reached ();
329 store->opcode = mono_type_to_stind (cfg->varinfo [i]->inst_vtype);
330 store->ssa_op = MONO_SSA_STORE;
331 store->inst_i0 = cfg->varinfo [i];
332 store->inst_i1 = inst;
333 store->klass = store->inst_i0->klass;
335 store->next = bb->code;
338 bb->last_ins = bb->code;
341 printf ("ADD PHI BB%d %s\n", cfg->bblocks [idx]->block_num, mono_method_full_name (cfg->method, TRUE));
347 for (i = 0; i < cfg->num_varinfo; ++i)
348 mono_bitset_free (vinfo [i].def_in);
352 stack = alloca (sizeof (MonoInst *) * cfg->num_varinfo);
354 for (i = 0; i < cfg->num_varinfo; i++)
357 mono_ssa_rename_vars (cfg, cfg->num_varinfo, cfg->bb_entry, stack);
359 cfg->comp_done |= MONO_COMP_SSA;
362 #ifndef USE_ORIGINAL_VARS
364 mono_ssa_get_allocatable_vars (MonoCompile *cfg)
366 GHashTable *type_hash;
367 GPtrArray *varlist_array = g_ptr_array_new ();
370 g_assert (cfg->comp_done & MONO_COMP_LIVENESS);
372 type_hash = g_hash_table_new (NULL, NULL);
374 for (i = 0; i < cfg->num_varinfo; i++) {
375 MonoInst *ins = cfg->varinfo [i];
376 MonoMethodVar *vmv = MONO_VARINFO (cfg, i);
379 if (vmv->range.first_use.abs_pos > vmv->range.last_use.abs_pos)
382 if (ins->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT) ||
383 (ins->opcode != OP_LOCAL && ins->opcode != OP_ARG) || vmv->reg != -1)
386 g_assert (ins->inst_vtype);
387 g_assert (vmv->reg == -1);
388 g_assert (i == vmv->idx);
390 if (!(tidx = (int)g_hash_table_lookup (type_hash, ins->inst_vtype))) {
391 GList *vars = g_list_append (NULL, vmv);
392 g_ptr_array_add (varlist_array, vars);
393 g_hash_table_insert (type_hash, ins->inst_vtype, (gpointer)varlist_array->len);
396 g_ptr_array_index (varlist_array, tidx) =
397 mono_varlist_insert_sorted (cfg, g_ptr_array_index (varlist_array, tidx), vmv, FALSE);
401 g_hash_table_destroy (type_hash);
403 return varlist_array;
408 mono_ssa_replace_copies (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *inst, char *is_live)
415 arity = mono_burg_arity [inst->opcode];
417 if ((inst->ssa_op == MONO_SSA_LOAD || inst->ssa_op == MONO_SSA_ADDRESS_TAKEN || inst->ssa_op == MONO_SSA_STORE) &&
418 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG)) {
420 int idx = inst->inst_i0->inst_c0;
421 MonoMethodVar *mv = MONO_VARINFO (cfg, idx);
423 if (mv->reg != -1 && mv->reg != mv->idx) {
425 is_live [mv->reg] = 1;
427 new_var = cfg->varinfo [mv->reg];
430 printf ("REPLACE COPY BB%d %d %d\n", bb->block_num, idx, new_var->inst_c0);
431 g_assert (cfg->varinfo [mv->reg]->inst_vtype == cfg->varinfo [idx]->inst_vtype);
433 inst->inst_p0 = new_var;
435 is_live [mv->idx] = 1;
441 mono_ssa_replace_copies (cfg, bb, inst->inst_left, is_live);
443 mono_ssa_replace_copies (cfg, bb, inst->inst_right, is_live);
446 if (inst->ssa_op == MONO_SSA_STORE && inst->inst_i1->ssa_op == MONO_SSA_LOAD &&
447 inst->inst_i0->inst_c0 == inst->inst_i1->inst_i0->inst_c0) {
448 inst->ssa_op = MONO_SSA_NOP;
449 inst->opcode = OP_NOP;
455 mono_ssa_remove (MonoCompile *cfg)
457 MonoInst *inst, *phi;
460 #ifndef USE_ORIGINAL_VARS
461 GPtrArray *varlist_array;
464 g_assert (cfg->comp_done & MONO_COMP_SSA);
466 for (i = 0; i < cfg->num_bblocks; ++i) {
467 MonoBasicBlock *bb = cfg->bblocks [i];
468 MONO_BB_FOR_EACH_INS (bb, inst) {
469 if (inst->ssa_op == MONO_SSA_STORE && inst->inst_i1->opcode == OP_PHI) {
472 g_assert (phi->inst_phi_args [0] == bb->in_count);
474 for (j = 0; j < bb->in_count; j++) {
475 MonoBasicBlock *pred = bb->in_bb [j];
476 int idx = phi->inst_phi_args [j + 1];
477 MonoMethodVar *mv = MONO_VARINFO (cfg, idx);
479 if (mv->reg != -1 && mv->reg != mv->idx) {
480 //printf ("PHICOPY %d %d -> %d\n", idx, mv->reg, inst->inst_i0->inst_c0);
485 if (idx != inst->inst_i0->inst_c0) {
487 printf ("MOVE %d to %d in BB%d\n", idx, inst->inst_i0->inst_c0, pred->block_num);
489 mono_add_varcopy_to_end (cfg, pred, idx, inst->inst_i0->inst_c0);
493 /* remove the phi functions */
494 inst->opcode = OP_NOP;
495 inst->ssa_op = MONO_SSA_NOP;
500 #ifndef USE_ORIGINAL_VARS
501 /* we compute liveness again */
502 cfg->comp_done &= ~MONO_COMP_LIVENESS;
503 mono_analyze_liveness (cfg);
505 varlist_array = mono_ssa_get_allocatable_vars (cfg);
507 for (i = 0; i < varlist_array->len; i++) {
508 GList *l, *regs, *vars = g_ptr_array_index (varlist_array, i);
509 MonoMethodVar *vmv, *amv;
511 if (g_list_length (vars) <= 1) {
518 for (l = vars; l; l = l->next) {
521 /* expire old intervals in active */
523 amv = (MonoMethodVar *)active->data;
525 if (amv->range.last_use.abs_pos >= vmv->range.first_use.abs_pos)
528 active = g_list_delete_link (active, active);
529 regs = g_list_prepend (regs, (gpointer)amv->reg);
533 regs = g_list_prepend (regs, (gpointer)vmv->idx);
535 vmv->reg = (int)regs->data;
536 regs = g_list_delete_link (regs, regs);
537 active = mono_varlist_insert_sorted (cfg, active, vmv, TRUE);
540 g_list_free (active);
545 g_ptr_array_free (varlist_array, TRUE);
549 is_live = alloca (cfg->num_varinfo);
550 memset (is_live, 0, cfg->num_varinfo);
552 for (i = 0; i < cfg->num_bblocks; ++i) {
553 MonoBasicBlock *bb = cfg->bblocks [i];
555 MONO_BB_FOR_EACH_INS (bb, inst)
556 mono_ssa_replace_copies (cfg, bb, inst, is_live);
559 for (i = 0; i < cfg->num_varinfo; ++i) {
560 MONO_VARINFO (cfg, i)->reg = -1;
561 if (!is_live [i] && !(cfg->varinfo [i]->flags & MONO_INST_VOLATILE)) {
562 cfg->varinfo [i]->flags |= MONO_INST_IS_DEAD;
566 if (cfg->comp_done & MONO_COMP_REACHABILITY)
567 unlink_unused_bblocks (cfg);
569 cfg->comp_done &= ~MONO_COMP_SSA;
573 #define IS_CALL(op) (op == CEE_CALLI || op == OP_CALL || op == OP_CALLVIRT || (op >= OP_VOIDCALL && op <= OP_CALL_MEMBASE))
584 * Returns TRUE if the tree can have side effects.
587 analyze_dev_use (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *root, MonoInst *inst)
591 gboolean has_side_effects;
596 arity = mono_burg_arity [inst->opcode];
597 switch (inst->opcode) {
598 #define ANALYZE_DEV_USE_SPECIFIC_OPS 1
599 #define OPDEF(a1,a2,a3,a4,a5,a6,a7,a8,a9,a10) case a1:
600 #include "simple-cee-ops.h"
602 #define MINI_OP(a1,a2) case a1:
603 #include "simple-mini-ops.h"
605 #undef ANALYZE_DEV_USE_SPECIFIC_OPS
606 has_side_effects = FALSE;
609 has_side_effects = TRUE;
612 if ((inst->ssa_op == MONO_SSA_STORE) &&
613 (inst->inst_i0->opcode == OP_LOCAL /*|| inst->inst_i0->opcode == OP_ARG */)) {
614 idx = inst->inst_i0->inst_c0;
615 info = MONO_VARINFO (cfg, idx);
616 //printf ("%d defined in BB%d %p\n", idx, bb->block_num, root);
618 g_warning ("more than one definition of variable %d in %s", idx,
619 mono_method_full_name (cfg->method, TRUE));
620 g_assert_not_reached ();
622 if (!IS_CALL (inst->inst_i1->opcode) /* && inst->inst_i1->opcode == OP_ICONST */) {
623 g_assert (inst == root);
628 if (inst->inst_i1->opcode == OP_PHI) {
629 for (i = inst->inst_i1->inst_phi_args [0]; i > 0; i--) {
630 MonoVarUsageInfo *ui = mono_mempool_alloc (cfg->mempool, sizeof (MonoVarUsageInfo));
631 idx = inst->inst_i1->inst_phi_args [i];
632 info = MONO_VARINFO (cfg, idx);
633 //printf ("FOUND %d\n", idx);
636 info->uses = g_list_prepend_mempool (cfg->mempool, info->uses, ui);
641 if ((inst->ssa_op == MONO_SSA_LOAD || inst->ssa_op == MONO_SSA_ADDRESS_TAKEN) &&
642 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG)) {
643 MonoVarUsageInfo *ui = mono_mempool_alloc (cfg->mempool, sizeof (MonoVarUsageInfo));
644 idx = inst->inst_i0->inst_c0;
645 info = MONO_VARINFO (cfg, idx);
646 //printf ("FOUND %d\n", idx);
649 info->uses = g_list_prepend_mempool (cfg->mempool, info->uses, ui);
652 //if (inst->ssa_op != MONO_SSA_STORE)
653 if (analyze_dev_use (cfg, bb, root, inst->inst_left))
654 has_side_effects = TRUE;
656 if (analyze_dev_use (cfg, bb, root, inst->inst_right))
657 has_side_effects = TRUE;
661 return has_side_effects;
665 /* avoid unnecessary copies of variables:
666 * Y <= X; Z = Y; is translated to Z = X;
669 mono_ssa_avoid_copies (MonoCompile *cfg)
671 MonoInst *inst, *next;
673 MonoMethodVar *i1, *i2;
675 g_assert ((cfg->comp_done & MONO_COMP_SSA_DEF_USE));
677 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
678 MONO_BB_FOR_EACH_INS (bb, inst) {
679 if (inst->ssa_op == MONO_SSA_STORE && inst->inst_i0->opcode == OP_LOCAL &&
680 !IS_CALL (inst->inst_i1->opcode) && inst->inst_i1->opcode != OP_PHI && !inst->flags) {
681 i1 = MONO_VARINFO (cfg, inst->inst_i0->inst_c0);
683 /* fixme: compiling mcs does not work when I enable this */
685 if (g_list_length (i1->uses) == 1 && !extends_live (inst->inst_i1)) {
686 MonoVarUsageInfo *vi = (MonoVarUsageInfo *)i1->uses->data;
689 //printf ("VAR %d %s\n", i1->idx, mono_method_full_name (cfg->method, TRUE));
690 //mono_print_tree (inst); printf ("\n");
691 //mono_print_tree (u); printf ("\n");
693 if (replace_usage_new (cfg, u, inst->inst_i0->inst_c0, inst->inst_i1)) {
695 //mono_print_tree (u); printf ("\n");
697 inst->opcode = OP_NOP;
698 inst->ssa_op = MONO_SSA_NOP;
703 if (next && next->ssa_op == MONO_SSA_STORE &&
704 next->inst_i0->opcode == OP_LOCAL &&
705 next->inst_i1->ssa_op == MONO_SSA_LOAD &&
706 next->inst_i1->inst_i0->opcode == OP_LOCAL &&
707 next->inst_i1->inst_i0->inst_c0 == inst->inst_i0->inst_c0 &&
708 g_list_length (i1->uses) == 1 &&
709 inst->opcode == next->opcode &&
710 inst->inst_i0->type == next->inst_i0->type) {
711 i2 = MONO_VARINFO (cfg, next->inst_i0->inst_c0);
712 //printf ("ELIM. COPY in BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
713 inst->inst_i0 = next->inst_i0;
717 next->opcode = OP_NOP;
718 next->ssa_op = MONO_SSA_NOP;
726 mono_ssa_create_def_use (MonoCompile *cfg)
730 g_assert (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE));
732 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
734 MONO_BB_FOR_EACH_INS (bb, inst) {
735 gboolean has_side_effects = analyze_dev_use (cfg, bb, inst, inst);
736 if (has_side_effects && (inst->ssa_op == MONO_SSA_STORE) &&
737 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG)) {
738 inst->inst_i0->flags |= MONO_INST_DEFINITION_HAS_SIDE_EFFECTS;
743 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
747 simulate_compare (int opcode, int a, int b)
763 return (unsigned)a >= (unsigned)b;
765 return (unsigned)a > (unsigned)b;
767 return (unsigned)a <= (unsigned)b;
769 return (unsigned)a < (unsigned)b;
771 g_assert_not_reached ();
778 simulate_long_compare (int opcode, gint64 a, gint64 b)
794 return (guint64)a >= (guint64)b;
796 return (guint64)a > (guint64)b;
798 return (guint64)a <= (guint64)b;
800 return (guint64)a < (guint64)b;
802 g_assert_not_reached ();
808 #define EVAL_CXX(name,op,cast) \
810 if ((inst->inst_i0->opcode == OP_COMPARE) || (inst->inst_i0->opcode == OP_LCOMPARE)) { \
811 r1 = evaluate_const_tree (cfg, inst->inst_i0->inst_i0, &a, carray); \
812 r2 = evaluate_const_tree (cfg, inst->inst_i0->inst_i1, &b, carray); \
813 if (r1 == 1 && r2 == 1) { \
814 *res = ((cast)a op (cast)b); \
817 return MAX (r1, r2); \
822 #define EVAL_BINOP(name,op) \
824 r1 = evaluate_const_tree (cfg, inst->inst_i0, &a, carray); \
825 r2 = evaluate_const_tree (cfg, inst->inst_i1, &b, carray); \
826 if (r1 == 1 && r2 == 1) { \
830 return MAX (r1, r2); \
835 /* fixme: this only works for interger constants, but not for other types (long, float) */
837 evaluate_const_tree (MonoCompile *cfg, MonoInst *inst, int *res, MonoInst **carray)
845 if (inst->ssa_op == MONO_SSA_LOAD &&
846 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG) &&
847 (c0 = carray [inst->inst_i0->inst_c0])) {
852 switch (inst->opcode) {
854 *res = inst->inst_c0;
857 EVAL_CXX (OP_CEQ,==,gint32)
858 EVAL_CXX (OP_CGT,>,gint32)
859 EVAL_CXX (OP_CGT_UN,>,guint32)
860 EVAL_CXX (OP_CLT,<,gint32)
861 EVAL_CXX (OP_CLT_UN,<,guint32)
863 EVAL_BINOP (CEE_ADD,+)
864 EVAL_BINOP (CEE_SUB,-)
865 EVAL_BINOP (CEE_MUL,*)
866 EVAL_BINOP (CEE_AND,&)
867 EVAL_BINOP (CEE_OR,|)
868 EVAL_BINOP (CEE_XOR,^)
869 EVAL_BINOP (CEE_SHL,<<)
870 EVAL_BINOP (CEE_SHR,>>)
880 fold_tree (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *inst, MonoInst **carray)
888 arity = mono_burg_arity [inst->opcode];
890 if (inst->ssa_op == MONO_SSA_STORE &&
891 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG) &&
892 inst->inst_i1->opcode == OP_PHI && (c0 = carray [inst->inst_i0->inst_c0])) {
893 //{static int cn = 0; printf ("PHICONST %d %d %s\n", cn++, c0->inst_c0, mono_method_full_name (cfg->method, TRUE));}
894 *inst->inst_i1 = *c0;
895 } else if (inst->ssa_op == MONO_SSA_LOAD &&
896 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG) &&
897 (c0 = carray [inst->inst_i0->inst_c0])) {
898 //{static int cn = 0; printf ("YCCOPY %d %d %s\n", cn++, c0->inst_c0, mono_method_full_name (cfg->method, TRUE));}
903 fold_tree (cfg, bb, inst->inst_left, carray);
905 fold_tree (cfg, bb, inst->inst_right, carray);
906 mono_constant_fold_inst (inst, NULL);
910 if ((inst->opcode >= CEE_BEQ && inst->opcode <= CEE_BLT_UN) &&
911 ((inst->inst_i0->opcode == OP_COMPARE) || (inst->inst_i0->opcode == OP_LCOMPARE))) {
912 MonoInst *v0 = inst->inst_i0->inst_i0;
913 MonoInst *v1 = inst->inst_i0->inst_i1;
914 MonoBasicBlock *target = NULL;
916 /* hack for longs to optimize the simply cases */
917 if (v0->opcode == OP_I8CONST && v1->opcode == OP_I8CONST) {
918 if (simulate_long_compare (inst->opcode, v0->inst_l, v1->inst_l)) {
919 //unlink_target (bb, inst->inst_false_bb);
920 target = inst->inst_true_bb;
922 //unlink_target (bb, inst->inst_true_bb);
923 target = inst->inst_false_bb;
925 } else if (evaluate_const_tree (cfg, v0, &a, carray) == 1 &&
926 evaluate_const_tree (cfg, v1, &b, carray) == 1) {
927 if (simulate_compare (inst->opcode, a, b)) {
928 //unlink_target (bb, inst->inst_false_bb);
929 target = inst->inst_true_bb;
931 //unlink_target (bb, inst->inst_true_bb);
932 target = inst->inst_false_bb;
937 bb->out_bb [0] = target;
939 inst->opcode = OP_BR;
940 inst->inst_target_bb = target;
942 } else if (inst->opcode == OP_SWITCH && (evaluate_const_tree (cfg, inst->inst_left, &a, carray) == 1) && (a >= 0) && (a < GPOINTER_TO_INT (inst->klass))) {
943 bb->out_bb [0] = inst->inst_many_bb [a];
945 inst->inst_target_bb = bb->out_bb [0];
946 inst->opcode = OP_BR;
952 change_varstate (MonoCompile *cfg, GList **cvars, MonoMethodVar *info, int state, MonoInst *c0, MonoInst **carray)
954 if (info->cpstate >= state)
957 info->cpstate = state;
959 //printf ("SETSTATE %d to %d\n", info->idx, info->cpstate);
962 carray [info->idx] = c0;
964 carray [info->idx] = NULL;
966 if (!g_list_find (*cvars, info)) {
967 *cvars = g_list_prepend (*cvars, info);
972 visit_inst (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *inst, GList **cvars, GList **bblist, MonoInst **carray)
976 if (inst->opcode == OP_SWITCH) {
978 int cases = GPOINTER_TO_INT (inst->klass);
980 r1 = evaluate_const_tree (cfg, inst->inst_left, &a, carray);
981 if ((r1 == 1) && ((a < 0) || (a >= cases)))
984 MonoBasicBlock *tb = inst->inst_many_bb [a];
985 if (!(tb->flags & BB_REACHABLE)) {
986 tb->flags |= BB_REACHABLE;
987 *bblist = g_list_prepend (*bblist, tb);
989 } else if (r1 == 2) {
990 for (i = GPOINTER_TO_INT (inst->klass); i >= 0; i--) {
991 MonoBasicBlock *tb = inst->inst_many_bb [i];
992 if (!(tb->flags & BB_REACHABLE)) {
993 tb->flags |= BB_REACHABLE;
994 *bblist = g_list_prepend (*bblist, tb);
998 } else if (inst->opcode == OP_BR) {
999 MonoBasicBlock *target = inst->inst_target_bb;
1001 if (!(target->flags & BB_REACHABLE)) {
1002 target->flags |= BB_REACHABLE;
1003 *bblist = g_list_prepend (*bblist, target);
1005 } else if ((inst->opcode >= CEE_BEQ && inst->opcode <= CEE_BLT_UN) &&
1006 ((inst->inst_i0->opcode == OP_COMPARE) || (inst->inst_i0->opcode == OP_LCOMPARE))) {
1008 MonoInst *v0 = inst->inst_i0->inst_i0;
1009 MonoInst *v1 = inst->inst_i0->inst_i1;
1011 r1 = evaluate_const_tree (cfg, v0, &a, carray);
1012 r2 = evaluate_const_tree (cfg, v1, &b, carray);
1014 if (r1 == 1 && r2 == 1) {
1015 MonoBasicBlock *target;
1017 if (simulate_compare (inst->opcode, a, b)) {
1018 target = inst->inst_true_bb;
1020 target = inst->inst_false_bb;
1022 if (!(target->flags & BB_REACHABLE)) {
1023 target->flags |= BB_REACHABLE;
1024 *bblist = g_list_prepend (*bblist, target);
1026 } else if (r1 == 2 || r2 == 2) {
1027 if (!(inst->inst_true_bb->flags & BB_REACHABLE)) {
1028 inst->inst_true_bb->flags |= BB_REACHABLE;
1029 *bblist = g_list_prepend (*bblist, inst->inst_true_bb);
1031 if (!(inst->inst_false_bb->flags & BB_REACHABLE)) {
1032 inst->inst_false_bb->flags |= BB_REACHABLE;
1033 *bblist = g_list_prepend (*bblist, inst->inst_false_bb);
1036 } else if (inst->ssa_op == MONO_SSA_STORE &&
1037 (inst->inst_i0->opcode == OP_LOCAL || inst->inst_i0->opcode == OP_ARG)) {
1038 MonoMethodVar *info = MONO_VARINFO (cfg, inst->inst_i0->inst_c0);
1039 MonoInst *i1 = inst->inst_i1;
1042 if (info->cpstate < 2) {
1043 if (i1->opcode == OP_ICONST) {
1044 change_varstate (cfg, cvars, info, 1, i1, carray);
1045 } else if (i1->opcode == OP_PHI) {
1046 MonoInst *c0 = NULL;
1049 for (j = 1; j <= i1->inst_phi_args [0]; j++) {
1050 MonoMethodVar *mv = MONO_VARINFO (cfg, i1->inst_phi_args [j]);
1051 MonoInst *src = mv->def;
1053 if (mv->def_bb && !(mv->def_bb->flags & BB_REACHABLE)) {
1057 if (!mv->def || !src || src->ssa_op != MONO_SSA_STORE ||
1058 !(src->inst_i0->opcode == OP_LOCAL || src->inst_i0->opcode == OP_ARG) ||
1060 change_varstate (cfg, cvars, info, 2, NULL, carray);
1064 if (mv->cpstate == 0)
1067 //g_assert (src->inst_i1->opcode == OP_ICONST);
1068 g_assert (carray [mv->idx]);
1071 c0 = carray [mv->idx];
1074 if (carray [mv->idx]->inst_c0 != c0->inst_c0) {
1075 change_varstate (cfg, cvars, info, 2, NULL, carray);
1080 if (c0 && info->cpstate < 1) {
1081 change_varstate (cfg, cvars, info, 1, c0, carray);
1084 int state = evaluate_const_tree (cfg, i1, &res, carray);
1086 NEW_ICONST (cfg, i1, res);
1087 change_varstate (cfg, cvars, info, 1, i1, carray);
1089 change_varstate (cfg, cvars, info, 2, NULL, carray);
1097 mono_ssa_cprop (MonoCompile *cfg)
1101 GList *bblock_list, *cvars;
1104 //printf ("SIMPLE OPTS BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
1106 carray = g_new0 (MonoInst*, cfg->num_varinfo);
1108 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1109 mono_ssa_create_def_use (cfg);
1111 bblock_list = g_list_prepend (NULL, cfg->bb_entry);
1112 cfg->bb_entry->flags |= BB_REACHABLE;
1114 memset (carray, 0, sizeof (MonoInst *) * cfg->num_varinfo);
1116 for (i = 0; i < cfg->num_varinfo; i++) {
1117 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1124 while (bblock_list) {
1127 bb = (MonoBasicBlock *)bblock_list->data;
1129 bblock_list = g_list_delete_link (bblock_list, bblock_list);
1131 g_assert (bb->flags & BB_REACHABLE);
1133 if (bb->out_count == 1) {
1134 if (!(bb->out_bb [0]->flags & BB_REACHABLE)) {
1135 bb->out_bb [0]->flags |= BB_REACHABLE;
1136 bblock_list = g_list_prepend (bblock_list, bb->out_bb [0]);
1140 MONO_BB_FOR_EACH_INS (bb, inst)
1141 visit_inst (cfg, bb, inst, &cvars, &bblock_list, carray);
1144 MonoMethodVar *info = (MonoMethodVar *)cvars->data;
1145 cvars = g_list_delete_link (cvars, cvars);
1147 for (tmp = info->uses; tmp; tmp = tmp->next) {
1148 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1149 if (!(ui->bb->flags & BB_REACHABLE))
1151 visit_inst (cfg, ui->bb, ui->inst, &cvars, &bblock_list, carray);
1156 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1158 MONO_BB_FOR_EACH_INS (bb, inst)
1159 fold_tree (cfg, bb, inst, carray);
1164 cfg->comp_done |= MONO_COMP_REACHABILITY;
1168 add_to_dce_worklist (MonoCompile *cfg, MonoMethodVar *var, MonoMethodVar *use, GList **wl)
1172 *wl = g_list_prepend (*wl, use);
1174 for (tmp = use->uses; tmp; tmp = tmp->next) {
1175 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1176 if (ui->inst == var->def) {
1177 /* from the mempool */
1178 use->uses = g_list_remove_link (use->uses, tmp);
1185 mono_ssa_deadce (MonoCompile *cfg)
1190 g_assert (cfg->comp_done & MONO_COMP_SSA);
1192 //printf ("DEADCE %s\n", mono_method_full_name (cfg->method, TRUE));
1194 /* fixme: we should update usage infos during cprop, instead of computing it again */
1195 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1196 for (i = 0; i < cfg->num_varinfo; i++) {
1197 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1202 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1203 mono_ssa_create_def_use (cfg);
1205 mono_ssa_avoid_copies (cfg);
1208 for (i = 0; i < cfg->num_varinfo; i++) {
1209 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1210 work_list = g_list_prepend (work_list, info);
1212 //if ((info->def != NULL) && (info->def->inst_i1->opcode != OP_PHI)) printf ("SSA DEADCE TOTAL LOCAL\n");
1216 MonoMethodVar *info = (MonoMethodVar *)work_list->data;
1217 work_list = g_list_delete_link (work_list, work_list);
1219 if (!info->uses && info->def && (!(cfg->varinfo [info->idx]->flags & (MONO_INST_DEFINITION_HAS_SIDE_EFFECTS|MONO_INST_VOLATILE|MONO_INST_INDIRECT)))) {
1221 //printf ("ELIMINATE %s: ", mono_method_full_name (cfg->method, TRUE)); mono_print_tree (info->def); printf ("\n");
1223 i1 = info->def->inst_i1;
1224 if (i1->opcode == OP_PHI) {
1226 for (j = i1->inst_phi_args [0]; j > 0; j--) {
1227 MonoMethodVar *u = MONO_VARINFO (cfg, i1->inst_phi_args [j]);
1228 add_to_dce_worklist (cfg, info, u, &work_list);
1230 } else if (i1->ssa_op == MONO_SSA_LOAD &&
1231 (i1->inst_i0->opcode == OP_LOCAL || i1->inst_i0->opcode == OP_ARG)) {
1232 MonoMethodVar *u = MONO_VARINFO (cfg, i1->inst_i0->inst_c0);
1233 add_to_dce_worklist (cfg, info, u, &work_list);
1235 //if (i1->opcode != OP_PHI) printf ("SSA DEADCE DEAD LOCAL\n");
1237 info->def->opcode = OP_NOP;
1238 info->def->ssa_op = MONO_SSA_NOP;
1246 mono_ssa_strength_reduction (MonoCompile *cfg)
1251 g_assert (cfg->comp_done & MONO_COMP_SSA);
1252 g_assert (cfg->comp_done & MONO_COMP_LOOPS);
1253 g_assert (cfg->comp_done & MONO_COMP_SSA_DEF_USE);
1255 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1256 GList *lp = bb->loop_blocks;
1259 MonoBasicBlock *h = (MonoBasicBlock *)lp->data;
1261 /* we only consider loops with 2 in bblocks */
1262 if (!h->in_count == 2)
1265 for (i = 0; i < cfg->num_varinfo; i++) {
1266 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1268 if (info->def && info->def->ssa_op == MONO_SSA_STORE &&
1269 info->def->inst_i0->opcode == OP_LOCAL && g_list_find (lp, info->def_bb)) {
1270 MonoInst *v = info->def->inst_i1;
1273 printf ("FOUND %d in %s\n", info->idx, mono_method_full_name (cfg->method, TRUE));
1281 #endif /* DISABLE_SSA */
1283 #endif /* DISABLE_JIT */