3 * File name: ir/ir/iropt.c
4 * Purpose: iropt --- optimizations intertwined with IR construction.
5 * Author: Christian Schaefer
6 * Modified by: Goetz Lindenmaier
9 * Copyright: (c) 1998-2003 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
17 # include "irnode_t.h"
18 # include "irgraph_t.h"
19 # include "irmode_t.h"
25 # include "dbginfo_t.h"
26 # include "iropt_dbg.h"
27 # include "irflag_t.h"
28 # include "firmstat.h"
30 /* Make types visible to allow most efficient access */
31 # include "entity_t.h"
34 * Trivial INLINEable routine for copy propagation.
35 * Does follow Ids, needed to optimize INLINEd code.
37 static INLINE ir_node *
38 follow_Id (ir_node *n)
40 while (get_irn_op (n) == op_Id) n = get_Id_pred (n);
45 * Returns the tarval of a Const node or tarval_bad for all other nodes.
47 static INLINE tarval *
50 if ((n != NULL) && (get_irn_op(n) == op_Const))
51 return get_Const_tarval(n); /* might return tarval_bad */
56 static tarval *computed_value_Const(ir_node *n)
58 return get_Const_tarval(n);
61 static tarval *computed_value_SymConst(ir_node *n)
63 if ((get_SymConst_kind(n) ==symconst_size) &&
64 (get_type_state(get_SymConst_type(n))) == layout_fixed)
65 return new_tarval_from_long(get_type_size_bytes(get_SymConst_type(n)), mode_Is);
69 static tarval *computed_value_Add(ir_node *n)
71 ir_node *a = get_Add_left(n);
72 ir_node *b = get_Add_right(n);
74 tarval *ta = value_of(a);
75 tarval *tb = value_of(b);
77 if ((ta != tarval_bad) && (tb != tarval_bad)
78 && (get_irn_mode(a) == get_irn_mode(b))
79 && !(get_mode_sort(get_irn_mode(a)) == irms_reference)) {
80 return tarval_add(ta, tb);
85 static tarval *computed_value_Sub(ir_node *n)
87 ir_node *a = get_Sub_left(n);
88 ir_node *b = get_Sub_right(n);
90 tarval *ta = value_of(a);
91 tarval *tb = value_of(b);
93 if ((ta != tarval_bad) && (tb != tarval_bad)
94 && (get_irn_mode(a) == get_irn_mode(b))
95 && !(get_mode_sort(get_irn_mode(a)) == irms_reference)) {
96 return tarval_sub(ta, tb);
101 static tarval *computed_value_Minus(ir_node *n)
103 ir_node *a = get_Minus_op(n);
104 tarval *ta = value_of(a);
106 if ((ta != tarval_bad) && mode_is_signed(get_irn_mode(a)))
107 return tarval_neg(ta);
112 static tarval *computed_value_Mul(ir_node *n)
114 ir_node *a = get_Mul_left(n);
115 ir_node *b = get_Mul_right(n);
117 tarval *ta = value_of(a);
118 tarval *tb = value_of(b);
120 if ((ta != tarval_bad) && (tb != tarval_bad) && (get_irn_mode(a) == get_irn_mode(b))) {
121 return tarval_mul(ta, tb);
123 /* a*0 = 0 or 0*b = 0:
124 calls computed_value recursive and returns the 0 with proper
128 if ( ( ((v = ta) != tarval_bad)
129 && (v == get_mode_null(get_tarval_mode(v))) )
130 || ( ((v = tb) != tarval_bad)
131 && (v == get_mode_null(get_tarval_mode(v))) )) {
138 static tarval *computed_value_Quot(ir_node *n)
140 ir_node *a = get_Quot_left(n);
141 ir_node *b = get_Quot_right(n);
143 tarval *ta = value_of(a);
144 tarval *tb = value_of(b);
146 /* This was missing in original implementation. Why? */
147 if ((ta != tarval_bad) && (tb != tarval_bad) && (get_irn_mode(a) == get_irn_mode(b))) {
148 if (tb != get_mode_null(get_tarval_mode(tb))) /* div by zero: return tarval_bad */
149 return tarval_quo(ta, tb);
154 static tarval *computed_value_Div(ir_node *n)
156 ir_node *a = get_Div_left(n);
157 ir_node *b = get_Div_right(n);
159 tarval *ta = value_of(a);
160 tarval *tb = value_of(b);
162 /* This was missing in original implementation. Why? */
163 if ((ta != tarval_bad) && (tb != tarval_bad) && (get_irn_mode(a) == get_irn_mode(b))) {
164 if (tb != get_mode_null(get_tarval_mode(tb))) /* div by zero: return tarval_bad */
165 return tarval_div(ta, tb);
170 static tarval *computed_value_Mod(ir_node *n)
172 ir_node *a = get_Mod_left(n);
173 ir_node *b = get_Mod_right(n);
175 tarval *ta = value_of(a);
176 tarval *tb = value_of(b);
178 /* This was missing in original implementation. Why? */
179 if ((ta != tarval_bad) && (tb != tarval_bad) && (get_irn_mode(a) == get_irn_mode(b))) {
180 if (tb != get_mode_null(get_tarval_mode(tb))) /* div by zero: return tarval_bad */
181 return tarval_mod(ta, tb);
186 static tarval *computed_value_Abs(ir_node *n)
188 ir_node *a = get_Abs_op(n);
189 tarval *ta = value_of(a);
191 if (ta != tarval_bad)
192 return tarval_abs(ta);
197 static tarval *computed_value_And(ir_node *n)
199 ir_node *a = get_And_left(n);
200 ir_node *b = get_And_right(n);
202 tarval *ta = value_of(a);
203 tarval *tb = value_of(b);
205 if ((ta != tarval_bad) && (tb != tarval_bad)) {
206 return tarval_and (ta, tb);
210 if ( (tarval_classify ((v = computed_value (a))) == TV_CLASSIFY_NULL)
211 || (tarval_classify ((v = computed_value (b))) == TV_CLASSIFY_NULL)) {
218 static tarval *computed_value_Or(ir_node *n)
220 ir_node *a = get_Or_left(n);
221 ir_node *b = get_Or_right(n);
223 tarval *ta = value_of(a);
224 tarval *tb = value_of(b);
226 if ((ta != tarval_bad) && (tb != tarval_bad)) {
227 return tarval_or (ta, tb);
230 if ( (tarval_classify ((v = computed_value (a))) == TV_CLASSIFY_ALL_ONE)
231 || (tarval_classify ((v = computed_value (b))) == TV_CLASSIFY_ALL_ONE)) {
238 static tarval *computed_value_Eor(ir_node *n)
240 ir_node *a = get_Eor_left(n);
241 ir_node *b = get_Eor_right(n);
243 tarval *ta = value_of(a);
244 tarval *tb = value_of(b);
246 if ((ta != tarval_bad) && (tb != tarval_bad)) {
247 return tarval_eor (ta, tb);
252 static tarval *computed_value_Not(ir_node *n)
254 ir_node *a = get_Not_op(n);
255 tarval *ta = value_of(a);
257 if (ta != tarval_bad)
258 return tarval_not(ta);
263 static tarval *computed_value_Shl(ir_node *n)
265 ir_node *a = get_Shl_left(n);
266 ir_node *b = get_Shl_right(n);
268 tarval *ta = value_of(a);
269 tarval *tb = value_of(b);
271 if ((ta != tarval_bad) && (tb != tarval_bad)) {
272 return tarval_shl (ta, tb);
277 static tarval *computed_value_Shr(ir_node *n)
279 ir_node *a = get_Shr_left(n);
280 ir_node *b = get_Shr_right(n);
282 tarval *ta = value_of(a);
283 tarval *tb = value_of(b);
285 if ((ta != tarval_bad) && (tb != tarval_bad)) {
286 return tarval_shr (ta, tb);
291 static tarval *computed_value_Shrs(ir_node *n)
293 ir_node *a = get_Shrs_left(n);
294 ir_node *b = get_Shrs_right(n);
296 tarval *ta = value_of(a);
297 tarval *tb = value_of(b);
299 if ((ta != tarval_bad) && (tb != tarval_bad)) {
300 return tarval_shrs (ta, tb);
305 static tarval *computed_value_Rot(ir_node *n)
307 ir_node *a = get_Rot_left(n);
308 ir_node *b = get_Rot_right(n);
310 tarval *ta = value_of(a);
311 tarval *tb = value_of(b);
313 if ((ta != tarval_bad) && (tb != tarval_bad)) {
314 /* return tarval_rot (ta, tb); */
319 static tarval *computed_value_Conv(ir_node *n)
321 ir_node *a = get_Conv_op(n);
322 tarval *ta = value_of(a);
324 if (ta != tarval_bad)
325 return tarval_convert_to(ta, get_irn_mode(n));
330 static tarval *computed_value_Proj(ir_node *n)
332 ir_node *a = get_Proj_pred(n), *b;
335 /* Optimize Cmp nodes.
336 This performs a first step of unreachable code elimination.
337 Proj can not be computed, but folding a Cmp above the Proj here is
338 not as wasteful as folding a Cmp into a Tuple of 16 Consts of which
340 There are several case where we can evaluate a Cmp node:
341 1. The nodes compared are both the same. If we compare for
342 equal, greater equal, ... this will return true, else it
343 will return false. This step relies on cse.
344 2. The predecessors of Cmp are target values. We can evaluate
346 3. The predecessors are Allocs or void* constants. Allocs never
347 return NULL, they raise an exception. Therefore we can predict
349 if (get_irn_op(a) == op_Cmp) {
350 aa = get_Cmp_left(a);
351 ab = get_Cmp_right(a);
353 if (aa == ab) { /* 1.: */
354 /* This is a tric with the bits used for encoding the Cmp
355 Proj numbers, the following statement is not the same:
356 return new_tarval_from_long ((get_Proj_proj(n) == Eq), mode_b) */
357 return new_tarval_from_long ((get_Proj_proj(n) & Eq), mode_b);
359 tarval *taa = computed_value (aa);
360 tarval *tab = computed_value (ab);
362 if ((taa != tarval_bad) && (tab != tarval_bad)) { /* 2.: */
363 /* strange checks... */
364 pnc_number flags = tarval_cmp (taa, tab);
365 if (flags != False) {
366 return new_tarval_from_long (get_Proj_proj(n) & flags, mode_b);
368 } else { /* check for 3.: */
369 ir_node *aaa = skip_nop(skip_Proj(aa));
370 ir_node *aba = skip_nop(skip_Proj(ab));
372 if ( ( (/* aa is ProjP and aaa is Alloc */
373 (get_irn_op(aa) == op_Proj)
374 && (mode_is_reference(get_irn_mode(aa)))
375 && (get_irn_op(aaa) == op_Alloc))
376 && ( (/* ab is constant void */
377 (get_irn_op(ab) == op_Const)
378 && (mode_is_reference(get_irn_mode(ab)))
379 && (get_Const_tarval(ab) == get_mode_null(get_irn_mode(ab))))
380 || (/* ab is other Alloc */
381 (get_irn_op(ab) == op_Proj)
382 && (mode_is_reference(get_irn_mode(ab)))
383 && (get_irn_op(aba) == op_Alloc)
385 || (/* aa is void and aba is Alloc */
386 (get_irn_op(aa) == op_Const)
387 && (mode_is_reference(get_irn_mode(aa)))
388 && (get_Const_tarval(aa) == get_mode_null(get_irn_mode(aa)))
389 && (get_irn_op(ab) == op_Proj)
390 && (mode_is_reference(get_irn_mode(ab)))
391 && (get_irn_op(aba) == op_Alloc)))
393 return new_tarval_from_long (get_Proj_proj(n) & Ne, mode_b);
396 } else if (get_irn_op(a) == op_DivMod) {
397 tarval *tb = value_of(b = get_DivMod_right(a));
398 tarval *ta = value_of(a = get_DivMod_left(a));
400 if ((ta != tarval_bad) && (tb != tarval_bad) && (get_irn_mode(a) == get_irn_mode(b))) {
401 if (tb == get_mode_null(get_tarval_mode(tb))) /* div by zero: return tarval_bad */
403 if (get_Proj_proj(n)== 0) /* Div */
404 return tarval_div(ta, tb);
406 return tarval_mod(ta, tb);
413 * If the parameter n can be computed, return its value, else tarval_bad.
414 * Performs constant folding.
416 tarval *computed_value(ir_node *n)
418 if (n->op->computed_value)
419 return n->op->computed_value(n);
424 * set the default computed_value evaluator
426 static ir_op *firm_set_default_computed_value(ir_op *op)
430 op->computed_value = computed_value_##a; \
455 op->computed_value = NULL;
463 /* returns 1 if the a and b are pointers to different locations. */
465 different_identity (ir_node *a, ir_node *b)
467 assert (mode_is_reference(get_irn_mode (a))
468 && mode_is_reference(get_irn_mode (b)));
470 if (get_irn_op (a) == op_Proj && get_irn_op(b) == op_Proj) {
471 ir_node *a1 = get_Proj_pred (a);
472 ir_node *b1 = get_Proj_pred (b);
473 if (a1 != b1 && get_irn_op (a1) == op_Alloc
474 && get_irn_op (b1) == op_Alloc)
481 static ir_node *equivalent_node_Block(ir_node *n)
485 /* The Block constructor does not call optimize, but mature_block
486 calls the optimization. */
487 assert(get_Block_matured(n));
489 /* Straightening: a single entry Block following a single exit Block
490 can be merged, if it is not the Start block. */
491 /* !!! Beware, all Phi-nodes of n must have been optimized away.
492 This should be true, as the block is matured before optimize is called.
493 But what about Phi-cycles with the Phi0/Id that could not be resolved?
494 Remaining Phi nodes are just Ids. */
495 if ((get_Block_n_cfgpreds(n) == 1) &&
496 (get_irn_op(get_Block_cfgpred(n, 0)) == op_Jmp)) {
497 ir_node *predblock = get_nodes_Block(get_Block_cfgpred(n, 0));
498 if (predblock == oldn) {
499 /* Jmp jumps into the block it is in -- deal self cycle. */
500 n = new_Bad(); DBG_OPT_DEAD;
501 } else if (get_opt_control_flow_straightening()) {
502 n = predblock; DBG_OPT_STG;
505 else if ((get_Block_n_cfgpreds(n) == 1) &&
506 (get_irn_op(skip_Proj(get_Block_cfgpred(n, 0))) == op_Cond)) {
507 ir_node *predblock = get_nodes_Block(get_Block_cfgpred(n, 0));
508 if (predblock == oldn) {
509 /* Jmp jumps into the block it is in -- deal self cycle. */
510 n = new_Bad(); DBG_OPT_DEAD;
513 else if ((get_Block_n_cfgpreds(n) == 2) &&
514 (get_opt_control_flow_weak_simplification())) {
515 /* Test whether Cond jumps twice to this block
516 @@@ we could do this also with two loops finding two preds from several ones. */
517 ir_node *a = get_Block_cfgpred(n, 0);
518 ir_node *b = get_Block_cfgpred(n, 1);
520 if ((get_irn_op(a) == op_Proj) &&
521 (get_irn_op(b) == op_Proj) &&
522 (get_Proj_pred(a) == get_Proj_pred(b)) &&
523 (get_irn_op(get_Proj_pred(a)) == op_Cond) &&
524 (get_irn_mode(get_Cond_selector(get_Proj_pred(a))) == mode_b)) {
525 /* Also a single entry Block following a single exit Block. Phis have
526 twice the same operand and will be optimized away. */
527 n = get_nodes_Block(a); DBG_OPT_IFSIM;
529 } else if (get_opt_unreachable_code() &&
530 (n != current_ir_graph->start_block) &&
531 (n != current_ir_graph->end_block) ) {
533 /* If all inputs are dead, this block is dead too, except if it is
534 the start or end block. This is a step of unreachable code
536 for (i = 0; i < get_Block_n_cfgpreds(n); i++) {
537 if (!is_Bad(get_Block_cfgpred(n, i))) break;
539 if (i == get_Block_n_cfgpreds(n))
547 * Returns a equivalent node for a Jmp, a Bad :-)
548 * Of course this only happens if the Block of the Jmp is Bad.
550 static ir_node *equivalent_node_Jmp(ir_node *n)
552 /* GL: Why not same for op_Raise?? */
553 /* unreachable code elimination */
554 if (is_Bad(get_nodes_Block(n)))
560 static ir_node *equivalent_node_Cond(ir_node *n)
562 /* We do not evaluate Cond here as we replace it by a new node, a Jmp.
563 See cases for iro_Cond and iro_Proj in transform_node. */
568 * Use algebraic simplification a v a = a.
570 static ir_node *equivalent_node_Or(ir_node *n)
574 ir_node *a = get_Or_left(n);
575 ir_node *b = get_Or_right(n);
579 n = a; DBG_OPT_ALGSIM1;
586 * optimize operations that are commutative and have neutral 0,
587 * so a op 0 = 0 op a = a.
589 static ir_node *equivalent_node_neutral_zero(ir_node *n)
593 ir_node *a = get_binop_left(n);
594 ir_node *b = get_binop_right(n);
599 /* After running compute_node there is only one constant predecessor.
600 Find this predecessors value and remember the other node: */
601 if ((tv = computed_value(a)) != tarval_bad) {
603 } else if ((tv = computed_value(b)) != tarval_bad) {
608 /* If this predecessors constant value is zero, the operation is
609 unnecessary. Remove it: */
610 if (tarval_classify (tv) == TV_CLASSIFY_NULL) {
611 n = on; DBG_OPT_ALGSIM1;
617 #define equivalent_node_Add equivalent_node_neutral_zero
618 #define equivalent_node_Eor equivalent_node_neutral_zero
621 * optimize operations that are not commutative but have neutral 0 on left,
624 static ir_node *equivalent_node_left_zero(ir_node *n)
628 ir_node *a = get_binop_left(n);
629 ir_node *b = get_binop_right(n);
631 if (tarval_classify(computed_value(b)) == TV_CLASSIFY_NULL) {
632 n = a; DBG_OPT_ALGSIM1;
638 #define equivalent_node_Sub equivalent_node_left_zero
639 #define equivalent_node_Shl equivalent_node_left_zero
640 #define equivalent_node_Shr equivalent_node_left_zero
641 #define equivalent_node_Shrs equivalent_node_left_zero
642 #define equivalent_node_Rot equivalent_node_left_zero
645 * Er, a "symmetic unop", ie op(op(n)) = n.
647 static ir_node *equivalent_node_symmetric_unop(ir_node *n)
651 /* optimize symmetric unop */
652 if (get_irn_op(get_unop_op(n)) == get_irn_op(n)) {
653 n = get_unop_op(get_unop_op(n)); DBG_OPT_ALGSIM2;
659 #define equivalent_node_Not equivalent_node_symmetric_unop
661 /* --x == x */ /* ??? Is this possible or can --x raise an
662 out of bounds exception if min =! max? */
663 #define equivalent_node_Minus equivalent_node_symmetric_unop
666 * Optimize a * 1 = 1 * a = a.
668 static ir_node *equivalent_node_Mul(ir_node *n)
672 ir_node *a = get_Mul_left(n);
673 ir_node *b = get_Mul_right(n);
675 /* Mul is commutative and has again an other neutral element. */
676 if (tarval_classify (computed_value (a)) == TV_CLASSIFY_ONE) {
677 n = b; DBG_OPT_ALGSIM1;
678 } else if (tarval_classify (computed_value (b)) == TV_CLASSIFY_ONE) {
679 n = a; DBG_OPT_ALGSIM1;
685 * Optimize a / 1 = a.
687 static ir_node *equivalent_node_Div(ir_node *n)
689 ir_node *a = get_Div_left(n);
690 ir_node *b = get_Div_right(n);
692 /* Div is not commutative. */
693 if (tarval_classify(computed_value(b)) == TV_CLASSIFY_ONE) { /* div(x, 1) == x */
694 /* Turn Div into a tuple (mem, bad, a) */
695 ir_node *mem = get_Div_mem(n);
696 turn_into_tuple(n, 3);
697 set_Tuple_pred(n, pn_Div_M, mem);
698 set_Tuple_pred(n, pn_Div_X_except, new_Bad()); /* no exception */
699 set_Tuple_pred(n, pn_Div_res, a);
705 * Optimize a & 0b1...1 = 0b1...1 & a = a & a = a.
707 static ir_node *equivalent_node_And(ir_node *n)
711 ir_node *a = get_And_left(n);
712 ir_node *b = get_And_right(n);
715 n = a; /* And has it's own neutral element */
716 } else if (tarval_classify(computed_value(a)) == TV_CLASSIFY_ALL_ONE) {
718 } else if (tarval_classify(computed_value(b)) == TV_CLASSIFY_ALL_ONE) {
721 if (n != oldn) DBG_OPT_ALGSIM1;
726 * Try to remove useless conv's:
728 static ir_node *equivalent_node_Conv(ir_node *n)
731 ir_node *a = get_Conv_op(n);
734 ir_mode *n_mode = get_irn_mode(n);
735 ir_mode *a_mode = get_irn_mode(a);
737 if (n_mode == a_mode) { /* No Conv necessary */
738 n = a; DBG_OPT_ALGSIM3;
739 } else if (get_irn_op(a) == op_Conv) { /* Conv(Conv(b)) */
743 n_mode = get_irn_mode(n);
744 b_mode = get_irn_mode(b);
746 if (n_mode == b_mode) {
747 if (n_mode == mode_b) {
748 n = b; /* Convb(Conv*(xxxb(...))) == xxxb(...) */ DBG_OPT_ALGSIM1;
750 else if (mode_is_int(n_mode) || mode_is_character(n_mode)) {
751 if (smaller_mode(b_mode, a_mode)){
752 n = b; /* ConvS(ConvL(xxxS(...))) == xxxS(...) */ DBG_OPT_ALGSIM1;
760 static ir_node *equivalent_node_Phi(ir_node *n)
762 /* Several optimizations:
763 - no Phi in start block.
764 - remove Id operators that are inputs to Phi
765 - fold Phi-nodes, iff they have only one predecessor except
771 ir_node *block = NULL; /* to shutup gcc */
772 ir_node *first_val = NULL; /* to shutup gcc */
773 ir_node *scnd_val = NULL; /* to shutup gcc */
775 if (!get_opt_normalize()) return n;
777 n_preds = get_Phi_n_preds(n);
779 block = get_nodes_block(n);
780 /* @@@ fliegt 'raus, sollte aber doch immer wahr sein!!!
781 assert(get_irn_arity(block) == n_preds && "phi in wrong block!"); */
782 if ((is_Bad(block)) || /* Control dead */
783 (block == current_ir_graph->start_block)) /* There should be no Phi nodes */
784 return new_Bad(); /* in the Start Block. */
786 if (n_preds == 0) return n; /* Phi of dead Region without predecessors. */
789 /* first we test for a special case: */
790 /* Confirm is a special node fixing additional information for a
791 value that is known at a certain point. This is useful for
792 dataflow analysis. */
794 ir_node *a = get_Phi_pred(n, 0);
795 ir_node *b = get_Phi_pred(n, 1);
796 if ( (get_irn_op(a) == op_Confirm)
797 && (get_irn_op(b) == op_Confirm)
798 && follow_Id (get_irn_n(a, 0) == get_irn_n(b, 0))
799 && (get_irn_n(a, 1) == get_irn_n (b, 1))
800 && (a->data.num == (~b->data.num & irpn_True) )) {
801 return get_irn_n(a, 0);
806 /* If the Block has a Bad pred, we also have one. */
807 for (i = 0; i < n_preds; ++i)
808 if (is_Bad (get_Block_cfgpred(block, i)))
809 set_Phi_pred(n, i, new_Bad());
811 /* Find first non-self-referencing input */
812 for (i = 0; i < n_preds; ++i) {
813 first_val = get_Phi_pred(n, i);
814 if ( (first_val != n) /* not self pointer */
816 && (get_irn_op(first_val) != op_Bad)
818 ) { /* value not dead */
819 break; /* then found first value. */
823 /* A totally Bad or self-referencing Phi (we didn't break the above loop) */
824 if (i >= n_preds) { return new_Bad(); }
828 /* follow_Id () for rest of inputs, determine if any of these
829 are non-self-referencing */
830 while (++i < n_preds) {
831 scnd_val = get_Phi_pred(n, i);
833 && (scnd_val != first_val)
835 && (get_irn_op(scnd_val) != op_Bad)
842 /* Fold, if no multiple distinct non-self-referencing inputs */
844 n = first_val; DBG_OPT_PHI;
846 /* skip the remaining Ids (done in get_Phi_pred). */
847 /* superfluous, since we walk all to propagate Block's Bads.
848 while (++i < n_preds) get_Phi_pred(n, i); */
853 static ir_node *equivalent_node_Load(ir_node *n)
855 #if 0 /* Is an illegal transformation: different nodes can
856 represent the same pointer value!! */
857 ir_node *a = skip_Proj(get_Load_mem(n));
858 ir_node *b = get_Load_ptr(n);
860 if (get_irn_op(a) == op_Store) {
861 if ( different_identity (b, get_Store_ptr(a))) {
862 /* load and store use different pointers, therefore load
863 needs not take store's memory but the state before. */
864 set_Load_mem (n, get_Store_mem(a));
865 } else if (( 0 /* ???didn't get cryptic test that returns 0 */ )) {
873 * Optimize store after store and load atfter store.
875 * @todo FAILS for volatile entities
877 static ir_node *equivalent_node_Store(ir_node *n)
881 /* remove unnecessary store. */
882 ir_node *a = skip_Proj(get_Store_mem(n));
883 ir_node *b = get_Store_ptr(n);
884 ir_node *c = skip_Proj(get_Store_value(n));
886 if (get_irn_op(a) == op_Store
887 && get_Store_ptr(a) == b
888 && skip_Proj(get_Store_value(a)) == c) {
889 /* We have twice exactly the same store -- a write after write. */
891 } else if (get_irn_op(c) == op_Load
892 && (a == c || skip_Proj(get_Load_mem(c)) == a)
893 && get_Load_ptr(c) == b ) {
894 /* We just loaded the value from the same memory, i.e., the store
895 doesn't change the memory -- a write after read. */
896 a = get_Store_mem(n);
897 turn_into_tuple(n, 2);
898 set_Tuple_pred(n, pn_Store_M, a);
899 set_Tuple_pred(n, pn_Store_X_except, new_Bad()); DBG_OPT_WAR;
904 static ir_node *equivalent_node_Proj(ir_node *n)
908 ir_node *a = get_Proj_pred(n);
910 if ( get_irn_op(a) == op_Tuple) {
911 /* Remove the Tuple/Proj combination. */
912 if ( get_Proj_proj(n) <= get_Tuple_n_preds(a) ) {
913 n = get_Tuple_pred(a, get_Proj_proj(n)); DBG_OPT_TUPLE;
915 assert(0); /* This should not happen! */
918 } else if (get_irn_mode(n) == mode_X &&
919 is_Bad(get_nodes_Block(n))) {
920 /* Remove dead control flow -- early gigo. */
929 static ir_node *equivalent_node_Id(ir_node *n)
933 n = follow_Id(n); DBG_OPT_ID;
938 case iro_Mod, Quot, DivMod
939 DivMod allocates new nodes --> it's treated in transform node.
940 What about Quot, DivMod?
944 * equivalent_node() returns a node equivalent to input n. It skips all nodes that
945 * perform no actual computation, as, e.g., the Id nodes. It does not create
946 * new nodes. It is therefore safe to free n if the node returned is not n.
947 * If a node returns a Tuple we can not just skip it. If the size of the
948 * in array fits, we transform n into a tuple (e.g., Div).
951 equivalent_node(ir_node *n)
953 if (n->op->equivalent_node)
954 return n->op->equivalent_node(n);
959 * set the default equivalent node operation
961 static ir_op *firm_set_default_equivalent_node(ir_op *op)
965 op->equivalent_node = equivalent_node_##a; \
987 CASE(Load); /* dangerous */
988 CASE(Store); /* dangerous, see todo */
992 op->equivalent_node = NULL;
1000 * Do node specific optimizations of nodes predecessors.
1003 optimize_preds(ir_node *n) {
1004 ir_node *a = NULL, *b = NULL;
1006 /* get the operands we will work on for simple cases. */
1008 a = get_binop_left(n);
1009 b = get_binop_right(n);
1010 } else if (is_unop(n)) {
1014 switch (get_irn_opcode(n)) {
1017 /* We don't want Cast as input to Cmp. */
1018 if (get_irn_op(a) == op_Cast) {
1022 if (get_irn_op(b) == op_Cast) {
1024 set_Cmp_right(n, b);
1032 static ir_node *transform_node_Div(ir_node *n)
1034 tarval *tv = computed_value(n);
1036 /* BEWARE: it is NOT possible to optimize a/a to 1, as this may cause a exception */
1038 if (tv != tarval_bad) {
1039 /* Turn Div into a tuple (mem, bad, value) */
1040 ir_node *mem = get_Div_mem(n);
1042 turn_into_tuple(n, 3);
1043 set_Tuple_pred(n, pn_Div_M, mem);
1044 set_Tuple_pred(n, pn_Div_X_except, new_Bad());
1045 set_Tuple_pred(n, pn_Div_res, new_Const(get_tarval_mode(tv), tv));
1050 static ir_node *transform_node_Mod(ir_node *n)
1052 tarval *tv = computed_value(n);
1054 /* BEWARE: it is NOT possible to optimize a%a to 0, as this may cause a exception */
1056 if (tv != tarval_bad) {
1057 /* Turn Mod into a tuple (mem, bad, value) */
1058 ir_node *mem = get_Mod_mem(n);
1059 turn_into_tuple(n, 3);
1060 set_Tuple_pred(n, pn_Mod_M, mem);
1061 set_Tuple_pred(n, pn_Mod_X_except, new_Bad());
1062 set_Tuple_pred(n, pn_Mod_res, new_Const(get_tarval_mode(tv), tv));
1067 static ir_node *transform_node_DivMod(ir_node *n)
1071 ir_node *a = get_DivMod_left(n);
1072 ir_node *b = get_DivMod_right(n);
1073 ir_mode *mode = get_irn_mode(a);
1074 tarval *ta = value_of(a);
1075 tarval *tb = value_of(b);
1077 if (!(mode_is_int(mode) && mode_is_int(get_irn_mode(b))))
1080 /* BEWARE: it is NOT possible to optimize a/a to 1, as this may cause a exception */
1082 if (tb != tarval_bad) {
1083 if (tb == get_mode_one(get_tarval_mode(tb))) {
1084 b = new_Const (mode, get_mode_null(mode));
1086 } else if (ta != tarval_bad) {
1087 tarval *resa, *resb;
1088 resa = tarval_div (ta, tb);
1089 if (resa == tarval_bad) return n; /* Causes exception!!! Model by replacing through
1090 Jmp for X result!? */
1091 resb = tarval_mod (ta, tb);
1092 if (resb == tarval_bad) return n; /* Causes exception! */
1093 a = new_Const (mode, resa);
1094 b = new_Const (mode, resb);
1097 } else if (ta == get_mode_null(mode)) {
1101 if (evaluated) { /* replace by tuple */
1102 ir_node *mem = get_DivMod_mem(n);
1103 turn_into_tuple(n, 4);
1104 set_Tuple_pred(n, pn_DivMod_M, mem);
1105 set_Tuple_pred(n, pn_DivMod_X_except, new_Bad()); /* no exception */
1106 set_Tuple_pred(n, pn_DivMod_res_div, a);
1107 set_Tuple_pred(n, pn_DivMod_res_mod, b);
1108 assert(get_nodes_Block(n));
1114 static ir_node *transform_node_Cond(ir_node *n)
1116 /* Replace the Cond by a Jmp if it branches on a constant
1119 ir_node *a = get_Cond_selector(n);
1120 tarval *ta = value_of(a);
1122 if ((ta != tarval_bad) &&
1123 (get_irn_mode(a) == mode_b) &&
1124 (get_opt_unreachable_code())) {
1125 /* It's a boolean Cond, branching on a boolean constant.
1126 Replace it by a tuple (Bad, Jmp) or (Jmp, Bad) */
1127 jmp = new_r_Jmp(current_ir_graph, get_nodes_Block(n));
1128 turn_into_tuple(n, 2);
1129 if (ta == tarval_b_true) {
1130 set_Tuple_pred(n, pn_Cond_false, new_Bad());
1131 set_Tuple_pred(n, pn_Cond_true, jmp);
1133 set_Tuple_pred(n, pn_Cond_false, jmp);
1134 set_Tuple_pred(n, pn_Cond_true, new_Bad());
1136 /* We might generate an endless loop, so keep it alive. */
1137 add_End_keepalive(get_irg_end(current_ir_graph), get_nodes_Block(n));
1138 } else if ((ta != tarval_bad) &&
1139 (get_irn_mode(a) == mode_Iu) &&
1140 (get_Cond_kind(n) == dense) &&
1141 (get_opt_unreachable_code())) {
1142 /* I don't want to allow Tuples smaller than the biggest Proj.
1143 Also this tuple might get really big...
1144 I generate the Jmp here, and remember it in link. Link is used
1145 when optimizing Proj. */
1146 set_irn_link(n, new_r_Jmp(current_ir_graph, get_nodes_Block(n)));
1147 /* We might generate an endless loop, so keep it alive. */
1148 add_End_keepalive(get_irg_end(current_ir_graph), get_nodes_Block(n));
1149 } else if ((get_irn_op(a) == op_Eor)
1150 && (get_irn_mode(a) == mode_b)
1151 && (tarval_classify(computed_value(get_Eor_right(a))) == TV_CLASSIFY_ONE)) {
1152 /* The Eor is a negate. Generate a new Cond without the negate,
1153 simulate the negate by exchanging the results. */
1154 set_irn_link(n, new_r_Cond(current_ir_graph, get_nodes_Block(n),
1156 } else if ((get_irn_op(a) == op_Not)
1157 && (get_irn_mode(a) == mode_b)) {
1158 /* A Not before the Cond. Generate a new Cond without the Not,
1159 simulate the Not by exchanging the results. */
1160 set_irn_link(n, new_r_Cond(current_ir_graph, get_nodes_Block(n),
1166 static ir_node *transform_node_Eor(ir_node *n)
1168 ir_node *a = get_Eor_left(n);
1169 ir_node *b = get_Eor_right(n);
1171 if ((get_irn_mode(n) == mode_b)
1172 && (get_irn_op(a) == op_Proj)
1173 && (get_irn_mode(a) == mode_b)
1174 && (tarval_classify (computed_value (b)) == TV_CLASSIFY_ONE)
1175 && (get_irn_op(get_Proj_pred(a)) == op_Cmp))
1176 /* The Eor negates a Cmp. The Cmp has the negated result anyways! */
1177 n = new_r_Proj(current_ir_graph, get_nodes_Block(n), get_Proj_pred(a),
1178 mode_b, get_negated_pnc(get_Proj_proj(a)));
1179 else if ((get_irn_mode(n) == mode_b)
1180 && (tarval_classify (computed_value (b)) == TV_CLASSIFY_ONE))
1181 /* The Eor is a Not. Replace it by a Not. */
1182 /* ????!!!Extend to bitfield 1111111. */
1183 n = new_r_Not(current_ir_graph, get_nodes_Block(n), a, mode_b);
1189 * Transfor a boolean Not.
1191 static ir_node *transform_node_Not(ir_node *n)
1193 ir_node *a = get_Not_op(n);
1195 if ( (get_irn_mode(n) == mode_b)
1196 && (get_irn_op(a) == op_Proj)
1197 && (get_irn_mode(a) == mode_b)
1198 && (get_irn_op(get_Proj_pred(a)) == op_Cmp))
1199 /* We negate a Cmp. The Cmp has the negated result anyways! */
1200 n = new_r_Proj(current_ir_graph, get_nodes_Block(n), get_Proj_pred(a),
1201 mode_b, get_negated_pnc(get_Proj_proj(a)));
1207 * Transform a Div/Mod/DivMod with a non-zero constant. Must be
1208 * done here to avoid that this optimization runs more than once...
1210 static ir_node *transform_node_Proj(ir_node *proj)
1212 ir_node *n = get_Proj_pred(proj);
1216 switch (get_irn_opcode(n)) {
1218 b = get_Div_right(n);
1219 tb = computed_value(b);
1221 if (tb != tarval_bad && tarval_classify(tb) != TV_CLASSIFY_NULL) { /* div(x, c) && c != 0 */
1222 ir_node *div, *proj;
1223 ir_node *a = get_Div_left(n);
1224 ir_node *mem = get_Div_mem(n);
1225 int rem = get_optimize();
1229 div = new_rd_Div(get_irn_dbg_info(n), current_ir_graph,
1230 get_nodes_Block(n), get_irg_initial_mem(current_ir_graph), a, b);
1232 proj = new_r_Proj(current_ir_graph, get_nodes_Block(n), div, get_irn_mode(a), pn_Div_res);
1236 turn_into_tuple(n, 3);
1237 set_Tuple_pred(n, pn_Mod_M, mem);
1238 set_Tuple_pred(n, pn_Mod_X_except, new_Bad());
1239 set_Tuple_pred(n, pn_Mod_res, proj);
1243 b = get_Mod_right(n);
1244 tb = computed_value(b);
1246 if (tb != tarval_bad && tarval_classify(tb) != TV_CLASSIFY_NULL) { /* mod(x, c) && c != 0 */
1247 ir_node *mod, *proj;
1248 ir_node *a = get_Mod_left(n);
1249 ir_node *mem = get_Mod_mem(n);
1250 int rem = get_optimize();
1254 mod = new_rd_Mod(get_irn_dbg_info(n), current_ir_graph,
1255 get_nodes_Block(n), get_irg_initial_mem(current_ir_graph), a, b);
1257 proj = new_r_Proj(current_ir_graph, get_nodes_Block(n), mod, get_irn_mode(a), pn_Mod_res);
1261 turn_into_tuple(n, 3);
1262 set_Tuple_pred(n, pn_Mod_M, mem);
1263 set_Tuple_pred(n, pn_Mod_X_except, new_Bad());
1264 set_Tuple_pred(n, pn_Mod_res, proj);
1268 b = get_DivMod_right(n);
1269 tb = computed_value(b);
1271 if (tb != tarval_bad && tarval_classify(tb) != TV_CLASSIFY_NULL) { /* DivMod(x, c) && c != 0 */
1272 ir_node *div_mod, *proj_div, *proj_mod;
1273 ir_node *a = get_Mod_left(n);
1274 ir_node *mem = get_Mod_mem(n);
1275 int rem = get_optimize();
1279 div_mod = new_rd_DivMod(get_irn_dbg_info(n), current_ir_graph,
1280 get_nodes_Block(n), get_irg_initial_mem(current_ir_graph), a, b);
1282 proj_div = new_r_Proj(current_ir_graph, get_nodes_Block(n), div_mod, get_irn_mode(a), pn_DivMod_res_div);
1283 proj_mod = new_r_Proj(current_ir_graph, get_nodes_Block(n), div_mod, get_irn_mode(a), pn_DivMod_res_mod);
1287 turn_into_tuple(n, 4);
1288 set_Tuple_pred(n, pn_DivMod_M, mem);
1289 set_Tuple_pred(n, pn_DivMod_X_except, new_Bad());
1290 set_Tuple_pred(n, pn_DivMod_res_div, proj_div);
1291 set_Tuple_pred(n, pn_DivMod_res_mod, proj_mod);
1299 /* we have added a Tuple, optimize it for the current Proj away */
1300 return equivalent_node_Proj(proj);
1304 * Tries several [inplace] [optimizing] transformations and returns an
1305 * equivalent node. The difference to equivalent_node() is that these
1306 * transformations _do_ generate new nodes, and thus the old node must
1307 * not be freed even if the equivalent node isn't the old one.
1309 static ir_node *transform_node(ir_node *n)
1311 if (n->op->transform_node)
1312 n = n->op->transform_node(n);
1317 * set the default transform node operation
1319 static ir_op *firm_set_default_transform_node(ir_op *op)
1323 op->transform_node = transform_node_##a; \
1335 op->transform_node = NULL;
1343 /* **************** Common Subexpression Elimination **************** */
1345 /** The size of the hash table used, should estimate the number of nodes
1347 #define N_IR_NODES 512
1349 static int node_cmp_attr_Const(ir_node *a, ir_node *b)
1351 return (get_Const_tarval(a) != get_Const_tarval(b))
1352 || (get_Const_type(a) != get_Const_type(b));
1355 static int node_cmp_attr_Proj(ir_node *a, ir_node *b)
1357 return get_irn_proj_attr (a) != get_irn_proj_attr (b);
1360 static int node_cmp_attr_Filter(ir_node *a, ir_node *b)
1362 return get_Filter_proj(a) != get_Filter_proj(b);
1365 static int node_cmp_attr_Alloc(ir_node *a, ir_node *b)
1367 return (get_irn_alloc_attr(a).where != get_irn_alloc_attr(b).where)
1368 || (get_irn_alloc_attr(a).type != get_irn_alloc_attr(b).type);
1371 static int node_cmp_attr_Free(ir_node *a, ir_node *b)
1373 return (get_irn_free_attr(a) != get_irn_free_attr(b));
1376 static int node_cmp_attr_SymConst(ir_node *a, ir_node *b)
1378 return (get_irn_symconst_attr(a).num != get_irn_symconst_attr(b).num)
1379 || (get_irn_symconst_attr(a).sym.type_p != get_irn_symconst_attr(b).sym.type_p);
1382 static int node_cmp_attr_Call(ir_node *a, ir_node *b)
1384 return (get_irn_call_attr(a) != get_irn_call_attr(b));
1387 static int node_cmp_attr_FuncCall(ir_node *a, ir_node *b)
1389 return (get_irn_funccall_attr(a) != get_irn_funccall_attr(b));
1392 static int node_cmp_attr_Sel(ir_node *a, ir_node *b)
1394 return (get_irn_sel_attr(a).ent->kind != get_irn_sel_attr(b).ent->kind)
1395 || (get_irn_sel_attr(a).ent->name != get_irn_sel_attr(b).ent->name)
1396 || (get_irn_sel_attr(a).ent->owner != get_irn_sel_attr(b).ent->owner)
1397 || (get_irn_sel_attr(a).ent->ld_name != get_irn_sel_attr(b).ent->ld_name)
1398 || (get_irn_sel_attr(a).ent->type != get_irn_sel_attr(b).ent->type);
1401 static int node_cmp_attr_Phi(ir_node *a, ir_node *b)
1403 return get_irn_phi_attr (a) != get_irn_phi_attr (b);
1406 static int node_cmp_attr_Cast(ir_node *a, ir_node *b)
1408 return get_Cast_type(a) != get_Cast_type(b);
1412 * set the default node attribute compare operation
1414 static ir_op *firm_set_default_node_cmp_attr(ir_op *op)
1418 op->node_cmp_attr = node_cmp_attr_##a; \
1434 op->node_cmp_attr = NULL;
1442 * Compare function for two nodes in the hash table. Gets two
1443 * nodes as parameters. Returns 0 if the nodes are a cse.
1446 vt_cmp (const void *elt, const void *key)
1454 if (a == b) return 0;
1456 if ((get_irn_op(a) != get_irn_op(b)) ||
1457 (get_irn_mode(a) != get_irn_mode(b))) return 1;
1459 /* compare if a's in and b's in are equal */
1460 irn_arity_a = get_irn_arity (a);
1461 if (irn_arity_a != get_irn_arity(b))
1464 /* for block-local cse and pinned nodes: */
1465 if (!get_opt_global_cse() || (get_op_pinned(get_irn_op(a)) == pinned)) {
1466 if (get_irn_n(a, -1) != get_irn_n(b, -1))
1470 /* compare a->in[0..ins] with b->in[0..ins] */
1471 for (i = 0; i < irn_arity_a; i++)
1472 if (get_irn_n(a, i) != get_irn_n(b, i))
1476 * here, we already now that the nodes are identical except their
1479 if (a->op->node_cmp_attr)
1480 return a->op->node_cmp_attr(a, b);
1486 * Calculate a hash value of a node.
1489 ir_node_hash (ir_node *node)
1494 if (node->op == op_Const) {
1495 /* special value for const, as they only differ in their tarval. */
1496 h = ((unsigned) node->attr.con.tv)>>3 ;
1497 h = 9*h + (unsigned)get_irn_mode(node);
1498 } else if (node->op == op_SymConst) {
1499 /* special value for const, as they only differ in their symbol. */
1500 h = ((unsigned) node->attr.i.sym.type_p)>>3 ;
1501 h = 9*h + (unsigned)get_irn_mode(node);
1504 /* hash table value = 9*(9*(9*(9*(9*arity+in[0])+in[1])+ ...)+mode)+code */
1505 h = irn_arity = get_irn_arity(node);
1507 /* consider all in nodes... except the block. */
1508 for (i = 0; i < irn_arity; i++) {
1509 h = 9*h + (unsigned)get_irn_n(node, i);
1513 h = 9*h + (unsigned) get_irn_mode (node);
1515 h = 9*h + (unsigned) get_irn_op (node);
1522 new_identities (void)
1524 return new_pset (vt_cmp, N_IR_NODES);
1528 del_identities (pset *value_table)
1530 del_pset (value_table);
1534 * Return the canonical node computing the same value as n.
1535 * Looks up the node in a hash table.
1537 * For Const nodes this is performed in the constructor, too. Const
1538 * nodes are extremely time critical because of their frequent use in
1539 * constant string arrays.
1541 static INLINE ir_node *
1542 identify (pset *value_table, ir_node *n)
1546 if (!value_table) return n;
1548 /* TODO: use a generic commutative attribute */
1549 if (get_opt_reassociation()) {
1550 if (is_op_commutative(get_irn_op(n))) {
1551 /* for commutative operators perform a OP b == b OP a */
1552 if (get_binop_left(n) > get_binop_right(n)) {
1553 ir_node *h = get_binop_left(n);
1554 set_binop_left(n, get_binop_right(n));
1555 set_binop_right(n, h);
1560 o = pset_find (value_table, n, ir_node_hash (n));
1567 * During construction we set the pinned flag in the graph right when the
1568 * optimization is performed. The flag turning on procedure global cse could
1569 * be changed between two allocations. This way we are safe.
1571 static INLINE ir_node *
1572 identify_cons (pset *value_table, ir_node *n) {
1574 n = identify(value_table, n);
1575 if (get_irn_n(old, -1) != get_irn_n(n, -1))
1576 set_irg_pinned(current_ir_graph, floats);
1581 * Return the canonical node computing the same value as n.
1582 * Looks up the node in a hash table, enters it in the table
1583 * if it isn't there yet.
1586 identify_remember (pset *value_table, ir_node *node)
1590 if (!value_table) return node;
1592 /* lookup or insert in hash table with given hash key. */
1593 o = pset_insert (value_table, node, ir_node_hash (node));
1595 if (o == node) return node;
1601 add_identities (pset *value_table, ir_node *node) {
1602 identify_remember (value_table, node);
1606 * garbage in, garbage out. If a node has a dead input, i.e., the
1607 * Bad node is input to the node, return the Bad node.
1609 static INLINE ir_node *
1610 gigo (ir_node *node)
1613 ir_op* op = get_irn_op(node);
1615 /* remove garbage blocks by looking at control flow that leaves the block
1616 and replacing the control flow by Bad. */
1617 if (get_irn_mode(node) == mode_X) {
1618 ir_node *block = get_nodes_block(node);
1619 if (op == op_End) return node; /* Don't optimize End, may have Bads. */
1620 if (get_irn_op(block) == op_Block && get_Block_matured(block)) {
1621 irn_arity = get_irn_arity(block);
1622 for (i = 0; i < irn_arity; i++) {
1623 if (!is_Bad(get_irn_n(block, i))) break;
1625 if (i == irn_arity) return new_Bad();
1629 /* Blocks, Phis and Tuples may have dead inputs, e.g., if one of the
1630 blocks predecessors is dead. */
1631 if ( op != op_Block && op != op_Phi && op != op_Tuple) {
1632 irn_arity = get_irn_arity(node);
1633 for (i = -1; i < irn_arity; i++) {
1634 if (is_Bad(get_irn_n(node, i))) {
1640 /* With this code we violate the agreement that local_optimize
1641 only leaves Bads in Block, Phi and Tuple nodes. */
1642 /* If Block has only Bads as predecessors it's garbage. */
1643 /* If Phi has only Bads as predecessors it's garbage. */
1644 if ((op == op_Block && get_Block_matured(node)) || op == op_Phi) {
1645 irn_arity = get_irn_arity(node);
1646 for (i = 0; i < irn_arity; i++) {
1647 if (!is_Bad(get_irn_n(node, i))) break;
1649 if (i == irn_arity) node = new_Bad();
1657 * These optimizations deallocate nodes from the obstack.
1658 * It can only be called if it is guaranteed that no other nodes
1659 * reference this one, i.e., right after construction of a node.
1662 optimize_node (ir_node *n)
1666 opcode iro = get_irn_opcode(n);
1668 /* Allways optimize Phi nodes: part of the construction. */
1669 if ((!get_opt_optimize()) && (iro != iro_Phi)) return n;
1671 /* constant expression evaluation / constant folding */
1672 if (get_opt_constant_folding()) {
1673 /* constants can not be evaluated */
1674 if (iro != iro_Const) {
1675 /* try to evaluate */
1676 tv = computed_value (n);
1677 if ((get_irn_mode(n) != mode_T) && (tv != tarval_bad)) {
1679 * we MUST copy the node here temparary, because it's still needed
1680 * for DBG_OPT_ALGSIM0
1682 int node_size = offsetof(ir_node, attr) + n->op->attr_size;
1683 ir_node *x = alloca(node_size);
1685 memcpy(x, n, node_size);
1688 /* evaluation was successful -- replace the node. */
1689 obstack_free (current_ir_graph->obst, n);
1690 n = new_Const (get_tarval_mode (tv), tv);
1697 /* remove unnecessary nodes */
1698 if (get_opt_constant_folding() ||
1699 (iro == iro_Phi) || /* always optimize these nodes. */
1701 (iro == iro_Proj) ||
1702 (iro == iro_Block) ) /* Flags tested local. */
1703 n = equivalent_node (n);
1705 optimize_preds(n); /* do node specific optimizations of nodes predecessors. */
1707 /** common subexpression elimination **/
1708 /* Checks whether n is already available. */
1709 /* The block input is used to distinguish different subexpressions. Right
1710 now all nodes are pinned to blocks, i.e., the cse only finds common
1711 subexpressions within a block. */
1713 n = identify_cons (current_ir_graph->value_table, n);
1716 /* We found an existing, better node, so we can deallocate the old node. */
1717 obstack_free (current_ir_graph->obst, oldn);
1722 /* Some more constant expression evaluation that does not allow to
1724 iro = get_irn_opcode(n);
1725 if (get_opt_constant_folding() ||
1726 (iro == iro_Cond) ||
1727 (iro == iro_Proj)) /* Flags tested local. */
1728 n = transform_node (n);
1730 /* Remove nodes with dead (Bad) input.
1731 Run always for transformation induced Bads. */
1734 /* Now we have a legal, useful node. Enter it in hash table for cse */
1735 if (get_opt_cse() && (get_irn_opcode(n) != iro_Block)) {
1736 n = identify_remember (current_ir_graph->value_table, n);
1744 * These optimizations never deallocate nodes. This can cause dead
1745 * nodes lying on the obstack. Remove these by a dead node elimination,
1746 * i.e., a copying garbage collection.
1749 optimize_in_place_2 (ir_node *n)
1753 opcode iro = get_irn_opcode(n);
1755 if (!get_opt_optimize() && (get_irn_op(n) != op_Phi)) return n;
1757 /* if not optimize return n */
1760 /* Here this is possible. Why? */
1765 /* constant expression evaluation / constant folding */
1766 if (get_opt_constant_folding()) {
1767 /* constants can not be evaluated */
1768 if (iro != iro_Const) {
1769 /* try to evaluate */
1770 tv = computed_value (n);
1771 if ((get_irn_mode(n) != mode_T) && (tv != tarval_bad)) {
1772 /* evaluation was successful -- replace the node. */
1773 n = new_Const (get_tarval_mode (tv), tv);
1780 /* remove unnecessary nodes */
1781 /*if (get_opt_constant_folding()) */
1782 if (get_opt_constant_folding() ||
1783 (iro == iro_Phi) || /* always optimize these nodes. */
1784 (iro == iro_Id) || /* ... */
1785 (iro == iro_Proj) || /* ... */
1786 (iro == iro_Block) ) /* Flags tested local. */
1787 n = equivalent_node (n);
1789 optimize_preds(n); /* do node specific optimizations of nodes predecessors. */
1791 /** common subexpression elimination **/
1792 /* Checks whether n is already available. */
1793 /* The block input is used to distinguish different subexpressions. Right
1794 now all nodes are pinned to blocks, i.e., the cse only finds common
1795 subexpressions within a block. */
1796 if (get_opt_cse()) {
1797 n = identify (current_ir_graph->value_table, n);
1800 /* Some more constant expression evaluation. */
1801 iro = get_irn_opcode(n);
1802 if (get_opt_constant_folding() ||
1803 (iro == iro_Cond) ||
1804 (iro == iro_Proj)) /* Flags tested local. */
1805 n = transform_node (n);
1807 /* Remove nodes with dead (Bad) input.
1808 Run always for transformation induced Bads. */
1811 /* Now we can verify the node, as it has no dead inputs any more. */
1814 /* Now we have a legal, useful node. Enter it in hash table for cse.
1815 Blocks should be unique anyways. (Except the successor of start:
1816 is cse with the start block!) */
1817 if (get_opt_cse() && (get_irn_opcode(n) != iro_Block))
1818 n = identify_remember (current_ir_graph->value_table, n);
1824 * Wrapper for external use, set proper status bits after optimization.
1827 optimize_in_place (ir_node *n)
1829 /* Handle graph state */
1830 assert(get_irg_phase_state(current_ir_graph) != phase_building);
1832 if (get_opt_global_cse())
1833 set_irg_pinned(current_ir_graph, floats);
1834 if (get_irg_outs_state(current_ir_graph) == outs_consistent)
1835 set_irg_outs_inconsistent(current_ir_graph);
1836 /* Maybe we could also test whether optimizing the node can
1837 change the control graph. */
1838 if (get_irg_dom_state(current_ir_graph) == dom_consistent)
1839 set_irg_dom_inconsistent(current_ir_graph);
1840 return optimize_in_place_2 (n);
1844 * set the default ir op operations
1846 ir_op *firm_set_default_operations(ir_op *op)
1848 op = firm_set_default_computed_value(op);
1849 op = firm_set_default_equivalent_node(op);
1850 op = firm_set_default_transform_node(op);
1851 op = firm_set_default_node_cmp_attr(op);