2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * File name: ir/opt/opt_osr.c
23 * Purpose: Operator Strength Reduction, based on
24 * Keith D. Cooper, L. Taylor Simpson, Christopher A. Vick
25 * Author: Michael Beck
29 * Copyright: (c) 2006 Universität Karlsruhe
56 /** The debug handle. */
57 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
61 ir_node *head; /**< the head of the list */
65 typedef struct node_entry {
66 unsigned DFSnum; /**< the DFS number of this node */
67 unsigned low; /**< the low number of this node */
68 ir_node *header; /**< the header of this node */
69 int in_stack; /**< flag, set if the node is on the stack */
70 ir_node *next; /**< link to the next node the the same scc */
71 scc *pscc; /**< the scc of this node */
72 unsigned POnum; /**< the post order number for blocks */
75 /** The environment. */
76 typedef struct iv_env {
77 struct obstack obst; /**< an obstack for allocations */
78 ir_node **stack; /**< the node stack */
79 int tos; /**< tos index */
80 unsigned nextDFSnum; /**< the current DFS number */
81 unsigned POnum; /**< current post order number */
82 set *quad_map; /**< a map from (op, iv, rc) to node */
83 set *lftr_edges; /**< the set of lftr edges */
84 unsigned replaced; /**< number of replaced ops */
85 unsigned lftr_replaced; /**< number of applied linear function test replacements */
86 unsigned flags; /**< additional flags */
87 /** Function called to process a SCC. */
88 void (*process_scc)(scc *pscc, struct iv_env *env);
92 * An entry in the (op, node, node) -> node map.
94 typedef struct quadruple_t {
95 ir_opcode code; /**< the opcode of the reduced operation */
96 ir_node *op1; /**< the first operand the reduced operation */
97 ir_node *op2; /**< the second operand of the reduced operation */
99 ir_node *res; /**< the reduced operation */
105 typedef struct LFTR_edge {
106 ir_node *src; /**< the source node */
107 ir_node *dst; /**< the destination node */
108 ir_opcode code; /**< the opcode that must be applied */
109 ir_node *rc; /**< the region const that must be applied */
113 static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env);
116 * Compare two LFTR edges.
118 static int LFTR_cmp(const void *e1, const void *e2, size_t size) {
119 const LFTR_edge *l1 = e1;
120 const LFTR_edge *l2 = e2;
122 return l1->src != l2->src;
129 static LFTR_edge *LFTR_find(ir_node *src, iv_env *env) {
134 return set_find(env->lftr_edges, &key, sizeof(key), HASH_PTR(src));
141 static void LFTR_add(ir_node *src, ir_node *dst, ir_opcode code, ir_node *rc, iv_env *env) {
150 * There might be more than one edge here. This is rather bad
151 * because we currently store only one.
153 // assert(LFTR_find(src, env) == NULL);
154 set_insert(env->lftr_edges, &key, sizeof(key), HASH_PTR(src));
158 * Gets the node_entry of a node
160 static node_entry *get_irn_ne(ir_node *irn, iv_env *env) {
161 node_entry *e = get_irn_link(irn);
164 e = obstack_alloc(&env->obst, sizeof(*e));
165 memset(e, 0, sizeof(*e));
166 set_irn_link(irn, e);
172 * Check if irn is an IV.
174 * @param irn the node to check
175 * @param env the environment
177 * @returns the header if it is one, NULL else
179 static ir_node *is_iv(ir_node *irn, iv_env *env) {
180 return get_irn_ne(irn, env)->header;
184 * Check if irn is a region constant.
185 * The block or irn must strictly dominate the header block.
187 * @param irn the node to check
188 * @param header_block the header block of the induction variable
190 static int is_rc(ir_node *irn, ir_node *header_block) {
191 ir_node *block = get_nodes_block(irn);
193 return (block != header_block) && block_dominates(block, header_block);
197 * Set compare function for the quad set.
199 static int quad_cmp(const void *e1, const void *e2, size_t size) {
200 const quadruple_t *c1 = e1;
201 const quadruple_t *c2 = e2;
203 return c1->code != c2->code || c1->op1 != c2->op1 || c1->op2 != c2->op2;
207 * Check if an reduced operation was already calculated.
209 * @param code the opcode of the operation
210 * @param op1 the first operand of the operation
211 * @param op2 the second operand of the operation
212 * @param env the environment
214 * @return the already reduced node or NULL if this operation is not yet reduced
216 static ir_node *search(ir_opcode code, ir_node *op1, ir_node *op2, iv_env *env) {
217 quadruple_t key, *entry;
223 entry = set_find(env->quad_map, &key, sizeof(key),
224 (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
231 * Add an reduced operation.
233 * @param code the opcode of the operation
234 * @param op1 the first operand of the operation
235 * @param op2 the second operand of the operation
236 * @param result the result of the reduced operation
237 * @param env the environment
239 static void add(ir_opcode code, ir_node *op1, ir_node *op2, ir_node *result, iv_env *env) {
247 set_insert(env->quad_map, &key, sizeof(key),
248 (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
252 * Find a location where to place a bin-op whose operands are in
255 * @param block1 the block of the first operand
256 * @param block2 the block of the second operand
258 * Note that we know here that such a place must exists. Moreover, this means
259 * that either block1 dominates block2 or vice versa. So, just return
262 static ir_node *find_location(ir_node *block1, ir_node *block2) {
263 if (block_dominates(block1, block2))
265 assert(block_dominates(block2, block1));
270 * Create a node that executes an op1 code op1 operation.
272 * @param code the opcode to execute
273 * @param db debug info to add to the new node
274 * @param op1 the first operand
275 * @param op2 the second operand
276 * @param mode the mode of the new operation
278 * @return the newly created node
280 static ir_node *do_apply(ir_opcode code, dbg_info *db, ir_node *op1, ir_node *op2, ir_mode *mode) {
281 ir_graph *irg = current_ir_graph;
283 ir_node *block = find_location(get_nodes_block(op1), get_nodes_block(op2));
287 result = new_rd_Mul(db, irg, block, op1, op2, mode);
290 result = new_rd_Add(db, irg, block, op1, op2, mode);
293 result = new_rd_Sub(db, irg, block, op1, op2, mode);
303 * The Apply operation.
305 * @param orig the node that represent the original operation and determines
306 * the opcode, debug-info and mode of a newly created one
307 * @param op1 the first operand
308 * @param op2 the second operand
309 * @param env the environment
311 * @return the newly created node
313 static ir_node *apply(ir_node *orig, ir_node *op1, ir_node *op2, iv_env *env) {
314 ir_opcode code = get_irn_opcode(orig);
315 ir_node *result = search(code, op1, op2, env);
318 dbg_info *db = get_irn_dbg_info(orig);
319 ir_node *op1_header = get_irn_ne(op1, env)->header;
320 ir_node *op2_header = get_irn_ne(op2, env)->header;
322 if (op1_header != NULL && is_rc(op2, op1_header)) {
323 result = reduce(orig, op1, op2, env);
325 else if (op2_header != NULL && is_rc(op1, op2_header)) {
326 result = reduce(orig, op2, op1, env);
329 result = do_apply(code, db, op1, op2, get_irn_mode(orig));
330 get_irn_ne(result, env)->header = NULL; }
336 * The Reduce operation.
338 * @param orig the node that represent the original operation and determines
339 * the opcode, debug-info and mode of a newly created one
340 * @param iv the induction variable
341 * @param rc the region constant
342 * @param env the environment
344 * @return the reduced node
346 static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
347 ir_opcode code = get_irn_opcode(orig);
348 ir_node *result = search(code, iv, rc, env);
351 node_entry *e, *iv_e;
353 ir_mode *mode = get_irn_mode(orig);
355 result = exact_copy(iv);
357 /* Beware: we must always create a new nduction variable with the same mode
358 as the node we are replacing. Espicially this means the mode might be changed
359 from P to I and back. This is always possible, because we have only Phi, Add
361 set_irn_mode(result, mode);
362 add(code, iv, rc, result, env);
363 DB((dbg, LEVEL_3, " Created new %+F for %+F (%s %+F)\n", result, iv,
364 get_irn_opname(orig), rc));
366 iv_e = get_irn_ne(iv, env);
367 e = get_irn_ne(result, env);
368 e->header = iv_e->header;
370 /* create the LFTR edge */
371 LFTR_add(iv, result, code, rc, env);
373 n = get_irn_arity(result);
374 for (i = 0; i < n; ++i) {
375 ir_node *o = get_irn_n(result, i);
377 e = get_irn_ne(o, env);
378 if (e->header == iv_e->header)
379 o = reduce(orig, o, rc, env);
380 else if (is_Phi(result))
381 o = apply(orig, o, rc, env);
384 o = apply(orig, o, rc, env);
386 set_irn_n(result, i, o);
390 DB((dbg, LEVEL_3, " Already Created %+F for %+F (%s %+F)\n", result, iv,
391 get_irn_opname(orig), rc));
397 * The Replace operation.
399 * @param irn the node that will be replaced
400 * @param iv the induction variable
401 * @param rc the region constant
402 * @param env the environment
404 static int replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env) {
406 ir_loop *iv_loop = get_irn_loop(get_nodes_block(iv));
407 ir_loop *irn_loop = get_irn_loop(get_nodes_block(irn));
409 /* only replace nodes that are in the same (or deeper loops) */
410 if (get_loop_depth(irn_loop) >= get_loop_depth(iv_loop)) {
411 DB((dbg, LEVEL_2, " Replacing %+F\n", irn));
413 result = reduce(irn, iv, rc, env);
415 node_entry *e, *iv_e;
417 hook_strength_red(current_ir_graph, irn);
418 exchange(irn, result);
419 e = get_irn_ne(result, env);
420 iv_e = get_irn_ne(iv, env);
421 e->header = iv_e->header;
429 * Check if a node can be replaced (+, -, *).
431 * @param irn the node to check
432 * @param env the environment
434 * @return non-zero if irn should be Replace'd
436 static int check_replace(ir_node *irn, iv_env *env) {
437 ir_node *left, *right, *iv, *rc;
438 ir_op *op = get_irn_op(irn);
439 ir_opcode code = get_op_code(op);
448 left = get_binop_left(irn);
449 right = get_binop_right(irn);
451 liv = is_iv(left, env);
452 riv = is_iv(right, env);
453 if (liv && is_rc(right, liv)) {
454 iv = left; rc = right;
456 else if (riv && is_op_commutative(op) &&
458 iv = right; rc = left;
462 if (code == iro_Mul && env->flags & osr_flag_ignore_x86_shift) {
464 tarval *tv = get_Const_tarval(rc);
466 if (tarval_is_long(tv)) {
467 long value = get_tarval_long(tv);
469 if (value == 2 || value == 4 || value == 8) {
470 /* do not reduce multiplications by 2, 4, 8 */
477 return replace(irn, iv, rc, env);
487 * Check which SCC's are induction variables.
490 * @param env the environment
492 static void classify_iv(scc *pscc, iv_env *env) {
493 ir_node *irn, *next, *header = NULL;
494 node_entry *b, *h = NULL;
495 int j, only_phi, num_outside;
498 /* find the header block for this scc */
499 for (irn = pscc->head; irn; irn = next) {
500 node_entry *e = get_irn_link(irn);
501 ir_node *block = get_nodes_block(irn);
504 b = get_irn_ne(block, env);
507 if (h->POnum < b->POnum) {
518 /* check if this scc contains only Phi, Add or Sub nodes */
522 for (irn = pscc->head; irn; irn = next) {
523 node_entry *e = get_irn_ne(irn, env);
526 switch (get_irn_opcode(irn)) {
532 for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
533 ir_node *pred = get_irn_n(irn, j);
534 node_entry *pe = get_irn_ne(pred, env);
536 if (pe->pscc != e->pscc) {
537 /* not in the same SCC, must be a region const */
538 if (! is_rc(pred, header)) {
539 /* not an induction variable */
545 } else if (out_rc != pred) {
552 /* not an induction variable */
556 /* found an induction variable */
557 DB((dbg, LEVEL_2, " Found an induction variable:\n "));
558 if (only_phi && num_outside == 1) {
559 /* a phi cycle with only one real predecessor can be collapsed */
560 DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
562 for (irn = pscc->head; irn; irn = next) {
563 node_entry *e = get_irn_ne(irn, env);
566 exchange(irn, out_rc);
572 /* set the header for every node in this scc */
573 for (irn = pscc->head; irn; irn = next) {
574 node_entry *e = get_irn_ne(irn, env);
577 DB((dbg, LEVEL_2, " %+F,", irn));
579 DB((dbg, LEVEL_2, "\n"));
583 for (irn = pscc->head; irn; irn = next) {
584 node_entry *e = get_irn_ne(irn, env);
587 if (! check_replace(irn, env))
593 * Process a SCC for the operator strength reduction.
595 * @param pscc the SCC
596 * @param env the environment
598 static void process_scc(scc *pscc, iv_env *env) {
599 ir_node *head = pscc->head;
600 node_entry *e = get_irn_link(head);
606 DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
607 for (irn = pscc->head; irn; irn = next) {
608 node_entry *e = get_irn_link(irn);
612 DB((dbg, LEVEL_4, " %+F,", irn));
614 DB((dbg, LEVEL_4, "\n"));
618 if (e->next == NULL) {
619 /* this SCC has only a single member */
620 check_replace(head, env);
622 classify_iv(pscc, env);
627 * If an SCC is a Phi only cycle, remove it.
629 static void remove_phi_cycle(scc *pscc, iv_env *env) {
634 /* check if this scc contains only Phi, Add or Sub nodes */
636 for (irn = pscc->head; irn; irn = next) {
637 node_entry *e = get_irn_ne(irn, env);
643 for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
644 ir_node *pred = get_irn_n(irn, j);
645 node_entry *pe = get_irn_ne(pred, env);
647 if (pe->pscc != e->pscc) {
648 /* not in the same SCC, must be the only input */
651 } else if (out_rc != pred) {
657 /* found a Phi cycle */
658 DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
660 for (irn = pscc->head; irn; irn = next) {
661 node_entry *e = get_irn_ne(irn, env);
664 exchange(irn, out_rc);
670 * Process a SCC for the Phi cycle removement.
672 * @param pscc the SCC
673 * @param env the environment
675 static void process_phi_only_scc(scc *pscc, iv_env *env) {
676 ir_node *head = pscc->head;
677 node_entry *e = get_irn_link(head);
683 DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
684 for (irn = pscc->head; irn; irn = next) {
685 node_entry *e = get_irn_link(irn);
689 DB((dbg, LEVEL_4, " %+F,", irn));
691 DB((dbg, LEVEL_4, "\n"));
696 remove_phi_cycle(pscc, env);
701 * Push a node onto the stack.
703 * @param env the environment
704 * @param n the node to push
706 static void push(iv_env *env, ir_node *n) {
709 if (env->tos == ARR_LEN(env->stack)) {
710 int nlen = ARR_LEN(env->stack) * 2;
711 ARR_RESIZE(ir_node *, env->stack, nlen);
713 env->stack[env->tos++] = n;
714 e = get_irn_ne(n, env);
719 * pop a node from the stack
721 * @param env the environment
723 * @return The topmost node
725 static ir_node *pop(iv_env *env)
727 ir_node *n = env->stack[--env->tos];
728 node_entry *e = get_irn_ne(n, env);
735 * Do Tarjan's SCC algorithm and drive OSR.
737 * @param irn start at this node
738 * @param env the environment
740 static void dfs(ir_node *irn, iv_env *env)
743 node_entry *node = get_irn_ne(irn, env);
745 mark_irn_visited(irn);
747 /* do not put blocks into the scc */
749 n = get_irn_arity(irn);
750 for (i = 0; i < n; ++i) {
751 ir_node *pred = get_irn_n(irn, i);
753 if (irn_not_visited(pred))
758 ir_node *block = get_nodes_block(irn);
760 node->DFSnum = env->nextDFSnum++;
761 node->low = node->DFSnum;
764 /* handle the block */
765 if (irn_not_visited(block))
768 n = get_irn_arity(irn);
769 for (i = 0; i < n; ++i) {
770 ir_node *pred = get_irn_n(irn, i);
771 node_entry *o = get_irn_ne(pred, env);
773 if (irn_not_visited(pred)) {
775 node->low = MIN(node->low, o->low);
777 if (o->DFSnum < node->DFSnum && o->in_stack)
778 node->low = MIN(o->DFSnum, node->low);
780 if (node->low == node->DFSnum) {
781 scc *pscc = obstack_alloc(&env->obst, sizeof(*pscc));
789 e = get_irn_ne(x, env);
791 e->next = pscc->head;
795 env->process_scc(pscc, env);
801 * Do the DFS by starting at the End node of a graph.
803 * @param irg the graph to process
804 * @param env the environment
806 static void do_dfs(ir_graph *irg, iv_env *env) {
807 ir_graph *rem = current_ir_graph;
808 ir_node *end = get_irg_end(irg);
811 current_ir_graph = irg;
812 inc_irg_visited(irg);
814 /* visit all visible nodes */
817 /* visit the keep-alives */
818 n = get_End_n_keepalives(end);
819 for (i = 0; i < n; ++i) {
820 ir_node *ka = get_End_keepalive(end, i);
822 if (irn_not_visited(ka))
826 current_ir_graph = rem;
830 * Post-block-walker: assign the post-order number.
832 static void assign_po(ir_node *block, void *ctx) {
834 node_entry *e = get_irn_ne(block, env);
836 e->POnum = env->POnum++;
841 * Follows the LFTR edges and return the last node in the chain.
843 * @param irn the node that should be followed
844 * @param env the IV environment
847 * In the current implementation only the last edge is stored, so
848 * only one chain exists. That's why we might miss some opportunities.
850 static ir_node *followEdges(ir_node *irn, iv_env *env) {
852 LFTR_edge *e = LFTR_find(irn, env);
861 * Apply one LFTR edge operation.
862 * Return NULL if the transformation cannot be done safely without
865 * @param rc the IV node that should be translated
866 * @param e the LFTR edge
867 * @param env the IV environment
869 * @return the translated region constant or NULL
870 * if the translation was not possible
873 * In the current implementation only the last edge is stored, so
874 * only one chain exists. That's why we might miss some opportunities.
876 static ir_node *applyOneEdge(ir_node *rc, LFTR_edge *e, iv_env *env) {
877 if (env->flags & osr_flag_lftr_with_ov_check) {
878 tarval *tv_l, *tv_r, *tv;
879 tarval_int_overflow_mode_t ovmode;
881 /* overflow can only be decided for Consts */
882 if (! is_Const(e->rc)) {
883 DB((dbg, LEVEL_4, " = UNKNOWN (%+F)", e->rc));
887 tv_l = get_Const_tarval(rc);
888 tv_r = get_Const_tarval(e->rc);
890 ovmode = tarval_get_integer_overflow_mode();
891 tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
895 tv = tarval_mul(tv_l, tv_r);
896 DB((dbg, LEVEL_4, " * %+F", tv_r));
899 tv = tarval_add(tv_l, tv_r);
900 DB((dbg, LEVEL_4, " + %+F", tv_r));
903 tv = tarval_sub(tv_l, tv_r);
904 DB((dbg, LEVEL_4, " - %+F", tv_r));
910 tarval_set_integer_overflow_mode(ovmode);
912 if (tv == tarval_bad) {
913 DB((dbg, LEVEL_4, " = OVERFLOW"));
916 return new_r_Const(current_ir_graph, get_irn_n(rc, -1), get_tarval_mode(tv), tv);
918 return do_apply(e->code, NULL, rc, e->rc, get_irn_mode(rc));
922 * Applies the operations represented by the LFTR edges to a
923 * region constant and returns the value.
924 * Return NULL if the transformation cannot be done safely without
927 * @param iv the IV node that starts the LFTR edge chain
928 * @param rc the region constant that should be translated
929 * @param env the IV environment
931 * @return the translated region constant or NULL
932 * if the translation was not possible
934 static ir_node *applyEdges(ir_node *iv, ir_node *rc, iv_env *env) {
937 if (env->flags & osr_flag_lftr_with_ov_check) {
938 /* overflow can only be decided for Consts */
939 if (! is_Const(rc)) {
940 DB((dbg, LEVEL_4, " = UNKNOWN (%+F)\n", rc));
943 DB((dbg, LEVEL_4, "%+F", get_Const_tarval(rc)));
946 for (irn = iv; rc;) {
947 LFTR_edge *e = LFTR_find(irn, env);
949 rc = applyOneEdge(rc, e, env);
955 DB((dbg, LEVEL_3, "\n"));
960 * Walker, finds Cmp(iv, rc) or Cmp(rc, iv)
961 * and tries to optimize them.
963 static void do_lftr(ir_node *cmp, void *ctx) {
965 ir_node *left, *right, *liv, *riv;
967 ir_node *nleft = NULL, *nright = NULL;
969 if (get_irn_op(cmp) != op_Cmp)
972 left = get_Cmp_left(cmp);
973 right = get_Cmp_right(cmp);
975 liv = is_iv(left, env);
976 riv = is_iv(right, env);
977 if (liv && is_rc(right, liv)) {
978 iv = left; rc = right;
980 nright = applyEdges(iv, rc, env);
981 if (nright && nright != rc) {
982 nleft = followEdges(iv, env);
985 else if (riv && is_rc(left, riv)) {
986 iv = right; rc = left;
988 nleft = applyEdges(iv, rc, env);
989 if (nleft && nleft != rc) {
990 nright = followEdges(iv, env);
994 if (nleft && nright) {
995 DB((dbg, LEVEL_2, " LFTR for %+F\n", cmp));
996 set_Cmp_left(cmp, nleft);
997 set_Cmp_right(cmp, nright);
998 ++env->lftr_replaced;
1003 * do linear function test replacement.
1005 * @param irg the graph that should be optimized
1006 * @param env the IV environment
1008 static void lftr(ir_graph *irg, iv_env *env) {
1009 irg_walk_graph(irg, NULL, do_lftr, env);
1014 * Pre-walker: set all node links to NULL and fix the
1015 * block of Proj nodes.
1017 static void clear_and_fix(ir_node *irn, void *env)
1019 set_irn_link(irn, NULL);
1022 ir_node *pred = get_Proj_pred(irn);
1023 set_irn_n(irn, -1, get_irn_n(pred, -1));
1027 /* Performs Operator Strength Reduction for the passed graph. */
1028 void opt_osr(ir_graph *irg, unsigned flags) {
1032 if (! get_opt_strength_red()) {
1033 /* only kill Phi cycles */
1034 remove_phi_cycles(irg);
1038 rem = current_ir_graph;
1039 current_ir_graph = irg;
1041 FIRM_DBG_REGISTER(dbg, "firm.opt.osr");
1043 DB((dbg, LEVEL_1, "Doing Operator Strength Reduction for %+F\n", irg));
1045 obstack_init(&env.obst);
1046 env.stack = NEW_ARR_F(ir_node *, 128);
1050 env.quad_map = new_set(quad_cmp, 64);
1051 env.lftr_edges = new_set(LFTR_cmp, 64);
1053 env.lftr_replaced = 0;
1055 env.process_scc = process_scc;
1057 /* Clear all links and move Proj nodes into the
1058 the same block as it's predecessors.
1059 This can improve the placement of new nodes.
1061 irg_walk_graph(irg, NULL, clear_and_fix, NULL);
1063 /* we need dominance */
1065 assure_irg_outs(irg);
1067 /* calculate the post order number for blocks. */
1068 irg_out_block_walk(get_irg_start_block(irg), NULL, assign_po, &env);
1070 /* calculate the SCC's and drive OSR. */
1074 /* try linear function test replacements */
1077 set_irg_outs_inconsistent(irg);
1078 DB((dbg, LEVEL_1, "Replacements: %u + %u (lftr)\n\n", env.replaced, env.lftr_replaced));
1081 del_set(env.lftr_edges);
1082 del_set(env.quad_map);
1083 DEL_ARR_F(env.stack);
1084 obstack_free(&env.obst, NULL);
1086 current_ir_graph = rem;
1089 /* Remove any Phi cycles with only one real input. */
1090 void remove_phi_cycles(ir_graph *irg) {
1094 rem = current_ir_graph;
1095 current_ir_graph = irg;
1097 FIRM_DBG_REGISTER(dbg, "firm.opt.remove_phi");
1099 DB((dbg, LEVEL_1, "Doing Phi cycle removement for %+F\n", irg));
1101 obstack_init(&env.obst);
1102 env.stack = NEW_ARR_F(ir_node *, 128);
1106 env.quad_map = NULL;
1107 env.lftr_edges = NULL;
1109 env.lftr_replaced = 0;
1111 env.process_scc = process_phi_only_scc;
1113 /* Clear all links and move Proj nodes into the
1114 the same block as it's predecessors.
1115 This can improve the placement of new nodes.
1117 irg_walk_graph(irg, NULL, clear_and_fix, NULL);
1119 /* we need dominance */
1120 assure_irg_outs(irg);
1122 /* calculate the post order number for blocks. */
1123 irg_out_block_walk(get_irg_start_block(irg), NULL, assign_po, &env);
1125 /* calculate the SCC's and drive OSR. */
1129 set_irg_outs_inconsistent(irg);
1130 DB((dbg, LEVEL_1, "remove_phi_cycles: %u Cycles removed\n\n", env.replaced));
1133 DEL_ARR_F(env.stack);
1134 obstack_free(&env.obst, NULL);
1136 current_ir_graph = rem;