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 * @brief Operator Strength Reduction.
24 * @author Michael Beck
27 * Implementation of the Operator Strength Reduction algorithm
28 * by Keith D. Cooper, L. Taylor Simpson, Christopher A. Vick.
34 #include "iroptimize.h"
55 /** The debug handle. */
56 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
60 ir_node *head; /**< the head of the list */
64 typedef struct node_entry {
65 unsigned DFSnum; /**< the DFS number of this node */
66 unsigned low; /**< the low number of this node */
67 ir_node *header; /**< the header of this node */
68 int in_stack; /**< flag, set if the node is on the stack */
69 ir_node *next; /**< link to the next node the the same scc */
70 scc *pscc; /**< the scc of this node */
71 unsigned POnum; /**< the post order number for blocks */
74 /** The environment. */
75 typedef struct iv_env {
76 struct obstack obst; /**< an obstack for allocations */
77 ir_node **stack; /**< the node stack */
78 int tos; /**< tos index */
79 unsigned nextDFSnum; /**< the current DFS number */
80 unsigned POnum; /**< current post order number */
81 set *quad_map; /**< a map from (op, iv, rc) to node */
82 set *lftr_edges; /**< the set of lftr edges */
83 unsigned replaced; /**< number of replaced ops */
84 unsigned lftr_replaced; /**< number of applied linear function test replacements */
85 unsigned flags; /**< additional flags */
86 /** Function called to process a SCC. */
87 void (*process_scc)(scc *pscc, struct iv_env *env);
91 * An entry in the (op, node, node) -> node map.
93 typedef struct quadruple_t {
94 ir_opcode code; /**< the opcode of the reduced operation */
95 ir_node *op1; /**< the first operand the reduced operation */
96 ir_node *op2; /**< the second operand of the reduced operation */
98 ir_node *res; /**< the reduced operation */
104 typedef struct LFTR_edge {
105 ir_node *src; /**< the source node */
106 ir_node *dst; /**< the destination node */
107 ir_opcode code; /**< the opcode that must be applied */
108 ir_node *rc; /**< the region const that must be applied */
112 static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env);
115 * Compare two LFTR edges.
117 static int LFTR_cmp(const void *e1, const void *e2, size_t size) {
118 const LFTR_edge *l1 = e1;
119 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;
204 return c1->code != c2->code || c1->op1 != c2->op1 || c1->op2 != c2->op2;
208 * Check if an reduced operation was already calculated.
210 * @param code the opcode of the operation
211 * @param op1 the first operand of the operation
212 * @param op2 the second operand of the operation
213 * @param env the environment
215 * @return the already reduced node or NULL if this operation is not yet reduced
217 static ir_node *search(ir_opcode code, ir_node *op1, ir_node *op2, iv_env *env) {
218 quadruple_t key, *entry;
224 entry = set_find(env->quad_map, &key, sizeof(key),
225 (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
232 * Add an reduced operation.
234 * @param code the opcode of the operation
235 * @param op1 the first operand of the operation
236 * @param op2 the second operand of the operation
237 * @param result the result of the reduced operation
238 * @param env the environment
240 static void add(ir_opcode code, ir_node *op1, ir_node *op2, ir_node *result, iv_env *env) {
248 set_insert(env->quad_map, &key, sizeof(key),
249 (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
253 * Find a location where to place a bin-op whose operands are in
256 * @param block1 the block of the first operand
257 * @param block2 the block of the second operand
259 * Note that we know here that such a place must exists. Moreover, this means
260 * that either block1 dominates block2 or vice versa. So, just return
263 static ir_node *find_location(ir_node *block1, ir_node *block2) {
264 if (block_dominates(block1, block2))
266 assert(block_dominates(block2, block1));
271 * Create a node that executes an op1 code op1 operation.
273 * @param code the opcode to execute
274 * @param db debug info to add to the new node
275 * @param op1 the first operand
276 * @param op2 the second operand
277 * @param mode the mode of the new operation
279 * @return the newly created node
281 static ir_node *do_apply(ir_opcode code, dbg_info *db, ir_node *op1, ir_node *op2, ir_mode *mode) {
282 ir_graph *irg = current_ir_graph;
284 ir_node *block = find_location(get_nodes_block(op1), get_nodes_block(op2));
288 result = new_rd_Mul(db, irg, block, op1, op2, mode);
291 result = new_rd_Add(db, irg, block, op1, op2, mode);
294 result = new_rd_Sub(db, irg, block, op1, op2, mode);
304 * The Apply operation.
306 * @param orig the node that represent the original operation and determines
307 * the opcode, debug-info and mode of a newly created one
308 * @param op1 the first operand
309 * @param op2 the second operand
310 * @param env the environment
312 * @return the newly created node
314 static ir_node *apply(ir_node *orig, ir_node *op1, ir_node *op2, iv_env *env) {
315 ir_opcode code = get_irn_opcode(orig);
316 ir_node *result = search(code, op1, op2, env);
319 dbg_info *db = get_irn_dbg_info(orig);
320 ir_node *op1_header = get_irn_ne(op1, env)->header;
321 ir_node *op2_header = get_irn_ne(op2, env)->header;
323 if (op1_header != NULL && is_rc(op2, op1_header)) {
324 result = reduce(orig, op1, op2, env);
326 else if (op2_header != NULL && is_rc(op1, op2_header)) {
327 result = reduce(orig, op2, op1, env);
330 result = do_apply(code, db, op1, op2, get_irn_mode(orig));
331 get_irn_ne(result, env)->header = NULL; }
337 * The Reduce operation.
339 * @param orig the node that represent the original operation and determines
340 * the opcode, debug-info and mode of a newly created one
341 * @param iv the induction variable
342 * @param rc the region constant
343 * @param env the environment
345 * @return the reduced node
347 static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
348 ir_opcode code = get_irn_opcode(orig);
349 ir_node *result = search(code, iv, rc, env);
352 node_entry *e, *iv_e;
354 ir_mode *mode = get_irn_mode(orig);
356 result = exact_copy(iv);
358 /* Beware: we must always create a new nduction variable with the same mode
359 as the node we are replacing. Espicially this means the mode might be changed
360 from P to I and back. This is always possible, because we have only Phi, Add
362 set_irn_mode(result, mode);
363 add(code, iv, rc, result, env);
364 DB((dbg, LEVEL_3, " Created new %+F for %+F (%s %+F)\n", result, iv,
365 get_irn_opname(orig), rc));
367 iv_e = get_irn_ne(iv, env);
368 e = get_irn_ne(result, env);
369 e->header = iv_e->header;
371 /* create the LFTR edge */
372 LFTR_add(iv, result, code, rc, env);
374 n = get_irn_arity(result);
375 for (i = 0; i < n; ++i) {
376 ir_node *o = get_irn_n(result, i);
378 e = get_irn_ne(o, env);
379 if (e->header == iv_e->header)
380 o = reduce(orig, o, rc, env);
381 else if (is_Phi(result))
382 o = apply(orig, o, rc, env);
385 o = apply(orig, o, rc, env);
387 set_irn_n(result, i, o);
391 DB((dbg, LEVEL_3, " Already Created %+F for %+F (%s %+F)\n", result, iv,
392 get_irn_opname(orig), rc));
398 * The Replace operation.
400 * @param irn the node that will be replaced
401 * @param iv the induction variable
402 * @param rc the region constant
403 * @param env the environment
405 static int replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env) {
407 ir_loop *iv_loop = get_irn_loop(get_nodes_block(iv));
408 ir_loop *irn_loop = get_irn_loop(get_nodes_block(irn));
410 /* only replace nodes that are in the same (or deeper loops) */
411 if (get_loop_depth(irn_loop) >= get_loop_depth(iv_loop)) {
412 DB((dbg, LEVEL_2, " Replacing %+F\n", irn));
414 result = reduce(irn, iv, rc, env);
416 node_entry *e, *iv_e;
418 hook_strength_red(current_ir_graph, irn);
419 exchange(irn, result);
420 e = get_irn_ne(result, env);
421 iv_e = get_irn_ne(iv, env);
422 e->header = iv_e->header;
430 * Check if a node can be replaced (+, -, *).
432 * @param irn the node to check
433 * @param env the environment
435 * @return non-zero if irn should be Replace'd
437 static int check_replace(ir_node *irn, iv_env *env) {
438 ir_node *left, *right, *iv, *rc;
439 ir_op *op = get_irn_op(irn);
440 ir_opcode code = get_op_code(op);
449 left = get_binop_left(irn);
450 right = get_binop_right(irn);
452 liv = is_iv(left, env);
453 riv = is_iv(right, env);
454 if (liv && is_rc(right, liv)) {
455 iv = left; rc = right;
457 else if (riv && is_op_commutative(op) &&
459 iv = right; rc = left;
463 if (code == iro_Mul && env->flags & osr_flag_ignore_x86_shift) {
465 tarval *tv = get_Const_tarval(rc);
467 if (tarval_is_long(tv)) {
468 long value = get_tarval_long(tv);
470 if (value == 2 || value == 4 || value == 8) {
471 /* do not reduce multiplications by 2, 4, 8 */
478 return replace(irn, iv, rc, env);
488 * Check which SCC's are induction variables.
491 * @param env the environment
493 static void classify_iv(scc *pscc, iv_env *env) {
494 ir_node *irn, *next, *header = NULL;
495 node_entry *b, *h = NULL;
496 int j, only_phi, num_outside;
499 /* find the header block for this scc */
500 for (irn = pscc->head; irn; irn = next) {
501 node_entry *e = get_irn_link(irn);
502 ir_node *block = get_nodes_block(irn);
505 b = get_irn_ne(block, env);
508 if (h->POnum < b->POnum) {
519 /* check if this scc contains only Phi, Add or Sub nodes */
523 for (irn = pscc->head; irn; irn = next) {
524 node_entry *e = get_irn_ne(irn, env);
527 switch (get_irn_opcode(irn)) {
533 for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
534 ir_node *pred = get_irn_n(irn, j);
535 node_entry *pe = get_irn_ne(pred, env);
537 if (pe->pscc != e->pscc) {
538 /* not in the same SCC, must be a region const */
539 if (! is_rc(pred, header)) {
540 /* not an induction variable */
546 } else if (out_rc != pred) {
553 /* not an induction variable */
557 /* found an induction variable */
558 DB((dbg, LEVEL_2, " Found an induction variable:\n "));
559 if (only_phi && num_outside == 1) {
560 /* a phi cycle with only one real predecessor can be collapsed */
561 DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
563 for (irn = pscc->head; irn; irn = next) {
564 node_entry *e = get_irn_ne(irn, env);
567 exchange(irn, out_rc);
573 /* set the header for every node in this scc */
574 for (irn = pscc->head; irn; irn = next) {
575 node_entry *e = get_irn_ne(irn, env);
578 DB((dbg, LEVEL_2, " %+F,", irn));
580 DB((dbg, LEVEL_2, "\n"));
584 for (irn = pscc->head; irn; irn = next) {
585 node_entry *e = get_irn_ne(irn, env);
588 if (! check_replace(irn, env))
594 * Process a SCC for the operator strength reduction.
596 * @param pscc the SCC
597 * @param env the environment
599 static void process_scc(scc *pscc, iv_env *env) {
600 ir_node *head = pscc->head;
601 node_entry *e = get_irn_link(head);
607 DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
608 for (irn = pscc->head; irn; irn = next) {
609 node_entry *e = get_irn_link(irn);
613 DB((dbg, LEVEL_4, " %+F,", irn));
615 DB((dbg, LEVEL_4, "\n"));
619 if (e->next == NULL) {
620 /* this SCC has only a single member */
621 check_replace(head, env);
623 classify_iv(pscc, env);
628 * If an SCC is a Phi only cycle, remove it.
630 static void remove_phi_cycle(scc *pscc, iv_env *env) {
635 /* check if this scc contains only Phi, Add or Sub nodes */
637 for (irn = pscc->head; irn; irn = next) {
638 node_entry *e = get_irn_ne(irn, env);
644 for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
645 ir_node *pred = get_irn_n(irn, j);
646 node_entry *pe = get_irn_ne(pred, env);
648 if (pe->pscc != e->pscc) {
649 /* not in the same SCC, must be the only input */
652 } else if (out_rc != pred) {
658 /* found a Phi cycle */
659 DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
661 for (irn = pscc->head; irn; irn = next) {
662 node_entry *e = get_irn_ne(irn, env);
665 exchange(irn, out_rc);
671 * Process a SCC for the Phi cycle removement.
673 * @param pscc the SCC
674 * @param env the environment
676 static void process_phi_only_scc(scc *pscc, iv_env *env) {
677 ir_node *head = pscc->head;
678 node_entry *e = get_irn_link(head);
684 DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
685 for (irn = pscc->head; irn; irn = next) {
686 node_entry *e = get_irn_link(irn);
690 DB((dbg, LEVEL_4, " %+F,", irn));
692 DB((dbg, LEVEL_4, "\n"));
697 remove_phi_cycle(pscc, env);
702 * Push a node onto the stack.
704 * @param env the environment
705 * @param n the node to push
707 static void push(iv_env *env, ir_node *n) {
710 if (env->tos == ARR_LEN(env->stack)) {
711 int nlen = ARR_LEN(env->stack) * 2;
712 ARR_RESIZE(ir_node *, env->stack, nlen);
714 env->stack[env->tos++] = n;
715 e = get_irn_ne(n, env);
720 * pop a node from the stack
722 * @param env the environment
724 * @return The topmost node
726 static ir_node *pop(iv_env *env)
728 ir_node *n = env->stack[--env->tos];
729 node_entry *e = get_irn_ne(n, env);
736 * Do Tarjan's SCC algorithm and drive OSR.
738 * @param irn start at this node
739 * @param env the environment
741 static void dfs(ir_node *irn, iv_env *env)
744 node_entry *node = get_irn_ne(irn, env);
746 mark_irn_visited(irn);
748 /* do not put blocks into the scc */
750 n = get_irn_arity(irn);
751 for (i = 0; i < n; ++i) {
752 ir_node *pred = get_irn_n(irn, i);
754 if (irn_not_visited(pred))
759 ir_node *block = get_nodes_block(irn);
761 node->DFSnum = env->nextDFSnum++;
762 node->low = node->DFSnum;
765 /* handle the block */
766 if (irn_not_visited(block))
769 n = get_irn_arity(irn);
770 for (i = 0; i < n; ++i) {
771 ir_node *pred = get_irn_n(irn, i);
772 node_entry *o = get_irn_ne(pred, env);
774 if (irn_not_visited(pred)) {
776 node->low = MIN(node->low, o->low);
778 if (o->DFSnum < node->DFSnum && o->in_stack)
779 node->low = MIN(o->DFSnum, node->low);
781 if (node->low == node->DFSnum) {
782 scc *pscc = obstack_alloc(&env->obst, sizeof(*pscc));
790 e = get_irn_ne(x, env);
792 e->next = pscc->head;
796 env->process_scc(pscc, env);
802 * Do the DFS by starting at the End node of a graph.
804 * @param irg the graph to process
805 * @param env the environment
807 static void do_dfs(ir_graph *irg, iv_env *env) {
808 ir_graph *rem = current_ir_graph;
809 ir_node *end = get_irg_end(irg);
812 current_ir_graph = irg;
813 inc_irg_visited(irg);
815 /* visit all visible nodes */
818 /* visit the keep-alives */
819 n = get_End_n_keepalives(end);
820 for (i = 0; i < n; ++i) {
821 ir_node *ka = get_End_keepalive(end, i);
823 if (irn_not_visited(ka))
827 current_ir_graph = rem;
831 * Post-block-walker: assign the post-order number.
833 static void assign_po(ir_node *block, void *ctx) {
835 node_entry *e = get_irn_ne(block, env);
837 e->POnum = env->POnum++;
842 * Follows the LFTR edges and return the last node in the chain.
844 * @param irn the node that should be followed
845 * @param env the IV environment
848 * In the current implementation only the last edge is stored, so
849 * only one chain exists. That's why we might miss some opportunities.
851 static ir_node *followEdges(ir_node *irn, iv_env *env) {
853 LFTR_edge *e = LFTR_find(irn, env);
862 * Apply one LFTR edge operation.
863 * Return NULL if the transformation cannot be done safely without
866 * @param rc the IV node that should be translated
867 * @param e the LFTR edge
868 * @param env the IV environment
870 * @return the translated region constant or NULL
871 * if the translation was not possible
874 * In the current implementation only the last edge is stored, so
875 * only one chain exists. That's why we might miss some opportunities.
877 static ir_node *applyOneEdge(ir_node *rc, LFTR_edge *e, iv_env *env) {
878 if (env->flags & osr_flag_lftr_with_ov_check) {
879 tarval *tv_l, *tv_r, *tv;
880 tarval_int_overflow_mode_t ovmode;
882 /* overflow can only be decided for Consts */
883 if (! is_Const(e->rc)) {
884 DB((dbg, LEVEL_4, " = UNKNOWN (%+F)", e->rc));
888 tv_l = get_Const_tarval(rc);
889 tv_r = get_Const_tarval(e->rc);
891 ovmode = tarval_get_integer_overflow_mode();
892 tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
896 tv = tarval_mul(tv_l, tv_r);
897 DB((dbg, LEVEL_4, " * %+F", tv_r));
900 tv = tarval_add(tv_l, tv_r);
901 DB((dbg, LEVEL_4, " + %+F", tv_r));
904 tv = tarval_sub(tv_l, tv_r);
905 DB((dbg, LEVEL_4, " - %+F", tv_r));
911 tarval_set_integer_overflow_mode(ovmode);
913 if (tv == tarval_bad) {
914 DB((dbg, LEVEL_4, " = OVERFLOW"));
917 return new_r_Const(current_ir_graph, get_nodes_block(rc), get_tarval_mode(tv), tv);
919 return do_apply(e->code, NULL, rc, e->rc, get_irn_mode(rc));
923 * Applies the operations represented by the LFTR edges to a
924 * region constant and returns the value.
925 * Return NULL if the transformation cannot be done safely without
928 * @param iv the IV node that starts the LFTR edge chain
929 * @param rc the region constant that should be translated
930 * @param env the IV environment
932 * @return the translated region constant or NULL
933 * if the translation was not possible
935 static ir_node *applyEdges(ir_node *iv, ir_node *rc, iv_env *env) {
938 if (env->flags & osr_flag_lftr_with_ov_check) {
939 /* overflow can only be decided for Consts */
940 if (! is_Const(rc)) {
941 DB((dbg, LEVEL_4, " = UNKNOWN (%+F)\n", rc));
944 DB((dbg, LEVEL_4, "%+F", get_Const_tarval(rc)));
947 for (irn = iv; rc;) {
948 LFTR_edge *e = LFTR_find(irn, env);
950 rc = applyOneEdge(rc, e, env);
956 DB((dbg, LEVEL_3, "\n"));
961 * Walker, finds Cmp(iv, rc) or Cmp(rc, iv)
962 * and tries to optimize them.
964 static void do_lftr(ir_node *cmp, void *ctx) {
966 ir_node *left, *right, *liv, *riv;
968 ir_node *nleft = NULL, *nright = NULL;
970 if (get_irn_op(cmp) != op_Cmp)
973 left = get_Cmp_left(cmp);
974 right = get_Cmp_right(cmp);
976 liv = is_iv(left, env);
977 riv = is_iv(right, env);
978 if (liv && is_rc(right, liv)) {
979 iv = left; rc = right;
981 nright = applyEdges(iv, rc, env);
982 if (nright && nright != rc) {
983 nleft = followEdges(iv, env);
986 else if (riv && is_rc(left, riv)) {
987 iv = right; rc = left;
989 nleft = applyEdges(iv, rc, env);
990 if (nleft && nleft != rc) {
991 nright = followEdges(iv, env);
995 if (nleft && nright) {
996 DB((dbg, LEVEL_2, " LFTR for %+F\n", cmp));
997 set_Cmp_left(cmp, nleft);
998 set_Cmp_right(cmp, nright);
999 ++env->lftr_replaced;
1004 * do linear function test replacement.
1006 * @param irg the graph that should be optimized
1007 * @param env the IV environment
1009 static void lftr(ir_graph *irg, iv_env *env) {
1010 irg_walk_graph(irg, NULL, do_lftr, env);
1015 * Pre-walker: set all node links to NULL and fix the
1016 * block of Proj nodes.
1018 static void clear_and_fix(ir_node *irn, void *env)
1021 set_irn_link(irn, NULL);
1023 /* FIXME: must be removed but edges must be fixed first*/
1025 ir_node *pred = get_Proj_pred(irn);
1026 set_irn_n(irn, -1, get_nodes_block(pred));
1030 /* Performs Operator Strength Reduction for the passed graph. */
1031 void opt_osr(ir_graph *irg, unsigned flags) {
1035 if (! get_opt_strength_red()) {
1036 /* only kill Phi cycles */
1037 remove_phi_cycles(irg);
1041 rem = current_ir_graph;
1042 current_ir_graph = irg;
1044 FIRM_DBG_REGISTER(dbg, "firm.opt.osr");
1046 DB((dbg, LEVEL_1, "Doing Operator Strength Reduction for %+F\n", irg));
1048 obstack_init(&env.obst);
1049 env.stack = NEW_ARR_F(ir_node *, 128);
1053 env.quad_map = new_set(quad_cmp, 64);
1054 env.lftr_edges = new_set(LFTR_cmp, 64);
1056 env.lftr_replaced = 0;
1058 env.process_scc = process_scc;
1060 /* Clear all links and move Proj nodes into the
1061 the same block as it's predecessors.
1062 This can improve the placement of new nodes.
1064 irg_walk_graph(irg, NULL, clear_and_fix, NULL);
1066 /* we need dominance */
1068 assure_irg_outs(irg);
1070 /* calculate the post order number for blocks. */
1071 irg_out_block_walk(get_irg_start_block(irg), NULL, assign_po, &env);
1073 /* calculate the SCC's and drive OSR. */
1077 /* try linear function test replacements */
1080 set_irg_outs_inconsistent(irg);
1081 DB((dbg, LEVEL_1, "Replacements: %u + %u (lftr)\n\n", env.replaced, env.lftr_replaced));
1084 del_set(env.lftr_edges);
1085 del_set(env.quad_map);
1086 DEL_ARR_F(env.stack);
1087 obstack_free(&env.obst, NULL);
1089 current_ir_graph = rem;
1092 /* Remove any Phi cycles with only one real input. */
1093 void remove_phi_cycles(ir_graph *irg) {
1097 rem = current_ir_graph;
1098 current_ir_graph = irg;
1100 FIRM_DBG_REGISTER(dbg, "firm.opt.remove_phi");
1102 DB((dbg, LEVEL_1, "Doing Phi cycle removement for %+F\n", irg));
1104 obstack_init(&env.obst);
1105 env.stack = NEW_ARR_F(ir_node *, 128);
1109 env.quad_map = NULL;
1110 env.lftr_edges = NULL;
1112 env.lftr_replaced = 0;
1114 env.process_scc = process_phi_only_scc;
1116 /* Clear all links and move Proj nodes into the
1117 the same block as it's predecessors.
1118 This can improve the placement of new nodes.
1120 irg_walk_graph(irg, NULL, clear_and_fix, NULL);
1122 /* we need dominance */
1123 assure_irg_outs(irg);
1125 /* calculate the post order number for blocks. */
1126 irg_out_block_walk(get_irg_start_block(irg), NULL, assign_po, &env);
1128 /* calculate the SCC's and drive OSR. */
1132 set_irg_outs_inconsistent(irg);
1133 DB((dbg, LEVEL_1, "remove_phi_cycles: %u Cycles removed\n\n", env.replaced));
1136 DEL_ARR_F(env.stack);
1137 obstack_free(&env.obst, NULL);
1139 current_ir_graph = rem;