3 * File name: ir/ana/irscc.c
4 * Purpose: Compute the strongly connected regions and build
5 * backedge/loop datastructures.
6 * A variation on the Tarjan algorithm. See also [Trapp:99],
8 * Author: Goetz Lindenmaier
12 * Copyright: (c) 2002-2003 Universität Karlsruhe
13 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
24 #include "irgraph_t.h"
30 ir_graph *outermost_ir_graph; /* The outermost graph the scc is computed
32 static ir_loop *current_loop; /* Current loop construction is working
34 static int loop_node_cnt = 0; /* Counts the number of allocated loop nodes.
35 Each loop node gets a unique number.
36 What for? ev. remove. @@@ */
37 static int current_dfn = 1; /* Counter to generate depth first numbering
40 /**********************************************************************/
41 /* Node attributes **/
42 /**********************************************************************/
44 /* A map to get from irnodes to loop nodes. */
45 static pmap *node_loop_map = NULL;
47 /**********************************************************************/
48 /* Node attributes needed for the construction. **/
49 /**********************************************************************/
51 typedef struct scc_info {
52 bool in_stack; /* Marks whether node is on the stack. */
53 int dfn; /* Depth first search number. */
54 int uplink; /* dfn number of ancestor. */
55 // ir_loop *loop; /* Refers to the containing loop. */
57 struct section *section;
63 static INLINE scc_info* new_scc_info(void) {
64 scc_info *info = obstack_alloc (outermost_ir_graph->obst, sizeof (scc_info));
65 memset (info, 0, sizeof (scc_info));
70 mark_irn_in_stack (ir_node *n) {
71 assert(get_irn_link(n));
72 ((scc_info *)get_irn_link(n))->in_stack = true;
76 mark_irn_not_in_stack (ir_node *n) {
77 assert(get_irn_link(n));
78 ((scc_info *)get_irn_link(n))->in_stack = false;
82 irn_is_in_stack (ir_node *n) {
83 assert(get_irn_link(n));
84 return ((scc_info *)get_irn_link(n))->in_stack;
88 set_irn_uplink (ir_node *n, int uplink) {
89 assert(get_irn_link(n));
90 ((scc_info *)get_irn_link(n))->uplink = uplink;
94 get_irn_uplink (ir_node *n) {
95 assert(get_irn_link(n));
96 return ((scc_info *)get_irn_link(n))->uplink;
100 set_irn_dfn (ir_node *n, int dfn) {
101 if (! get_irn_link(n)) { DDMN(n); DDME(get_irg_ent(current_ir_graph));}
102 assert(get_irn_link(n));
103 ((scc_info *)get_irn_link(n))->dfn = dfn;
107 get_irn_dfn (ir_node *n) {
108 assert(get_irn_link(n));
109 return ((scc_info *)get_irn_link(n))->dfn;
112 /* Uses temporary information to set the loop */
114 set_irn_loop (ir_node *n, ir_loop* loop) {
115 //assert(get_irn_link(n));
116 //((scc_info *)get_irn_link(n))->loop = loop;
117 assert(node_loop_map && "not initialized!");
118 pmap_insert(node_loop_map, (void *)n, (void *)loop);
121 /* Uses temporary information to get the loop */
123 get_irn_loop (ir_node *n) {
125 //assert(get_irn_link(n));
126 //return ((scc_info *)get_irn_link(n))->loop;
127 assert(node_loop_map && "not initialized!");
129 if (pmap_contains(node_loop_map, (void *)n))
130 res = (ir_loop *) pmap_get(node_loop_map, (void *)n);
136 static ir_loop *find_nodes_loop (ir_node *n, ir_loop *l) {
140 /* Test whether n is contained in this loop. */
141 for (i = 0; i < get_loop_n_nodes(l); i++)
142 if (n == get_loop_node(l, i)) return l;
144 /* Is this a leave in the loop tree? If so loop not found. */
145 if (get_loop_n_sons(l) == 0) return NULL;
147 /* Else descend in the loop tree. */
148 for (i = 0; i < get_loop_n_sons(l); i++) {
149 res = find_nodes_loop(n, get_loop_son(l, i));
155 /* @@@ temporary implementation, costly!!! */
156 ir_loop * get_irn_loop(ir_node *n) {
157 ir_loop *l = get_irg_loop(current_ir_graph);
158 l = find_nodes_loop(n, l);
163 /**********************************************************************/
165 /**********************************************************************/
167 static ir_node **stack = NULL;
168 static int tos = 0; /* top of stack */
170 static INLINE void init_stack(void) {
172 ARR_RESIZE (ir_node *, stack, 1000);
174 stack = NEW_ARR_F (ir_node *, 1000);
180 static INLINE void free_stack(void) {
192 if (tos == ARR_LEN (stack)) {
193 int nlen = ARR_LEN (stack) * 2;
194 ARR_RESIZE (ir_node *, stack, nlen);
197 mark_irn_in_stack(n);
200 static INLINE ir_node *
203 ir_node *n = stack[--tos];
204 mark_irn_not_in_stack(n);
208 /* The nodes up to n belong to the current loop.
209 Removes them from the stack and adds them to the current loop. */
211 pop_scc_to_loop (ir_node *n)
221 set_irn_dfn(m, loop_node_cnt);
222 add_loop_node(current_loop, m);
223 set_irn_loop(m, current_loop);
225 /* if (m==n) break;*/
229 printf("Mehr als eine Iteration!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n");
232 /* GL ??? my last son is my grandson??? Removes loops with no
233 ir_nodes in them. Such loops have only another loop as son. (Why
234 can't they have two loops as sons? Does it never get that far? ) */
235 void close_loop (ir_loop *l)
237 int last = get_loop_n_elements(l) - 1;
238 loop_element lelement = get_loop_element(l, last);
239 ir_loop *last_son = lelement.son;
241 if (get_kind(last_son) == k_ir_loop &&
242 get_loop_n_elements(last_son) == 1)
246 lelement = get_loop_element(last_son, 0);
248 if(get_kind(gson) == k_ir_loop)
250 loop_element new_last_son;
252 gson -> outer_loop = l;
253 new_last_son.son = gson;
254 l -> children[last] = new_last_son;
261 /* Removes and unmarks all nodes up to n from the stack.
262 The nodes must be visited once more to assign them to a scc. */
264 pop_scc_unmark_visit (ir_node *n)
270 set_irn_visited(m, 0);
274 /**********************************************************************/
275 /* The loop datastructure. **/
276 /**********************************************************************/
278 /* Allocates a new loop as son of current_loop. Sets current_loop
279 to the new loop and returns the father. */
280 static ir_loop *new_loop (void) {
281 ir_loop *father, *son;
283 father = current_loop;
285 son = (ir_loop *) obstack_alloc (outermost_ir_graph->obst, sizeof (ir_loop));
286 memset (son, 0, sizeof (ir_loop));
287 son->kind = k_ir_loop;
288 son->children = NEW_ARR_F (loop_element, 0);
292 son->outer_loop = father;
293 add_loop_son(father, son);
294 son->depth = father->depth+1;
295 } else { /* The root loop */
296 son->outer_loop = son;
301 son->loop_nr = get_irp_new_node_nr();
310 /* Finishes the datastructures, copies the arrays to the obstack
312 A. Schoesser: Caution: loop -> sons is gone. */
313 static void mature_loop (ir_loop *loop) {
316 new_sons = NEW_ARR_D (ir_loop *, current_ir_graph->obst, ARR_LEN(loop->sons));
317 memcpy (new_sons, loop->sons, sizeof (ir_loop *) * ARR_LEN(loop->sons));
318 DEL_ARR_F(loop->sons);
319 loop->sons = new_sons;
323 /* Returns outer loop, itself if outermost. */
324 ir_loop *get_loop_outer_loop (ir_loop *loop) {
325 assert(loop && loop->kind == k_ir_loop);
326 return loop->outer_loop;
329 /* Returns nesting depth of this loop */
330 int get_loop_depth (ir_loop *loop) {
331 assert(loop); assert(loop->kind == k_ir_loop);
335 /* Returns the number of inner loops */
336 int get_loop_n_sons (ir_loop *loop) {
337 assert(loop && loop->kind == k_ir_loop);
338 return(loop -> n_sons);
341 /* Returns the pos`th loop_node-child *
342 * TODO: This method isn`t very efficient ! *
343 * Returns NULL if there isnt`t a pos`th loop_node */
344 ir_loop *get_loop_son (ir_loop *loop, int pos) {
345 int child_nr = 0, loop_nr = -1;
347 assert(loop && loop->kind == k_ir_loop);
348 while(child_nr < ARR_LEN(loop->children))
350 if(*(loop -> children[child_nr].kind) == k_ir_loop)
353 return(loop -> children[child_nr].son);
359 /* Use EXCLUSIVELY this function to add sons, otherwise the loop->n_sons
363 add_loop_son(ir_loop *loop, ir_loop *son) {
366 assert(loop && loop->kind == k_ir_loop);
367 assert(get_kind(son) == k_ir_loop);
368 ARR_APP1 (loop_element, loop->children, lson);
372 /* Returns the number of nodes in the loop */
373 int get_loop_n_nodes (ir_loop *loop) {
374 assert(loop); assert(loop->kind == k_ir_loop);
375 return loop -> n_nodes;
376 /* return ARR_LEN(loop->nodes); */
379 /* Returns the pos`th ir_node-child *
380 * TODO: This method isn`t very efficient ! *
381 * Returns NULL if there isnt`t a pos`th ir_node */
382 ir_node *get_loop_node (ir_loop *loop, int pos) {
383 int child_nr, node_nr = -1;
385 assert(loop && loop->kind == k_ir_loop);
386 assert(pos < get_loop_n_nodes(loop));
388 for (child_nr = 0; child_nr < ARR_LEN(loop->children); child_nr++) {
389 if(*(loop -> children[child_nr].kind) == k_ir_node)
392 return(loop -> children[child_nr].node);
394 assert(0 && "no child at pos found");
398 /* Use EXCLUSIVELY this function to add nodes, otherwise the loop->n_nodes
402 add_loop_node(ir_loop *loop, ir_node *n) {
405 assert(loop && loop->kind == k_ir_loop);
406 assert(get_kind(n) == k_ir_node);
407 ARR_APP1 (loop_element, loop->children, ln);
411 /** Returns the number of elements contained in loop. */
412 int get_loop_n_elements (ir_loop *loop) {
413 assert(loop && loop->kind == k_ir_loop);
414 return(ARR_LEN(loop->children));
418 Returns the pos`th loop element.
419 This may be a loop_node or a ir_node. The caller of this function has
420 to check the *(loop_element.kind) field for "k_ir_node" or "k_ir_loop"
421 and then select the apropriate "loop_element.node" or "loop_element.son".
424 loop_element get_loop_element (ir_loop *loop, int pos) {
425 assert(loop && loop->kind == k_ir_loop && pos < ARR_LEN(loop->children));
427 return(loop -> children[pos]);
430 int get_loop_element_pos(ir_loop *loop, void *le) {
431 assert(loop && loop->kind == k_ir_loop);
434 for (i = 0; i < get_loop_n_elements(loop); i++)
435 if (get_loop_element(loop, i).node == le) return i;
439 int get_loop_loop_nr(ir_loop *loop) {
440 assert(loop && loop->kind == k_ir_loop);
442 return loop->loop_nr;
449 /** A field to connect additional information to a loop. Only valid
450 if libfirm_debug is set. */
451 void set_loop_link (ir_loop *loop, void *link) {
452 assert(loop && loop->kind == k_ir_loop);
457 void *get_loop_link (const ir_loop *loop) {
458 assert(loop && loop->kind == k_ir_loop);
466 /* The outermost loop is remarked in the surrounding graph. */
467 void set_irg_loop(ir_graph *irg, ir_loop *loop) {
471 ir_loop *get_irg_loop(ir_graph *irg) {
477 /**********************************************************************/
478 /* Constructing and destructing the loop/backedge information. **/
479 /**********************************************************************/
481 /* Initialization steps. **********************************************/
484 init_node (ir_node *n, void *env) {
485 set_irn_link (n, new_scc_info());
488 /* Also init nodes not visible in intraproc_view. */
489 /* @@@ init_node is called for too many nodes -- this wastes memory!.
490 The mem is not lost as its on the obstack. */
491 if (get_irn_op(n) == op_Filter) {
492 for (i = 0; i < get_Filter_n_cg_preds(n); i++)
493 init_node(get_Filter_cg_pred(n, i), NULL);
495 if (get_irn_op(n) == op_Block) {
496 for (i = 0; i < get_Block_cg_n_cfgpreds(n); i++) {
497 init_node(get_Block_cg_cfgpred(n, i), NULL);
500 /* The following pattern matches only after a call from above pattern. */
501 if ((get_irn_op(n) == op_Proj) /*&& (get_Proj_proj(n) == 0)*/) {
502 /* @@@ init_node is called for every proj -- this wastes memory!.
503 The mem is not lost as its on the obstack. */
504 ir_node *cb = get_Proj_pred(n);
505 if ((get_irn_op(cb) == op_CallBegin) ||
506 (get_irn_op(cb) == op_EndReg) ||
507 (get_irn_op(cb) == op_EndExcept)) {
509 init_node(get_nodes_Block(cb), NULL);
516 init_scc_common (void) {
519 if (!node_loop_map) node_loop_map = pmap_create();
524 init_scc (ir_graph *irg) {
526 irg_walk_graph (irg, init_node, NULL, NULL);
528 irg_walk (irg, link_to_reg_end, NULL, NULL);
535 cg_walk (init_node, NULL, NULL);
538 /* Condition for breaking the recursion. */
539 static bool is_outermost_Start(ir_node *n) {
540 /* Test whether this is the outermost Start node. If so
541 recursion must end. */
542 if ((get_irn_op(n) == op_Block) &&
543 (get_Block_n_cfgpreds(n) == 1) &&
544 (get_irn_op(skip_Proj(get_Block_cfgpred(n, 0))) == op_Start) &&
545 (get_nodes_Block(skip_Proj(get_Block_cfgpred(n, 0))) == n)) {
549 /* @@@ Bad condition:
550 not possible in interprocedural view as outermost_graph is
551 not necessarily the only with a dead-end start block.
552 Besides current_ir_graph is not set properly. */
553 if ((get_irn_op(n) == op_Block) &&
554 (n == get_irg_start_block(current_ir_graph))) {
555 if ((!interprocedural_view) ||
556 (current_ir_graph == outermost_ir_graph))
563 /* Don't walk from nodes to blocks except for Control flow operations. */
565 get_start_index(ir_node *n) {
566 if (is_cfop(n) || is_fragile_op(n) || get_irn_op(n) == op_Start)
572 /* Returns current_ir_graph and set it to the irg of predecessor index
574 static INLINE ir_graph *
575 switch_irg (ir_node *n, int index) {
576 ir_graph *old_current = current_ir_graph;
578 if (interprocedural_view) {
579 /* Only Filter and Block nodes can have predecessors in other graphs. */
580 if (get_irn_op(n) == op_Filter)
581 n = get_nodes_Block(n);
582 if (get_irn_op(n) == op_Block) {
583 ir_node *cfop = skip_Proj(get_Block_cfgpred(n, index));
584 if (is_ip_cfop(cfop)) {
585 current_ir_graph = get_irn_irg(cfop);
586 set_irg_visited(current_ir_graph, get_max_irg_visited());
595 /* Walks up the stack passing n and then finding the node
596 where we walked into the irg n is contained in.
597 Here we switch the irg. */
599 find_irg_on_stack (ir_node *n) {
601 ir_graph *old_current = current_ir_graph;
604 if (interprocedural_view) {
605 for (i = tos; i >= 0; i--) {
606 if (stack[i] == n) break;
611 for (; i >= 0; i--) {
613 /*printf(" Visiting %d ", i); DDMN(m);*/
615 current_ir_graph = get_irn_irg(m);
618 if (get_irn_op(m) == op_Filter) {
619 /* Find the corresponding ip_cfop */
620 ir_node *pred = stack[i+1];
622 for (j = 0; j < get_Filter_n_cg_preds(m); j++)
623 if (get_Filter_cg_pred(m, j) == pred) break;
624 if (j >= get_Filter_n_cg_preds(m))
625 /* It is a filter we didn't pass as the predecessors are marked. */
627 assert(get_Filter_cg_pred(m, j) == pred);
639 static void test(ir_node *pred, ir_node *root, ir_node *this) {
641 if (get_irn_uplink(pred) >= get_irn_uplink(root)) return;
643 printf("this: %d ", get_irn_uplink(this)); DDMN(this);
644 printf("pred: %d ", get_irn_uplink(pred)); DDMN(pred);
645 printf("root: %d ", get_irn_uplink(root)); DDMN(root);
647 printf("tos: %d\n", tos);
649 for (i = tos; i >= 0; i--) {
650 ir_node *n = stack[i];
652 printf(" uplink: %d, pos: %d ", get_irn_uplink(n), i); DDMN(n);
657 /* Test for legal loop header: Block, Phi, ... */
658 INLINE static bool is_possible_loop_head(ir_node *n) {
659 return ((get_irn_op(n) == op_Block) ||
660 (get_irn_op(n) == op_Phi) ||
661 ((get_irn_op(n) == op_Filter) && interprocedural_view));
664 /* Returns true if n is a loop header, i.e., it is a Block, Phi
665 or Filter node and has predecessors within the loop and out
667 @arg root: only needed for assertion. */
669 is_head (ir_node *n, ir_node *root)
672 int some_outof_loop = 0, some_in_loop = 0;
674 /* Test for legal loop header: Block, Phi, ... */
675 if (!is_possible_loop_head(n))
678 if (!is_outermost_Start(n)) {
679 for (i = get_start_index(n); i < get_irn_arity(n); i++) {
680 ir_node *pred = get_irn_n(n, i);
682 if (is_backedge(n, i)) continue;
683 if (!irn_is_in_stack(pred)) {
686 assert(get_irn_uplink(pred) >= get_irn_uplink(root));
691 return some_outof_loop && some_in_loop;
694 /* Returns index of the predecessor with the smallest dfn number
695 greater-equal than limit. */
697 smallest_dfn_pred (ir_node *n, int limit)
699 int i, index = -2, min = -1;
701 if (!is_outermost_Start(n)) {
702 for (i = get_start_index(n); i < get_irn_arity(n); i++) {
703 ir_node *pred = get_irn_n(n, i);
705 if (is_backedge(n, i) || !irn_is_in_stack(pred)) continue;
706 if (get_irn_dfn(pred) >= limit && (min == -1 || get_irn_dfn(pred) < min)) {
708 min = get_irn_dfn(pred);
715 /* Returns index of the predecessor with the largest dfn number. */
717 largest_dfn_pred (ir_node *n)
719 int i, index = -2, max = -1;
721 if (!is_outermost_Start(n)) {
722 for (i = get_start_index(n); i < get_irn_arity(n); i++) {
723 ir_node *pred = get_irn_n(n, i);
724 if (is_backedge (n, i) || !irn_is_in_stack(pred)) continue;
725 if (get_irn_dfn(pred) > max) {
727 max = get_irn_dfn(pred);
734 /* Searches the stack for possible loop heads. Tests these for backedges.
735 If it finds a head with an unmarked backedge it marks this edge and
736 returns the tail of the loop.
737 If it finds no backedge returns NULL.
738 ("disable_backedge" in fiasco) */
741 find_tail (ir_node *n) {
743 int i, res_index = -2;
746 if (!icfg && rm_cyclic_phis && remove_cyclic_phis (n)) return NULL;
749 m = stack[tos-1]; /* tos = top of stack */
750 if (is_head (m, n)) {
751 res_index = smallest_dfn_pred(m, 0);
752 if ((res_index == -2) && /* no smallest dfn pred found. */
756 if (m == n) return NULL;
757 for (i = tos-2; ; --i) {
759 if (is_head (m, n)) {
760 res_index = smallest_dfn_pred (m, get_irn_dfn(m) + 1);
761 if (res_index == -2) /* no smallest dfn pred found. */
762 res_index = largest_dfn_pred (m);
767 assert (res_index > -2);
769 set_backedge (m, res_index);
770 return is_outermost_Start(n) ? NULL : get_irn_n(m, res_index);
774 /* The core algorithm. *****************************************/
776 static void scc (ir_node *n) {
778 // GL @@@ remove experimental stuff ir_graph *rem;
780 if (irn_visited(n)) return;
783 /* Initialize the node */
784 set_irn_dfn(n, current_dfn); /* Depth first number for this node */
785 set_irn_uplink(n, current_dfn); /* ... is default uplink. */
786 set_irn_loop(n, NULL);
789 /* What's this good for?
790 n->ana.scc.section = NULL;
795 /* AS: get_start_index might return -1 for Control Flow Nodes, and thus a negative
796 array index would be passed to is_backedge(). But CFG Nodes dont't have a backedge array,
797 so is_backedge does not access array[-1] but correctly returns false! */
799 if (!is_outermost_Start(n)) {
800 for (i = get_start_index(n); i < get_irn_arity(n); i++) {
802 if (is_backedge(n, i)) continue;
804 m = get_irn_n(n, i); /*get_irn_ip_pred(n, i);*/
806 //if ((!m) || (get_irn_op(m) == op_Unknown)) continue;
808 // GL @@@ remove experimental stuff /*return_recur(n, i);*/
810 if (irn_is_in_stack(m)) {
811 /* Uplink of m is smaller if n->m is a backedge.
812 Propagate the uplink to mark the loop. */
813 if (get_irn_uplink(m) < get_irn_uplink(n))
814 set_irn_uplink(n, get_irn_uplink(m));
819 if (get_irn_dfn(n) == get_irn_uplink(n)) {
820 /* This condition holds for the node with the incoming backedge.
821 AS: That is: For the loop head. */
822 ir_node *tail = find_tail(n);
824 /* We found a new inner loop! */
826 /* This is an adaption of the algorithm from fiasco / optscc to
827 * avoid loops without Block or Phi as first node. This should
828 * severely reduce the number of evaluations of nodes to detect
829 * a fixpoint in the heap analyses.
830 * Further it avoids loops without firm nodes that cause errors
831 * in the heap analyses. */
832 #define NO_LOOPS_WITHOUT_HEAD 1
833 #if NO_LOOPS_WITHOUT_HEAD
836 if (get_loop_n_elements(current_loop) > 0) {
844 ir_loop *l = new_loop();
847 /* Remove the loop from the stack ... */
848 pop_scc_unmark_visit (n);
849 /* and recompute it in a better order; and so that it goes into
851 // GL @@@ remove experimental stuff rem = find_irg_on_stack(tail);
854 // GL @@@ remove experimental stuff current_ir_graph = rem;
856 assert (irn_visited(n));
857 #if NO_LOOPS_WITHOUT_HEAD
862 /* AS: No inner loop was found. Pop all nodes from the stack
863 to the current loop. */
869 /* Constructs backedge information for irg. In interprocedural view constructs
870 backedges for all methods called by irg, too. */
871 void construct_backedges(ir_graph *irg) {
872 ir_graph *rem = current_ir_graph;
875 assert(!interprocedural_view &&
876 "not implemented, use construct_ip_backedges");
878 current_ir_graph = irg;
879 outermost_ir_graph = irg;
881 init_scc(current_ir_graph);
884 new_loop(); /* sets current_loop */
885 head_rem = current_loop; /* Just for assertion */
887 if (interprocedural_view) {
888 set_irg_visited(current_ir_graph, inc_max_irg_visited());
891 inc_irg_visited(current_ir_graph);
894 scc(get_irg_end(current_ir_graph));
896 if (interprocedural_view) finish_ip_walk();
898 assert(head_rem == current_loop);
899 set_irg_loop(current_ir_graph, current_loop);
900 assert(get_irg_loop(current_ir_graph)->kind == k_ir_loop);
902 irg->loops = current_loop;
906 count_loop (the_loop, &count, &depth);
910 current_ir_graph = rem;
915 void construct_ip_backedges (void) {
916 ir_graph *rem = current_ir_graph;
917 int rem_ipv = interprocedural_view;
920 outermost_ir_graph = get_irp_main_irg();
925 new_loop(); /* sets current_loop */
926 interprocedural_view = 1;
928 inc_max_irg_visited();
929 for (i = 0; i < get_irp_n_irgs(); i++)
930 set_irg_visited(get_irp_irg(i), get_max_irg_visited());
932 for (i = 0; i < get_irp_n_irgs(); i++) {
934 current_ir_graph = get_irp_irg(i);
935 /* Find real entry points */
936 sb = get_irg_start_block(current_ir_graph);
937 if ((get_Block_n_cfgpreds(sb) > 1) ||
938 (get_nodes_Block(get_Block_cfgpred(sb, 0)) != sb)) continue;
939 /* Compute scc for this graph */
940 outermost_ir_graph = current_ir_graph;
941 set_irg_visited(outermost_ir_graph, get_max_irg_visited());
942 scc(get_irg_end(current_ir_graph));
943 for (j = 0; j < get_End_n_keepalives(get_irg_end(outermost_ir_graph)); j++)
944 scc(get_End_keepalive(get_irg_end(outermost_ir_graph), j));
947 set_irg_loop(outermost_ir_graph, current_loop);
948 assert(get_irg_loop(outermost_ir_graph)->kind == k_ir_loop);
950 current_ir_graph = rem;
951 interprocedural_view = rem_ipv;
954 void construct_ip_backedges (void) {
955 ir_graph *rem = current_ir_graph;
956 int rem_ipv = interprocedural_view;
959 outermost_ir_graph = get_irp_main_irg();
964 new_loop(); /* sets current_loop */
965 interprocedural_view = 1;
967 inc_max_irg_visited();
968 for (i = 0; i < get_irp_n_irgs(); i++)
969 set_irg_visited(get_irp_irg(i), get_max_irg_visited());
971 /** We have to start the walk at the same nodes as cg_walk. **/
972 /* Walk starting at unreachable procedures. Only these
973 * have End blocks visible in interprocedural view. */
974 for (i = 0; i < get_irp_n_irgs(); i++) {
976 current_ir_graph = get_irp_irg(i);
978 sb = get_irg_start_block(current_ir_graph);
980 if ((get_Block_n_cfgpreds(sb) > 1) ||
981 (get_nodes_block(get_Block_cfgpred(sb, 0)) != sb)) continue;
983 scc(get_irg_end(current_ir_graph));
986 /* Check whether we walked all procedures: there could be procedures
987 with cyclic calls but no call from the outside. */
988 for (i = 0; i < get_irp_n_irgs(); i++) {
990 current_ir_graph = get_irp_irg(i);
992 /* Test start block: if inner procedure end and end block are not
993 * visible and therefore not marked. */
994 sb = get_irg_start_block(current_ir_graph);
995 if (get_irn_visited(sb) < get_irg_visited(current_ir_graph)) scc(sb);
998 /* Walk all endless loops in inner procedures.
999 * We recognize an inner procedure if the End node is not visited. */
1000 for (i = 0; i < get_irp_n_irgs(); i++) {
1002 current_ir_graph = get_irp_irg(i);
1004 e = get_irg_end(current_ir_graph);
1005 if (get_irn_visited(e) < get_irg_visited(current_ir_graph)) {
1007 /* Don't visit the End node. */
1008 for (j = 0; j < get_End_n_keepalives(e); j++) scc(get_End_keepalive(e, j));
1012 set_irg_loop(outermost_ir_graph, current_loop);
1013 assert(get_irg_loop(outermost_ir_graph)->kind == k_ir_loop);
1015 current_ir_graph = rem;
1016 interprocedural_view = rem_ipv;
1020 static void reset_backedges(ir_node *n) {
1021 if (is_possible_loop_head(n)) {
1022 int rem = interprocedural_view;
1023 interprocedural_view = 1;
1025 interprocedural_view = 0;
1027 interprocedural_view = rem;
1031 static void loop_reset_backedges(ir_loop *l) {
1033 reset_backedges(get_loop_node(l, 0));
1034 for (i = 0; i < get_loop_n_sons(l); ++i) {
1035 loop_reset_backedges(get_loop_son(l, i));
1039 /** Removes all loop information.
1040 Resets all backedges */
1041 void free_loop_information(ir_graph *irg) {
1042 if (get_irg_loop(irg))
1043 loop_reset_backedges(get_irg_loop(irg));
1044 set_irg_loop(irg, NULL);
1045 /* We cannot free the loop nodes, they are on the obstack. */
1049 void free_all_loop_information (void) {
1051 int rem = interprocedural_view;
1052 interprocedural_view = 1; /* To visit all filter nodes */
1053 for (i = 0; i < get_irp_n_irgs(); i++) {
1054 free_loop_information(get_irp_irg(i));
1056 pmap_destroy(node_loop_map);
1057 node_loop_map = NULL;
1058 interprocedural_view = rem;
1065 /* Debug stuff *************************************************/
1067 static int test_loop_node(ir_loop *l) {
1068 int i, has_node = 0, found_problem = 0;
1070 assert(l && l->kind == k_ir_loop);
1072 if (get_loop_n_elements(l) == 0) {
1073 printf(" Loop completely empty! "); DDML(l);
1075 dump_loop(l, "-ha");
1078 le = get_loop_element(l, 0);
1079 if (*(le.kind) != k_ir_node) {
1080 assert(le.kind && *(le.kind) == k_ir_loop);
1081 printf(" First loop element is not a node! "); DDML(l);
1082 printf(" "); DDML(le.son);
1085 dump_loop(l, "-ha");
1088 if ((*(le.kind) == k_ir_node) && !is_possible_loop_head(le.node)) {
1089 printf(" Wrong node as head! "); DDML(l);
1090 printf(" "); DDMN(le.node);
1092 dump_loop(l, "-ha");
1095 if ((get_loop_depth(l) != 0) &&
1096 (*(le.kind) == k_ir_node) && !has_backedges(le.node)) {
1097 printf(" Loop head has no backedges! "); DDML(l);
1098 printf(" "); DDMN(le.node);
1100 dump_loop(l, "-ha");
1105 for (i = 0; i < get_loop_n_elements(l); ++i) {
1106 le = get_loop_element(l, i);
1107 if (*(le.kind) == k_ir_node)
1110 if (test_loop_node(le.son)) found_problem = 1;
1113 if (has_node == 0) {
1114 printf(" Loop has no firm node! "); DDML(l);
1116 dump_loop(l, "-ha");
1119 if (get_loop_loop_nr(l) == 11819)
1120 dump_loop(l, "-ha-debug");
1122 return found_problem;
1125 /** Prints all loop nodes that
1126 * - do not have any firm nodes, only loop sons
1127 * - the header is not a Phi, Block or Filter.
1129 void find_strange_loop_nodes(ir_loop *l) {
1130 int found_problem = 0;
1131 printf("\nTesting loop "); DDML(l);
1132 found_problem = test_loop_node(l);
1133 printf("Finished Test\n\n");
1134 if (found_problem) exit(0);