2 * Copyright (C) 1995-2008 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 Load/Store optimizations.
23 * @author Michael Beck
32 #include "iroptimize.h"
34 #include "irgraph_t.h"
42 #include "dbginfo_t.h"
43 #include "iropt_dbg.h"
49 #include "opt_polymorphy.h"
52 #include "irphase_t.h"
56 /** The debug handle. */
57 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
60 #include "cacheopt/cachesim.h"
64 #define IMAX(a,b) ((a) > (b) ? (a) : (b))
66 #define MAX_PROJ IMAX(IMAX(pn_Load_max, pn_Store_max), pn_Call_max)
69 DF_CHANGED = 1, /**< data flow changed */
70 CF_CHANGED = 2, /**< control flow changed */
76 typedef struct _walk_env_t {
77 struct obstack obst; /**< list of all stores */
78 unsigned changes; /**< a bitmask of graph changes */
81 /** A Load/Store info. */
82 typedef struct _ldst_info_t {
83 ir_node *projs[MAX_PROJ]; /**< list of Proj's of this node */
84 ir_node *exc_block; /**< the exception block if available */
85 int exc_idx; /**< predecessor index in the exception block */
86 unsigned visited; /**< visited counter for breaking loops */
90 * flags for control flow.
93 BLOCK_HAS_COND = 1, /**< Block has conditional control flow */
94 BLOCK_HAS_EXC = 2 /**< Block has exceptional control flow */
100 typedef struct _block_info_t {
101 unsigned flags; /**< flags for the block */
104 /** the master visited flag for loop detection. */
105 static unsigned master_visited = 0;
107 #define INC_MASTER() ++master_visited
108 #define MARK_NODE(info) (info)->visited = master_visited
109 #define NODE_VISITED(info) (info)->visited >= master_visited
112 * get the Load/Store info of a node
114 static ldst_info_t *get_ldst_info(ir_node *node, struct obstack *obst) {
115 ldst_info_t *info = get_irn_link(node);
118 info = obstack_alloc(obst, sizeof(*info));
119 memset(info, 0, sizeof(*info));
120 set_irn_link(node, info);
123 } /* get_ldst_info */
126 * get the Block info of a node
128 static block_info_t *get_block_info(ir_node *node, struct obstack *obst) {
129 block_info_t *info = get_irn_link(node);
132 info = obstack_alloc(obst, sizeof(*info));
133 memset(info, 0, sizeof(*info));
134 set_irn_link(node, info);
137 } /* get_block_info */
140 * update the projection info for a Load/Store
142 static unsigned update_projs(ldst_info_t *info, ir_node *proj)
144 long nr = get_Proj_proj(proj);
146 assert(0 <= nr && nr <= MAX_PROJ && "Wrong proj from LoadStore");
148 if (info->projs[nr]) {
149 /* there is already one, do CSE */
150 exchange(proj, info->projs[nr]);
154 info->projs[nr] = proj;
160 * update the exception block info for a Load/Store node.
162 * @param info the load/store info struct
163 * @param block the exception handler block for this load/store
164 * @param pos the control flow input of the block
166 static unsigned update_exc(ldst_info_t *info, ir_node *block, int pos)
168 assert(info->exc_block == NULL && "more than one exception block found");
170 info->exc_block = block;
175 /** Return the number of uses of an address node */
176 #define get_irn_n_uses(adr) get_irn_n_edges(adr)
179 * walker, collects all Load/Store/Proj nodes
181 * walks from Start -> End
183 static void collect_nodes(ir_node *node, void *env)
185 ir_opcode opcode = get_irn_opcode(node);
186 ir_node *pred, *blk, *pred_blk;
187 ldst_info_t *ldst_info;
188 walk_env_t *wenv = env;
190 if (opcode == iro_Proj) {
191 pred = get_Proj_pred(node);
192 opcode = get_irn_opcode(pred);
194 if (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call) {
195 ldst_info = get_ldst_info(pred, &wenv->obst);
197 wenv->changes |= update_projs(ldst_info, node);
200 * Place the Proj's to the same block as the
201 * predecessor Load. This is always ok and prevents
202 * "non-SSA" form after optimizations if the Proj
203 * is in a wrong block.
205 blk = get_nodes_block(node);
206 pred_blk = get_nodes_block(pred);
207 if (blk != pred_blk) {
208 wenv->changes |= DF_CHANGED;
209 set_nodes_block(node, pred_blk);
212 } else if (opcode == iro_Block) {
215 for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
216 ir_node *pred_block, *proj;
217 block_info_t *bl_info;
220 pred = proj = get_Block_cfgpred(node, i);
223 pred = get_Proj_pred(proj);
224 is_exc = get_Proj_proj(proj) == pn_Generic_X_except;
227 /* ignore Bad predecessors, they will be removed later */
231 pred_block = get_nodes_block(pred);
232 bl_info = get_block_info(pred_block, &wenv->obst);
234 if (is_fragile_op(pred) && is_exc)
235 bl_info->flags |= BLOCK_HAS_EXC;
236 else if (is_irn_forking(pred))
237 bl_info->flags |= BLOCK_HAS_COND;
239 opcode = get_irn_opcode(pred);
240 if (is_exc && (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call)) {
241 ldst_info = get_ldst_info(pred, &wenv->obst);
243 wenv->changes |= update_exc(ldst_info, node, i);
247 } /* collect_nodes */
250 * Returns an entity if the address ptr points to a constant one.
252 * @param ptr the address
254 * @return an entity or NULL
256 static ir_entity *find_constant_entity(ir_node *ptr)
259 if (is_SymConst(ptr) && get_SymConst_kind(ptr) == symconst_addr_ent) {
260 ir_entity *ent = get_SymConst_entity(ptr);
261 if (variability_constant == get_entity_variability(ent))
264 } else if (is_Sel(ptr)) {
265 ir_entity *ent = get_Sel_entity(ptr);
266 ir_type *tp = get_entity_owner(ent);
268 /* Do not fiddle with polymorphism. */
269 if (is_Class_type(get_entity_owner(ent)) &&
270 ((get_entity_n_overwrites(ent) != 0) ||
271 (get_entity_n_overwrittenby(ent) != 0) ) )
274 if (is_Array_type(tp)) {
278 for (i = 0, n = get_Sel_n_indexs(ptr); i < n; ++i) {
280 tarval *tlower, *tupper;
281 ir_node *index = get_Sel_index(ptr, i);
282 tarval *tv = computed_value(index);
284 /* check if the index is constant */
285 if (tv == tarval_bad)
288 bound = get_array_lower_bound(tp, i);
289 tlower = computed_value(bound);
290 bound = get_array_upper_bound(tp, i);
291 tupper = computed_value(bound);
293 if (tlower == tarval_bad || tupper == tarval_bad)
296 if (tarval_cmp(tv, tlower) & pn_Cmp_Lt)
298 if (tarval_cmp(tupper, tv) & pn_Cmp_Lt)
301 /* ok, bounds check finished */
305 if (variability_constant == get_entity_variability(ent))
309 ptr = get_Sel_ptr(ptr);
310 } else if (is_Add(ptr)) {
311 ir_node *l = get_Add_left(ptr);
312 ir_node *r = get_Add_right(ptr);
314 if (get_irn_mode(l) == get_irn_mode(ptr) && is_Const(r))
316 else if (get_irn_mode(r) == get_irn_mode(ptr) && is_Const(l))
321 /* for now, we support only one addition, reassoc should fold all others */
322 if (! is_SymConst(ptr) && !is_Sel(ptr))
324 } else if (is_Sub(ptr)) {
325 ir_node *l = get_Sub_left(ptr);
326 ir_node *r = get_Sub_right(ptr);
328 if (get_irn_mode(l) == get_irn_mode(ptr) && is_Const(r))
332 /* for now, we support only one substraction, reassoc should fold all others */
333 if (! is_SymConst(ptr) && !is_Sel(ptr))
338 } /* find_constant_entity */
341 * Return the Selection index of a Sel node from dimension n
343 static long get_Sel_array_index_long(ir_node *n, int dim) {
344 ir_node *index = get_Sel_index(n, dim);
345 assert(is_Const(index));
346 return get_tarval_long(get_Const_tarval(index));
347 } /* get_Sel_array_index_long */
350 * Returns the accessed component graph path for an
351 * node computing an address.
353 * @param ptr the node computing the address
354 * @param depth current depth in steps upward from the root
357 static compound_graph_path *rec_get_accessed_path(ir_node *ptr, int depth) {
358 compound_graph_path *res = NULL;
359 ir_entity *root, *field, *ent;
360 int path_len, pos, idx;
364 if (is_SymConst(ptr)) {
365 /* a SymConst. If the depth is 0, this is an access to a global
366 * entity and we don't need a component path, else we know
367 * at least it's length.
369 assert(get_SymConst_kind(ptr) == symconst_addr_ent);
370 root = get_SymConst_entity(ptr);
371 res = (depth == 0) ? NULL : new_compound_graph_path(get_entity_type(root), depth);
372 } else if (is_Sel(ptr)) {
373 /* it's a Sel, go up until we find the root */
374 res = rec_get_accessed_path(get_Sel_ptr(ptr), depth+1);
378 /* fill up the step in the path at the current position */
379 field = get_Sel_entity(ptr);
380 path_len = get_compound_graph_path_length(res);
381 pos = path_len - depth - 1;
382 set_compound_graph_path_node(res, pos, field);
384 if (is_Array_type(get_entity_owner(field))) {
385 assert(get_Sel_n_indexs(ptr) == 1 && "multi dim arrays not implemented");
386 set_compound_graph_path_array_index(res, pos, get_Sel_array_index_long(ptr, 0));
388 } else if (is_Add(ptr)) {
389 ir_node *l = get_Add_left(ptr);
390 ir_node *r = get_Add_right(ptr);
395 tv = get_Const_tarval(r);
398 tv = get_Const_tarval(l);
401 mode = get_tarval_mode(tv);
403 /* ptr must be a Sel or a SymConst, this was checked in find_constant_entity() */
405 field = get_Sel_entity(ptr);
407 field = get_SymConst_entity(ptr);
410 for (ent = field;;) {
412 tarval *sz, *tv_index, *tlower, *tupper;
416 tp = get_entity_type(ent);
417 if (! is_Array_type(tp))
419 ent = get_array_element_entity(tp);
420 size = get_type_size_bytes(get_entity_type(ent));
421 sz = new_tarval_from_long(size, mode);
423 tv_index = tarval_div(tv, sz);
424 tv = tarval_mod(tv, sz);
426 if (tv_index == tarval_bad || tv == tarval_bad)
429 assert(get_array_n_dimensions(tp) == 1 && "multiarrays not implemented");
430 bound = get_array_lower_bound(tp, 0);
431 tlower = computed_value(bound);
432 bound = get_array_upper_bound(tp, 0);
433 tupper = computed_value(bound);
435 if (tlower == tarval_bad || tupper == tarval_bad)
438 if (tarval_cmp(tv_index, tlower) & pn_Cmp_Lt)
440 if (tarval_cmp(tupper, tv_index) & pn_Cmp_Lt)
443 /* ok, bounds check finished */
444 index = get_tarval_long(tv_index);
447 if (! tarval_is_null(tv)) {
448 /* access to some struct/union member */
452 /* should be at least ONE array */
456 res = rec_get_accessed_path(ptr, depth + idx);
460 path_len = get_compound_graph_path_length(res);
461 pos = path_len - depth - idx;
463 for (ent = field;;) {
465 tarval *sz, *tv_index;
468 tp = get_entity_type(ent);
469 if (! is_Array_type(tp))
471 ent = get_array_element_entity(tp);
472 set_compound_graph_path_node(res, pos, ent);
474 size = get_type_size_bytes(get_entity_type(ent));
475 sz = new_tarval_from_long(size, mode);
477 tv_index = tarval_div(tv, sz);
478 tv = tarval_mod(tv, sz);
480 /* worked above, should work again */
481 assert(tv_index != tarval_bad && tv != tarval_bad);
483 /* bounds already checked above */
484 index = get_tarval_long(tv_index);
485 set_compound_graph_path_array_index(res, pos, index);
488 } else if (is_Sub(ptr)) {
489 ir_node *l = get_Sub_left(ptr);
490 ir_node *r = get_Sub_right(ptr);
493 tv = get_Const_tarval(r);
498 } /* rec_get_accessed_path */
501 * Returns an access path or NULL. The access path is only
502 * valid, if the graph is in phase_high and _no_ address computation is used.
504 static compound_graph_path *get_accessed_path(ir_node *ptr) {
505 return rec_get_accessed_path(ptr, 0);
506 } /* get_accessed_path */
508 typedef struct path_entry {
510 struct path_entry *next;
514 static ir_node *rec_find_compound_ent_value(ir_node *ptr, path_entry *next) {
515 path_entry entry, *p;
516 ir_entity *ent, *field;
517 ir_initializer_t *initializer;
523 if (is_SymConst(ptr)) {
525 ent = get_SymConst_entity(ptr);
526 initializer = get_entity_initializer(ent);
527 for (p = next; p != NULL;) {
528 if (initializer->kind != IR_INITIALIZER_COMPOUND)
530 n = get_initializer_compound_n_entries(initializer);
531 tp = get_entity_type(ent);
533 if (is_Array_type(tp)) {
534 ent = get_array_element_entity(tp);
539 initializer = get_initializer_compound_value(initializer, 0);
545 initializer = get_initializer_compound_value(initializer, p->index);
550 tp = get_entity_type(ent);
551 while (is_Array_type(tp)) {
552 ent = get_array_element_entity(tp);
553 tp = get_entity_type(ent);
555 n = get_initializer_compound_n_entries(initializer);
558 initializer = get_initializer_compound_value(initializer, 0);
561 switch (initializer->kind) {
562 case IR_INITIALIZER_CONST:
563 return get_initializer_const_value(initializer);
564 case IR_INITIALIZER_TARVAL:
565 case IR_INITIALIZER_NULL:
569 } else if (is_Sel(ptr)) {
570 entry.ent = field = get_Sel_entity(ptr);
571 tp = get_entity_owner(field);
572 if (is_Array_type(tp)) {
573 assert(get_Sel_n_indexs(ptr) == 1 && "multi dim arrays not implemented");
574 entry.index = get_Sel_array_index_long(ptr, 0) - get_array_lower_bound_int(tp, 0);
576 int i, n_members = get_compound_n_members(tp);
577 for (i = 0; i < n_members; ++i) {
578 if (get_compound_member(tp, i) == field)
581 if (i >= n_members) {
582 /* not found: should NOT happen */
587 return rec_find_compound_ent_value(get_Sel_ptr(ptr), &entry);
588 } else if (is_Add(ptr)) {
589 ir_node *l = get_Add_left(ptr);
590 ir_node *r = get_Add_right(ptr);
596 tv = get_Const_tarval(r);
599 tv = get_Const_tarval(l);
602 mode = get_tarval_mode(tv);
604 /* ptr must be a Sel or a SymConst, this was checked in find_constant_entity() */
606 field = get_Sel_entity(ptr);
608 field = get_SymConst_entity(ptr);
611 /* count needed entries */
613 for (ent = field;;) {
614 tp = get_entity_type(ent);
615 if (! is_Array_type(tp))
617 ent = get_array_element_entity(tp);
620 /* should be at least ONE entry */
624 /* allocate the right number of entries */
625 NEW_ARR_A(path_entry, p, pos);
629 for (ent = field;;) {
631 tarval *sz, *tv_index, *tlower, *tupper;
635 tp = get_entity_type(ent);
636 if (! is_Array_type(tp))
638 ent = get_array_element_entity(tp);
640 p[pos].next = &p[pos + 1];
642 size = get_type_size_bytes(get_entity_type(ent));
643 sz = new_tarval_from_long(size, mode);
645 tv_index = tarval_div(tv, sz);
646 tv = tarval_mod(tv, sz);
648 if (tv_index == tarval_bad || tv == tarval_bad)
651 assert(get_array_n_dimensions(tp) == 1 && "multiarrays not implemented");
652 bound = get_array_lower_bound(tp, 0);
653 tlower = computed_value(bound);
654 bound = get_array_upper_bound(tp, 0);
655 tupper = computed_value(bound);
657 if (tlower == tarval_bad || tupper == tarval_bad)
660 if (tarval_cmp(tv_index, tlower) & pn_Cmp_Lt)
662 if (tarval_cmp(tupper, tv_index) & pn_Cmp_Lt)
665 /* ok, bounds check finished */
666 index = get_tarval_long(tv_index);
667 p[pos].index = index;
670 if (! tarval_is_null(tv)) {
671 /* hmm, wrong access */
674 p[pos - 1].next = next;
675 return rec_find_compound_ent_value(ptr, p);
676 } else if (is_Sub(ptr)) {
677 ir_node *l = get_Sub_left(ptr);
678 ir_node *r = get_Sub_right(ptr);
681 tv = get_Const_tarval(r);
688 static ir_node *find_compound_ent_value(ir_node *ptr) {
689 return rec_find_compound_ent_value(ptr, NULL);
693 static void reduce_adr_usage(ir_node *ptr);
696 * Update a Load that may lost it's usage.
698 static void handle_load_update(ir_node *load) {
699 ldst_info_t *info = get_irn_link(load);
701 /* do NOT touch volatile loads for now */
702 if (get_Load_volatility(load) == volatility_is_volatile)
705 if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) {
706 ir_node *ptr = get_Load_ptr(load);
707 ir_node *mem = get_Load_mem(load);
709 /* a Load which value is neither used nor exception checked, remove it */
710 exchange(info->projs[pn_Load_M], mem);
711 if (info->projs[pn_Load_X_regular])
712 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
714 reduce_adr_usage(ptr);
716 } /* handle_load_update */
719 * A Use of an address node is vanished. Check if this was a Proj
720 * node and update the counters.
722 static void reduce_adr_usage(ir_node *ptr) {
724 if (get_irn_n_edges(ptr) <= 0) {
725 /* this Proj is dead now */
726 ir_node *pred = get_Proj_pred(ptr);
729 ldst_info_t *info = get_irn_link(pred);
730 info->projs[get_Proj_proj(ptr)] = NULL;
732 /* this node lost it's result proj, handle that */
733 handle_load_update(pred);
737 } /* reduce_adr_usage */
740 * Check, if an already existing value of mode old_mode can be converted
741 * into the needed one new_mode without loss.
743 static int can_use_stored_value(ir_mode *old_mode, ir_mode *new_mode) {
744 if (old_mode == new_mode)
747 /* if both modes are two-complement ones, we can always convert the
748 Stored value into the needed one. */
749 if (get_mode_size_bits(old_mode) >= get_mode_size_bits(new_mode) &&
750 get_mode_arithmetic(old_mode) == irma_twos_complement &&
751 get_mode_arithmetic(new_mode) == irma_twos_complement)
754 } /* can_use_stored_value */
757 * Check whether a Call is at least pure, ie. does only read memory.
759 static unsigned is_Call_pure(ir_node *call) {
760 ir_type *call_tp = get_Call_type(call);
761 unsigned prop = get_method_additional_properties(call_tp);
763 /* check first the call type */
764 if ((prop & (mtp_property_const|mtp_property_pure)) == 0) {
765 /* try the called entity */
766 ir_node *ptr = get_Call_ptr(call);
768 if (is_Global(ptr)) {
769 ir_entity *ent = get_Global_entity(ptr);
771 prop = get_entity_additional_properties(ent);
774 return (prop & (mtp_property_const|mtp_property_pure)) != 0;
778 * Follow the memory chain as long as there are only Loads,
779 * alias free Stores, and constant Calls and try to replace the
780 * current Load by a previous ones.
781 * Note that in unreachable loops it might happen that we reach
782 * load again, as well as we can fall into a cycle.
783 * We break such cycles using a special visited flag.
785 * INC_MASTER() must be called before dive into
787 static unsigned follow_Mem_chain(ir_node *load, ir_node *curr) {
789 ldst_info_t *info = get_irn_link(load);
791 ir_node *ptr = get_Load_ptr(load);
792 ir_node *mem = get_Load_mem(load);
793 ir_mode *load_mode = get_Load_mode(load);
795 for (pred = curr; load != pred; ) {
796 ldst_info_t *pred_info = get_irn_link(pred);
799 * BEWARE: one might think that checking the modes is useless, because
800 * if the pointers are identical, they refer to the same object.
801 * This is only true in strong typed languages, not in C were the following
802 * is possible a = *(ir_type1 *)p; b = *(ir_type2 *)p ...
804 if (is_Store(pred) && get_Store_ptr(pred) == ptr &&
805 can_use_stored_value(get_irn_mode(get_Store_value(pred)), load_mode)) {
807 * a Load immediately after a Store -- a read after write.
808 * We may remove the Load, if both Load & Store does not have an exception handler
809 * OR they are in the same MacroBlock. In the latter case the Load cannot
810 * throw an exception when the previous Store was quiet.
812 * Why we need to check for Store Exception? If the Store cannot
813 * be executed (ROM) the exception handler might simply jump into
814 * the load MacroBlock :-(
815 * We could make it a little bit better if we would know that the exception
816 * handler of the Store jumps directly to the end...
818 if ((pred_info->projs[pn_Store_X_except] == NULL && info->projs[pn_Load_X_except] == NULL) ||
819 get_nodes_MacroBlock(load) == get_nodes_MacroBlock(pred)) {
820 ir_node *value = get_Store_value(pred);
822 DBG_OPT_RAW(load, value);
824 /* add an convert if needed */
825 if (get_irn_mode(get_Store_value(pred)) != load_mode) {
826 value = new_r_Conv(current_ir_graph, get_nodes_block(load), value, load_mode);
829 if (info->projs[pn_Load_M])
830 exchange(info->projs[pn_Load_M], mem);
833 if (info->projs[pn_Load_X_except]) {
834 exchange( info->projs[pn_Load_X_except], new_Bad());
837 if (info->projs[pn_Load_X_regular]) {
838 exchange( info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
842 if (info->projs[pn_Load_res])
843 exchange(info->projs[pn_Load_res], value);
846 reduce_adr_usage(ptr);
847 return res | DF_CHANGED;
849 } else if (is_Load(pred) && get_Load_ptr(pred) == ptr &&
850 can_use_stored_value(get_Load_mode(pred), load_mode)) {
852 * a Load after a Load -- a read after read.
853 * We may remove the second Load, if it does not have an exception handler
854 * OR they are in the same MacroBlock. In the later case the Load cannot
855 * throw an exception when the previous Load was quiet.
857 * Here, there is no need to check if the previous Load has an exception
858 * hander because they would have exact the same exception...
860 if (info->projs[pn_Load_X_except] == NULL || get_nodes_MacroBlock(load) == get_nodes_MacroBlock(pred)) {
863 DBG_OPT_RAR(load, pred);
865 /* the result is used */
866 if (info->projs[pn_Load_res]) {
867 if (pred_info->projs[pn_Load_res] == NULL) {
868 /* create a new Proj again */
869 pred_info->projs[pn_Load_res] = new_r_Proj(current_ir_graph, get_nodes_block(pred), pred, get_Load_mode(pred), pn_Load_res);
871 value = pred_info->projs[pn_Load_res];
873 /* add an convert if needed */
874 if (get_Load_mode(pred) != load_mode) {
875 value = new_r_Conv(current_ir_graph, get_nodes_block(load), value, load_mode);
878 exchange(info->projs[pn_Load_res], value);
881 if (info->projs[pn_Load_M])
882 exchange(info->projs[pn_Load_M], mem);
885 if (info->projs[pn_Load_X_except]) {
886 exchange(info->projs[pn_Load_X_except], new_Bad());
889 if (info->projs[pn_Load_X_regular]) {
890 exchange( info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
895 reduce_adr_usage(ptr);
896 return res |= DF_CHANGED;
900 if (is_Store(pred)) {
901 /* check if we can pass through this store */
902 ir_alias_relation rel = get_alias_relation(
905 get_irn_mode(get_Store_value(pred)),
907 /* if the might be an alias, we cannot pass this Store */
908 if (rel != ir_no_alias)
910 pred = skip_Proj(get_Store_mem(pred));
911 } else if (is_Load(pred)) {
912 pred = skip_Proj(get_Load_mem(pred));
913 } else if (is_Call(pred)) {
914 if (is_Call_pure(pred)) {
915 /* The called graph is at least pure, so there are no Store's
916 in it. We can handle it like a Load and skip it. */
917 pred = skip_Proj(get_Call_mem(pred));
919 /* there might be Store's in the graph, stop here */
923 /* follow only Load chains */
927 /* check for cycles */
928 if (NODE_VISITED(pred_info))
930 MARK_NODE(pred_info);
936 /* handle all Sync predecessors */
937 for (i = get_Sync_n_preds(pred) - 1; i >= 0; --i) {
938 res |= follow_Mem_chain(load, skip_Proj(get_Sync_pred(pred, i)));
945 } /* follow_Mem_chain */
950 * @param load the Load node
952 static unsigned optimize_load(ir_node *load)
954 ldst_info_t *info = get_irn_link(load);
955 ir_node *mem, *ptr, *new_node;
959 /* do NOT touch volatile loads for now */
960 if (get_Load_volatility(load) == volatility_is_volatile)
963 /* the address of the load to be optimized */
964 ptr = get_Load_ptr(load);
967 * Check if we can remove the exception from a Load:
968 * This can be done, if the address is from an Sel(Alloc) and
969 * the Sel type is a subtype of the allocated type.
971 * This optimizes some often used OO constructs,
972 * like x = new O; x->t;
974 if (info->projs[pn_Load_X_except]) {
976 ir_node *mem = get_Sel_mem(ptr);
978 /* FIXME: works with the current FE, but better use the base */
979 if (is_Alloc(skip_Proj(mem))) {
980 /* ok, check the types */
981 ir_entity *ent = get_Sel_entity(ptr);
982 ir_type *s_type = get_entity_type(ent);
983 ir_type *a_type = get_Alloc_type(mem);
985 if (is_SubClass_of(s_type, a_type)) {
986 /* ok, condition met: there can't be an exception because
987 * Alloc guarantees that enough memory was allocated */
989 exchange(info->projs[pn_Load_X_except], new_Bad());
990 info->projs[pn_Load_X_except] = NULL;
991 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
992 info->projs[pn_Load_X_regular] = NULL;
996 } else if (is_Alloc(skip_Proj(skip_Cast(ptr)))) {
997 /* simple case: a direct load after an Alloc. Firm Alloc throw
998 * an exception in case of out-of-memory. So, there is no way for an
999 * exception in this load.
1000 * This code is constructed by the "exception lowering" in the Jack compiler.
1002 exchange(info->projs[pn_Load_X_except], new_Bad());
1003 info->projs[pn_Load_X_except] = NULL;
1004 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
1005 info->projs[pn_Load_X_regular] = NULL;
1010 /* The mem of the Load. Must still be returned after optimization. */
1011 mem = get_Load_mem(load);
1013 if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) {
1014 /* a Load which value is neither used nor exception checked, remove it */
1015 exchange(info->projs[pn_Load_M], mem);
1017 if (info->projs[pn_Load_X_regular]) {
1018 /* should not happen, but if it does, remove it */
1019 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
1023 reduce_adr_usage(ptr);
1024 return res | DF_CHANGED;
1027 /* Load from a constant polymorphic field, where we can resolve
1029 new_node = transform_node_Load(load);
1030 if (new_node != load) {
1031 if (info->projs[pn_Load_M]) {
1032 exchange(info->projs[pn_Load_M], mem);
1033 info->projs[pn_Load_M] = NULL;
1035 if (info->projs[pn_Load_X_except]) {
1036 exchange(info->projs[pn_Load_X_except], new_Bad());
1037 info->projs[pn_Load_X_except] = NULL;
1040 if (info->projs[pn_Load_X_regular]) {
1041 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
1042 info->projs[pn_Load_X_regular] = NULL;
1045 if (info->projs[pn_Load_res])
1046 exchange(info->projs[pn_Load_res], new_node);
1049 reduce_adr_usage(ptr);
1050 return res | DF_CHANGED;
1053 /* check if we can determine the entity that will be loaded */
1054 ent = find_constant_entity(ptr);
1056 if ((allocation_static == get_entity_allocation(ent)) &&
1057 (visibility_external_allocated != get_entity_visibility(ent))) {
1058 /* a static allocation that is not external: there should be NO exception
1061 /* no exception, clear the info field as it might be checked later again */
1062 if (info->projs[pn_Load_X_except]) {
1063 exchange(info->projs[pn_Load_X_except], new_Bad());
1064 info->projs[pn_Load_X_except] = NULL;
1067 if (info->projs[pn_Load_X_regular]) {
1068 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(current_ir_graph, get_nodes_block(load)));
1069 info->projs[pn_Load_X_regular] = NULL;
1073 if (variability_constant == get_entity_variability(ent)) {
1074 if (is_atomic_entity(ent)) {
1075 /* Might not be atomic after
1076 lowering of Sels. In this
1077 case we could also load, but
1078 it's more complicated. */
1079 /* more simpler case: we load the content of a constant value:
1080 * replace it by the constant itself
1084 if (info->projs[pn_Load_M]) {
1085 exchange(info->projs[pn_Load_M], mem);
1089 if (info->projs[pn_Load_res]) {
1090 if (is_atomic_entity(ent)) {
1091 ir_node *c = copy_const_value(get_irn_dbg_info(load), get_atomic_ent_value(ent));
1093 DBG_OPT_RC(load, c);
1094 exchange(info->projs[pn_Load_res], c);
1099 reduce_adr_usage(ptr);
1103 if (ent->has_initializer) {
1104 /* new style initializer */
1105 c = find_compound_ent_value(ptr);
1107 /* old style initializer */
1108 compound_graph_path *path = get_accessed_path(ptr);
1111 assert(is_proper_compound_graph_path(path, get_compound_graph_path_length(path)-1));
1113 c = get_compound_ent_value_by_path(ent, path);
1114 free_compound_graph_path(path);
1118 /* check, if the mode matches OR can be easily converted info */
1119 ir_mode *c_mode = get_irn_mode(c);
1120 ir_mode *l_mode = get_Load_mode(load);
1122 if (c_mode != l_mode) {
1123 if (is_reinterpret_cast(c_mode, l_mode)) {
1124 /* we can safely cast */
1125 dbg_info *dbg = get_irn_dbg_info(load);
1126 ir_node *block = get_nodes_block(load);
1128 /* copy the value from the const code irg and cast it */
1129 c = copy_const_value(dbg, c);
1130 c = new_rd_Conv(dbg, current_ir_graph, block, c, l_mode);
1132 /* must be some operation */
1136 /* copy the value from the const code irg */
1137 c = copy_const_value(get_irn_dbg_info(load), c);
1141 if (info->projs[pn_Load_M]) {
1142 exchange(info->projs[pn_Load_M], mem);
1145 if (info->projs[pn_Load_res]) {
1146 exchange(info->projs[pn_Load_res], c);
1150 reduce_adr_usage(ptr);
1153 /* We can not determine a correct access path. E.g., in jack, we load
1154 a byte from an object to generate an exception. Happens in test program
1156 printf(">>>>>>>>>>>>> Found access to constant entity %s in function %s\n", get_entity_name(ent),
1157 get_entity_name(get_irg_entity(current_ir_graph)));
1158 ir_printf(" load: %+F\n", load);
1159 ir_printf(" ptr: %+F\n", ptr);
1167 /* Check, if the address of this load is used more than once.
1168 * If not, this load cannot be removed in any case. */
1169 if (get_irn_n_uses(ptr) <= 1)
1173 * follow the memory chain as long as there are only Loads
1174 * and try to replace current Load or Store by a previous one.
1175 * Note that in unreachable loops it might happen that we reach
1176 * load again, as well as we can fall into a cycle.
1177 * We break such cycles using a special visited flag.
1180 res = follow_Mem_chain(load, skip_Proj(mem));
1182 } /* optimize_load */
1185 * Check whether a value of mode new_mode would completely overwrite a value
1186 * of mode old_mode in memory.
1188 static int is_completely_overwritten(ir_mode *old_mode, ir_mode *new_mode)
1190 return get_mode_size_bits(new_mode) >= get_mode_size_bits(old_mode);
1191 } /* is_completely_overwritten */
1194 * follow the memory chain as long as there are only Loads and alias free Stores.
1196 * INC_MASTER() must be called before dive into
1198 static unsigned follow_Mem_chain_for_Store(ir_node *store, ir_node *curr) {
1200 ldst_info_t *info = get_irn_link(store);
1202 ir_node *ptr = get_Store_ptr(store);
1203 ir_node *mem = get_Store_mem(store);
1204 ir_node *value = get_Store_value(store);
1205 ir_mode *mode = get_irn_mode(value);
1206 ir_node *block = get_nodes_block(store);
1207 ir_node *mblk = get_Block_MacroBlock(block);
1209 for (pred = curr; pred != store;) {
1210 ldst_info_t *pred_info = get_irn_link(pred);
1213 * BEWARE: one might think that checking the modes is useless, because
1214 * if the pointers are identical, they refer to the same object.
1215 * This is only true in strong typed languages, not is C were the following
1216 * is possible *(ir_type1 *)p = a; *(ir_type2 *)p = b ...
1217 * However, if the mode that is written have a bigger or equal size the the old
1218 * one, the old value is completely overwritten and can be killed ...
1220 if (is_Store(pred) && get_Store_ptr(pred) == ptr &&
1221 get_nodes_MacroBlock(pred) == mblk &&
1222 is_completely_overwritten(get_irn_mode(get_Store_value(pred)), mode)) {
1224 * a Store after a Store in the same MacroBlock -- a write after write.
1225 * We may remove the first Store, if it does not have an exception handler.
1227 * TODO: What, if both have the same exception handler ???
1229 if (get_Store_volatility(pred) != volatility_is_volatile && !pred_info->projs[pn_Store_X_except]) {
1230 DBG_OPT_WAW(pred, store);
1231 exchange(pred_info->projs[pn_Store_M], get_Store_mem(pred));
1233 reduce_adr_usage(ptr);
1236 } else if (is_Load(pred) && get_Load_ptr(pred) == ptr &&
1237 value == pred_info->projs[pn_Load_res]) {
1239 * a Store of a value just loaded from the same address
1240 * -- a write after read.
1241 * We may remove the Store, if it does not have an exception
1244 if (! info->projs[pn_Store_X_except]) {
1245 DBG_OPT_WAR(store, pred);
1246 exchange(info->projs[pn_Store_M], mem);
1248 reduce_adr_usage(ptr);
1253 if (is_Store(pred)) {
1254 /* check if we can pass thru this store */
1255 ir_alias_relation rel = get_alias_relation(
1257 get_Store_ptr(pred),
1258 get_irn_mode(get_Store_value(pred)),
1260 /* if the might be an alias, we cannot pass this Store */
1261 if (rel != ir_no_alias)
1263 pred = skip_Proj(get_Store_mem(pred));
1264 } else if (is_Load(pred)) {
1265 ir_alias_relation rel = get_alias_relation(
1266 current_ir_graph, get_Load_ptr(pred), get_Load_mode(pred),
1268 if (rel != ir_no_alias)
1271 pred = skip_Proj(get_Load_mem(pred));
1273 /* follow only Load chains */
1277 /* check for cycles */
1278 if (NODE_VISITED(pred_info))
1280 MARK_NODE(pred_info);
1283 if (is_Sync(pred)) {
1286 /* handle all Sync predecessors */
1287 for (i = get_Sync_n_preds(pred) - 1; i >= 0; --i) {
1288 res |= follow_Mem_chain_for_Store(store, skip_Proj(get_Sync_pred(pred, i)));
1294 } /* follow_Mem_chain_for_Store */
1299 * @param store the Store node
1301 static unsigned optimize_store(ir_node *store) {
1304 if (get_Store_volatility(store) == volatility_is_volatile)
1307 ptr = get_Store_ptr(store);
1309 /* Check, if the address of this Store is used more than once.
1310 * If not, this Store cannot be removed in any case. */
1311 if (get_irn_n_uses(ptr) <= 1)
1314 mem = get_Store_mem(store);
1316 /* follow the memory chain as long as there are only Loads */
1319 return follow_Mem_chain_for_Store(store, skip_Proj(mem));
1320 } /* optimize_store */
1323 * walker, optimizes Phi after Stores to identical places:
1324 * Does the following optimization:
1327 * val1 val2 val3 val1 val2 val3
1329 * Store Store Store \ | /
1336 * This reduces the number of stores and allows for predicated execution.
1337 * Moves Stores back to the end of a function which may be bad.
1339 * This is only possible if the predecessor blocks have only one successor.
1341 static unsigned optimize_phi(ir_node *phi, walk_env_t *wenv)
1344 ir_node *store, *old_store, *ptr, *block, *phi_block, *phiM, *phiD, *exc, *projM;
1346 ir_node **inM, **inD, **projMs;
1348 dbg_info *db = NULL;
1350 block_info_t *bl_info;
1353 /* Must be a memory Phi */
1354 if (get_irn_mode(phi) != mode_M)
1357 n = get_Phi_n_preds(phi);
1361 /* must be only one user */
1362 projM = get_Phi_pred(phi, 0);
1363 if (get_irn_n_edges(projM) != 1)
1366 store = skip_Proj(projM);
1368 if (!is_Store(store))
1371 block = get_nodes_block(store);
1373 /* abort on dead blocks */
1374 if (is_Block_dead(block))
1377 /* check if the block is post dominated by Phi-block
1378 and has no exception exit */
1379 bl_info = get_irn_link(block);
1380 if (bl_info->flags & BLOCK_HAS_EXC)
1383 phi_block = get_nodes_block(phi);
1384 if (! block_strictly_postdominates(phi_block, block))
1387 /* this is the address of the store */
1388 ptr = get_Store_ptr(store);
1389 mode = get_irn_mode(get_Store_value(store));
1390 info = get_irn_link(store);
1391 exc = info->exc_block;
1393 for (i = 1; i < n; ++i) {
1394 ir_node *pred = get_Phi_pred(phi, i);
1396 if (get_irn_n_edges(pred) != 1)
1399 pred = skip_Proj(pred);
1400 if (!is_Store(pred))
1403 if (ptr != get_Store_ptr(pred) || mode != get_irn_mode(get_Store_value(pred)))
1406 info = get_irn_link(pred);
1408 /* check, if all stores have the same exception flow */
1409 if (exc != info->exc_block)
1412 /* abort on dead blocks */
1413 block = get_nodes_block(pred);
1414 if (is_Block_dead(block))
1417 /* check if the block is post dominated by Phi-block
1418 and has no exception exit. Note that block must be different from
1419 Phi-block, else we would move a Store from end End of a block to its
1421 bl_info = get_irn_link(block);
1422 if (bl_info->flags & BLOCK_HAS_EXC)
1424 if (block == phi_block || ! block_postdominates(phi_block, block))
1429 * ok, when we are here, we found all predecessors of a Phi that
1430 * are Stores to the same address and size. That means whatever
1431 * we do before we enter the block of the Phi, we do a Store.
1432 * So, we can move the Store to the current block:
1434 * val1 val2 val3 val1 val2 val3
1436 * | Str | | Str | | Str | \ | /
1442 * Is only allowed if the predecessor blocks have only one successor.
1445 NEW_ARR_A(ir_node *, projMs, n);
1446 NEW_ARR_A(ir_node *, inM, n);
1447 NEW_ARR_A(ir_node *, inD, n);
1448 NEW_ARR_A(int, idx, n);
1450 /* Prepare: Collect all Store nodes. We must do this
1451 first because we otherwise may loose a store when exchanging its
1454 for (i = n - 1; i >= 0; --i) {
1457 projMs[i] = get_Phi_pred(phi, i);
1458 assert(is_Proj(projMs[i]));
1460 store = get_Proj_pred(projMs[i]);
1461 info = get_irn_link(store);
1463 inM[i] = get_Store_mem(store);
1464 inD[i] = get_Store_value(store);
1465 idx[i] = info->exc_idx;
1467 block = get_nodes_block(phi);
1469 /* second step: create a new memory Phi */
1470 phiM = new_rd_Phi(get_irn_dbg_info(phi), current_ir_graph, block, n, inM, mode_M);
1472 /* third step: create a new data Phi */
1473 phiD = new_rd_Phi(get_irn_dbg_info(phi), current_ir_graph, block, n, inD, mode);
1475 /* rewire memory and kill the node */
1476 for (i = n - 1; i >= 0; --i) {
1477 ir_node *proj = projMs[i];
1480 ir_node *store = get_Proj_pred(proj);
1481 exchange(proj, inM[i]);
1486 /* fourth step: create the Store */
1487 store = new_rd_Store(db, current_ir_graph, block, phiM, ptr, phiD);
1489 co_set_irn_name(store, co_get_irn_ident(old_store));
1492 projM = new_rd_Proj(NULL, current_ir_graph, block, store, mode_M, pn_Store_M);
1494 info = get_ldst_info(store, &wenv->obst);
1495 info->projs[pn_Store_M] = projM;
1497 /* fifths step: repair exception flow */
1499 ir_node *projX = new_rd_Proj(NULL, current_ir_graph, block, store, mode_X, pn_Store_X_except);
1501 info->projs[pn_Store_X_except] = projX;
1502 info->exc_block = exc;
1503 info->exc_idx = idx[0];
1505 for (i = 0; i < n; ++i) {
1506 set_Block_cfgpred(exc, idx[i], projX);
1510 /* the exception block should be optimized as some inputs are identical now */
1516 /* sixth step: replace old Phi */
1517 exchange(phi, projM);
1519 return res | DF_CHANGED;
1520 } /* optimize_phi */
1523 * walker, do the optimizations
1525 static void do_load_store_optimize(ir_node *n, void *env) {
1526 walk_env_t *wenv = env;
1528 switch (get_irn_opcode(n)) {
1531 wenv->changes |= optimize_load(n);
1535 wenv->changes |= optimize_store(n);
1539 wenv->changes |= optimize_phi(n, wenv);
1545 } /* do_load_store_optimize */
1548 typedef struct scc {
1549 ir_node *head; /**< the head of the list */
1552 /** A node entry. */
1553 typedef struct node_entry {
1554 unsigned DFSnum; /**< the DFS number of this node */
1555 unsigned low; /**< the low number of this node */
1556 ir_node *header; /**< the header of this node */
1557 int in_stack; /**< flag, set if the node is on the stack */
1558 ir_node *next; /**< link to the next node the the same scc */
1559 scc *pscc; /**< the scc of this node */
1560 unsigned POnum; /**< the post order number for blocks */
1563 /** A loop entry. */
1564 typedef struct loop_env {
1565 ir_phase ph; /**< the phase object */
1566 ir_node **stack; /**< the node stack */
1567 int tos; /**< tos index */
1568 unsigned nextDFSnum; /**< the current DFS number */
1569 unsigned POnum; /**< current post order number */
1571 unsigned changes; /**< a bitmask of graph changes */
1575 * Gets the node_entry of a node
1577 static node_entry *get_irn_ne(ir_node *irn, loop_env *env) {
1578 ir_phase *ph = &env->ph;
1579 node_entry *e = phase_get_irn_data(&env->ph, irn);
1582 e = phase_alloc(ph, sizeof(*e));
1583 memset(e, 0, sizeof(*e));
1584 phase_set_irn_data(ph, irn, e);
1590 * Push a node onto the stack.
1592 * @param env the loop environment
1593 * @param n the node to push
1595 static void push(loop_env *env, ir_node *n) {
1598 if (env->tos == ARR_LEN(env->stack)) {
1599 int nlen = ARR_LEN(env->stack) * 2;
1600 ARR_RESIZE(ir_node *, env->stack, nlen);
1602 env->stack[env->tos++] = n;
1603 e = get_irn_ne(n, env);
1608 * pop a node from the stack
1610 * @param env the loop environment
1612 * @return The topmost node
1614 static ir_node *pop(loop_env *env) {
1615 ir_node *n = env->stack[--env->tos];
1616 node_entry *e = get_irn_ne(n, env);
1623 * Check if irn is a region constant.
1624 * The block or irn must strictly dominate the header block.
1626 * @param irn the node to check
1627 * @param header_block the header block of the induction variable
1629 static int is_rc(ir_node *irn, ir_node *header_block) {
1630 ir_node *block = get_nodes_block(irn);
1632 return (block != header_block) && block_dominates(block, header_block);
1635 typedef struct phi_entry phi_entry;
1637 ir_node *phi; /**< A phi with a region const memory. */
1638 int pos; /**< The position of the region const memory */
1639 ir_node *load; /**< the newly created load for this phi */
1644 * Move loops out of loops if possible.
1646 * @param pscc the loop described by an SCC
1647 * @param env the loop environment
1649 static void move_loads_out_of_loops(scc *pscc, loop_env *env) {
1650 ir_node *phi, *load, *next, *other, *next_other;
1653 phi_entry *phi_list = NULL;
1655 /* collect all outer memories */
1656 for (phi = pscc->head; phi != NULL; phi = next) {
1657 node_entry *ne = get_irn_ne(phi, env);
1660 /* check all memory Phi's */
1664 assert(get_irn_mode(phi) == mode_M && "DFS geturn non-memory Phi");
1666 for (j = get_irn_arity(phi) - 1; j >= 0; --j) {
1667 ir_node *pred = get_irn_n(phi, j);
1668 node_entry *pe = get_irn_ne(pred, env);
1670 if (pe->pscc != ne->pscc) {
1671 /* not in the same SCC, is region const */
1672 phi_entry *pe = phase_alloc(&env->ph, sizeof(*pe));
1676 pe->next = phi_list;
1681 /* no Phis no fun */
1682 assert(phi_list != NULL && "DFS found a loop without Phi");
1684 for (load = pscc->head; load; load = next) {
1686 node_entry *ne = get_irn_ne(load, env);
1689 if (is_Load(load)) {
1690 ldst_info_t *info = get_irn_link(load);
1691 ir_node *ptr = get_Load_ptr(load);
1693 /* for now, we cannot handle Loads with exceptions */
1694 if (info->projs[pn_Load_res] == NULL || info->projs[pn_Load_X_regular] != NULL || info->projs[pn_Load_X_except] != NULL)
1697 /* for now, we can only handle Load(Global) */
1698 if (! is_Global(ptr))
1700 ent = get_Global_entity(ptr);
1701 load_mode = get_Load_mode(load);
1702 for (other = pscc->head; other != NULL; other = next_other) {
1703 node_entry *ne = get_irn_ne(other, env);
1704 next_other = ne->next;
1706 if (is_Store(other)) {
1707 ir_alias_relation rel = get_alias_relation(
1709 get_Store_ptr(other),
1710 get_irn_mode(get_Store_value(other)),
1712 /* if the might be an alias, we cannot pass this Store */
1713 if (rel != ir_no_alias)
1716 /* only pure Calls are allowed here, so ignore them */
1718 if (other == NULL) {
1723 /* for now, we cannot handle more than one input */
1724 if (phi_list->next != NULL)
1727 /* yep, no aliasing Store found, Load can be moved */
1728 DB((dbg, LEVEL_1, " Found a Load that could be moved: %+F\n", load));
1730 db = get_irn_dbg_info(load);
1731 for (pe = phi_list; pe != NULL; pe = pe->next) {
1733 ir_node *phi = pe->phi;
1734 ir_node *blk = get_nodes_block(phi);
1735 ir_node *pred = get_Block_cfgpred_block(blk, pos);
1738 pe->load = irn = new_rd_Load(db, current_ir_graph, pred, get_Phi_pred(phi, pos), ptr, load_mode);
1739 ninfo = get_ldst_info(irn, phase_obst(&env->ph));
1741 ninfo->projs[pn_Load_M] = mem = new_r_Proj(current_ir_graph, pred, irn, mode_M, pn_Load_M);
1742 set_Phi_pred(phi, pos, mem);
1744 ninfo->projs[pn_Load_res] = new_r_Proj(current_ir_graph, pred, irn, load_mode, pn_Load_res);
1746 DB((dbg, LEVEL_1, " Created %+F in %+F\n", irn, pred));
1749 /* now kill the old Load */
1750 exchange(info->projs[pn_Load_M], get_Load_mem(load));
1751 exchange(info->projs[pn_Load_res], ninfo->projs[pn_Load_res]);
1753 env->changes |= DF_CHANGED;
1757 } /* move_loads_out_of_loops */
1760 * Process a loop SCC.
1762 * @param pscc the SCC
1763 * @param env the loop environment
1765 static void process_loop(scc *pscc, loop_env *env) {
1766 ir_node *irn, *next, *header = NULL;
1767 node_entry *b, *h = NULL;
1768 int j, only_phi, num_outside, process = 0;
1771 /* find the header block for this scc */
1772 for (irn = pscc->head; irn; irn = next) {
1773 node_entry *e = get_irn_ne(irn, env);
1774 ir_node *block = get_nodes_block(irn);
1777 b = get_irn_ne(block, env);
1780 if (h->POnum < b->POnum) {
1791 /* check if this scc contains only Phi, Loads or Stores nodes */
1795 for (irn = pscc->head; irn; irn = next) {
1796 node_entry *e = get_irn_ne(irn, env);
1799 switch (get_irn_opcode(irn)) {
1801 if (is_Call_pure(irn)) {
1802 /* pure calls can be treated like loads */
1806 /* non-pure calls must be handle like may-alias Stores */
1809 /* cannot handle CopyB yet */
1813 if (get_Load_volatility(irn) == volatility_is_volatile) {
1814 /* cannot handle loops with volatile Loads */
1820 if (get_Store_volatility(irn) == volatility_is_volatile) {
1821 /* cannot handle loops with volatile Stores */
1830 for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
1831 ir_node *pred = get_irn_n(irn, j);
1832 node_entry *pe = get_irn_ne(pred, env);
1834 if (pe->pscc != e->pscc) {
1835 /* not in the same SCC, must be a region const */
1836 if (! is_rc(pred, header)) {
1837 /* not a memory loop */
1843 } else if (out_rc != pred) {
1854 /* found a memory loop */
1855 DB((dbg, LEVEL_2, " Found a memory loop:\n "));
1856 if (only_phi && num_outside == 1) {
1857 /* a phi cycle with only one real predecessor can be collapsed */
1858 DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
1860 for (irn = pscc->head; irn; irn = next) {
1861 node_entry *e = get_irn_ne(irn, env);
1864 exchange(irn, out_rc);
1866 env->changes |= DF_CHANGED;
1870 /* set the header for every node in this scc */
1871 for (irn = pscc->head; irn; irn = next) {
1872 node_entry *e = get_irn_ne(irn, env);
1875 DB((dbg, LEVEL_2, " %+F,", irn));
1877 DB((dbg, LEVEL_2, "\n"));
1879 move_loads_out_of_loops(pscc, env);
1883 } /* process_loop */
1888 * @param pscc the SCC
1889 * @param env the loop environment
1891 static void process_scc(scc *pscc, loop_env *env) {
1892 ir_node *head = pscc->head;
1893 node_entry *e = get_irn_ne(head, env);
1895 #ifdef DEBUG_libfirm
1897 ir_node *irn, *next;
1899 DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
1900 for (irn = pscc->head; irn; irn = next) {
1901 node_entry *e = get_irn_ne(irn, env);
1905 DB((dbg, LEVEL_4, " %+F,", irn));
1907 DB((dbg, LEVEL_4, "\n"));
1911 if (e->next != NULL) {
1912 /* this SCC has more than one member */
1913 process_loop(pscc, env);
1918 * Do Tarjan's SCC algorithm and drive load/store optimization.
1920 * @param irn start at this node
1921 * @param env the loop environment
1923 static void dfs(ir_node *irn, loop_env *env)
1926 node_entry *node = get_irn_ne(irn, env);
1928 mark_irn_visited(irn);
1930 node->DFSnum = env->nextDFSnum++;
1931 node->low = node->DFSnum;
1935 if (is_Phi(irn) || is_Sync(irn)) {
1936 n = get_irn_arity(irn);
1937 for (i = 0; i < n; ++i) {
1938 ir_node *pred = get_irn_n(irn, i);
1939 node_entry *o = get_irn_ne(pred, env);
1941 if (irn_not_visited(pred)) {
1943 node->low = MIN(node->low, o->low);
1945 if (o->DFSnum < node->DFSnum && o->in_stack)
1946 node->low = MIN(o->DFSnum, node->low);
1948 } else if (is_fragile_op(irn)) {
1949 ir_node *pred = get_fragile_op_mem(irn);
1950 node_entry *o = get_irn_ne(pred, env);
1952 if (irn_not_visited(pred)) {
1954 node->low = MIN(node->low, o->low);
1956 if (o->DFSnum < node->DFSnum && o->in_stack)
1957 node->low = MIN(o->DFSnum, node->low);
1958 } else if (is_Proj(irn)) {
1959 ir_node *pred = get_Proj_pred(irn);
1960 node_entry *o = get_irn_ne(pred, env);
1962 if (irn_not_visited(pred)) {
1964 node->low = MIN(node->low, o->low);
1966 if (o->DFSnum < node->DFSnum && o->in_stack)
1967 node->low = MIN(o->DFSnum, node->low);
1970 /* IGNORE predecessors */
1973 if (node->low == node->DFSnum) {
1974 scc *pscc = phase_alloc(&env->ph, sizeof(*pscc));
1982 e = get_irn_ne(x, env);
1984 e->next = pscc->head;
1988 process_scc(pscc, env);
1993 * Do the DFS on the memory edges a graph.
1995 * @param irg the graph to process
1996 * @param env the loop environment
1998 static void do_dfs(ir_graph *irg, loop_env *env) {
1999 ir_graph *rem = current_ir_graph;
2000 ir_node *endblk, *end;
2003 current_ir_graph = irg;
2004 inc_irg_visited(irg);
2006 /* visit all memory nodes */
2007 endblk = get_irg_end_block(irg);
2008 for (i = get_Block_n_cfgpreds(endblk) - 1; i >= 0; --i) {
2009 ir_node *pred = get_Block_cfgpred(endblk, i);
2011 pred = skip_Proj(pred);
2012 if (is_Return(pred))
2013 dfs(get_Return_mem(pred), env);
2014 else if (is_Raise(pred))
2015 dfs(get_Raise_mem(pred), env);
2016 else if (is_fragile_op(pred))
2017 dfs(get_fragile_op_mem(pred), env);
2019 assert(0 && "Unknown EndBlock predecessor");
2023 /* visit the keep-alives */
2024 end = get_irg_end(irg);
2025 for (i = get_End_n_keepalives(end) - 1; i >= 0; --i) {
2026 ir_node *ka = get_End_keepalive(end, i);
2028 if (is_Phi(ka) && irn_not_visited(ka))
2031 current_ir_graph = rem;
2035 * Initialize new phase data. We do this always explicit, so return NULL here
2037 static void *init_loop_data(ir_phase *ph, const ir_node *irn, void *data) {
2042 } /* init_loop_data */
2045 * Optimize Loads/Stores in loops.
2047 * @param irg the graph
2049 static int optimize_loops(ir_graph *irg) {
2052 env.stack = NEW_ARR_F(ir_node *, 128);
2057 phase_init(&env.ph, "ldstopt", irg, PHASE_DEFAULT_GROWTH, init_loop_data, NULL);
2059 /* calculate the SCC's and drive loop optimization. */
2062 DEL_ARR_F(env.stack);
2063 phase_free(&env.ph);
2066 } /* optimize_loops */
2069 * do the load store optimization
2071 void optimize_load_store(ir_graph *irg) {
2074 FIRM_DBG_REGISTER(dbg, "firm.opt.ldstopt");
2076 assert(get_irg_phase_state(irg) != phase_building);
2077 assert(get_irg_pinned(irg) != op_pin_state_floats &&
2078 "LoadStore optimization needs pinned graph");
2080 /* we need landing pads */
2081 remove_critical_cf_edges(irg);
2085 /* for Phi optimization post-dominators are needed ... */
2086 assure_postdoms(irg);
2088 if (get_opt_alias_analysis()) {
2089 assure_irg_address_taken_computed(irg);
2090 assure_irp_globals_address_taken_computed();
2093 obstack_init(&env.obst);
2096 /* init the links, then collect Loads/Stores/Proj's in lists */
2098 irg_walk_graph(irg, firm_clear_link, collect_nodes, &env);
2100 /* now we have collected enough information, optimize */
2101 irg_walk_graph(irg, NULL, do_load_store_optimize, &env);
2103 env.changes |= optimize_loops(irg);
2105 obstack_free(&env.obst, NULL);
2107 /* Handle graph state */
2109 set_irg_outs_inconsistent(irg);
2112 if (env.changes & CF_CHANGED) {
2113 /* is this really needed: Yes, control flow changed, block might
2114 have Bad() predecessors. */
2115 set_irg_doms_inconsistent(irg);
2117 } /* optimize_load_store */