2 * Copyright (C) 1995-2011 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
30 #include "iroptimize.h"
32 #include "irgraph_t.h"
40 #include "dbginfo_t.h"
41 #include "iropt_dbg.h"
47 #include "opt_polymorphy.h"
49 #include "irnodehashmap.h"
54 #include "opt_manage.h"
56 /** The debug handle. */
57 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
60 #define IMAX(a,b) ((a) > (b) ? (a) : (b))
62 #define MAX_PROJ IMAX(IMAX((long)pn_Load_max, (long)pn_Store_max), (long)pn_Call_max)
65 DF_CHANGED = 1, /**< data flow changed */
66 CF_CHANGED = 2, /**< control flow changed */
72 typedef struct walk_env_t {
73 struct obstack obst; /**< list of all stores */
74 unsigned changes; /**< a bitmask of graph changes */
77 /** A Load/Store info. */
78 typedef struct ldst_info_t {
79 ir_node *projs[MAX_PROJ+1]; /**< list of Proj's of this node */
80 ir_node *exc_block; /**< the exception block if available */
81 int exc_idx; /**< predecessor index in the exception block */
82 unsigned visited; /**< visited counter for breaking loops */
86 * flags for control flow.
89 BLOCK_HAS_COND = 1, /**< Block has conditional control flow */
90 BLOCK_HAS_EXC = 2 /**< Block has exceptional control flow */
96 typedef struct block_info_t {
97 unsigned flags; /**< flags for the block */
100 /** the master visited flag for loop detection. */
101 static unsigned master_visited = 0;
103 #define INC_MASTER() ++master_visited
104 #define MARK_NODE(info) (info)->visited = master_visited
105 #define NODE_VISITED(info) (info)->visited >= master_visited
108 * get the Load/Store info of a node
110 static ldst_info_t *get_ldst_info(ir_node *node, struct obstack *obst)
112 ldst_info_t *info = (ldst_info_t*)get_irn_link(node);
115 info = OALLOCZ(obst, ldst_info_t);
116 set_irn_link(node, info);
119 } /* get_ldst_info */
122 * get the Block info of a node
124 static block_info_t *get_block_info(ir_node *node, struct obstack *obst)
126 block_info_t *info = (block_info_t*)get_irn_link(node);
129 info = OALLOCZ(obst, block_info_t);
130 set_irn_link(node, info);
133 } /* get_block_info */
136 * update the projection info for a Load/Store
138 static unsigned update_projs(ldst_info_t *info, ir_node *proj)
140 long nr = get_Proj_proj(proj);
142 assert(0 <= nr && nr <= MAX_PROJ && "Wrong proj from LoadStore");
144 if (info->projs[nr]) {
145 /* there is already one, do CSE */
146 exchange(proj, info->projs[nr]);
150 info->projs[nr] = proj;
156 * update the exception block info for a Load/Store node.
158 * @param info the load/store info struct
159 * @param block the exception handler block for this load/store
160 * @param pos the control flow input of the block
162 static unsigned update_exc(ldst_info_t *info, ir_node *block, int pos)
164 assert(info->exc_block == NULL && "more than one exception block found");
166 info->exc_block = block;
171 /** Return the number of uses of an address node */
172 #define get_irn_n_uses(adr) get_irn_n_edges(adr)
175 * walker, collects all Load/Store/Proj nodes
177 * walks from Start -> End
179 static void collect_nodes(ir_node *node, void *env)
181 walk_env_t *wenv = (walk_env_t *)env;
182 unsigned opcode = get_irn_opcode(node);
183 ir_node *pred, *blk, *pred_blk;
184 ldst_info_t *ldst_info;
186 if (opcode == iro_Proj) {
187 pred = get_Proj_pred(node);
188 opcode = get_irn_opcode(pred);
190 if (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call) {
191 ldst_info = get_ldst_info(pred, &wenv->obst);
193 wenv->changes |= update_projs(ldst_info, node);
196 * Place the Proj's to the same block as the
197 * predecessor Load. This is always ok and prevents
198 * "non-SSA" form after optimizations if the Proj
199 * is in a wrong block.
201 blk = get_nodes_block(node);
202 pred_blk = get_nodes_block(pred);
203 if (blk != pred_blk) {
204 wenv->changes |= DF_CHANGED;
205 set_nodes_block(node, pred_blk);
208 } else if (opcode == iro_Block) {
211 for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
212 ir_node *pred_block, *proj;
213 block_info_t *bl_info;
216 pred = proj = get_Block_cfgpred(node, i);
219 pred = get_Proj_pred(proj);
220 is_exc = is_x_except_Proj(proj);
223 /* ignore Bad predecessors, they will be removed later */
227 pred_block = get_nodes_block(pred);
228 bl_info = get_block_info(pred_block, &wenv->obst);
230 if (is_fragile_op(pred) && is_exc)
231 bl_info->flags |= BLOCK_HAS_EXC;
232 else if (is_irn_forking(pred))
233 bl_info->flags |= BLOCK_HAS_COND;
235 opcode = get_irn_opcode(pred);
236 if (is_exc && (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call)) {
237 ldst_info = get_ldst_info(pred, &wenv->obst);
239 wenv->changes |= update_exc(ldst_info, node, i);
243 } /* collect_nodes */
246 * Returns an entity if the address ptr points to a constant one.
248 * @param ptr the address
250 * @return an entity or NULL
252 static ir_entity *find_constant_entity(ir_node *ptr)
255 if (is_SymConst(ptr) && get_SymConst_kind(ptr) == symconst_addr_ent) {
256 return get_SymConst_entity(ptr);
257 } else if (is_Sel(ptr)) {
258 ir_entity *ent = get_Sel_entity(ptr);
259 ir_type *tp = get_entity_owner(ent);
261 /* Do not fiddle with polymorphism. */
262 if (is_Class_type(get_entity_owner(ent)) &&
263 ((get_entity_n_overwrites(ent) != 0) ||
264 (get_entity_n_overwrittenby(ent) != 0) ) )
267 if (is_Array_type(tp)) {
271 for (i = 0, n = get_Sel_n_indexs(ptr); i < n; ++i) {
273 ir_tarval *tlower, *tupper;
274 ir_node *index = get_Sel_index(ptr, i);
275 ir_tarval *tv = computed_value(index);
277 /* check if the index is constant */
278 if (tv == tarval_bad)
281 bound = get_array_lower_bound(tp, i);
282 tlower = computed_value(bound);
283 bound = get_array_upper_bound(tp, i);
284 tupper = computed_value(bound);
286 if (tlower == tarval_bad || tupper == tarval_bad)
289 if (tarval_cmp(tv, tlower) == ir_relation_less)
291 if (tarval_cmp(tupper, tv) == ir_relation_less)
294 /* ok, bounds check finished */
298 if (get_entity_linkage(ent) & IR_LINKAGE_CONSTANT)
302 ptr = get_Sel_ptr(ptr);
303 } else if (is_Add(ptr)) {
304 ir_node *l = get_Add_left(ptr);
305 ir_node *r = get_Add_right(ptr);
307 if (get_irn_mode(l) == get_irn_mode(ptr) && is_Const(r))
309 else if (get_irn_mode(r) == get_irn_mode(ptr) && is_Const(l))
314 /* for now, we support only one addition, reassoc should fold all others */
315 if (! is_SymConst(ptr) && !is_Sel(ptr))
317 } else if (is_Sub(ptr)) {
318 ir_node *l = get_Sub_left(ptr);
319 ir_node *r = get_Sub_right(ptr);
321 if (get_irn_mode(l) == get_irn_mode(ptr) && is_Const(r))
325 /* for now, we support only one substraction, reassoc should fold all others */
326 if (! is_SymConst(ptr) && !is_Sel(ptr))
331 } /* find_constant_entity */
334 * Return the Selection index of a Sel node from dimension n
336 static long get_Sel_array_index_long(ir_node *n, int dim)
338 ir_node *index = get_Sel_index(n, dim);
339 assert(is_Const(index));
340 return get_tarval_long(get_Const_tarval(index));
341 } /* get_Sel_array_index_long */
344 * Returns the accessed component graph path for an
345 * node computing an address.
347 * @param ptr the node computing the address
348 * @param depth current depth in steps upward from the root
351 static compound_graph_path *rec_get_accessed_path(ir_node *ptr, size_t depth)
353 compound_graph_path *res = NULL;
354 ir_entity *root, *field, *ent;
355 size_t path_len, pos, idx;
359 if (is_SymConst(ptr)) {
360 /* a SymConst. If the depth is 0, this is an access to a global
361 * entity and we don't need a component path, else we know
362 * at least its length.
364 assert(get_SymConst_kind(ptr) == symconst_addr_ent);
365 root = get_SymConst_entity(ptr);
366 res = (depth == 0) ? NULL : new_compound_graph_path(get_entity_type(root), depth);
367 } else if (is_Sel(ptr)) {
368 /* it's a Sel, go up until we find the root */
369 res = rec_get_accessed_path(get_Sel_ptr(ptr), depth+1);
373 /* fill up the step in the path at the current position */
374 field = get_Sel_entity(ptr);
375 path_len = get_compound_graph_path_length(res);
376 pos = path_len - depth - 1;
377 set_compound_graph_path_node(res, pos, field);
379 if (is_Array_type(get_entity_owner(field))) {
380 assert(get_Sel_n_indexs(ptr) == 1 && "multi dim arrays not implemented");
381 set_compound_graph_path_array_index(res, pos, get_Sel_array_index_long(ptr, 0));
383 } else if (is_Add(ptr)) {
388 ir_node *l = get_Add_left(ptr);
389 ir_node *r = get_Add_right(ptr);
390 if (is_Const(r) && get_irn_mode(l) == get_irn_mode(ptr)) {
392 tv = get_Const_tarval(r);
395 tv = get_Const_tarval(l);
399 mode = get_tarval_mode(tv);
402 /* ptr must be a Sel or a SymConst, this was checked in find_constant_entity() */
404 field = get_Sel_entity(ptr);
406 field = get_SymConst_entity(ptr);
409 for (ent = field;;) {
411 ir_tarval *sz, *tv_index, *tlower, *tupper;
414 tp = get_entity_type(ent);
415 if (! is_Array_type(tp))
417 ent = get_array_element_entity(tp);
418 size = get_type_size_bytes(get_entity_type(ent));
419 sz = new_tarval_from_long(size, mode);
421 tv_index = tarval_div(tmp, sz);
422 tmp = tarval_mod(tmp, sz);
424 if (tv_index == tarval_bad || tmp == tarval_bad)
427 assert(get_array_n_dimensions(tp) == 1 && "multiarrays not implemented");
428 bound = get_array_lower_bound(tp, 0);
429 tlower = computed_value(bound);
430 bound = get_array_upper_bound(tp, 0);
431 tupper = computed_value(bound);
433 if (tlower == tarval_bad || tupper == tarval_bad)
436 if (tarval_cmp(tv_index, tlower) == ir_relation_less)
438 if (tarval_cmp(tupper, tv_index) == ir_relation_less)
441 /* ok, bounds check finished */
444 if (! tarval_is_null(tmp)) {
445 /* access to some struct/union member */
449 /* should be at least ONE array */
453 res = rec_get_accessed_path(ptr, depth + idx);
457 path_len = get_compound_graph_path_length(res);
458 pos = path_len - depth - idx;
460 for (ent = field;;) {
462 ir_tarval *sz, *tv_index;
465 tp = get_entity_type(ent);
466 if (! is_Array_type(tp))
468 ent = get_array_element_entity(tp);
469 set_compound_graph_path_node(res, pos, ent);
471 size = get_type_size_bytes(get_entity_type(ent));
472 sz = new_tarval_from_long(size, mode);
474 tv_index = tarval_div(tv, sz);
475 tv = tarval_mod(tv, sz);
477 /* worked above, should work again */
478 assert(tv_index != tarval_bad && tv != tarval_bad);
480 /* bounds already checked above */
481 index = get_tarval_long(tv_index);
482 set_compound_graph_path_array_index(res, pos, index);
485 } else if (is_Sub(ptr)) {
486 ir_node *l = get_Sub_left(ptr);
487 ir_node *r = get_Sub_right(ptr);
490 tv = get_Const_tarval(r);
495 } /* rec_get_accessed_path */
498 * Returns an access path or NULL. The access path is only
499 * valid, if the graph is in phase_high and _no_ address computation is used.
501 static compound_graph_path *get_accessed_path(ir_node *ptr)
503 compound_graph_path *gr = rec_get_accessed_path(ptr, 0);
505 } /* get_accessed_path */
507 typedef struct path_entry {
509 struct path_entry *next;
513 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 size_t 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)) {
593 ir_node *l = get_Add_left(ptr);
594 ir_node *r = get_Add_right(ptr);
597 tv = get_Const_tarval(r);
600 tv = get_Const_tarval(l);
604 mode = get_tarval_mode(tv);
606 /* ptr must be a Sel or a SymConst, this was checked in find_constant_entity() */
608 field = get_Sel_entity(ptr);
610 field = get_SymConst_entity(ptr);
613 /* count needed entries */
615 for (ent = field;;) {
616 tp = get_entity_type(ent);
617 if (! is_Array_type(tp))
619 ent = get_array_element_entity(tp);
622 /* should be at least ONE entry */
626 /* allocate the right number of entries */
627 NEW_ARR_A(path_entry, p, pos);
631 for (ent = field;;) {
633 ir_tarval *sz, *tv_index, *tlower, *tupper;
637 tp = get_entity_type(ent);
638 if (! is_Array_type(tp))
640 ent = get_array_element_entity(tp);
642 p[pos].next = &p[pos + 1];
644 size = get_type_size_bytes(get_entity_type(ent));
645 sz = new_tarval_from_long(size, mode);
647 tv_index = tarval_div(tv, sz);
648 tv = tarval_mod(tv, sz);
650 if (tv_index == tarval_bad || tv == tarval_bad)
653 assert(get_array_n_dimensions(tp) == 1 && "multiarrays not implemented");
654 bound = get_array_lower_bound(tp, 0);
655 tlower = computed_value(bound);
656 bound = get_array_upper_bound(tp, 0);
657 tupper = computed_value(bound);
659 if (tlower == tarval_bad || tupper == tarval_bad)
662 if (tarval_cmp(tv_index, tlower) == ir_relation_less)
664 if (tarval_cmp(tupper, tv_index) == ir_relation_less)
667 /* ok, bounds check finished */
668 index = get_tarval_long(tv_index);
669 p[pos].index = index;
672 if (! tarval_is_null(tv)) {
673 /* hmm, wrong access */
676 p[pos - 1].next = next;
677 return rec_find_compound_ent_value(ptr, p);
678 } else if (is_Sub(ptr)) {
679 ir_node *l = get_Sub_left(ptr);
680 ir_node *r = get_Sub_right(ptr);
683 tv = get_Const_tarval(r);
690 static ir_node *find_compound_ent_value(ir_node *ptr)
692 return rec_find_compound_ent_value(ptr, NULL);
696 static void reduce_adr_usage(ir_node *ptr);
699 * Update a Load that may have lost its users.
701 static void handle_load_update(ir_node *load)
703 ldst_info_t *info = (ldst_info_t*)get_irn_link(load);
705 /* do NOT touch volatile loads for now */
706 if (get_Load_volatility(load) == volatility_is_volatile)
709 if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) {
710 ir_node *ptr = get_Load_ptr(load);
711 ir_node *mem = get_Load_mem(load);
713 /* a Load whose value is neither used nor exception checked, remove it */
714 exchange(info->projs[pn_Load_M], mem);
715 if (info->projs[pn_Load_X_regular])
716 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(get_nodes_block(load)));
718 reduce_adr_usage(ptr);
720 } /* handle_load_update */
723 * A use of an address node has vanished. Check if this was a Proj
724 * node and update the counters.
726 static void reduce_adr_usage(ir_node *ptr)
731 if (get_irn_n_edges(ptr) > 0)
734 /* this Proj is dead now */
735 pred = get_Proj_pred(ptr);
737 ldst_info_t *info = (ldst_info_t*)get_irn_link(pred);
738 info->projs[get_Proj_proj(ptr)] = NULL;
740 /* this node lost its result proj, handle that */
741 handle_load_update(pred);
743 } /* reduce_adr_usage */
746 * Check, if an already existing value of mode old_mode can be converted
747 * into the needed one new_mode without loss.
749 static int can_use_stored_value(ir_mode *old_mode, ir_mode *new_mode)
753 if (old_mode == new_mode)
756 old_size = get_mode_size_bits(old_mode);
757 new_size = get_mode_size_bits(new_mode);
759 /* if both modes are two-complement ones, we can always convert the
760 Stored value into the needed one. (on big endian machines we currently
761 only support this for modes of same size) */
762 if (old_size >= new_size &&
763 get_mode_arithmetic(old_mode) == irma_twos_complement &&
764 get_mode_arithmetic(new_mode) == irma_twos_complement &&
765 (!be_get_backend_param()->byte_order_big_endian
766 || old_size == new_size)) {
773 * Check whether a Call is at least pure, i.e. does only read memory.
775 static unsigned is_Call_pure(ir_node *call)
777 ir_type *call_tp = get_Call_type(call);
778 unsigned prop = get_method_additional_properties(call_tp);
780 /* check first the call type */
781 if ((prop & (mtp_property_const|mtp_property_pure)) == 0) {
782 /* try the called entity */
783 ir_node *ptr = get_Call_ptr(call);
785 if (is_SymConst_addr_ent(ptr)) {
786 ir_entity *ent = get_SymConst_entity(ptr);
788 prop = get_entity_additional_properties(ent);
791 return (prop & (mtp_property_const|mtp_property_pure)) != 0;
794 static ir_node *get_base_and_offset(ir_node *ptr, long *pOffset)
796 ir_mode *mode = get_irn_mode(ptr);
799 /* TODO: long might not be enough, we should probably use some tarval thingy... */
802 ir_node *l = get_Add_left(ptr);
803 ir_node *r = get_Add_right(ptr);
805 if (get_irn_mode(l) != mode || !is_Const(r))
808 offset += get_tarval_long(get_Const_tarval(r));
810 } else if (is_Sub(ptr)) {
811 ir_node *l = get_Sub_left(ptr);
812 ir_node *r = get_Sub_right(ptr);
814 if (get_irn_mode(l) != mode || !is_Const(r))
817 offset -= get_tarval_long(get_Const_tarval(r));
819 } else if (is_Sel(ptr)) {
820 ir_entity *ent = get_Sel_entity(ptr);
821 ir_type *tp = get_entity_owner(ent);
823 if (is_Array_type(tp)) {
827 /* only one dimensional arrays yet */
828 if (get_Sel_n_indexs(ptr) != 1)
830 index = get_Sel_index(ptr, 0);
831 if (! is_Const(index))
834 tp = get_entity_type(ent);
835 if (get_type_state(tp) != layout_fixed)
838 size = get_type_size_bytes(tp);
839 offset += size * get_tarval_long(get_Const_tarval(index));
841 if (get_type_state(tp) != layout_fixed)
843 offset += get_entity_offset(ent);
845 ptr = get_Sel_ptr(ptr);
854 static int try_load_after_store(ir_node *load,
855 ir_node *load_base_ptr, long load_offset, ir_node *store)
858 ir_node *store_ptr = get_Store_ptr(store);
860 ir_node *store_base_ptr = get_base_and_offset(store_ptr, &store_offset);
861 ir_node *store_value;
870 if (load_base_ptr != store_base_ptr)
873 load_mode = get_Load_mode(load);
874 load_mode_len = get_mode_size_bytes(load_mode);
875 store_mode = get_irn_mode(get_Store_value(store));
876 store_mode_len = get_mode_size_bytes(store_mode);
877 delta = load_offset - store_offset;
878 store_value = get_Store_value(store);
880 if (delta != 0 || store_mode != load_mode) {
881 /* TODO: implement for big-endian */
882 if (delta < 0 || delta + load_mode_len > store_mode_len
883 || (be_get_backend_param()->byte_order_big_endian
884 && load_mode_len != store_mode_len))
887 if (get_mode_arithmetic(store_mode) != irma_twos_complement ||
888 get_mode_arithmetic(load_mode) != irma_twos_complement)
892 /* produce a shift to adjust offset delta */
895 ir_graph *irg = get_irn_irg(load);
897 cnst = new_r_Const_long(irg, mode_Iu, delta * 8);
898 store_value = new_r_Shr(get_nodes_block(load),
899 store_value, cnst, store_mode);
902 /* add an convert if needed */
903 if (store_mode != load_mode) {
904 store_value = new_r_Conv(get_nodes_block(load), store_value, load_mode);
908 DBG_OPT_RAW(load, store_value);
910 info = (ldst_info_t*)get_irn_link(load);
911 if (info->projs[pn_Load_M])
912 exchange(info->projs[pn_Load_M], get_Load_mem(load));
916 if (info->projs[pn_Load_X_except]) {
917 ir_graph *irg = get_irn_irg(load);
918 exchange( info->projs[pn_Load_X_except], new_r_Bad(irg, mode_X));
921 if (info->projs[pn_Load_X_regular]) {
922 exchange( info->projs[pn_Load_X_regular], new_r_Jmp(get_nodes_block(load)));
926 if (info->projs[pn_Load_res])
927 exchange(info->projs[pn_Load_res], store_value);
929 load_ptr = get_Load_ptr(load);
931 reduce_adr_usage(load_ptr);
932 return res | DF_CHANGED;
936 * Follow the memory chain as long as there are only Loads,
937 * alias free Stores, and constant Calls and try to replace the
938 * current Load by a previous ones.
939 * Note that in unreachable loops it might happen that we reach
940 * load again, as well as we can fall into a cycle.
941 * We break such cycles using a special visited flag.
943 * INC_MASTER() must be called before dive into
945 static unsigned follow_Mem_chain(ir_node *load, ir_node *curr)
948 ldst_info_t *info = (ldst_info_t*)get_irn_link(load);
950 ir_node *ptr = get_Load_ptr(load);
951 ir_node *mem = get_Load_mem(load);
952 ir_mode *load_mode = get_Load_mode(load);
954 for (pred = curr; load != pred; ) {
955 ldst_info_t *pred_info = (ldst_info_t*)get_irn_link(pred);
958 * a Load immediately after a Store -- a read after write.
959 * We may remove the Load, if both Load & Store does not have an
960 * exception handler OR they are in the same Block. In the latter
961 * case the Load cannot throw an exception when the previous Store was
964 * Why we need to check for Store Exception? If the Store cannot
965 * be executed (ROM) the exception handler might simply jump into
967 * We could make it a little bit better if we would know that the
968 * exception handler of the Store jumps directly to the end...
970 if (is_Store(pred) && ((pred_info->projs[pn_Store_X_except] == NULL
971 && info->projs[pn_Load_X_except] == NULL)
972 || get_nodes_block(load) == get_nodes_block(pred)))
975 ir_node *base_ptr = get_base_and_offset(ptr, &load_offset);
976 int changes = try_load_after_store(load, base_ptr, load_offset, pred);
979 return res | changes;
980 } else if (is_Load(pred) && get_Load_ptr(pred) == ptr &&
981 can_use_stored_value(get_Load_mode(pred), load_mode)) {
983 * a Load after a Load -- a read after read.
984 * We may remove the second Load, if it does not have an exception
985 * handler OR they are in the same Block. In the later case
986 * the Load cannot throw an exception when the previous Load was
989 * Here, there is no need to check if the previous Load has an
990 * exception hander because they would have exact the same
993 * TODO: implement load-after-load with different mode for big
996 if (info->projs[pn_Load_X_except] == NULL
997 || get_nodes_block(load) == get_nodes_block(pred)) {
1000 DBG_OPT_RAR(load, pred);
1002 /* the result is used */
1003 if (info->projs[pn_Load_res]) {
1004 if (pred_info->projs[pn_Load_res] == NULL) {
1005 /* create a new Proj again */
1006 pred_info->projs[pn_Load_res] = new_r_Proj(pred, get_Load_mode(pred), pn_Load_res);
1008 value = pred_info->projs[pn_Load_res];
1010 /* add an convert if needed */
1011 if (get_Load_mode(pred) != load_mode) {
1012 value = new_r_Conv(get_nodes_block(load), value, load_mode);
1015 exchange(info->projs[pn_Load_res], value);
1018 if (info->projs[pn_Load_M])
1019 exchange(info->projs[pn_Load_M], mem);
1022 if (info->projs[pn_Load_X_except]) {
1023 ir_graph *irg = get_irn_irg(load);
1024 exchange(info->projs[pn_Load_X_except], new_r_Bad(irg, mode_X));
1027 if (info->projs[pn_Load_X_regular]) {
1028 exchange( info->projs[pn_Load_X_regular], new_r_Jmp(get_nodes_block(load)));
1033 reduce_adr_usage(ptr);
1034 return res |= DF_CHANGED;
1038 if (is_Store(pred)) {
1039 /* check if we can pass through this store */
1040 ir_alias_relation rel = get_alias_relation(
1041 get_Store_ptr(pred),
1042 get_irn_mode(get_Store_value(pred)),
1044 /* if the might be an alias, we cannot pass this Store */
1045 if (rel != ir_no_alias)
1047 pred = skip_Proj(get_Store_mem(pred));
1048 } else if (is_Load(pred)) {
1049 pred = skip_Proj(get_Load_mem(pred));
1050 } else if (is_Call(pred)) {
1051 if (is_Call_pure(pred)) {
1052 /* The called graph is at least pure, so there are no Store's
1053 in it. We can handle it like a Load and skip it. */
1054 pred = skip_Proj(get_Call_mem(pred));
1056 /* there might be Store's in the graph, stop here */
1060 /* follow only Load chains */
1064 /* check for cycles */
1065 if (NODE_VISITED(pred_info))
1067 MARK_NODE(pred_info);
1070 if (is_Sync(pred)) {
1073 /* handle all Sync predecessors */
1074 for (i = get_Sync_n_preds(pred) - 1; i >= 0; --i) {
1075 res |= follow_Mem_chain(load, skip_Proj(get_Sync_pred(pred, i)));
1082 } /* follow_Mem_chain */
1085 * Check if we can replace the load by a given const from
1086 * the const code irg.
1088 ir_node *can_replace_load_by_const(const ir_node *load, ir_node *c)
1090 ir_mode *c_mode = get_irn_mode(c);
1091 ir_mode *l_mode = get_Load_mode(load);
1092 ir_node *block = get_nodes_block(load);
1093 dbg_info *dbgi = get_irn_dbg_info(load);
1094 ir_node *res = copy_const_value(dbgi, c, block);
1096 if (c_mode != l_mode) {
1097 /* check, if the mode matches OR can be easily converted info */
1098 if (is_reinterpret_cast(c_mode, l_mode)) {
1099 /* copy the value from the const code irg and cast it */
1100 res = new_rd_Conv(dbgi, block, res, l_mode);
1111 * @param load the Load node
1113 static unsigned optimize_load(ir_node *load)
1115 ldst_info_t *info = (ldst_info_t*)get_irn_link(load);
1116 ir_node *mem, *ptr, *value;
1121 /* do NOT touch volatile loads for now */
1122 if (get_Load_volatility(load) == volatility_is_volatile)
1125 /* the address of the load to be optimized */
1126 ptr = get_Load_ptr(load);
1128 /* The mem of the Load. Must still be returned after optimization. */
1129 mem = get_Load_mem(load);
1131 if (info->projs[pn_Load_res] == NULL
1132 && info->projs[pn_Load_X_except] == NULL) {
1133 /* the value is never used and we don't care about exceptions, remove */
1134 exchange(info->projs[pn_Load_M], mem);
1136 if (info->projs[pn_Load_X_regular]) {
1137 /* should not happen, but if it does, remove it */
1138 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(get_nodes_block(load)));
1142 reduce_adr_usage(ptr);
1143 return res | DF_CHANGED;
1146 /* Load from a constant polymorphic field, where we can resolve
1148 value = transform_polymorph_Load(load);
1149 if (value == load) {
1151 /* check if we can determine the entity that will be loaded */
1152 ent = find_constant_entity(ptr);
1154 && get_entity_visibility(ent) != ir_visibility_external) {
1155 /* a static allocation that is not external: there should be NO
1156 * exception when loading even if we cannot replace the load itself.
1159 /* no exception, clear the info field as it might be checked later again */
1160 if (info->projs[pn_Load_X_except]) {
1161 ir_graph *irg = get_irn_irg(load);
1162 exchange(info->projs[pn_Load_X_except], new_r_Bad(irg, mode_X));
1163 info->projs[pn_Load_X_except] = NULL;
1166 if (info->projs[pn_Load_X_regular]) {
1167 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(get_nodes_block(load)));
1168 info->projs[pn_Load_X_regular] = NULL;
1172 if (get_entity_linkage(ent) & IR_LINKAGE_CONSTANT) {
1173 if (has_entity_initializer(ent)) {
1174 /* new style initializer */
1175 value = find_compound_ent_value(ptr);
1176 } else if (entity_has_compound_ent_values(ent)) {
1177 /* old style initializer */
1178 compound_graph_path *path = get_accessed_path(ptr);
1181 assert(is_proper_compound_graph_path(path, get_compound_graph_path_length(path)-1));
1183 value = get_compound_ent_value_by_path(ent, path);
1184 DB((dbg, LEVEL_1, " Constant access at %F%F resulted in %+F\n", ent, path, value));
1185 free_compound_graph_path(path);
1188 if (value != NULL) {
1189 ir_graph *irg = get_irn_irg(load);
1190 value = can_replace_load_by_const(load, value);
1191 if (value != NULL && is_Sel(ptr) &&
1192 !is_irg_state(irg, IR_GRAPH_STATE_IMPLICIT_BITFIELD_MASKING)) {
1193 /* frontend has inserted masking operations after bitfield accesses,
1194 * so we might have to shift the const. */
1195 unsigned char bit_offset = get_entity_offset_bits_remainder(get_Sel_entity(ptr));
1196 ir_tarval *tv_old = get_Const_tarval(value);
1197 ir_tarval *tv_offset = new_tarval_from_long(bit_offset, mode_Bu);
1198 ir_tarval *tv_new = tarval_shl(tv_old, tv_offset);
1199 value = new_r_Const(irg, tv_new);
1205 if (value != NULL) {
1206 /* we completely replace the load by this value */
1207 if (info->projs[pn_Load_X_except]) {
1208 ir_graph *irg = get_irn_irg(load);
1209 exchange(info->projs[pn_Load_X_except], new_r_Bad(irg, mode_X));
1210 info->projs[pn_Load_X_except] = NULL;
1213 if (info->projs[pn_Load_X_regular]) {
1214 exchange(info->projs[pn_Load_X_regular], new_r_Jmp(get_nodes_block(load)));
1215 info->projs[pn_Load_X_regular] = NULL;
1218 if (info->projs[pn_Load_M]) {
1219 exchange(info->projs[pn_Load_M], mem);
1222 if (info->projs[pn_Load_res]) {
1223 exchange(info->projs[pn_Load_res], value);
1227 reduce_adr_usage(ptr);
1231 /* Check, if the address of this load is used more than once.
1232 * If not, more load cannot be removed in any case. */
1233 if (get_irn_n_uses(ptr) <= 1 && get_irn_n_uses(get_base_and_offset(ptr, &dummy)) <= 1)
1237 * follow the memory chain as long as there are only Loads
1238 * and try to replace current Load or Store by a previous one.
1239 * Note that in unreachable loops it might happen that we reach
1240 * load again, as well as we can fall into a cycle.
1241 * We break such cycles using a special visited flag.
1244 res = follow_Mem_chain(load, skip_Proj(mem));
1246 } /* optimize_load */
1249 * Check whether a value of mode new_mode would completely overwrite a value
1250 * of mode old_mode in memory.
1252 static int is_completely_overwritten(ir_mode *old_mode, ir_mode *new_mode)
1254 return get_mode_size_bits(new_mode) >= get_mode_size_bits(old_mode);
1255 } /* is_completely_overwritten */
1258 * Check whether small is a part of large (starting at same address).
1260 static int is_partially_same(ir_node *small, ir_node *large)
1262 ir_mode *sm = get_irn_mode(small);
1263 ir_mode *lm = get_irn_mode(large);
1265 /* FIXME: Check endianness */
1266 return is_Conv(small) && get_Conv_op(small) == large
1267 && get_mode_size_bytes(sm) < get_mode_size_bytes(lm)
1268 && get_mode_arithmetic(sm) == irma_twos_complement
1269 && get_mode_arithmetic(lm) == irma_twos_complement;
1270 } /* is_partially_same */
1273 * follow the memory chain as long as there are only Loads and alias free Stores.
1275 * INC_MASTER() must be called before dive into
1277 static unsigned follow_Mem_chain_for_Store(ir_node *store, ir_node *curr)
1280 ldst_info_t *info = (ldst_info_t*)get_irn_link(store);
1282 ir_node *ptr = get_Store_ptr(store);
1283 ir_node *mem = get_Store_mem(store);
1284 ir_node *value = get_Store_value(store);
1285 ir_mode *mode = get_irn_mode(value);
1286 ir_node *block = get_nodes_block(store);
1288 for (pred = curr; pred != store;) {
1289 ldst_info_t *pred_info = (ldst_info_t*)get_irn_link(pred);
1292 * BEWARE: one might think that checking the modes is useless, because
1293 * if the pointers are identical, they refer to the same object.
1294 * This is only true in strong typed languages, not is C were the following
1295 * is possible *(ir_type1 *)p = a; *(ir_type2 *)p = b ...
1296 * However, if the size of the mode that is written is bigger or equal the
1297 * size of the old one, the old value is completely overwritten and can be
1300 if (is_Store(pred) && get_Store_ptr(pred) == ptr &&
1301 get_nodes_block(pred) == block) {
1303 * a Store after a Store in the same Block -- a write after write.
1307 * We may remove the first Store, if the old value is completely
1308 * overwritten or the old value is a part of the new value,
1309 * and if it does not have an exception handler.
1311 * TODO: What, if both have the same exception handler ???
1313 if (get_Store_volatility(pred) != volatility_is_volatile
1314 && !pred_info->projs[pn_Store_X_except]) {
1315 ir_node *predvalue = get_Store_value(pred);
1316 ir_mode *predmode = get_irn_mode(predvalue);
1318 if (is_completely_overwritten(predmode, mode)
1319 || is_partially_same(predvalue, value)) {
1320 DBG_OPT_WAW(pred, store);
1321 exchange(pred_info->projs[pn_Store_M], get_Store_mem(pred));
1323 reduce_adr_usage(ptr);
1329 * We may remove the Store, if the old value already contains
1330 * the new value, and if it does not have an exception handler.
1332 * TODO: What, if both have the same exception handler ???
1334 if (get_Store_volatility(store) != volatility_is_volatile
1335 && !info->projs[pn_Store_X_except]) {
1336 ir_node *predvalue = get_Store_value(pred);
1338 if (is_partially_same(value, predvalue)) {
1339 DBG_OPT_WAW(pred, store);
1340 exchange(info->projs[pn_Store_M], mem);
1342 reduce_adr_usage(ptr);
1346 } else if (is_Load(pred) && get_Load_ptr(pred) == ptr &&
1347 value == pred_info->projs[pn_Load_res]) {
1349 * a Store of a value just loaded from the same address
1350 * -- a write after read.
1351 * We may remove the Store, if it does not have an exception
1354 if (! info->projs[pn_Store_X_except]) {
1355 DBG_OPT_WAR(store, pred);
1356 exchange(info->projs[pn_Store_M], mem);
1358 reduce_adr_usage(ptr);
1363 if (is_Store(pred)) {
1364 /* check if we can pass through this store */
1365 ir_alias_relation rel = get_alias_relation(
1366 get_Store_ptr(pred),
1367 get_irn_mode(get_Store_value(pred)),
1369 /* if the might be an alias, we cannot pass this Store */
1370 if (rel != ir_no_alias)
1372 pred = skip_Proj(get_Store_mem(pred));
1373 } else if (is_Load(pred)) {
1374 ir_alias_relation rel = get_alias_relation(
1375 get_Load_ptr(pred), get_Load_mode(pred),
1377 if (rel != ir_no_alias)
1380 pred = skip_Proj(get_Load_mem(pred));
1382 /* follow only Load chains */
1386 /* check for cycles */
1387 if (NODE_VISITED(pred_info))
1389 MARK_NODE(pred_info);
1392 if (is_Sync(pred)) {
1395 /* handle all Sync predecessors */
1396 for (i = get_Sync_n_preds(pred) - 1; i >= 0; --i) {
1397 res |= follow_Mem_chain_for_Store(store, skip_Proj(get_Sync_pred(pred, i)));
1403 } /* follow_Mem_chain_for_Store */
1405 /** find entity used as base for an address calculation */
1406 static ir_entity *find_entity(ir_node *ptr)
1408 switch (get_irn_opcode(ptr)) {
1410 return get_SymConst_entity(ptr);
1412 ir_node *pred = get_Sel_ptr(ptr);
1413 if (get_irg_frame(get_irn_irg(ptr)) == pred)
1414 return get_Sel_entity(ptr);
1416 return find_entity(pred);
1420 ir_node *left = get_binop_left(ptr);
1422 if (mode_is_reference(get_irn_mode(left)))
1423 return find_entity(left);
1424 right = get_binop_right(ptr);
1425 if (mode_is_reference(get_irn_mode(right)))
1426 return find_entity(right);
1437 * @param store the Store node
1439 static unsigned optimize_store(ir_node *store)
1445 if (get_Store_volatility(store) == volatility_is_volatile)
1448 ptr = get_Store_ptr(store);
1449 entity = find_entity(ptr);
1451 /* a store to an entity which is never read is unnecessary */
1452 if (entity != NULL && !(get_entity_usage(entity) & ir_usage_read)) {
1453 ldst_info_t *info = (ldst_info_t*)get_irn_link(store);
1454 if (info->projs[pn_Store_X_except] == NULL) {
1455 DB((dbg, LEVEL_1, " Killing useless %+F to never read entity %+F\n", store, entity));
1456 exchange(info->projs[pn_Store_M], get_Store_mem(store));
1458 reduce_adr_usage(ptr);
1463 /* Check, if the address of this Store is used more than once.
1464 * If not, this Store cannot be removed in any case. */
1465 if (get_irn_n_uses(ptr) <= 1)
1468 mem = get_Store_mem(store);
1470 /* follow the memory chain as long as there are only Loads */
1473 return follow_Mem_chain_for_Store(store, skip_Proj(mem));
1474 } /* optimize_store */
1477 * walker, optimizes Phi after Stores to identical places:
1478 * Does the following optimization:
1481 * val1 val2 val3 val1 val2 val3
1483 * Store Store Store \ | /
1490 * This reduces the number of stores and allows for predicated execution.
1491 * Moves Stores back to the end of a function which may be bad.
1493 * This is only possible if the predecessor blocks have only one successor.
1495 static unsigned optimize_phi(ir_node *phi, walk_env_t *wenv)
1498 ir_node *store, *ptr, *block, *phi_block, *phiM, *phiD, *exc, *projM;
1503 ir_node **inM, **inD, **projMs;
1505 dbg_info *db = NULL;
1507 block_info_t *bl_info;
1510 /* Must be a memory Phi */
1511 if (get_irn_mode(phi) != mode_M)
1514 n = get_Phi_n_preds(phi);
1518 /* must be only one user */
1519 projM = get_Phi_pred(phi, 0);
1520 if (get_irn_n_edges(projM) != 1)
1523 store = skip_Proj(projM);
1527 if (!is_Store(store))
1530 block = get_nodes_block(store);
1532 /* check if the block is post dominated by Phi-block
1533 and has no exception exit */
1534 bl_info = (block_info_t*)get_irn_link(block);
1535 if (bl_info->flags & BLOCK_HAS_EXC)
1538 phi_block = get_nodes_block(phi);
1539 if (! block_strictly_postdominates(phi_block, block))
1542 /* this is the address of the store */
1543 ptr = get_Store_ptr(store);
1544 mode = get_irn_mode(get_Store_value(store));
1545 info = (ldst_info_t*)get_irn_link(store);
1546 exc = info->exc_block;
1548 for (i = 1; i < n; ++i) {
1549 ir_node *pred = get_Phi_pred(phi, i);
1551 if (get_irn_n_edges(pred) != 1)
1554 pred = skip_Proj(pred);
1555 if (!is_Store(pred))
1558 if (ptr != get_Store_ptr(pred) || mode != get_irn_mode(get_Store_value(pred)))
1561 info = (ldst_info_t*)get_irn_link(pred);
1563 /* check, if all stores have the same exception flow */
1564 if (exc != info->exc_block)
1567 block = get_nodes_block(pred);
1569 /* check if the block is post dominated by Phi-block
1570 and has no exception exit. Note that block must be different from
1571 Phi-block, else we would move a Store from end End of a block to its
1573 bl_info = (block_info_t*)get_irn_link(block);
1574 if (bl_info->flags & BLOCK_HAS_EXC)
1576 if (block == phi_block || ! block_postdominates(phi_block, block))
1581 * ok, when we are here, we found all predecessors of a Phi that
1582 * are Stores to the same address and size. That means whatever
1583 * we do before we enter the block of the Phi, we do a Store.
1584 * So, we can move the Store to the current block:
1586 * val1 val2 val3 val1 val2 val3
1588 * | Str | | Str | | Str | \ | /
1594 * Is only allowed if the predecessor blocks have only one successor.
1597 NEW_ARR_A(ir_node *, projMs, n);
1598 NEW_ARR_A(ir_node *, inM, n);
1599 NEW_ARR_A(ir_node *, inD, n);
1600 NEW_ARR_A(int, idx, n);
1602 /* Prepare: Collect all Store nodes. We must do this
1603 first because we otherwise may loose a store when exchanging its
1606 for (i = n - 1; i >= 0; --i) {
1609 projMs[i] = get_Phi_pred(phi, i);
1610 assert(is_Proj(projMs[i]));
1612 store = get_Proj_pred(projMs[i]);
1613 info = (ldst_info_t*)get_irn_link(store);
1615 inM[i] = get_Store_mem(store);
1616 inD[i] = get_Store_value(store);
1617 idx[i] = info->exc_idx;
1619 block = get_nodes_block(phi);
1621 /* second step: create a new memory Phi */
1622 phiM = new_rd_Phi(get_irn_dbg_info(phi), block, n, inM, mode_M);
1624 /* third step: create a new data Phi */
1625 phiD = new_rd_Phi(get_irn_dbg_info(phi), block, n, inD, mode);
1627 /* rewire memory and kill the node */
1628 for (i = n - 1; i >= 0; --i) {
1629 ir_node *proj = projMs[i];
1631 if (is_Proj(proj)) {
1632 ir_node *store = get_Proj_pred(proj);
1633 exchange(proj, inM[i]);
1638 /* fourth step: create the Store */
1639 store = new_rd_Store(db, block, phiM, ptr, phiD, cons_none);
1641 co_set_irn_name(store, co_get_irn_ident(old_store));
1644 projM = new_rd_Proj(NULL, store, mode_M, pn_Store_M);
1646 info = get_ldst_info(store, &wenv->obst);
1647 info->projs[pn_Store_M] = projM;
1649 /* fifths step: repair exception flow */
1651 ir_node *projX = new_rd_Proj(NULL, store, mode_X, pn_Store_X_except);
1653 info->projs[pn_Store_X_except] = projX;
1654 info->exc_block = exc;
1655 info->exc_idx = idx[0];
1657 for (i = 0; i < n; ++i) {
1658 set_Block_cfgpred(exc, idx[i], projX);
1662 /* the exception block should be optimized as some inputs are identical now */
1668 /* sixth step: replace old Phi */
1669 exchange(phi, projM);
1671 return res | DF_CHANGED;
1672 } /* optimize_phi */
1675 * walker, do the optimizations
1677 static void do_load_store_optimize(ir_node *n, void *env)
1679 walk_env_t *wenv = (walk_env_t*)env;
1681 switch (get_irn_opcode(n)) {
1684 wenv->changes |= optimize_load(n);
1688 wenv->changes |= optimize_store(n);
1692 wenv->changes |= optimize_phi(n, wenv);
1698 } /* do_load_store_optimize */
1701 typedef struct scc {
1702 ir_node *head; /**< the head of the list */
1705 /** A node entry. */
1706 typedef struct node_entry {
1707 unsigned DFSnum; /**< the DFS number of this node */
1708 unsigned low; /**< the low number of this node */
1709 int in_stack; /**< flag, set if the node is on the stack */
1710 ir_node *next; /**< link to the next node the the same scc */
1711 scc *pscc; /**< the scc of this node */
1712 unsigned POnum; /**< the post order number for blocks */
1715 /** A loop entry. */
1716 typedef struct loop_env {
1717 ir_nodehashmap_t map;
1718 struct obstack obst;
1719 ir_node **stack; /**< the node stack */
1720 size_t tos; /**< tos index */
1721 unsigned nextDFSnum; /**< the current DFS number */
1722 unsigned POnum; /**< current post order number */
1724 unsigned changes; /**< a bitmask of graph changes */
1728 * Gets the node_entry of a node
1730 static node_entry *get_irn_ne(ir_node *irn, loop_env *env)
1732 node_entry *e = (node_entry*)ir_nodehashmap_get(&env->map, irn);
1735 e = OALLOC(&env->obst, node_entry);
1736 memset(e, 0, sizeof(*e));
1737 ir_nodehashmap_insert(&env->map, irn, e);
1743 * Push a node onto the stack.
1745 * @param env the loop environment
1746 * @param n the node to push
1748 static void push(loop_env *env, ir_node *n)
1752 if (env->tos == ARR_LEN(env->stack)) {
1753 size_t nlen = ARR_LEN(env->stack) * 2;
1754 ARR_RESIZE(ir_node *, env->stack, nlen);
1756 env->stack[env->tos++] = n;
1757 e = get_irn_ne(n, env);
1762 * pop a node from the stack
1764 * @param env the loop environment
1766 * @return The topmost node
1768 static ir_node *pop(loop_env *env)
1770 ir_node *n = env->stack[--env->tos];
1771 node_entry *e = get_irn_ne(n, env);
1778 * Check if irn is a region constant.
1779 * The block or irn must strictly dominate the header block.
1781 * @param irn the node to check
1782 * @param header_block the header block of the induction variable
1784 static int is_rc(ir_node *irn, ir_node *header_block)
1786 ir_node *block = get_nodes_block(irn);
1788 return (block != header_block) && block_dominates(block, header_block);
1791 typedef struct phi_entry phi_entry;
1793 ir_node *phi; /**< A phi with a region const memory. */
1794 int pos; /**< The position of the region const memory */
1795 ir_node *load; /**< the newly created load for this phi */
1800 * An entry in the avail set.
1802 typedef struct avail_entry_t {
1803 ir_node *ptr; /**< the address pointer */
1804 ir_mode *mode; /**< the load mode */
1805 ir_node *load; /**< the associated Load */
1809 * Compare two avail entries.
1811 static int cmp_avail_entry(const void *elt, const void *key, size_t size)
1813 const avail_entry_t *a = (const avail_entry_t*)elt;
1814 const avail_entry_t *b = (const avail_entry_t*)key;
1817 return a->ptr != b->ptr || a->mode != b->mode;
1818 } /* cmp_avail_entry */
1821 * Calculate the hash value of an avail entry.
1823 static unsigned hash_cache_entry(const avail_entry_t *entry)
1825 return get_irn_idx(entry->ptr) * 9 + HASH_PTR(entry->mode);
1826 } /* hash_cache_entry */
1829 * Move loops out of loops if possible.
1831 * @param pscc the loop described by an SCC
1832 * @param env the loop environment
1834 static void move_loads_out_of_loops(scc *pscc, loop_env *env)
1836 ir_node *phi, *load, *next, *other, *next_other;
1838 phi_entry *phi_list = NULL;
1841 avail = new_set(cmp_avail_entry, 8);
1843 /* collect all outer memories */
1844 for (phi = pscc->head; phi != NULL; phi = next) {
1845 node_entry *ne = get_irn_ne(phi, env);
1848 /* check all memory Phi's */
1852 assert(get_irn_mode(phi) == mode_M && "DFS return non-memory Phi");
1854 for (j = get_irn_arity(phi) - 1; j >= 0; --j) {
1855 ir_node *pred = get_irn_n(phi, j);
1856 node_entry *pe = get_irn_ne(pred, env);
1858 if (pe->pscc != ne->pscc) {
1859 /* not in the same SCC, is region const */
1860 phi_entry *pe = OALLOC(&env->obst, phi_entry);
1864 pe->next = phi_list;
1869 /* no Phis no fun */
1870 assert(phi_list != NULL && "DFS found a loop without Phi");
1872 /* for now, we cannot handle more than one input (only reducible cf) */
1873 if (phi_list->next != NULL)
1876 for (load = pscc->head; load; load = next) {
1878 node_entry *ne = get_irn_ne(load, env);
1881 if (is_Load(load)) {
1882 ldst_info_t *info = (ldst_info_t*)get_irn_link(load);
1883 ir_node *ptr = get_Load_ptr(load);
1885 /* for now, we cannot handle Loads with exceptions */
1886 if (info->projs[pn_Load_res] == NULL || info->projs[pn_Load_X_regular] != NULL || info->projs[pn_Load_X_except] != NULL)
1889 /* for now, we can only move Load(Global) */
1890 if (! is_SymConst_addr_ent(ptr))
1892 load_mode = get_Load_mode(load);
1893 for (other = pscc->head; other != NULL; other = next_other) {
1894 node_entry *ne = get_irn_ne(other, env);
1895 next_other = ne->next;
1897 if (is_Store(other)) {
1898 ir_alias_relation rel = get_alias_relation(
1899 get_Store_ptr(other),
1900 get_irn_mode(get_Store_value(other)),
1902 /* if the might be an alias, we cannot pass this Store */
1903 if (rel != ir_no_alias)
1906 /* only Phis and pure Calls are allowed here, so ignore them */
1908 if (other == NULL) {
1909 ldst_info_t *ninfo = NULL;
1913 /* yep, no aliasing Store found, Load can be moved */
1914 DB((dbg, LEVEL_1, " Found a Load that could be moved: %+F\n", load));
1916 db = get_irn_dbg_info(load);
1917 for (pe = phi_list; pe != NULL; pe = pe->next) {
1919 ir_node *phi = pe->phi;
1920 ir_node *blk = get_nodes_block(phi);
1921 ir_node *pred = get_Block_cfgpred_block(blk, pos);
1923 avail_entry_t entry, *res;
1926 entry.mode = load_mode;
1927 res = (avail_entry_t*)set_find(avail, &entry, sizeof(entry), hash_cache_entry(&entry));
1931 irn = new_rd_Load(db, pred, get_Phi_pred(phi, pos), ptr, load_mode, cons_none);
1933 set_insert(avail, &entry, sizeof(entry), hash_cache_entry(&entry));
1934 DB((dbg, LEVEL_1, " Created %+F in %+F\n", irn, pred));
1937 ninfo = get_ldst_info(irn, &env->obst);
1939 ninfo->projs[pn_Load_M] = mem = new_r_Proj(irn, mode_M, pn_Load_M);
1941 /* irn is from cache, so do not set phi pred again.
1942 * There might be other Loads between phi and irn already.
1944 set_Phi_pred(phi, pos, mem);
1947 ninfo->projs[pn_Load_res] = new_r_Proj(irn, load_mode, pn_Load_res);
1950 /* now kill the old Load */
1951 exchange(info->projs[pn_Load_M], get_Load_mem(load));
1952 exchange(info->projs[pn_Load_res], ninfo->projs[pn_Load_res]);
1954 env->changes |= DF_CHANGED;
1959 } /* move_loads_out_of_loops */
1962 * Process a loop SCC.
1964 * @param pscc the SCC
1965 * @param env the loop environment
1967 static void process_loop(scc *pscc, loop_env *env)
1969 ir_node *irn, *next, *header = NULL;
1970 node_entry *b, *h = NULL;
1971 int j, only_phi, num_outside, process = 0;
1974 /* find the header block for this scc */
1975 for (irn = pscc->head; irn; irn = next) {
1976 node_entry *e = get_irn_ne(irn, env);
1977 ir_node *block = get_nodes_block(irn);
1980 b = get_irn_ne(block, env);
1982 if (header != NULL) {
1983 if (h->POnum < b->POnum) {
1993 /* check if this scc contains only Phi, Loads or Stores nodes */
1997 for (irn = pscc->head; irn; irn = next) {
1998 node_entry *e = get_irn_ne(irn, env);
2001 switch (get_irn_opcode(irn)) {
2003 if (is_Call_pure(irn)) {
2004 /* pure calls can be treated like loads */
2008 /* non-pure calls must be handle like may-alias Stores */
2011 /* cannot handle CopyB yet */
2015 if (get_Load_volatility(irn) == volatility_is_volatile) {
2016 /* cannot handle loops with volatile Loads */
2022 if (get_Store_volatility(irn) == volatility_is_volatile) {
2023 /* cannot handle loops with volatile Stores */
2032 for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
2033 ir_node *pred = get_irn_n(irn, j);
2034 node_entry *pe = get_irn_ne(pred, env);
2036 if (pe->pscc != e->pscc) {
2037 /* not in the same SCC, must be a region const */
2038 if (! is_rc(pred, header)) {
2039 /* not a memory loop */
2042 if (out_rc == NULL) {
2043 /* first region constant */
2046 } else if (out_rc != pred) {
2047 /* another region constant */
2058 /* found a memory loop */
2059 DB((dbg, LEVEL_2, " Found a memory loop:\n "));
2060 if (only_phi && num_outside == 1) {
2061 /* a phi cycle with only one real predecessor can be collapsed */
2062 DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
2064 for (irn = pscc->head; irn; irn = next) {
2065 node_entry *e = get_irn_ne(irn, env);
2067 exchange(irn, out_rc);
2069 env->changes |= DF_CHANGED;
2073 #ifdef DEBUG_libfirm
2074 for (irn = pscc->head; irn; irn = next) {
2075 node_entry *e = get_irn_ne(irn, env);
2077 DB((dbg, LEVEL_2, " %+F,", irn));
2079 DB((dbg, LEVEL_2, "\n"));
2081 move_loads_out_of_loops(pscc, env);
2085 } /* process_loop */
2090 * @param pscc the SCC
2091 * @param env the loop environment
2093 static void process_scc(scc *pscc, loop_env *env)
2095 ir_node *head = pscc->head;
2096 node_entry *e = get_irn_ne(head, env);
2098 #ifdef DEBUG_libfirm
2100 ir_node *irn, *next;
2102 DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
2103 for (irn = pscc->head; irn; irn = next) {
2104 node_entry *e = get_irn_ne(irn, env);
2108 DB((dbg, LEVEL_4, " %+F,", irn));
2110 DB((dbg, LEVEL_4, "\n"));
2114 if (e->next != NULL) {
2115 /* this SCC has more than one member */
2116 process_loop(pscc, env);
2121 * Do Tarjan's SCC algorithm and drive load/store optimization.
2123 * @param irn start at this node
2124 * @param env the loop environment
2126 static void dfs(ir_node *irn, loop_env *env)
2129 node_entry *node = get_irn_ne(irn, env);
2131 mark_irn_visited(irn);
2133 node->DFSnum = env->nextDFSnum++;
2134 node->low = node->DFSnum;
2138 if (is_Phi(irn) || is_Sync(irn)) {
2139 n = get_irn_arity(irn);
2140 for (i = 0; i < n; ++i) {
2141 ir_node *pred = get_irn_n(irn, i);
2142 node_entry *o = get_irn_ne(pred, env);
2144 if (!irn_visited(pred)) {
2146 node->low = MIN(node->low, o->low);
2148 if (o->DFSnum < node->DFSnum && o->in_stack)
2149 node->low = MIN(o->DFSnum, node->low);
2151 } else if (is_fragile_op(irn)) {
2152 ir_node *pred = get_fragile_op_mem(irn);
2153 node_entry *o = get_irn_ne(pred, env);
2155 if (!irn_visited(pred)) {
2157 node->low = MIN(node->low, o->low);
2159 if (o->DFSnum < node->DFSnum && o->in_stack)
2160 node->low = MIN(o->DFSnum, node->low);
2161 } else if (is_Proj(irn)) {
2162 ir_node *pred = get_Proj_pred(irn);
2163 node_entry *o = get_irn_ne(pred, env);
2165 if (!irn_visited(pred)) {
2167 node->low = MIN(node->low, o->low);
2169 if (o->DFSnum < node->DFSnum && o->in_stack)
2170 node->low = MIN(o->DFSnum, node->low);
2173 /* IGNORE predecessors */
2176 if (node->low == node->DFSnum) {
2177 scc *pscc = OALLOC(&env->obst, scc);
2185 e = get_irn_ne(x, env);
2187 e->next = pscc->head;
2191 process_scc(pscc, env);
2196 * Do the DFS on the memory edges a graph.
2198 * @param irg the graph to process
2199 * @param env the loop environment
2201 static void do_dfs(ir_graph *irg, loop_env *env)
2203 ir_node *endblk, *end;
2206 inc_irg_visited(irg);
2208 /* visit all memory nodes */
2209 endblk = get_irg_end_block(irg);
2210 for (i = get_Block_n_cfgpreds(endblk) - 1; i >= 0; --i) {
2211 ir_node *pred = get_Block_cfgpred(endblk, i);
2213 pred = skip_Proj(pred);
2214 if (is_Return(pred)) {
2215 dfs(get_Return_mem(pred), env);
2216 } else if (is_Raise(pred)) {
2217 dfs(get_Raise_mem(pred), env);
2218 } else if (is_fragile_op(pred)) {
2219 dfs(get_fragile_op_mem(pred), env);
2220 } else if (is_Bad(pred)) {
2221 /* ignore non-optimized block predecessor */
2223 assert(0 && "Unknown EndBlock predecessor");
2227 /* visit the keep-alives */
2228 end = get_irg_end(irg);
2229 for (i = get_End_n_keepalives(end) - 1; i >= 0; --i) {
2230 ir_node *ka = get_End_keepalive(end, i);
2232 if (is_Phi(ka) && !irn_visited(ka))
2238 * Optimize Loads/Stores in loops.
2240 * @param irg the graph
2242 static int optimize_loops(ir_graph *irg)
2246 env.stack = NEW_ARR_F(ir_node *, 128);
2251 ir_nodehashmap_init(&env.map);
2252 obstack_init(&env.obst);
2254 /* calculate the SCC's and drive loop optimization. */
2257 DEL_ARR_F(env.stack);
2258 obstack_free(&env.obst, NULL);
2259 ir_nodehashmap_destroy(&env.map);
2262 } /* optimize_loops */
2265 * do the load store optimization
2267 static ir_graph_state_t do_loadstore_opt(ir_graph *irg)
2270 ir_graph_state_t res = 0;
2272 FIRM_DBG_REGISTER(dbg, "firm.opt.ldstopt");
2274 assert(get_irg_phase_state(irg) != phase_building);
2275 assert(get_irg_pinned(irg) != op_pin_state_floats &&
2276 "LoadStore optimization needs pinned graph");
2278 if (get_opt_alias_analysis()) {
2279 assure_irp_globals_entity_usage_computed();
2282 obstack_init(&env.obst);
2285 /* init the links, then collect Loads/Stores/Proj's in lists */
2287 irg_walk_graph(irg, firm_clear_link, collect_nodes, &env);
2289 /* now we have collected enough information, optimize */
2290 irg_walk_graph(irg, NULL, do_load_store_optimize, &env);
2292 env.changes |= optimize_loops(irg);
2294 obstack_free(&env.obst, NULL);
2296 /* Handle graph state */
2298 edges_deactivate(irg);
2301 if (!(env.changes & CF_CHANGED)) {
2302 res |= IR_GRAPH_STATE_CONSISTENT_DOMINANCE | IR_GRAPH_STATE_NO_BADS;
2308 static optdesc_t opt_loadstore = {
2310 IR_GRAPH_STATE_NO_UNREACHABLE_CODE | IR_GRAPH_STATE_CONSISTENT_OUT_EDGES | IR_GRAPH_STATE_NO_CRITICAL_EDGES | IR_GRAPH_STATE_CONSISTENT_DOMINANCE | IR_GRAPH_STATE_CONSISTENT_ENTITY_USAGE,
2314 int optimize_load_store(ir_graph *irg)
2316 perform_irg_optimization(irg, &opt_loadstore);
2320 ir_graph_pass_t *optimize_load_store_pass(const char *name)
2322 return def_graph_pass_ret(name ? name : "ldst", optimize_load_store);
2323 } /* optimize_load_store_pass */