X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fldstopt.c;h=70703a7e51dfbce392f17cd3e8ce87ce81d63948;hb=c7dc950ac0cdd7d24acffb798b5867d0db5dd7c8;hp=c1f214c08a6cab551cfb6a51a5ba374463b55540;hpb=36332e717eebd9b98603a99ea24e390a1d2aa3be;p=libfirm

diff --git a/ir/opt/ldstopt.c b/ir/opt/ldstopt.c
index c1f214c08..70703a7e5 100644
--- a/ir/opt/ldstopt.c
+++ b/ir/opt/ldstopt.c
@@ -887,7 +887,7 @@ static unsigned follow_Mem_chain_for_Store(ir_node *store, ir_node *curr) {
 		    get_nodes_MacroBlock(pred) == mblk &&
 		    is_completely_overwritten(get_irn_mode(get_Store_value(pred)), mode)) {
 			/*
-			 * a Store after a Store in the same block -- a write after write.
+			 * a Store after a Store in the same MacroBlock -- a write after write.
 			 * We may remove the first Store, if it does not have an exception handler.
 			 *
 			 * TODO: What, if both have the same exception handler ???
@@ -902,8 +902,10 @@ static unsigned follow_Mem_chain_for_Store(ir_node *store, ir_node *curr) {
 		} else if (is_Load(pred) && get_Load_ptr(pred) == ptr &&
 		           value == pred_info->projs[pn_Load_res]) {
 			/*
-			 * a Store of a value after a Load -- a write after read.
-			 * We may remove the second Store, if it does not have an exception handler.
+			 * a Store of a value just loaded from the same address
+			 * -- a write after read.
+			 * We may remove the Store, if it does not have an exception
+			 * handler.
 			 */
 			if (! info->projs[pn_Store_X_except]) {
 				DBG_OPT_WAR(store, pred);
@@ -926,6 +928,12 @@ static unsigned follow_Mem_chain_for_Store(ir_node *store, ir_node *curr) {
 				break;
 			pred = skip_Proj(get_Store_mem(pred));
 		} else if (get_irn_op(pred) == op_Load) {
+			ir_alias_relation rel = get_alias_relation(
+				current_ir_graph, get_Load_ptr(pred), get_Load_mode(pred),
+				ptr, mode);
+			if (rel != no_alias)
+				break;
+
 			pred = skip_Proj(get_Load_mem(pred));
 		} else {
 			/* follow only Load chains */
@@ -973,6 +981,7 @@ static unsigned optimize_store(ir_node *store) {
 
 	/* follow the memory chain as long as there are only Loads */
 	INC_MASTER();
+
 	return follow_Mem_chain_for_Store(store, skip_Proj(mem));
 }  /* optimize_store */