X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fana%2Firconsconfirm.c;h=57b8f3c5cce991f2ca0d3ab79aff275d84411c96;hb=dd4cd761ab637d4488c7e29f49843b1b02366acf;hp=c8f93461305a6de57516e238cdbd2508fc5cadcd;hpb=960d88fb7fd5805f957a66bdf7cbc034659b7a71;p=libfirm

diff --git a/ir/ana/irconsconfirm.c b/ir/ana/irconsconfirm.c
index c8f934613..57b8f3c5c 100644
--- a/ir/ana/irconsconfirm.c
+++ b/ir/ana/irconsconfirm.c
@@ -415,7 +415,31 @@ static void insert_Confirm_in_block(ir_node *block, void *env) {
 }  /* insert_Confirm_in_block */
 
 /**
- * The given will be dereferenced, add non-null confirms.
+ * Checks if a node is a non-null Confirm.
+ */
+static int is_non_null_Confirm(const ir_node *ptr) {
+	/*
+	 * While a SymConst is not a Confirm, it is non-null
+	 * anyway. This helps to reduce the number of
+	 * constructed Confirms.
+	 */
+	if (is_SymConst_addr_ent(ptr))
+		return 1;
+	for (;;) {
+		if (! is_Confirm(ptr))
+			return 0;
+		if (get_Confirm_cmp(ptr) == pn_Cmp_Lg) {
+			ir_node *bound = get_Confirm_bound(ptr);
+
+			if (is_Const(bound) && is_Const_null(bound))
+				return 1;
+		}
+		ptr = get_Confirm_value(ptr);
+	}
+}  /* is_non_null_Confirm */
+
+/**
+ * The given pointer will be dereferenced, add non-null Confirms.
  *
  * @param ptr    a node representing an address
  * @param block  the block of the dereferencing instruction
@@ -431,6 +455,11 @@ static void insert_non_null(ir_node *ptr, ir_node *block, env_t *env) {
 		ir_node *blk;
 
 
+		if (is_Confirm(succ)) {
+			/* beware of loops */
+			continue;
+		}
+
 		if ((is_Load(succ) || is_Store(succ)) &&
 			get_nodes_block(succ) == block) {
 			/* Ignore Loads and Store in the same block for now,
@@ -443,7 +472,7 @@ static void insert_non_null(ir_node *ptr, ir_node *block, env_t *env) {
 		pos = get_edge_src_pos(edge);
 		blk = get_effective_use_block(succ, pos);
 
-		if (block_dominates(block, blk)) {
+		if (block_dominates(block, blk) && !is_non_null_Confirm(get_irn_n(succ, pos))) {
 			/*
 			 * Ok, we found a usage of ptr in a block
 			 * dominated by the Load/Store block.
@@ -465,23 +494,6 @@ static void insert_non_null(ir_node *ptr, ir_node *block, env_t *env) {
 	}
 }  /* insert_non_null */
 
-/**
- * Checks if a node is a non-null Confirm.
- */
-static int is_non_null_Confirm(const ir_node *ptr) {
-	for (;;) {
-		if (! is_Confirm(ptr))
-			return 0;
-		if (get_Confirm_cmp(ptr) == pn_Cmp_Lg) {
-			ir_node *bound = get_Confirm_bound(ptr);
-
-			if (is_Const(bound) && is_Const_null(bound))
-				return 1;
-		}
-		ptr = get_Confirm_value(ptr);
-	}
-}  /* is_non_null_Confirm */
-
 /**
  * Pre-walker: Called for every node to insert Confirm nodes
  */
@@ -571,7 +583,7 @@ static void rem_Confirm(ir_node *n, void *env) {
 			exchange(n, value);
 		else {
 			/*
-			 * Strange: a Confirm is it's own bound. This can happen
+			 * Strange: a Confirm is its own bound. This can happen
 			 * in dead blocks when Phi nodes are already removed.
 			 */
 			exchange(n, new_Bad());