From: Andreas Zwinkau <zwinkau@kit.edu>
Date: Mon, 16 May 2011 11:56:08 +0000 (+0200)
Subject: Do not gcse unreachable code
X-Git-Url: http://nsz.repo.hu/git/?a=commitdiff_plain;h=c64fe29;p=libfirm

Do not gcse unreachable code

During global CSE we now ignore nodes in unreachable blocks,
otherwise cse could pick the wrong representative node
and use unreachable nodes in reachable code.
---

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index 679410da3..ba62501a6 100644
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -6129,6 +6129,16 @@ ir_node *identify_remember(ir_node *n)
 	if (value_table == NULL)
 		return n;
 
+	if (get_opt_global_cse()) {
+		/* do not remember unreachable nodes */
+		if (get_irg_dom_state(irg) == dom_consistent && !is_Block(n)) {
+			ir_node *block = get_nodes_block(n);
+			if (get_Block_dom_depth(block) < 0) {
+				return n;
+			}
+		}
+	}
+
 	ir_normalize_node(n);
 	/* lookup or insert in hash table with given hash key. */
 	nn = (ir_node*)pset_insert(value_table, n, ir_node_hash(n));