From: Matthias Braun <matze@braunis.de>
Date: Wed, 4 Jul 2007 12:13:51 +0000 (+0000)
Subject: cmov with unknowns are pointless
X-Git-Url: http://nsz.repo.hu/git/?a=commitdiff_plain;h=d07cec1341e61a5321ec44d93455bbbac312be75;p=libfirm

cmov with unknowns are pointless

[r14925]
---

diff --git a/ir/be/ia32/ia32_transform.c b/ir/be/ia32/ia32_transform.c
index b48bbbe8c..584417c73 100644
--- a/ir/be/ia32/ia32_transform.c
+++ b/ir/be/ia32/ia32_transform.c
@@ -1892,6 +1892,20 @@ static ir_node *create_cmov(long pnc, ir_node *cmp_left, ir_node *cmp_right,
 	ir_node  *new_cmp_right;
 	ir_node  *res;
 
+	/* cmovs with unknowns are pointless... */
+	if(is_Unknown(val_true)) {
+#ifdef DEBUG_libfirm
+		ir_fprintf(stderr, "Optimisation warning: psi with unknown operand\n");
+#endif
+		return new_val_false;
+	}
+	if(is_Unknown(val_false)) {
+#ifdef DEBUG_libfirm
+		ir_fprintf(stderr, "Optimisation warning: psi with unknown operand\n");
+#endif
+		return new_val_true;
+	}
+
 	/* can we use a test instruction? */
 	if(is_Const_0(cmp_right)) {
 		long pure_pnc = pnc & ~ia32_pn_Cmp_Unsigned;