From 943671ba37af9642eedd2a12a166db38006fe67b Mon Sep 17 00:00:00 2001
From: cfang <unknown>
Date: Tue, 5 May 2009 11:02:10 -0700
Subject: [PATCH] 6833879: Assigning positive zero is ignored when old value is
 negative zero Summary: Don't perform CMOVE identity optimization for floating
 point types Reviewed-by: kvn, never

---
 src/share/vm/opto/connode.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/share/vm/opto/connode.cpp b/src/share/vm/opto/connode.cpp
index 46f13c652..9e82a8e44 100644
--- a/src/share/vm/opto/connode.cpp
+++ b/src/share/vm/opto/connode.cpp
@@ -128,6 +128,10 @@ Node *CMoveNode::is_cmove_id( PhaseTransform *phase, Node *cmp, Node *t, Node *f
       // Swapped Cmp is OK
       (phase->eqv(cmp->in(2),f) &&
        phase->eqv(cmp->in(1),t)) ) {
+    // Give up this identity check for floating points because it may choose incorrect
+    // value around 0.0 and -0.0
+    if ( cmp->Opcode()==Op_CmpF || cmp->Opcode()==Op_CmpD )
+      return NULL;
     // Check for "(t==f)?t:f;" and replace with "f"
     if( b->_test._test == BoolTest::eq )
       return f;
-- 
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