6796786: invalid FP identity transform - (a - b) -> b - a

Reviewed-by: iveresov, twisti

src/share/vm/opto/subnode.cpp

@@ -1222,21 +1222,6 @@ bool BoolNode::is_counted_loop_exit_test() {
   return false;
 }
 
-//=============================================================================
-//------------------------------NegNode----------------------------------------
-Node *NegFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
-  if( in(1)->Opcode() == Op_SubF )
-    return new (phase->C, 3) SubFNode( in(1)->in(2), in(1)->in(1) );
-  return NULL;
-}
-
-Node *NegDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
-  if( in(1)->Opcode() == Op_SubD )
-    return new (phase->C, 3) SubDNode( in(1)->in(2), in(1)->in(1) );
-  return NULL;
-}
-
-
 //=============================================================================
 //------------------------------Value------------------------------------------
 // Compute sqrt

src/share/vm/opto/subnode.hpp

@@ -377,7 +377,6 @@ class NegFNode : public NegNode {
 public:
   NegFNode( Node *in1 ) : NegNode(in1) {}
   virtual int Opcode() const;
-  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
   const Type *bottom_type() const { return Type::FLOAT; }
   virtual uint ideal_reg() const { return Op_RegF; }
 };
@@ -391,7 +390,6 @@ class NegDNode : public NegNode {
 public:
   NegDNode( Node *in1 ) : NegNode(in1) {}
   virtual int Opcode() const;
-  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
   const Type *bottom_type() const { return Type::DOUBLE; }
   virtual uint ideal_reg() const { return Op_RegD; }
 };

test/compiler/6796786/Test6796786.java

+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+/**
+ * @test
+ * @bug 6796786
+ * @summary invalid FP identity transform - (a - b) -> b - a
+ *
+ * @run main Test6796786
+ */
+
+public class Test6796786 {
+    static volatile float d1;
+    static volatile float d2;
+    static float zero;
+
+    public static void main(String[] args) {
+        int total = 0;
+        for (int i = 0; i < 100000; i++) {
+            if (Float.floatToRawIntBits(- (d1 - d1)) == Float.floatToRawIntBits(0.0f)) {
+                total++;
+            }
+        }
+        if (total != 100000) {
+            throw new InternalError();
+        }
+    }
+}