Incorrect transformation of (sub,neg) to (sub) for fp

A pair (sub,neg) should not be transformed to (sub) for
floating point operations, otherwise we can lose the sign of
zero for instructions like this:
  - (A - B) != B - A if B == A

Change-Id: I4d612612d4dc0a067fac5721ad206f74168bcd36
Signed-off-by: Serguei Katkov <serguei.i.katkov@intel.com>

3 files changed, 52 insertions, 0 deletions

diff --git a/test/474-fp-sub-neg/expected.txt b/test/474-fp-sub-neg/expected.txt
new file mode 100644
index 0000000000..e6ffe0d430
--- /dev/null
+++ b/test/474-fp-sub-neg/expected.txt
@@ -0,0 +1,2 @@
+-0.0
+-0.0
diff --git a/test/474-fp-sub-neg/info.txt b/test/474-fp-sub-neg/info.txt
new file mode 100644
index 0000000000..eced93fef5
--- /dev/null
+++ b/test/474-fp-sub-neg/info.txt
@@ -0,0 +1,5 @@
+Regression check for optimizing simplify instruction pass.
+A pair (sub, neg) should not be transforemd to (sub) for
+fp calculation because we can lose the sign of zero for
+the following expression:
+  - ( A - B ) != B - A ; if B == A
diff --git a/test/474-fp-sub-neg/src/Main.java b/test/474-fp-sub-neg/src/Main.java
new file mode 100644
index 0000000000..e6bce6793f
--- /dev/null
+++ b/test/474-fp-sub-neg/src/Main.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class Main {
+    public static void floatTest() {
+      float f = 0;
+      float fc = 1f;
+      for (int i = 0; i < 2; i++) {
+        f -= fc;
+        f = -f;
+      }
+
+      System.out.println(f);
+    }
+
+    public static void doubleTest() {
+      double d = 0;
+      double dc = 1f;
+      for (int i = 0; i < 2; i++) {
+        d -= dc;
+        d = -d;
+      }
+
+      System.out.println(d);
+    }
+
+    public static void main(String[] args) {
+        doubleTest();
+        floatTest();
+    }
+
+}