7002594: Math.max and Math.min should use floatToRawIntBits() to check for -0.0

Reviewed-by: mduigou, lancea, alanb

src/share/classes/java/lang/Double.java

 /*
- * Copyright (c) 1994, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2010, 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
@@ -973,7 +973,8 @@ public final class Double extends Number implements Comparable<Double> {
         if (d1 > d2)
             return 1;            // Neither val is NaN, thisVal is larger
 
-        long thisBits = Double.doubleToLongBits(d1);
+        // Cannot use doubleToRawLongBits because of possibility of NaNs.
+        long thisBits    = Double.doubleToLongBits(d1);
         long anotherBits = Double.doubleToLongBits(d2);
 
         return (thisBits == anotherBits ?  0 : // Values are equal

src/share/classes/java/lang/Float.java

 /*
- * Copyright (c) 1994, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2010, 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
@@ -872,12 +872,13 @@ public final class Float extends Number implements Comparable<Float> {
      * @since 1.4
      */
     public static int compare(float f1, float f2) {
-       if (f1 < f2)
+        if (f1 < f2)
             return -1;           // Neither val is NaN, thisVal is smaller
         if (f1 > f2)
             return 1;            // Neither val is NaN, thisVal is larger
 
-        int thisBits = Float.floatToIntBits(f1);
+        // Cannot use floatToRawIntBits because of possibility of NaNs.
+        int thisBits    = Float.floatToIntBits(f1);
         int anotherBits = Float.floatToIntBits(f2);
 
         return (thisBits == anotherBits ?  0 : // Values are equal

src/share/classes/java/lang/StrictMath.java

 /*
- * Copyright (c) 1999, 2006, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2010, 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
@@ -801,8 +801,9 @@ public final class StrictMath {
         return (a >= b) ? a : b;
     }
 
-    private static long negativeZeroFloatBits = Float.floatToIntBits(-0.0f);
-    private static long negativeZeroDoubleBits = Double.doubleToLongBits(-0.0d);
+    // Use raw bit-wise conversions on guaranteed non-NaN arguments.
+    private static long negativeZeroFloatBits  = Float.floatToRawIntBits(-0.0f);
+    private static long negativeZeroDoubleBits = Double.doubleToRawLongBits(-0.0d);
 
     /**
      * Returns the greater of two {@code float} values.  That is,
@@ -819,9 +820,12 @@ public final class StrictMath {
      * @return  the larger of {@code a} and {@code b}.
      */
     public static float max(float a, float b) {
-        if (a != a) return a;   // a is NaN
-        if ((a == 0.0f) && (b == 0.0f)
-            && (Float.floatToIntBits(a) == negativeZeroFloatBits)) {
+        if (a != a)
+            return a;   // a is NaN
+        if ((a == 0.0f) &&
+            (b == 0.0f) &&
+            (Float.floatToRawIntBits(a) == negativeZeroFloatBits)) {
+            // Raw conversion ok since NaN can't map to -0.0.
             return b;
         }
         return (a >= b) ? a : b;
@@ -842,9 +846,12 @@ public final class StrictMath {
      * @return  the larger of {@code a} and {@code b}.
      */
     public static double max(double a, double b) {
-        if (a != a) return a;   // a is NaN
-        if ((a == 0.0d) && (b == 0.0d)
-            && (Double.doubleToLongBits(a) == negativeZeroDoubleBits)) {
+        if (a != a)
+            return a;   // a is NaN
+        if ((a == 0.0d) &&
+            (b == 0.0d) &&
+            (Double.doubleToRawLongBits(a) == negativeZeroDoubleBits)) {
+            // Raw conversion ok since NaN can't map to -0.0.
             return b;
         }
         return (a >= b) ? a : b;
@@ -893,9 +900,12 @@ public final class StrictMath {
      * @return  the smaller of {@code a} and {@code b.}
      */
     public static float min(float a, float b) {
-        if (a != a) return a;   // a is NaN
-        if ((a == 0.0f) && (b == 0.0f)
-            && (Float.floatToIntBits(b) == negativeZeroFloatBits)) {
+        if (a != a)
+            return a;   // a is NaN
+        if ((a == 0.0f) &&
+            (b == 0.0f) &&
+            (Float.floatToRawIntBits(b) == negativeZeroFloatBits)) {
+            // Raw conversion ok since NaN can't map to -0.0.
             return b;
         }
         return (a <= b) ? a : b;
@@ -916,9 +926,12 @@ public final class StrictMath {
      * @return  the smaller of {@code a} and {@code b}.
      */
     public static double min(double a, double b) {
-        if (a != a) return a;   // a is NaN
-        if ((a == 0.0d) && (b == 0.0d)
-            && (Double.doubleToLongBits(b) == negativeZeroDoubleBits)) {
+        if (a != a)
+            return a;   // a is NaN
+        if ((a == 0.0d) &&
+            (b == 0.0d) &&
+            (Double.doubleToRawLongBits(b) == negativeZeroDoubleBits)) {
+            // Raw conversion ok since NaN can't map to -0.0.
             return b;
         }
         return (a <= b) ? a : b;