2007-10-12 Ian Rogers <ian.rogers@manchester.ac.uk>

2007-10-12  Andrew Haley  <aph@redhat.com>

	PR classpath/33741:
	* java/lang/Double.java:
	(compare(double,double)): Increase performance
	of this method.
	* java/lang/Float.java:
	(compare(float,float)): Likewise.

2 files changed, 40 insertions, 22 deletions

diff --git a/java/lang/Double.java b/java/lang/Double.java
index c71620314..bf965dffb 100644
--- a/java/lang/Double.java
+++ b/java/lang/Double.java
@@ -587,16 +587,25 @@ public final class Double extends Number implements Comparable<Double>
    */
   public static int compare(double x, double y)
   {
-    if (isNaN(x))
-      return isNaN(y) ? 0 : 1;
-    if (isNaN(y))
-      return -1;
-    // recall that 0.0 == -0.0, so we convert to infinites and try again
-    if (x == 0 && y == 0)
-      return (int) (1 / x - 1 / y);
-    if (x == y)
-      return 0;
-
-    return x > y ? 1 : -1;
+      // handle the easy cases:
+      if (x < y)
+	  return -1;
+      if (x > y)
+	  return 1;
+
+      // handle equality respecting that 0.0 != -0.0 (hence not using x == y):
+      long lx = doubleToRawLongBits(x);
+      long ly = doubleToRawLongBits(y);
+      if (lx == ly)
+	  return 0;
+
+      // handle NaNs:
+      if (x != x)
+	  return (y != y) ? 0 : 1;
+      else if (y != y)
+	  return -1;
+
+      // handle +/- 0.0
+      return (lx < ly) ? -1 : 1;
   }
 }
diff --git a/java/lang/Float.java b/java/lang/Float.java
index dc39ec2af..d11045cc0 100644
--- a/java/lang/Float.java
+++ b/java/lang/Float.java
@@ -594,16 +594,25 @@ public final class Float extends Number implements Comparable<Float>
    */
   public static int compare(float x, float y)
   {
-    if (isNaN(x))
-      return isNaN(y) ? 0 : 1;
-    if (isNaN(y))
-      return -1;
-    // recall that 0.0 == -0.0, so we convert to infinities and try again
-    if (x == 0 && y == 0)
-      return (int) (1 / x - 1 / y);
-    if (x == y)
-      return 0;
-
-    return x > y ? 1 : -1;
+      // handle the easy cases:
+      if (x < y)
+	  return -1;
+      if (x > y)
+	  return 1;
+
+      // handle equality respecting that 0.0 != -0.0 (hence not using x == y):
+      int ix = floatToRawIntBits(x);
+      int iy = floatToRawIntBits(y);
+      if (ix == iy)
+	  return 0;
+
+      // handle NaNs:
+      if (x != x)
+	  return (y != y) ? 0 : 1;
+      else if (y != y)
+	  return -1;
+
+      // handle +/- 0.0
+      return (ix < iy) ? -1 : 1;
   }
 }