Float.compare(float, float) and Double.compare(double, double) are very expensive and in the heart of key loops

In Arrays.qsort the methods Float.compare and Double.compare are used depending on the values in the array. The compare operations perform the following (copied from GNU Classpath):

if (isNaN)
return isNaN ? 0 : 1;
if (isNaN)
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;

In the normal case we're going to hit 6 floating point compares. The case of 0, 0 is common due to using qsort on branch profiles, and this results in 2 divides and 1 subtract. Given we're just comparing to values we should be able to do this substantially cheaper in a VM specific/magic version.