On Thu, 8 Jul 2021 00:38:45 GMT, Joe Darcy <da...@openjdk.org> wrote:

>> Please consider this change to make the `float` and `double` versions of 
>> `java.lang.Math.abs()` branch-free.
>
> src/java.base/share/classes/java/lang/Math.java line 1530:
> 
>> 1528:     @IntrinsicCandidate
>> 1529:     public static float abs(float a) {
>> 1530:         return Float.intBitsToFloat(Float.floatToRawIntBits(a) & 
>> 0x7fffffff);
> 
> I'd like to see a brief comment on these methods along the lines of "zero out 
> sign bit in the representation." Using underscores in the literal to better 
> group the digits or using the constants in jdk.internal.math.DoubleConsts.

There is no specific constant in `{Float,Double}Consts` to mask all but the 
sign bit, but I had thought it might be good to add one there.

-------------

PR: https://git.openjdk.java.net/jdk/pull/4711

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