RFR: 6506405: Math.abs(float) is slow [v5]

[Brian Burkhalter]

On Fri, 9 Jul 2021 13:54:39 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   6506405: Add some tests
>
> test/jdk/java/lang/Math/AbsTests.java line 35:
> 
>> 33:  */
>> 34: public class AbsTests {
>> 35:     private static final float  EULER_F   = (float)Math.exp(1.0);
> 
> Could use Math.E here instead.

Yeah that was lame.

> test/jdk/java/lang/Math/AbsTests.java line 168:
> 
>> 166:     private static float testInRangeFloatAbs() {
>> 167:         int errors = 0;
>> 168:         float[][] testCases  = {
> 
> For the particulars of the test vector for abs, another way to structure this would be a 1-D array of positive numbers where nested test loops used the test value and its negation as the input with the positive number as the expected value.

Changed to 1-D array but can be either positive or negative.

> test/jdk/java/lang/Math/AbsTests.java line 198:
> 
>> 196:                            float argument, float expected) {
>> 197:         float result = absFunc.apply(argument);
>> 198:         if (result != expected) {
> 
> I suggest looking at some other math test for the "equivalent" test idiom so that NaNs could be used in the test vector.

Added `NaN` check in latest update but might be suspect.

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

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