[PATCH] 8217561 : X86: Add floating-point Math.min/max intrinsics, approval request

Andrew Haley aph at redhat.com
Sun Feb 17 18:02:56 UTC 2019

On 2/17/19 3:36 PM, B. Blaser wrote:

> We see that the new instruction sequence is about 2x faster than the
> previous one.  Could we have a Reviewer feedback and eventually a
> definitive approval for this?

I don't think that benchmark is necessarily representative either.
It's not so common to have totally unpredictable comparisons. For
comparison we need both predictable and unpredictable tests.

A good example of a predictable test would be

   public double fMinReduce(Blackhole bh) {
       double result = Double.MAX_DOUBLE;
       for (int i=0; i<COUNT; i++)
           result = Math.min(result, floats[i]);
       return result;

What does the intrinsic do to the performance of that test?

Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671

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