| commit | 92dba0d2780331d68e56bdb1a5e0af13b714be73 | [log] [tgz] |
|---|---|---|
| author | Russ Cox <rsc@golang.org> | Wed Apr 01 16:02:34 2015 -0400 |
| committer | Russ Cox <rsc@golang.org> | Fri Apr 03 16:13:36 2015 +0000 |
| tree | 85569ca34e7c2a65861156739b038cf74c4c5072 | |
| parent | 90c0fefe51b59f854f4eb7a8bc29348ae478b673 [diff] |
cmd/internal/gc: use hardware instruction for math.Sqrt (amd64/arm) I first prototyped this change in Sept 2011, and I discarded it because it made no difference in the obvious benchmark loop. It still makes no difference in the obvious benchmark loop, but in a less obvious one, doing some extra computation around the calls to Sqrt, not making the call does have a significant effect. benchmark old ns/op new ns/op delta BenchmarkSqrt 4.56 4.57 +0.22% BenchmarkSqrtIndirect 4.56 4.56 +0.00% BenchmarkSqrtGo 69.4 69.4 +0.00% BenchmarkSqrtPrime 4417 3647 -17.43% This is a warmup for using hardware expansions for some calls to 1-line assembly routines in the runtime (for example getg). Change-Id: Ie66be23f8c09d0f7dc4ddd7ca8a93cfce28f55a4 Reviewed-on: https://go-review.googlesource.com/8356 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
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