| commit | bd8a39b67a12ec3d271305105dea3b8521aa70bf | [log] [tgz] |
|---|---|---|
| author | Michael Munday <munday@ca.ibm.com> | Sun Feb 12 22:12:12 2017 -0500 |
| committer | Michael Munday <munday@ca.ibm.com> | Tue Feb 28 15:34:20 2017 +0000 |
| tree | 840138c7b3f628be2a3074d1ddf3eaac075f7070 | |
| parent | a38a2d02d5c26adb34ec18b495a1d698517c1735 [diff] |
cmd/compile: emit fused multiply-{add,subtract} instructions on s390x
Explcitly block fused multiply-add pattern matching when a cast is used
after the multiplication, for example:
- (a * b) + c // can emit fused multiply-add
- float64(a * b) + c // cannot emit fused multiply-add
float{32,64} and complex{64,128} casts of matching types are now kept
as OCONV operations rather than being replaced with OCONVNOP operations
because they now imply a rounding operation (and therefore aren't a
no-op anymore).
Operations (for example, multiplication) on complex types may utilize
fused multiply-add and -subtract instructions internally. There is no
way to disable this behavior at the moment.
Improves the performance of the floating point implementation of
poly1305:
name old speed new speed delta
64 246MB/s ± 0% 275MB/s ± 0% +11.48% (p=0.000 n=10+8)
1K 312MB/s ± 0% 357MB/s ± 0% +14.41% (p=0.000 n=10+10)
64Unaligned 246MB/s ± 0% 274MB/s ± 0% +11.43% (p=0.000 n=10+10)
1KUnaligned 312MB/s ± 0% 357MB/s ± 0% +14.39% (p=0.000 n=10+8)
Updates #17895.
Change-Id: Ia771d275bb9150d1a598f8cc773444663de5ce16
Reviewed-on: https://go-review.googlesource.com/36963
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
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