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| author | Michael Munday <mike.munday@ibm.com> | 2020-06-04 10:55:01 -0700 |
|---|---|---|
| committer | Michael Munday <mike.munday@ibm.com> | 2020-08-18 15:39:44 +0000 |
| commit | 6e876f19857a8fbd259571080f7f91bc03276559 (patch) | |
| tree | 4845861dc5048a34b8ea1b7a001515935b04d34c /test/codegen | |
| parent | 4149493443f09c14d9f0fad7030704ed57149b55 (diff) | |
| download | go-6e876f19857a8fbd259571080f7f91bc03276559.tar.gz go-6e876f19857a8fbd259571080f7f91bc03276559.zip | |
cmd/compile: clean up and optimize s390x multiplication rules
Some of the existing optimizations aren't triggered because they
are handled by the generic rules so this CL removes them. Also
some constraints were copied without much thought from the amd64
rules and they don't make sense on s390x, so we remove those
constraints.
Finally, add a 'multiply by the sum of two powers of two'
optimization. This makes sense on s390x as shifts are low latency
and can also sometimes be optimized further (especially if we add
support for RISBG instructions).
name old time/op new time/op delta
IntMulByConst/3-8 1.70ns ±11% 1.10ns ± 5% -35.26% (p=0.000 n=10+10)
IntMulByConst/5-8 1.64ns ± 7% 1.10ns ± 4% -32.94% (p=0.000 n=10+9)
IntMulByConst/12-8 1.65ns ± 6% 1.20ns ± 4% -27.16% (p=0.000 n=10+9)
IntMulByConst/120-8 1.66ns ± 4% 1.22ns ±13% -26.43% (p=0.000 n=10+10)
IntMulByConst/-120-8 1.65ns ± 7% 1.19ns ± 4% -28.06% (p=0.000 n=9+10)
IntMulByConst/65537-8 0.86ns ± 9% 1.12ns ±12% +30.41% (p=0.000 n=10+10)
IntMulByConst/65538-8 1.65ns ± 5% 1.23ns ± 5% -25.11% (p=0.000 n=10+10)
Change-Id: Ib196e6bff1e97febfd266134d0a2b2a62897989f
Reviewed-on: https://go-review.googlesource.com/c/go/+/248937
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'test/codegen')
| -rw-r--r-- | test/codegen/arithmetic.go | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/test/codegen/arithmetic.go b/test/codegen/arithmetic.go index 8f25974376..9f30ec8ce4 100644 --- a/test/codegen/arithmetic.go +++ b/test/codegen/arithmetic.go @@ -71,9 +71,15 @@ func Mul_96(n int) int { // 386:`SHLL\t[$]5`,`LEAL\t\(.*\)\(.*\*2\),`,-`IMULL` // arm64:`LSL\t[$]5`,`ADD\sR[0-9]+<<1,\sR[0-9]+`,-`MUL` // arm:`SLL\t[$]5`,`ADD\sR[0-9]+<<1,\sR[0-9]+`,-`MUL` + // s390x:`SLD\t[$]5`,`SLD\t[$]6`,-`MULLD` return n * 96 } +func Mul_n120(n int) int { + // s390x:`SLD\t[$]3`,`SLD\t[$]7`,-`MULLD` + return n * -120 +} + func MulMemSrc(a []uint32, b []float32) { // 386:`IMULL\s4\([A-Z]+\),\s[A-Z]+` a[0] *= a[1] |