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| author | Ben Shi <powerman1st@163.com> | 2019-08-07 05:20:32 +0000 |
|---|---|---|
| committer | Ben Shi <powerman1st@163.com> | 2019-08-28 02:29:54 +0000 |
| commit | 22355d6cd2421f13e560f90e77ca04ef816456da (patch) | |
| tree | 3ed677893926c8f3bbc21e2962d23ac517a31c70 /src/cmd/compile/internal/ssa/rewrite386.go | |
| parent | e1e4c499f0849af4fca353163e4ffabbda6f9089 (diff) | |
| download | go-22355d6cd2421f13e560f90e77ca04ef816456da.tar.gz go-22355d6cd2421f13e560f90e77ca04ef816456da.zip | |
cmd/compile: optimize 386's math.bits.TrailingZeros16
This CL optimizes math.bits.TrailingZeros16 on 386 with
a pair of BSFL and ORL instrcutions.
The case TrailingZeros16-4 of the benchmark test in
math/bits shows big improvement.
name old time/op new time/op delta
TrailingZeros16-4 1.55ns ± 1% 0.87ns ± 1% -43.87% (p=0.000 n=50+49)
Change-Id: Ia899975b0e46f45dcd20223b713ed632bc32740b
Reviewed-on: https://go-review.googlesource.com/c/go/+/189277
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/cmd/compile/internal/ssa/rewrite386.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/rewrite386.go | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/rewrite386.go b/src/cmd/compile/internal/ssa/rewrite386.go index 812aa9420d..2336561560 100644 --- a/src/cmd/compile/internal/ssa/rewrite386.go +++ b/src/cmd/compile/internal/ssa/rewrite386.go @@ -360,6 +360,8 @@ func rewriteValue386(v *Value) bool { return rewriteValue386_OpConstBool_0(v) case OpConstNil: return rewriteValue386_OpConstNil_0(v) + case OpCtz16: + return rewriteValue386_OpCtz16_0(v) case OpCvt32Fto32: return rewriteValue386_OpCvt32Fto32_0(v) case OpCvt32Fto64F: @@ -20783,6 +20785,22 @@ func rewriteValue386_OpConstNil_0(v *Value) bool { return true } } +func rewriteValue386_OpCtz16_0(v *Value) bool { + b := v.Block + typ := &b.Func.Config.Types + // match: (Ctz16 x) + // cond: + // result: (BSFL (ORLconst <typ.UInt32> [0x10000] x)) + for { + x := v.Args[0] + v.reset(Op386BSFL) + v0 := b.NewValue0(v.Pos, Op386ORLconst, typ.UInt32) + v0.AuxInt = 0x10000 + v0.AddArg(x) + v.AddArg(v0) + return true + } +} func rewriteValue386_OpCvt32Fto32_0(v *Value) bool { // match: (Cvt32Fto32 x) // cond: |