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cmd/compile: suboptimal compilation of reflect.isZero #64222

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qiulaidongfeng opened this issue Nov 17, 2023 · 0 comments
Open

cmd/compile: suboptimal compilation of reflect.isZero #64222

qiulaidongfeng opened this issue Nov 17, 2023 · 0 comments
Labels
compiler/runtime Issues related to the Go compiler and/or runtime. NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. Performance
Milestone
Unplanned

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@qiulaidongfeng
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What version of Go are you using (go version)?

$ go version
go version devel go1.22-b9a08f15 Thu Nov 16 22:15:45 2023 +0000 windows/amd64

Does this issue reproduce with the latest release?

yes.

What operating system and processor architecture are you using (go env)?

go env Output
$ go env
set GO111MODULE=auto
set GOARCH=amd64
set GOBIN=
set GOCACHE=D:\tmp\go-build
set GOENV=C:\Users\26454\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=D:\file\gofile\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=D:\file\gofile
set GOPRIVATE=
set GOPROXY=https://goproxy.cn,direct
set GOROOT=D:\file\gofile\gogit\go1
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLCHAIN=local
set GOTOOLDIR=D:\file\gofile\gogit\go1\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=devel go1.22-b9a08f15 Thu Nov 16 22:15:45 2023 +0000
set GCCGO=gccgo
set GOAMD64=v3
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=0
set GOMOD=D:\file\gofile\gogit\go1\src\go.mod
set GOWORK=
set CGO_CFLAGS=-O2 -g
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=C:\Users\26454\AppData\Local\Temp\go-build3613428875=/tmp/go-build -gno-record-gcc-switches

What did you do?

cd reflect
go test -c
go tool objdump reflect.test.exe

What did you expect to see?

I want reflect.isZero to use SIMD when GOAMD64 is greater than v1.
Avoid For all zeros, performance is not as good as return bytealg.Count(b, byte(0)) == len(b).

What did you see instead?

I see that reflect.isZero uses CMPQ when GOAMD64 is greater than v1.
@gopherbot gopherbot added the compiler/runtime Issues related to the Go compiler and/or runtime. label Nov 17, 2023
@randall77 randall77 added this to the Unplanned milestone Nov 17, 2023
@mknyszek mknyszek added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Nov 20, 2023
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Labels
compiler/runtime Issues related to the Go compiler and/or runtime. NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. Performance
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Milestone
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@mknyszek @randall77 @gopherbot @mauri870 @qiulaidongfeng