cmd/compile: Pow10 freeze the compiler on certain condition on Go 1.24

[etrnal70]

Go version

go version go1.24.0 darwin/arm64

Output of go env in your module/workspace:

AR='ar'
CC='clang'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='clang++'
GCCGO='gccgo'
GO111MODULE=''
GOARCH='arm64'
GOARM64='v8.0'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/Users/hanifrmn/Library/Caches/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/Users/hanifrmn/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/xd/37pvgts12bg_bk2wx9kp9gbm0000gp/T/go-build2186527099=/tmp/go-build -gno-record-gcc-switches -fno-common'
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMOD='/Users/hanifrmn/Repo/playground/go.mod'
GOMODCACHE='/Users/hanifrmn/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/hanifrmn/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/Users/hanifrmn/sdk/go1.24.0'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/hanifrmn/Library/Application Support/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/Users/hanifrmn/sdk/go1.24.0/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.24.0'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

package main

import (
	"math"
)

func main() {
	test(2)
}

func test(i int) {
	if i <= 0 {
		return
	}

	_ = math.Pow10(i + 2)
}

running go build will freeze the compiler

What did you see happen?

Running go build will freeze the compiler

Running with -gcflags=-l rans fine

What did you expect to see?

It compiles correctly on Go 1.23.6

[gabyhelp]

Related Issues

• cmd/compile: miscompilation of simple arithmetic program targeting darwin/arm64 #62723 (closed)
• cmd/compile: rerwrite cycle detection logic taking too long for large functions #66773 (closed)
• Unable to calculate math.Mod for numbers larger than 1e+16 #36456 (closed)
• math: Pow(negativeZero, number_that_overflows_int64) produces incorrect result on arm64 #57465 (closed)
• cmd/compile: incorrect math reduction #70481 (closed)
• cmd/compile: bad code generation for ARM (bounds test fails) #41780 (closed)
• Test #67906 (closed)
• cmd/compile: internal compiler error: panic during prove while compiling: unexpected induction with too many parents #63955 (closed)
• cmd/compile: generic code compile never end #50204
• compiler: infinite loop and closure assertion failed #69062 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[Jorropo]

I can't repro with:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v3'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/tmp/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/hugo/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1841902807=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/dev/null'
GOMODCACHE='/home/hugo/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/hugo/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/hugo/k/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/hugo/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='local'
GOTOOLDIR='/home/hugo/k/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.0'
GOWORK=''
PKG_CONFIG='pkg-config'

I've compiled:

+package a
+
 import (
 	"math"
 )
 
 func test(i int) {
 	if i <= 0 {
 		return
 	}
 
 	_ = math.Pow10(i)
 }

I've submitted https://go-review.googlesource.com/c/go/+/650895 to test reproing on the testing cluster.

[etrnal70]

Sorry, updated the repro

[etrnal70]

With the updated repro, can confirm it doesn't work on Go playground too

[Jorropo]

Well I am very confused:

git bisect start
# status: waiting for both good and bad commits
# bad: [4700bc41750c1a80c21b00baa0a93a64eb79e7ac] test: trying to reproduce 71852
git bisect bad 4700bc41750c1a80c21b00baa0a93a64eb79e7ac
# status: waiting for good commit(s), bad commit known
# good: [a991f9c34d454d3d844f21dc08f2d05df35a8c60] [release-branch.go1.23] go1.23.6
git bisect good a991f9c34d454d3d844f21dc08f2d05df35a8c60
# good: [5e8a7316658c2f300a375041b6e0a606fec4c5f2] README: fix CC BY license name
git bisect good 5e8a7316658c2f300a375041b6e0a606fec4c5f2
# bad: [2fd2718f6b64000fa25e0c5d1ee48aa1426d5a6f] bufio: add example for ReadFrom and remove unused code
git bisect bad 2fd2718f6b64000fa25e0c5d1ee48aa1426d5a6f
# bad: [123594d3863b0a4b9094a569957d1bd94ebe7512] runtime: remove cloudwego/frugal unused linkname from comment
git bisect bad 123594d3863b0a4b9094a569957d1bd94ebe7512
# good: [206df8e7ad8a736b0dcbf5d98ab237b6784e5007] net/http: rename server receiver for consistency
git bisect good 206df8e7ad8a736b0dcbf5d98ab237b6784e5007
# good: [e126129d7612349874828685c2bcd49de498a1a0] cmd/compile/internal/ssa: combine shift and addition for riscv64 rva22u64
git bisect good e126129d7612349874828685c2bcd49de498a1a0
# bad: [a00195d304e6858406c6c9c961d253eeb8cb0aec] all: use t.Chdir in tests
git bisect bad a00195d304e6858406c6c9c961d253eeb8cb0aec
# good: [9b6efc25cddad4bebfa64fd8543afd07fbb0ab3e] go/ast: remove unused code
git bisect good 9b6efc25cddad4bebfa64fd8543afd07fbb0ab3e
# good: [c3f346a485f2fa97a7bdee82d587419b3823a1ba] math,os,os/*: use testenv.Executable
git bisect good c3f346a485f2fa97a7bdee82d587419b3823a1ba
# good: [d91a2e5b11cc1badd7c760a911218a64d91ac8b0] cmd: replace many sort.Interface with slices.Sort and SortFunc
git bisect good d91a2e5b11cc1badd7c760a911218a64d91ac8b0
# bad: [820f58a27f7f64f21353db6a071bf5dbf658924c] cmd/compile: compute Negation's limits from argument's limits
git bisect bad 820f58a27f7f64f21353db6a071bf5dbf658924c
# good: [4f2c0e5d0806a2f6fbe2d0704683d2b71d8191be] cmd/compile: compute Trunc's limits from argument's limits
git bisect good 4f2c0e5d0806a2f6fbe2d0704683d2b71d8191be
# good: [2f3165973f9bf1e1a95d108c57e5257f4655ee59] cmd/compile: compute Complement's limits from argument's limits
git bisect good 2f3165973f9bf1e1a95d108c57e5257f4655ee59
# first bad commit: [820f58a27f7f64f21353db6a071bf5dbf658924c] cmd/compile: compute Negation's limits from argument's limits

820f58a is very simple, copying patterns and code from other patches.

I don't know when I'll be able to spend time investigating this,
I'll revert that for 1.24.1 but I think there is a latent bug hiding somewhere.

[gopherbot]

Change https://go.dev/cl/650975 mentions this issue: Revert "cmd/compile: compute Negation's limits from argument's limits"

[Jorropo]

cc @golang/compiler