[Bug target/94611] gccgo hangs (infinite loop) on complex projects, seemingly in simplify-rtx.c/simplify_plus_minus

[gcc at octaforge dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94611

--- Comment #3 from Daniel Kolesa <gcc at octaforge dot org> ---
The steps I took to reproduce the problem:

1) Grab a Go source release
2) Install gccgo including the 'go' command
3) Then do something like:

cd go-1.x
export GOROOT_BOOTSTRAP=/usr/lib/go/9.3.0
export GOROOT=$PWD
export GOROOT_FINAL=/usr/lib/go
export GOARCH=ppc64le # or amd64, or ...

cd src
bash make.bash --no-clean -v

The build will run for a while. Apparently the command that hangs is:

/usr/bin/gccgo -c -O2 -g
-fdebug-prefix-map=/tmp/go-build771879105=/tmp/go-build
-gno-record-gcc-switches -fgo-pkgpath=bootstrap/cmd/internal/obj/x86 -o
/tmp/go-build771879105/b032/_go_.o -I
/tmp/go-build771879105/b032/_importcfgroot_
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/a.out.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/aenum.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/anames.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/asm6.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/avx_optabs.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/evex.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/list6.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/obj6.go
/home/q66/go/pkg/bootstrap/src/bootstrap/cmd/internal/obj/x86/ytab.go