cmd/compile: segfault after inlining cgo function (-l=4)

[davidlazar]

x.go:

package main

import "C"

func main() {
	C.CString("foo")
}

Compiling:

$ go build -gcflags '-m -l=4' x.go
/tmp/go-build562940151/command-line-arguments/_obj/_cgo_gotypes.go:14: can inline _Cgo_ptr
/tmp/go-build562940151/command-line-arguments/_obj/_cgo_gotypes.go:51: can inline _cgo_cmalloc
/tmp/go-build562940151/command-line-arguments/_obj/_cgo_gotypes.go:37: can inline _Cfunc_CString
/tmp/go-build562940151/command-line-arguments/_obj/_cgo_gotypes.go:38: inlining call to _cgo_cmalloc
./x.go:5: can inline main
./x.go:6: inlining call to _Cfunc_CString
./x.go:6: inlining call to _cgo_cmalloc
...

$ go version
go version go1.7.3 linux/amd64

Running:

$ ./x
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x40131c]

goroutine 1 [running]:
panic(0x45c5e0, 0xc42000c120)
	/usr/lib/go/src/runtime/panic.go:500 +0x1a1
main.main()
	/home/david/x.go:6 +0x4c

[gopherbot]

CL https://golang.org/cl/33722 mentions this issue.