cmd/compile: panic during fuse with if true block containing a goto and a return #28616
Description
What version of Go are you using (go version)?
Does this issue reproduce with the latest release?
Reproduces on playground, master branch, and Go v1.11.2.
Doesn't reproduce on Go v1.10.5.
What did you do?
Tried to compile code which I've boiled down to:
https://play.golang.org/p/2fEsQtceadQ
What did you expect to see?
Compilation success
What did you see instead?
prog.go:5:2: internal compiler error: 'f1': panic during fuse while compiling f1: runtime error: index out of range goroutine 20 [running]: cmd/compile/internal/ssa.Compile.func1(0xc000403218, 0xc00034c6e0) /usr/local/go/src/cmd/compile/internal/ssa/compile.go:38 +0xc6 panic(0xc445e0, 0x12dc7e0) /usr/local/go/src/runtime/panic.go:513 +0x1b9 cmd/compile/internal/ssa.fuseBlockPlain(0xc0003dfce8, 0x47be00) /usr/local/go/src/cmd/compile/internal/ssa/fuse.go:123 +0x781 ...