gccgo: incorrect order of evaluation

[ianlancetaylor]

This program should print 0. When built with current gccgo, it prints 1.

The immediate problem is that the convert_shortcuts pass moves the function calls to FV1 and FV2 out of line so that they are executed before the call to F.

CC @cherrymui @thanm

package main

type S struct{ a [16]string }

var V1, V2 S

func FV1() S { return V1 }

func FV2() S { return V2 }

func F() int {
	V1 = S{[16]string{"hi"}}
	return 0
}

func G(f bool) int {
	if f {
		return 1
	}
	return 0
}

func H() int {
	return F() + G(FV1() == FV2())
}

func main() {
	println(H())
}

[zigo101]

related: #24448

[gopherbot]

Change https://golang.org/cl/125299 mentions this issue: compiler: do order_evaluations before remove_shortcuts

[gopherbot]

Change https://golang.org/cl/125301 mentions this issue: test: add test for gccgo bug #26495