What version of Go are you using (go version)?

$ go version
go version devel +576442b Fri Mar 29 23:05:45 2019 +0000 linux/amd64

Does this issue reproduce with the latest release?

Yes

What did you do?

I compiled the following code (simplified from a more complex program):

package test

var sink int

func aux() int {
    return 0
}

func test1() {
    sink = aux()
    sink = aux()
}

What did you expect to see?

I expected the double assignment to be compiled away, as in the code presented below:

package test

var sink int

func test1() {
    sink = 0
    sink = 0
}

What did you see instead?

Instead, the following code was generated:

        movq    $0, "".sink(SB)
        nop
        movq    $0, "".sink(SB)
        ret

Note: Before commit 69c2c56, the code snippets shown above behaved similarly.