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

<pre> $ go version go version devel +0dd120d Sun Aug 18 01:16:33 2019 +0000 linux/amd64 </pre>

Does this issue reproduce with the latest release?

Yes.

What did you do?

I compiled the following function and inspected the generated assembly (https://godbolt.org/z/q8MXUH):

func f(x string) int {
    var y int
    if x == "1" && len(x) == 2 {
        y = 1
    }

    return y
}

What did you expect to see?

I expected the generated code to be a simple return, as in this case: https://godbolt.org/z/o3uNbH.

        movq    $0, "".~r1+24(SP)
        ret

What did you see instead?

Instead, the generated code contains a redundant ´jump´ instruction:

        movq    "".x+16(SP), AX
        cmpq    AX, $1
        jne     f_pc11
f_pc11:
        pcdata  $1, $2
        xorps   X0, X0
        movups  X0, "".~r1+24(SP)
        ret

The same happens for this function https://godbolt.org/z/tDm4z2.

This CL https://go-review.googlesource.com/c/go/+/239457 seems to help this issue.