Golang cmd/compile: missing optimization: float constant should be loaded once outside loop

Go version

go version go1.25-devel_2363897 Sat Jul 19 21:15:12 2025 -0700 linux/amd64

Output of go env in your module/workspace:

Using service on https://go.godbolt.org/
Selected "x86-64 gc (tip)"

What did you do?

I entered following program

const (
    N = 1048576
    NN = 1.0 / N
)

func Bar(a []float64) {
    for i := range a {
        a[i] *= NN
    }
}

What did you see happen?

This was codegen result for a[i] *= NN part:

        MOVSD   (AX)(CX*8), X0
        MOVSD   $f64.3eb0000000000000(SB), X1
        MULSD   X1, X0
        MOVSD   X0, (AX)(CX*8)

https://go.godbolt.org/z/7cK5b54zh

What did you expect to see?

The statement MOVSD $f64.3eb0000000000000(SB), X1 should be happen once outside loop. There is no statements that invalidates content of X1 register inside loop.