I would like to know about the reuse of stack space in Go.

When writing code like the following, we can see that the variable x is allocated to the same stack space in each iteration, and its value is updated:

package main

import "time"

func main() {
    for range 3 {
        x := time.Now()
        println(&x)           // output same address for each iteration
        println(x.UnixNano()) // output different value for each iteration
    }
}

On the other hand, in the following code, stack space reuse does not occur, and different addresses are assigned:

package main

import "time"

func main() {
    {
        x := time.Now()
        println(&x) // 0x1400007cf20
    }
    {
        x := time.Now()
        println(&x) // 0x1400007cf08
    }
}

My question is, under what circumstances does the Go compiler attempt to reuse stack space? Additionally, where in the source code can this mechanism be understood?

I found a commit that seems to be related to this behavior, but I was unable to understand it.
https://github.com/golang/go/commit/366dcc4529d09c31f7b0df65003792022bc5ec09

Could you please help me with this question?