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Re: variable addresses on the stack

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On 2022-08-19, Thiago Adams <thiago.adams@gmail.com> wrote:
> I am curious with the following..
>
> void f(int i) {
>    if (i > 1)  {
>        int j ='a';       
>    }
>    if (i < 1)  {
>        int k ='b';       
>    }
> }
> When I see the assembly ouput I can see the compiler
> use the address  rbp-4 for j and rbp-8 for k
>
> Why not the same address considering that j and k don't exist 
> at the same time?
> Any reason?

Nothing exists in the above; it is indistinguishable from

  void f(int i) { }

and in the ideal circumstances, the optimized treatment
of it would be indistinguisahble from the like treatment
of the above.

If there is a difference, the compiler is not being operated in a way
which best reveals its abilities to remove dead code, or else is
somewhat lacking in those abilities.

-- 
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal

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variable addresses on the stack Thiago Adams <thiago.adams@gmail.com> - 2022-08-19 10:22 -0700
  Re: variable addresses on the stack Thiago Adams <thiago.adams@gmail.com> - 2022-08-19 10:27 -0700
  Re: variable addresses on the stack Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-19 10:59 -0700
    Re: variable addresses on the stack Thiago Adams <thiago.adams@gmail.com> - 2022-09-21 05:09 -0700
      Re: variable addresses on the stack Thiago Adams <thiago.adams@gmail.com> - 2022-09-21 05:18 -0700
        Re: variable addresses on the stack Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-21 15:30 -0700
      Re: variable addresses on the stack David Brown <david.brown@hesbynett.no> - 2022-09-21 15:34 +0200
      Re: variable addresses on the stack Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-21 15:23 -0700
  Re: variable addresses on the stack Kaz Kylheku <480-992-1380@kylheku.com> - 2022-08-19 20:58 +0000
  Re: variable addresses on the stack Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2022-08-19 15:47 -0600
  Re: variable addresses on the stack Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-08-19 18:47 -0700

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