On Fri, Oct 30, 2020 at 3:38 AM Eugene Rozenfeld via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> This patch adds a pattern for folding
>
> x >> x
>
> to
>
> 0
>
> as described in PR96701.
>
>
> Without this patch the x86_64-pc-linux-gnu code generated for this function
>
>
>
> int
>
> foo (int i)
>
> {
>
> return i >> i;
>
> }
>
>
>
> is
>
>
>
> mov ecx,edi
>
> sar edi,cl
>
> test edi,edi
>
> setne al
>
> ret
>
>
>
> With the patch the code is
>
>
> xor eax,eax
> ret
>
>
> Tested on x86_64-pc-linux-gnu.
OK.
Thanks,
Richard.
> Eugene
