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.
Eugene
0001-Optimize-self-right-shift-to-0.patch
Description: 0001-Optimize-self-right-shift-to-0.patch
