[PATCH] Improve {f,g}{char,short,int,long}xor in pr49095.c (PR rtl-optimization/89865)
Jeff Law
law@redhat.com
Fri Mar 29 21:07:00 GMT 2019
On 3/29/19 1:47 PM, Jakub Jelinek wrote:
> Hi!
>
> The following patch improves the last 8 cases (both -m64 and ia32)
> that were using RMW cycle, for xor we actually emit
> new = old ^ other; new != old
> rather than
> new = old ^ other; new != 0
> and thus the peephole2 needs to recognize that too.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2019-03-29 Jakub Jelinek <jakub@redhat.com>
>
> PR rtl-optimization/89865
> * config/i386/i386.md: Add peepholes for z = x; x ^= y; x != z.
>
> * gcc.target/i386/pr49095.c: Don't expect any RMW sequences.
Ewwww. But OK.
jeff
More information about the Gcc-patches
mailing list