[PATCH] ix86: Add peephole2 for *add<mode>3_cc_overflow_1 followed by matching memory store [PR94857]

[Jakub Jelinek]

On Fri, May 08, 2020 at 09:57:31AM +0200, Uros Bizjak wrote:
> On Fri, May 8, 2020 at 9:47 AM Jakub Jelinek <jakub@redhat.com> wrote:
> > The following peephole2 changes:
> > -       addl    (%rdi), %esi
> > +       xorl    %eax, %eax
> > +       addl    %esi, (%rdi)
> >         setc    %al
> > -       movl    %esi, (%rdi)
> > -       movzbl  %al, %eax
> >         ret
> > on the testcase.  *add<mode>3_cc_overflow_1, being an add{l,q} insn, is
> > commutative, so if TARGET_READ_MODIFY_WRITE we can replace
> > addl (%rdi), %esi; movl %esi, (%rdi)
> > with
> > addl %esi, (%rdi)
> > if %edi is dead after those two insns.
> 
> I assume you meant %esi here.

Of course, sorry.  Fixed in commit log.

> OK with a small test adjustment.

Done, thanks.

	Jakub