Subject: Re: [PATCH v6 1/4] powerpc/64: Align bytes before fall back to .Lshort in powerpc64 memcmp()

From: Segher Boessenkool <[email-masked]>
Date: Wed, 30 May 2018 03:27:39 -0500

Hi!

On Wed, May 30, 2018 at 04:11:50PM +0800, Simon Guo wrote:
> On Mon, May 28, 2018 at 05:35:12AM -0500, Segher Boessenkool wrote:
> > On Fri, May 25, 2018 at 12:07:33PM +0800, [email-masked] wrote:
> > If this doesn't use cr0 anymore, you can do  rlwinm r6,r6,0,7  instead of
> > andi r6,r6,7 .
> > 
> CR0 is used at .Lno_short handling.

Tricky.

> > > +	subfc.	r5,r6,r5
> > 
> > Why subfc?  You don't use the carry.
> OK. I will use subfc instead.

I meant subf -- no carry.  If you want CR0 set there is subf. just fine.

> > > +	bgt	cr0,8f
> > > +	li	r3,-1
> > > +8:
> > > +	blr
> > 
> >   blelr
> >   li r3,-1
> >   blr
> Sure. That looks more impact.

Should have been bgtlr of course -- well check please :-)

Segher