From: Segher Boessenkool <segher@kernel.crashing.org>
To: Bill Schmidt <wschmidt@linux.vnet.ibm.com>
Cc: gcc-patches@gcc.gnu.org, dje.gcc@gmail.com
Subject: Re: [PATCH, rs6000] Generate LE code for vec_lvsl and vec_lvsr that is compatible with BE code
Date: Tue, 30 Sep 2014 20:37:00 -0000 [thread overview]
Message-ID: <20140930203722.GA23788@gate.crashing.org> (raw)
In-Reply-To: <1412093919.2986.54.camel@gnopaine>
On Tue, Sep 30, 2014 at 11:18:39AM -0500, Bill Schmidt wrote:
> > I meant generating a sequence that just "falls out" as you want it after
> > optimisation. E.g. lvsr;vnot;vand(splat8(31));vperm can have the vand
> > absorbed by the vperm. But that splat is nasty when not optimised away :-(
>
> Especially since splat8(31) requires vsub(splat8(15),splat8(-16))...
vspltisb vT,-5 ; vsrb vD,vT,vT # :-)
> To get something that is correct with and without feeding a vperm and
> actually performs well just ain't happening here...
Yeah.
Segher
next prev parent reply other threads:[~2014-09-30 20:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-29 22:26 Bill Schmidt
2014-09-30 14:50 ` Segher Boessenkool
2014-09-30 15:24 ` Bill Schmidt
2014-09-30 16:04 ` Segher Boessenkool
2014-09-30 16:18 ` Bill Schmidt
2014-09-30 20:37 ` Segher Boessenkool [this message]
2014-10-02 19:20 ` Bill Schmidt
2014-10-03 18:18 ` David Edelsohn
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