From: Segher Boessenkool <segher@kernel.crashing.org>
To: Bill Schmidt <wschmidt@linux.vnet.ibm.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
David Edelsohn <dje.gcc@gmail.com>,
cel@linux.vnet.ibm.com
Subject: Re: [PATCH, rs6000] Fix endianness issue with vmrgew and vmrgow permute constant recognition
Date: Thu, 17 Aug 2017 01:39:00 -0000 [thread overview]
Message-ID: <20170816225738.GZ13471@gate.crashing.org> (raw)
In-Reply-To: <f505c094-92a7-773b-a647-5b55673d13c8@linux.vnet.ibm.com>
Hi!
On Tue, Aug 15, 2017 at 04:14:21PM -0500, Bill Schmidt wrote:
> One of Carl Love's proposed built-in function patches exposed a bug in the Power
> code that recognizes specific permute control vector patterns for a permute, and
> changes the permute to a more specific and more efficient instruction. The
> patterns for p8_vmrgew_v4si and p8_vmrgow are generated regardless of endianness,
> leading to problems on the little-endian port.
Ouch.
> The use in rs6000.c of p8_vmrgew_v4sf_direct, rather than p8_vmrgew_v4si_direct,
> is arbitrary. The existing code already handles converting (for free) a V4SI
> operand to a V4SF one, so there's no need to specify the mode directly; and it
> would actually complicate the code to extract the mode so the "proper" pattern
> would match. I think what I have here is better, but if you disagree I can
> change it.
It's fine I think.
This is okay for trunk, thanks!
Segher
prev parent reply other threads:[~2017-08-16 22:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-15 22:08 Bill Schmidt
2017-08-15 22:09 ` Bill Schmidt
2017-08-17 1:39 ` Segher Boessenkool [this message]
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