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From: "H.J. Lu" <hjl.tools@gmail.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Uros Bizjak <ubizjak@gmail.com>,
	Kirill Yukhin <kirill.yukhin@gmail.com>,
		GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Fix memory alignment on AVX512VL masked floating point stores (PR target/69198)
Date: Fri, 08 Jan 2016 21:59:00 -0000	[thread overview]
Message-ID: <CAMe9rOrs51WVL5muV0CMzRyVeDZ6kmmABwL94o4h87FNdsXwNw@mail.gmail.com> (raw)
In-Reply-To: <CAMe9rOqyfPmzSQYCi9-Nhn0JnztPTfaFhFEGy5LQa7kOyyzPsA@mail.gmail.com>

On Fri, Jan 8, 2016 at 1:53 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Jan 8, 2016 at 1:43 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Jan 8, 2016 at 1:38 PM, Jakub Jelinek <jakub@redhat.com> wrote:
>>> On Fri, Jan 08, 2016 at 01:27:08PM -0800, H.J. Lu wrote:
>>>> > That is just wrong and will severely pessimize correct code.
>>>> > Please don't waste time on that.
>>>> >
>>>>
>>>> Do you have an example to show it will pessimize correct code?
>>>
>>> Anything where the compiler can't figure out alignment info and you use the
>>> aligned functions, starting from trivial tests like:
>>>
>>> void foo (float *p, __m256 q)
>>> {
>>>   _mm256_store_ps (p, q);
>>> }
>>>
>>
>
> Is a bad example:
>

This is a better example:

__m256
foo (const void *p, __m256 yy, __mmask8 m)
{
  return _mm256_mask_load_ps (yy, m, p);
}


-- 
H.J.

  reply	other threads:[~2016-01-08 21:59 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-08 20:21 Jakub Jelinek
2016-01-08 20:28 ` H.J. Lu
2016-01-08 20:35   ` Jakub Jelinek
2016-01-08 20:39     ` H.J. Lu
2016-01-08 20:44       ` Jakub Jelinek
2016-01-08 20:46         ` H.J. Lu
2016-01-08 20:48           ` Jakub Jelinek
2016-01-08 21:14             ` H.J. Lu
2016-01-08 21:23               ` Jakub Jelinek
2016-01-08 21:27                 ` H.J. Lu
2016-01-08 21:38                   ` Jakub Jelinek
2016-01-08 21:43                     ` H.J. Lu
2016-01-08 21:53                       ` H.J. Lu
2016-01-08 21:59                         ` H.J. Lu [this message]
2016-01-08 22:02                           ` H.J. Lu
2016-01-12 13:13 ` Kirill Yukhin
2016-01-12 13:39   ` H.J. Lu
2016-01-12 13:42     ` Jakub Jelinek
2016-01-12 13:45       ` Uros Bizjak
2016-01-12 19:58         ` H.J. Lu

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