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From: Marc Glisse <marc.glisse@inria.fr>
To: Hongyu Wang <hongyu.wang@intel.com>
Cc: gcc-patches@gcc.gnu.org, hongtao.liu@intel.com
Subject: Re: [PATCH] Optimize VEC_PERM_EXPR with same permutation index and operation [PR98167]
Date: Wed, 16 Nov 2022 20:21:55 +0100 (CET)	[thread overview]
Message-ID: <c1956a81-56b2-89f7-7419-b2f35d2eadc9@inria.fr> (raw)
In-Reply-To: <20221104000432.15254-1-hongyu.wang@intel.com>

On Fri, 4 Nov 2022, Hongyu Wang via Gcc-patches wrote:

> This is a follow-up patch for PR98167
>
> The sequence
>     c1 = VEC_PERM_EXPR (a, a, mask)
>     c2 = VEC_PERM_EXPR (b, b, mask)
>     c3 = c1 op c2
> can be optimized to
>     c = a op b
>     c3 = VEC_PERM_EXPR (c, c, mask)
> for all integer vector operation, and float operation with
> full permutation.

Hello,

I assume the "full permutation" condition is to avoid performing some 
extra operations that would raise exception flags. If so, are there 
conditions (-fno-trapping-math?) where the transformation would be safe 
with arbitrary shuffles?

-- 
Marc Glisse

  parent reply	other threads:[~2022-11-16 19:21 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-04  0:04 Hongyu Wang
2022-11-04  6:43 ` Prathamesh Kulkarni
2022-11-08 14:37   ` Richard Biener
2022-11-10  2:22     ` Hongyu Wang
2022-11-10  8:56       ` Richard Biener
2022-11-10 14:27         ` Hongyu Wang
2022-11-14 14:53           ` Richard Biener
2022-11-16 15:25             ` Tamar Christina
2022-11-16 15:29               ` Richard Biener
2022-11-16 15:30                 ` Richard Biener
2022-11-16 15:34                   ` Tamar Christina
2022-11-16 15:37                   ` Jakub Jelinek
2022-11-16 15:40                     ` Tamar Christina
2022-11-16 15:41                       ` Jakub Jelinek
2022-11-16 19:21 ` Marc Glisse [this message]
2022-11-17  6:05   ` Hongyu Wang

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