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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/100173] telecom/viterb00data_1 has 16.92% regression compared O2 -ftree-vectorize -fvect-cost-model=very-cheap to O2  on CLX/ICX, 9% regression on znver3
Date: Thu, 29 Apr 2021 03:02:25 +0000	[thread overview]
Message-ID: <bug-100173-4-E85ua7WFr7@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-100173-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100173

--- Comment #2 from Hongtao.liu <crazylht at gmail dot com> ---

> but yes, cselim will also sink the first store, moving it across the
> scalar compute in the block.  I might note that ideally we'd sink
> all the compute as well and end up with just a conditional load of
> either pIn1->m_esState or pIn2_89->m_esState.  That might then allow
> scheduling to recover the original performance.
> 

I want to clasify this regression is not related to 2 sinked stores, it just
trigger some micro-architecture bound.

Also w/o -fvect-cost-model=very-cheap, it can be 2-3x faster, the tripper count
is constant, so i wonder why very-cheap cost model doesn't vectorize this loop?

  parent reply	other threads:[~2021-04-29  3:02 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-21  5:48 [Bug tree-optimization/100173] New: " crazylht at gmail dot com
2021-04-21  6:46 ` [Bug tree-optimization/100173] " rguenth at gcc dot gnu.org
2021-04-29  3:02 ` crazylht at gmail dot com [this message]
2021-04-29  6:57 ` rguenther at suse dot de
2021-04-29 11:02 ` crazylht at gmail dot com
2021-04-29 12:15 ` rguenth at gcc dot gnu.org

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