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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108724] [11 Regression] Poor codegen when summing two arrays without AVX or SSE
Date: Fri, 05 May 2023 08:34:59 +0000	[thread overview]
Message-ID: <bug-108724-4-Qqa0etDJU5@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108724-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108724

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note that the GCC 11 branch isn't affected by what's fixed on trunk and GCC 12,
the 11 branch still uses vect_worthwhile_without_simd_p which checks
vect_min_worthwhile_factor.

Instead the GCC 11 branch correctly doesn't vectorize the add but instead
vectorizes the stores only which results in stack spilling to build
the DImode values we then store.  We're also doing this in odd ways.

In GCC 13/12 we have fixed this in the costing:

node 0x4156628 1 times vec_construct costs 100 in prologue

while the GCC 11 branch costs this as 8.  Not sure where this happens in
the target.

Hmm, I think this happens in error.

  parent reply	other threads:[~2023-05-05  8:35 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-08 19:17 [Bug target/108724] New: [11 regression] " gbs at canishe dot com
2023-02-08 19:30 ` [Bug tree-optimization/108724] " pinskia at gcc dot gnu.org
2023-02-09  9:37 ` crazylht at gmail dot com
2023-02-09 13:54 ` rguenth at gcc dot gnu.org
2023-02-10 10:00 ` rguenth at gcc dot gnu.org
2023-02-10 10:07 ` [Bug tree-optimization/108724] [11/12/13 Regression] " rguenth at gcc dot gnu.org
2023-02-10 11:22 ` cvs-commit at gcc dot gnu.org
2023-02-10 11:22 ` [Bug tree-optimization/108724] [11/12 " rguenth at gcc dot gnu.org
2023-03-15  9:48 ` cvs-commit at gcc dot gnu.org
2023-05-05  8:34 ` rguenth at gcc dot gnu.org [this message]
2023-05-05 12:06 ` [Bug target/108724] [11 " rguenth at gcc dot gnu.org
2023-05-23 12:55 ` rguenth at gcc dot gnu.org
2023-05-29 10:08 ` jakub at gcc dot gnu.org

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