From: Marc Glisse <marc.glisse@inria.fr>
To: "Stéphane Glondu" <stephane.glondu@inria.fr>
Cc: Alexander Monakov <amonakov@ispras.ru>,
gcc-help@gcc.gnu.org, sibid@uvic.ca,
Paul Zimmermann <Paul.Zimmermann@inria.fr>
Subject: Re: slowdown with -std=gnu18 with respect to -std=c99
Date: Thu, 5 May 2022 16:41:28 +0200 (CEST) [thread overview]
Message-ID: <4d36d96-2de9-f8ac-2d52-ea32b1cc6d9@grove.saclay.inria.fr> (raw)
In-Reply-To: <c1a686bd-d2fa-a934-f931-6bf96f11e3d9@inria.fr>
On Thu, 5 May 2022, Stéphane Glondu via Gcc-help wrote:
> As additional data points, the performance with several versions of gcc
> (as packaged in Debian testing/unstable):
>
> | gcc-9 | gcc-10 | gcc-11 | gcc-12 |
> ------------|-------|--------|--------|--------|
> -std=c99 | 24 | 23.5 | 23 | 23 |
> -std=gnu18 | 43 | 16.8 | 38 | 38 |
>
> One can see that the performance stays relatively constant with
> -std=c99, but varies significantly with -std=gnu18.
Could you compare with c18 or gnu99, to determine if the issue is with c
vs gnu (most likely since fma seems important) or 99 vs 18?
--
Marc Glisse
next prev parent reply other threads:[~2022-05-05 14:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-03 8:28 Paul Zimmermann
2022-05-03 9:09 ` Alexander Monakov
2022-05-03 11:45 ` Paul Zimmermann
2022-05-03 12:12 ` Alexander Monakov
2022-05-05 8:57 ` Stéphane Glondu
2022-05-05 14:31 ` Stéphane Glondu
2022-05-05 14:41 ` Marc Glisse [this message]
2022-05-05 14:56 ` Alexander Monakov
2022-05-06 7:46 ` Paul Zimmermann
2022-05-06 9:27 ` Alexander Monakov
2022-05-07 6:11 ` Paul Zimmermann
2022-05-11 13:26 ` Alexander Monakov
2022-05-05 17:50 ` Paul Zimmermann
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