From: Xi Ruoyao <xry111@xry111.site>
To: Matthew Malcomson <matthew.malcomson@arm.com>, gcc-patches@gcc.gnu.org
Cc: richard.sandiford@arm.com, rguenther@suse.de
Subject: Re: [PATCH] Reduce floating-point difficulties in timevar.cc
Date: Fri, 21 Jul 2023 20:49:24 +0800 [thread overview]
Message-ID: <6b3903fd34a201e808cb0cd7c9a04e4a07e6c0a4.camel@xry111.site> (raw)
In-Reply-To: <ded23976-2873-45de-aebd-28839ec0ab82@AZ-NEU-EX03.Arm.com>
On Fri, 2023-07-21 at 13:11 +0100, Matthew Malcomson via Gcc-patches
wrote:
> This change ensures those operations are not fused and hence stops the test
> being flaky on that particular machine. There is no expected change in the
> generated code.
> Bootstrap & regtest on AArch64 passes with no regressions.
>
> gcc/ChangeLog:
>
> * timevar.cc (get_time): Make this noinline to avoid fusing
> behaviour and associated test flakyness.
I don't think it's correct. It will break bootstrapping GCC from other
ISO C++11 compilers, you need to at least guard it with #ifdef __GNUC__.
And IMO it's just hiding the real problem.
We need more info of the "particular machine". Is this a hardware bug
(i.e. the machine violates the AArch64 spec) or a GCC code generation
issue? Or should we generally use -ffp-contract=off in BOOT_CFLAGS?
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
next prev parent reply other threads:[~2023-07-21 12:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-21 12:11 Matthew Malcomson
2023-07-21 12:47 ` Richard Biener
2023-07-21 13:11 ` Matthew Malcomson
2023-07-21 13:41 ` Richard Biener
2023-07-21 13:45 ` Xi Ruoyao
2023-07-21 13:58 ` Alexander Monakov
2023-07-21 15:11 ` Xi Ruoyao
2023-07-21 15:56 ` Alexander Monakov
2023-07-21 15:24 ` Matthew Malcomson
2023-08-03 13:38 ` [PATCH] mid-end: Use integral time intervals " Matthew Malcomson
2023-08-03 14:09 ` David Malcolm
2023-08-03 14:54 ` Matthew Malcomson
2023-08-03 15:34 ` David Malcolm
2023-08-04 6:44 ` Richard Biener
2023-08-04 9:41 ` Matthew Malcomson
2023-08-04 10:18 ` Richard Biener
2023-07-21 12:49 ` Xi Ruoyao [this message]
2023-07-21 17:41 ` [PATCH] Reduce floating-point difficulties " Andrew Pinski
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