From: Alejandro Colomar <alx@kernel.org>
To: Xi Ruoyao <xry111@xry111.site>, libc-alpha@sourceware.org
Cc: Florian Weimer <fweimer@redhat.com>, Sam James <sam@gentoo.org>,
Richard Biener <rguenth@gcc.gnu.org>,
Andrew Pinski <apinski@marvell.com>
Subject: Re: [RFC v1 0/2] Use -fno-delete-null-pointer-checks to build glibc
Date: Tue, 11 Jul 2023 15:24:14 +0200 [thread overview]
Message-ID: <27ef517b-d9fa-99b4-6401-c67bb88a0074@kernel.org> (raw)
In-Reply-To: <0867b39d59162428d9092d1ffbc02ec4c0008b47.camel@xry111.site>
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On 2023-07-11 15:22, Xi Ruoyao wrote:
> On Tue, 2023-07-11 at 15:11 +0200, Alejandro Colomar wrote:
>> Florian reported that there's -fno-delete-null-pointer-checks to tell
>> the compiler to not optimize, and only warn about incorrect uses of null
>> pointers.
>
> One potential problem is -fno-delete-null-pointer-checks not only
> disables optimizations based on __nonnull, but also disables the
> optimizations based on other provable non-null pointer values. So maybe
> we should run a benchmark to see if there is some severe degradation, if
> there is any we may fix it by moving null checks away from hot paths.
>
Sure; I don't know how to run those, so I'll provide the patches, and
will let any of you run the benchmarks (or point me to some documentation
to learn how to run them).
Cheers,
Alex
--
<http://www.alejandro-colomar.es/>
GPG key fingerprint: A9348594CE31283A826FBDD8D57633D441E25BB5
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prev parent reply other threads:[~2023-07-11 13:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-11 13:11 Alejandro Colomar
2023-07-11 13:11 ` [RFC v1 1/2] Makeconfig: Use one line per token Alejandro Colomar
2023-07-11 18:05 ` Adhemerval Zanella Netto
2023-07-11 13:11 ` [RFC v1 2/2] Makeconfig: Compile glibc with -fno-delete-null-pointer-checks Alejandro Colomar
2023-07-11 13:41 ` Florian Weimer
2023-07-11 13:53 ` Siddhesh Poyarekar
2023-07-12 10:56 ` Richard Biener
2023-07-12 12:22 ` Cristian Rodríguez
2023-07-12 12:43 ` Florian Weimer
2023-07-11 13:18 ` [RFC v1 0/2] Use -fno-delete-null-pointer-checks to build glibc Florian Weimer
2023-07-11 13:19 ` Alejandro Colomar
2023-07-11 13:22 ` Xi Ruoyao
2023-07-11 13:24 ` Alejandro Colomar [this message]
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