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Re: [PATCH] Only build libm with -fno-math-errno
- From: Aurelien Jarno <aurelien at aurel32 dot net>
- To: Zack Weinberg <zackw at panix dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Sat, 22 Dec 2018 21:24:36 +0100
- Subject: Re: [PATCH] Only build libm with -fno-math-errno
- References: <20181222171618.15996-1-aurelien@aurel32.net> <CAKCAbMjeqJ4yXc7S7zkPork-Wrpq+3r-0EzPmqwyeO-7e=ZOpg@mail.gmail.com>
On 2018-12-22 14:37, Zack Weinberg wrote:
> On Sat, Dec 22, 2018 at 12:16 PM Aurelien Jarno <aurelien@aurel32.net> wrote:
> >
> > Commit 1294b1892e ("Add support for sqrt asm redirects") added the
> > -fno-math-errno flag to build most of the glibc in order to enable GCC
> > to inline math function. This allows GCC to optimize-out saving and
> > restoring errno around function calls. In turn this causes strerror to
> > set errno value to ENOMEM in case of an invalid error number and memory
> > allocation error, which is not allowed by POSIX.
>
> LGTM, except please mention GCC bug #88576 in the commit message.
> Hopefully we'll be able to turn -fno-math-errno back on for libc when
> that's fixed.
Thanks for the review. Now that we know it's a GCC bug, the commit
message clearly needs to be reworked.
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurelien@aurel32.net http://www.aurel32.net