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Re: [RFC PATCH] Disable uninitialized warnings around va_arg(, long double)
- From: Florian Weimer <fw at deneb dot enyo dot de>
- To: Zack Weinberg <zackw at panix dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Sun, 11 Mar 2018 11:34:29 +0100
- Subject: Re: [RFC PATCH] Disable uninitialized warnings around va_arg(, long double)
- Authentication-results: sourceware.org; auth=none
- References: <20180310203625.13515-1-zackw@panix.com>
* Zack Weinberg:
> My changes to vfprintf in that patchset tickle a bug in the
> PowerPC-SPE back end, leading to spurious "used uninitialized"
> warnings--not on any code we control, but on a scratch variable
> emitted as part of the expansion of __builtin_va_arg! This is
> <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84772>, Jakub already
> has a fix in hand, and I'm not sure whether it's worth bothering to
> include these DIAG_IGNOREs in our tree. I suppose it depends on
> whether the bug manifests in compilers older than 7.3 as well.
Will the default configuration of build-many-glibcs.py pick up a GCC
fix if it is backported to earlier release branches? If yes, then I
don't think we need to work around it in the glibc tree. The GCC will
eventually be able to powerpcspe users through a GCC release, and
until then, they can build with --disable-werror.