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Date: Thu, 13 Jun 2019 20:28:00 -0000
From: Jan Hubicka <hubicka@ucw.cz>
To: Christophe Lyon <christophe.lyon@linaro.org>
Cc: Richard Biener <rguenther@suse.de>,	gcc Patches <gcc-patches@gcc.gnu.org>, d@dcepelik.cz
Subject: Re: indirect_ref_may_alias_decl_p fix
Message-ID: <20190613202759.bdhem7sdfpo3oyri@kam.mff.cuni.cz>
References: <20190613120550.7wtzpieeszazjn7i@kam.mff.cuni.cz> <alpine.LSU.2.20.1906131408280.10704@zhemvz.fhfr.qr> <20190613122928.arp65f726mbnsxyz@kam.mff.cuni.cz> <CAKdteOb02LbSgttTRye8v4SuDvxi45Wu7SsmQ0EFyy2qzLf66g@mail.gmail.com>
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> Hi!
> 
> Since this was committed (r272247), I've noticed a failure to build
> glibc-2.29 for aarch64:
> #'target_mem_ref' not supported by expression#'pmap_rmt.c: In function
> 'clnt_broadcast':
> pmap_rmt.c:298:19: error:  may be used uninitialized in this function
> [-Werror=maybe-uninitialized]
>   298 |    baddr.sin_addr = addrs[i];
>       |    ~~~~~~~~~~~~~~~^~~~~~~~~~
> 
> while compiling sunrpc/pmap_rmt.os

It is hard to tell w/o preprocessed source, but looking at
https://github.com/lattera/glibc/blob/master/sunrpc/pmap_rmt.c addrs is
initialized by getbroadcastnests which has early exit when getifaddrs
fails leaving adds uninitialized. So this may be just an usual false
positive of -Wmaybe-uninitialized caused by better optimization :)

Honza
> 
> Christophe
> 
> 
> 
> > Honza