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From: "aldot at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/65534] tailcall not optimized away
Date: Thu, 09 Jul 2015 13:21:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65534

--- Comment #2 from Bernhard Reutner-Fischer <aldot at gcc dot gnu.org> ---
(In reply to Jan Hubicka from comment #1)
> > #ifndef OPTIMIZE_MANUALLY
> > void setutent(void) {
> >     ((void)0);
> >     __setutent_unlocked();
> >     ((void)0);
> > }
> > #else
> > extern __typeof (__setutent_unlocked) setutent
> >     __attribute__ ((alias ("__setutent_unlocked")));
> > #endif
> 
> I do not think GCC can safely optimize this, becuase in the first
> case &setutent != &__setutent_unlocked, wile in the optimized
> case the addresses are equal.

Note that __setutent_unlocked is static, so i don't see how this specific case
would prevent optimization?