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From: "jsm28 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/115311] -fno-builtin-xxx allowing anything for xxx
Date: Fri, 31 May 2024 20:39:07 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D115311

--- Comment #1 from Joseph S. Myers <jsm28 at gcc dot gnu.org> ---
This definitely wouldn't work for glibc; we freely use -fno-builtin-<func> =
when
e.g. aliasing double and long double functions when the formats are the sam=
e,
where GCC gives an error if it has the functions as built-in and so objects=
 to
the incompatible types, and we don't limit this to the functions GCC has as
built-in in a particular version but also use those options for functions t=
hat
might be built-in in future (e.g. C23 functions). The number of functions
involved is large, needing configure tests for all of them would be a bad i=
dea.
That is, it's useful to use -fno-builtin-<func> for a valid function name t=
hat
might be built-in in future without needing configure tests for whether it's
built-in in a particular version.=