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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/10837] noreturn attribute causes no sibling
 calling optimization
Date: Mon, 12 Feb 2024 02:39:17 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D10837

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=3D83324
                 CC|                            |xry111 at gcc dot gnu.org

--- Comment #16 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
(In reply to gooncreeper from comment #15)
> May I suggest we just add something like __attribute__((trace)) for the
> special abort case? Noreturn was added for code optimization after all, n=
ot
> for backtracing.

It will break any attempts to debug an abort until the libc headers are upd=
ated
to use __attribute__((trace)).

Note that in GCC noreturn has been added far before the WG14 _Noreturn paper
(even this ticket predates the WG14 paper), so the rationale in the paper m=
ay
not apply.

In practice most _Noreturn functions are abort, exit, ..., i.e. they are on=
ly
executed one time so optimizing against a cold path does not help much.  I
don't think it's a good idea to encourage people to construct some fancy co=
de
by a recursive _Noreturn function (why not just use a loop?!)  And if you m=
ust
write such fancy code anyway IMO musttail attribute (PR83324) will be a bet=
ter
solution.=