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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/102916] cmath constexpr can lead to ODR violations/incorrect results
Date: Wed, 30 Nov 2022 14:52:23 +0000	[thread overview]
Message-ID: <bug-102916-4-rQddrIoKBj@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102916-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102916

--- Comment #12 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Darrell Wright from comment #2)
> The constexpr value returned is different depending on the compiler.  If one
> uses clang and gcc this leads to an ODR issue as 
> 
> void bar( ) {
>   if constexpr( foo<[]{ return std::sqrt( 4.0 ); }>( ) ) {
>     doA( );
>   } else {
>     doB( );
>   }
> }


This is EXTREMELY contrived. You've basically set up a program where you detect
is std::sqrt is constexpr, and then said you get different results depending
whether std::sq

  parent reply	other threads:[~2022-11-30 14:52 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-24 17:27 [Bug c++/102916] New: " Darrell.Wright at gmail dot com
2021-10-24 19:24 ` [Bug c++/102916] " pinskia at gcc dot gnu.org
2021-10-24 19:57 ` Darrell.Wright at gmail dot com
2021-10-24 20:18 ` Darrell.Wright at gmail dot com
2021-10-24 20:30 ` pinskia at gcc dot gnu.org
2021-10-24 20:34 ` pinskia at gcc dot gnu.org
2021-10-24 20:41 ` [Bug libstdc++/102916] " Darrell.Wright at gmail dot com
2021-10-25  8:32 ` redi at gcc dot gnu.org
2021-10-25  8:35 ` redi at gcc dot gnu.org
2021-10-25  9:32 ` redi at gcc dot gnu.org
2021-10-25  9:34 ` redi at gcc dot gnu.org
2021-10-25 13:29 ` Darrell.Wright at gmail dot com
2022-11-30 14:52 ` redi at gcc dot gnu.org [this message]
2022-11-30 14:53 ` redi at gcc dot gnu.org
2024-05-21  3:46 ` pinskia at gcc dot gnu.org

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