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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/109991] stack-use-after-scope Date: Fri, 26 May 2023 14:58:42 +0000 [thread overview] Message-ID: <bug-109991-4-z446O2HkXn@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-109991-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109991 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic Status|UNCONFIRMED |NEW Component|sanitizer |c++ Last reconfirmed| |2023-05-26 Ever confirmed|0 |1 Blocks| |55004 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- That is because with constexpr, the code should have been rejected ... Take this C++20 GCC accepts it (incorrectly) but clang rejects it: ``` using T = int; struct Wrap { T const& v; constexpr Wrap(T const& in) : v{in} {} }; struct BadWrapUse final { T i{}; consteval BadWrapUse() { Wrap w{T{}}; // temporary T's lifetime ends after this expression i = w.v; // This should lead to stack-use-after-scope. } }; int main() { BadWrapUse c; } ``` Note there might be a dup of it somewhere. Basically in your original example, GCC is doing constexpr evulation but that is not valid for constant expression evulation ... Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55004 [Bug 55004] [meta-bug] constexpr issues
next prev parent reply other threads:[~2023-05-26 14:58 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-05-26 14:43 [Bug sanitizer/109991] New: stack-use-after-scope igkper at gmail dot com 2023-05-26 14:58 ` pinskia at gcc dot gnu.org [this message] 2023-05-26 15:00 ` [Bug c++/109991] stack-use-after-scope pinskia at gcc dot gnu.org 2023-05-26 19:56 ` igkper at gmail dot com 2023-05-26 19:59 ` pinskia at gcc dot gnu.org 2023-05-26 20:21 ` igkper at gmail dot com
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