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From: "ldalessandro at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/97790] New: constexpr evaluation reports false positive memory leak Date: Tue, 10 Nov 2020 21:09:41 +0000 [thread overview] Message-ID: <bug-97790-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97790 Bug ID: 97790 Summary: constexpr evaluation reports false positive memory leak Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: ldalessandro at gmail dot com Target Milestone: --- The constexpr evaluator seems to lose track of dynamic allocations in some contexts, resulting in false-positive leaks and rejected valid code. This particular example uses an immediately invoked function expression referencing an NTTP, which seems like a corner case but is actually extremely common in two-pass constexpr algorithms (i.e., compute constexpr size of result, then compute result to return). https://godbolt.org/z/Tnn6xh ``` struct vector { int *data; int n; constexpr vector() : data(new int[1]{}), n(1) {} constexpr ~vector() { delete [] data; } }; struct Foo { constexpr auto foo() const { return vector(); } }; template <auto& f> constexpr static auto bar() { [] { return f.foo().n; }(); return true; } constexpr Foo foo; constexpr auto dd = bar<foo>(); ```
next reply other threads:[~2020-11-10 21:09 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-10 21:09 ldalessandro at gmail dot com [this message] 2020-11-10 21:31 ` [Bug c++/97790] " ldalessandro at gmail dot com 2020-11-11 12:22 ` jakub at gcc dot gnu.org 2020-11-11 13:04 ` jakub at gcc dot gnu.org 2020-11-12 9:48 ` cvs-commit at gcc dot gnu.org 2020-11-12 10:06 ` cvs-commit at gcc dot gnu.org 2020-11-12 10:54 ` jakub at gcc dot gnu.org
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