https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103989
Bug ID: 103989
Summary: [12 regression] std::optional and bogus
-Wmaybe-unitialized at -Og
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: [email protected]
Target Milestone: ---
With the trunk version of GCC compiling the following program with
-std=c++17 -Og -Wall -Werror
gives a bogus maybe-uninitialized error (in the standard library component for
the shared pointer):
////
#include <optional>
#include <memory>
struct A {
A (int a) : a {a}
{}
const std::shared_ptr <int> x;
int a;
};
class B
{
public:
B (const std::optional <A>& a)
: a {a}
{
}
public:
const std::optional <A> a;
};
int
main ()
{
B b {std::nullopt};
}
////
Compiling it with
-std=c++17 -O1 -Wall -Werror
doesn't produce the error.
As the code compiles find at -Og and -O1 with GCC 11.2, this is a regression.
The error triggering is brittle. It goes away if the dummy member variable a in
class A is removed, for example.
For experimentation, the test case can be found here:
https://godbolt.org/z/arGKT7d5n.
