https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100835
Bug ID: 100835
Summary: defaulted equality gives wrong answer, if constexpr
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: barry.revzin at gmail dot com
Target Milestone: ---
Short example:
struct B {
int i;
CONSTEXPR bool operator==(B const&) const = default;
};
struct D : B {
CONSTEXPR bool operator==(D const&) const = default;
};
static_assert(D{0} == D{5});
When compiled with -DCONSTEXPR=constexpr, the static assertion passes. When
compiled with -DCONSTEXPR=, the static assertion fails.
For some reason, when the equality operator is declared constexpr, there is
just no work that happens for doing equality. For instance, the function
bool check(D a, D b) {
return a == b;
}
compiles to:
check(D, D):
mov eax, 1
ret
