[Bug c++/80039] `constexpr` member function calls in a `constexpr` constructor are ignored if the object is defined locally

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80039

Jakub Jelinek  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution|--- |DUPLICATE

--- Comment #3 from Jakub Jelinek  ---
Handled in PR99859.

*** This bug has been marked as a duplicate of bug 99859 ***

[Bug c++/80039] `constexpr` member function calls in a `constexpr` constructor are ignored if the object is defined locally

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80039

Jakub Jelinek  changed:

   What|Removed |Added

 CC||jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek  ---
See PR99859

[Bug c++/80039] `constexpr` member function calls in a `constexpr` constructor are ignored if the object is defined locally

[david at doublewise dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80039

David Stone  changed:

   What|Removed |Added

 CC||david at doublewise dot net

--- Comment #1 from David Stone  ---
Here's another reproduction

```
struct s {
int m_value = 0;

constexpr int value() const {
return m_value;
}

constexpr s()
{
value();
m_value = 1;
}
};

constexpr auto x = s();
static_assert(x.value() == 1);
```

Still a problem on trunk.

This example shows it's not just that side effects are ignored, but also that
the return value is cached. My guess is that there is some code path that
memoizes calls to constexpr functions, replacing them with their return value,
and that code is getting invoked when it shouldn't be.