[Bug c++/86678] New: constexpr evaluation incorrectly diagnoses unevaluated call to non-constexpr function

[eric at efcs dot ca]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86678

            Bug ID: 86678
           Summary: constexpr evaluation incorrectly diagnoses unevaluated
                    call to non-constexpr function
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: eric at efcs dot ca
  Target Milestone: ---

Reproducer:

#include <cassert>

template <class T>
constexpr int foo() {
    if (sizeof(T))
        return 1;
    assert(false && "BOOM!");
}

constexpr int V = foo<int>();