[Bug c++/80077] New: constant expressions and -fno-elide-constructors

[kaballo86 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80077

            Bug ID: 80077
           Summary: constant expressions and -fno-elide-constructors
           Product: gcc
           Version: 7.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kaballo86 at hotmail dot com
  Target Milestone: ---

The following snippet, extracted from libstdc++, causes the compiler to
generate an error when compiled using -fno-elide-constructors under C++11/14:

    /// piecewise_construct_t
    struct piecewise_construct_t { explicit piecewise_construct_t() = default;
};

    /// piecewise_construct
    constexpr piecewise_construct_t piecewise_construct =
piecewise_construct_t();
    // error: modification of 'piecewise_construct' is not a constant
expression

This appears to be a regression from 6.3.0.