[Bug c++/83116] [6/7/8 Regression] Statement with no effect causes wrong code of static object constexpr method

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83116

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-11-23
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |jason at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r230365.
Guess we need to remove the static var from constexpr caches at the end of
construction if the var isn't constexpr.

Testcase modified for the testsuite:

// PR c++/83116
// { dg-do run { target c++14 } }

struct S {
  constexpr S () : s(0) { foo (); }
  constexpr int foo () { return s; }
  int s;
};

int
main ()
{
  static S var;
  var.s = 5;
  if (var.s != 5 || var.foo () != 5)
    __builtin_abort ();
}