https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70139
--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Disabling the trivial copy ctor shortcut handling fixes this:
--- constexpr.c.xx 2016-03-11 17:37:42.000000000 +0100
+++ constexpr.c 2016-03-18 18:18:59.579595563 +0100
@@ -1240,7 +1240,7 @@ cxx_eval_call_expression (const constexp
}
/* Shortcut trivial constructor/op=. */
- if (trivial_fn_p (fun))
+ if (trivial_fn_p (fun) && 0)
{
if (call_expr_nargs (t) == 2)
{
so I bet the bug would be in there. I'm surprised the trivial copy ctor
handling doesn't evaluate it as a store to the first argument, the first
argument isn't mentioned there at all.
