https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91165
--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #6)
> Slightly further reduced #c3:
> template <typename T> constexpr T bar (T c) { return c; }
> template <typename T, typename U> struct S {
> T f;
> U g;
> constexpr S (T c, U h) : f(c), g(h) {}
> };
> template <typename T, typename U>
> constexpr S<T, U> foo (T &&c, U h) { return S<T, U> (c, bar (h)); }
> struct C { void baz (int); void qux (); };
> void C::baz (int a) { foo (a, ""); }
> void C::qux () { foo (0, ""); }
>
> Seems some TARGET_EXPR is not unshared during the constexpr evaluation.
The expression that isn't being unshared here is &"", which is built in baz,
cached as the result of bar(&""), and reused when we again see bar(&"") while
evaluating the call to foo in qux. This seems like reasonable sharing to me,
but perhaps we should strip locations from cached results.
