https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96354
--- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
We have indeed:
# DEBUG D#2 => MEM[(double *)&<retval>]
and on the caller side:
D.2566[_9] = foo<3, 3> (D.2559, D.2572); [return slot optimization]
So, that is why to &<retval> &D.2566[_9] is propagated.
Now, if I add to foo a call to some function template that takes &t as
argument, this is handled correctly because id->regimplify is set to true and
the
qux<C<3> > (&D.2572[_9]);
call is fixed up by gimple_regimplify_operands. That function really isn't
called on debug stmts though (and not prepared to be called for them).
If I use
template <int N, int M> C<N> foo (D<N>, C<M>) { C<N> t; double d = 1.25;
__builtin_memcpy (&t, &d, sizeof (double)); return t; }
instead so that before that inlining we get
MEM <long unsigned int> [(char * {ref-all})&<retval>] = _4;
then it is indeed again gimple_regimplify_operands that fixes up the
MEM <long unsigned int> [(char * {ref-all})&D.2569[_9]] = 4608308318706860032;
into:
_21 = &D.2569[_9];
MEM <long unsigned int> [(char * {ref-all})_21] = 4608308318706860032;
