https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96354
--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, looks like inlining C<3>::C into foo<3, 3> produces this debug stmt.
foo<3, 3> (struct D D.2506, struct C D.2507)
{
<bb 2> :
C<3>::C (&<retval>);
return <retval>;
and inlined from
C<3>::C (struct C * const this)
{
<bb 2> [local count: 1073741824]:
*this_2(D) ={v} {CLOBBER};
# DEBUG D#1 => &this_2(D)->d
# DEBUG this => D#1
# DEBUG INLINE_ENTRY baz
# DEBUG this => NULL
# DEBUG D#2 => MEM[(double *)this_2(D)]
# DEBUG c => D#2
return;
so if the MEM wouldn't be dead we'd face the same situation in regular
stmts I guess. And we do. But then the inliner sees
_10 = &D.2565[_9];
C<3>::C (_10);
_12 = &D.2564[_9];
C<3>::C (_12);
so value-substitution shouldn't happen here anyway... which means
it is eventually a over-eager mapping registered due to debug for
unused decls or so?
So we should fix this more "upstream" I bet. In declare_return_variable
we're doing insert_decl_map (id, result, var) with var == D.2567[_9]
which is problematic. We might want to gimplify this there into
ptr_42 = &D.2567[_9] and map <result> to MEM[ptr_42] instead?
That might simplify code elsewhere but eventually affects code generation.
Note this will only happen for return slots I think.
