https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126137
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
CC| |jakub at gcc dot gnu.org
Last reconfirmed| |2026-07-08
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The problem is that
make_rtl_for_nonlocal_decl
does:
8811 if (consteval_only_p (decl))
8812 {
8813 /* Disable assemble_variable. */
8814 DECL_EXTERNAL (decl) = true;
8815 /* Undo make_decl_one_only. */
8816 if (DECL_COMDAT_GROUP (decl))
8817 {
8818 symtab_node *node = symtab_node::get (decl);
8819 node->set_comdat_group (NULL);
8820 node->dissolve_same_comdat_group_list ();
8821 }
and later on cp_finish_decomp is called, copies the DECL_EXTERNAL flag to the
VAR_DECL created for each pack element:
11010 TREE_VEC_ELT (packv, j + 2) = t = copy_node
(v[pack]);
11011 set_sb_pack_name (t, j);
and
11214 if (!processing_template_decl)
11215 for (unsigned int i = 0; i < TREE_VEC_LENGTH (packv) - 2U; ++i)
11216 pushdecl (TREE_VEC_ELT (packv, 2 + i));
and crashes during the pushdecl because it asserts that
3671 if (TREE_CODE (decl) == FUNCTION_DECL
3672 || (VAR_P (decl) && DECL_EXTERNAL (decl)))
3673 /* Make sure local externs are marked as such. OMP UDRs really
3674 are nested functions. */
3675 gcc_checking_assert (DECL_LOCAL_DECL_P (decl)
3676 && (DECL_NAMESPACE_SCOPE_P (decl)
3677 || (TREE_CODE (decl) == FUNCTION_DECL
3678 && DECL_OMP_DECLARE_REDUCTION_P
(decl))));
Note, in this case it isn't a real extern, just a consteval only typed
variable.
Unsure if this is worth addressing before consteval-only types are killed and
replaced with consteval-only values (with https://wg21.link/P4101R1 ).
