https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047
--- Comment #11 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:01ea66a6c56e53163d9430f4d87615d570848aa8 commit r13-5075-g01ea66a6c56e53163d9430f4d87615d570848aa8 Author: Jakub Jelinek <ja...@redhat.com> Date: Mon Jan 9 23:41:20 2023 +0100 c++: Only do maybe_init_list_as_range optimization if !processing_template_decl [PR108047] The last testcase in this patch ICEs, because maybe_init_list_as_range -> maybe_init_list_as_array calls maybe_constant_init in: /* Don't do this if the conversion would be constant. */ first = maybe_constant_init (first); if (TREE_CONSTANT (first)) return NULL_TREE; but maybe_constant_init shouldn't be called when processing_template_decl. While we could replace that call with fold_non_dependent_init, my limited understanding is that this is an optimization and even if we don't optimize it when processing_template_decl, build_user_type_conversion_1 will be called again during instantiation with !processing_template_decl if it is every instantiated and we can do the optimization only then. 2023-01-09 Jakub Jelinek <ja...@redhat.com> PR c++/105838 PR c++/108047 PR c++/108266 * call.cc (maybe_init_list_as_range): Always return NULL_TREE if processing_template_decl. * g++.dg/tree-ssa/initlist-opt2.C: New test. * g++.dg/tree-ssa/initlist-opt3.C: New test.