https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116364
--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Nathaniel Shead <nsh...@gcc.gnu.org>: https://gcc.gnu.org/g:c310d29cac1c3a770f48ab8bb2d295ef9cc08c53 commit r15-3030-gc310d29cac1c3a770f48ab8bb2d295ef9cc08c53 Author: Nathaniel Shead <nathanielosh...@gmail.com> Date: Thu Aug 15 21:46:09 2024 +1000 c++/modules: Fix type lookup in DECL_TEMPLATE_INSTANTIATIONS [PR116364] We need to use the DECL_TEMPLATE_INSTANTIATIONS property to find reachable specialisations from a template to ensure that any GM specialisations are properly marked as reachable. Currently the modules code uses the decl when rebuilding this property, but this is not always correct; it appears that for type specialisations we need to use the TREE_TYPE of the decl instead so that the specialisation is correctly found. This patch makes the required adjustments. PR c++/116364 gcc/cp/ChangeLog: * cp-tree.h (get_mergeable_specialization_flags): Adjust signature. * module.cc (trees_out::decl_value): Indicate whether this is a type or decl specialisation. * pt.cc (get_mergeable_specialization_flags): Match against the type of a non-decl specialisation. (add_mergeable_specialization): Use the already calculated spec instead of always adding decl to DECL_TEMPLATE_INSTANTIATIONS. gcc/testsuite/ChangeLog: * g++.dg/modules/tpl-spec-9_a.C: New test. * g++.dg/modules/tpl-spec-9_b.C: New test. * g++.dg/modules/tpl-spec-9_c.C: New test. Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com> Reviewed-by: Jason Merrill <ja...@redhat.com>
