https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119864
--- Comment #22 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Nathaniel Shead <[email protected]>: https://gcc.gnu.org/g:858f300727833740f74d90378a0f302d4254ef37 commit r16-5727-g858f300727833740f74d90378a0f302d4254ef37 Author: Nathaniel Shead <[email protected]> Date: Sat Nov 15 15:27:13 2025 +1100 c++: Support template block-scope OpenMP user-defined reductions in modules [PR119864] There were two issues preventing OpenMP reductions of UDTs from working in modules. Firstly, we were failing a number of checking asserts in the streaming logic because the declaration is a DECL_LOCAL_DECL_P but was not correctly added to the BLOCK of the function template. This is because cp_parser_omp_declare_reduction only called pushdecl when !processing_template_decl; correcting this fixed this issue. The second issue is that modules saw this as a function definition and so attempted to call allocate_struct_function on it, which crashes. Given that these reduction functions don't really behave like real function definitions in any other way, I think the cleanest solution is to just skip all the function definition post-processing in modules; this seems to work to get the test functioning correctly, from what I can see. PR c++/119864 gcc/cp/ChangeLog: * module.cc (trees_in::read_function_def): Don't call post_process on OpenMP UDT reductions. * parser.cc (cp_parser_omp_declare_reduction): Call push_decl for block_scope, even when processing_template_decl. gcc/testsuite/ChangeLog: * g++.dg/modules/omp-4_a.C: New test. * g++.dg/modules/omp-4_b.C: New test. Signed-off-by: Nathaniel Shead <[email protected]> Reviewed-by: Jakub Jelinek <[email protected]> Reviewed-by: Jason Merrill <[email protected]>
