https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99294
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Nathan Sidwell <nat...@gcc.gnu.org>: https://gcc.gnu.org/g:2e0bb9eec2d455840bc4773391b3313a320b3c23 commit r11-7441-g2e0bb9eec2d455840bc4773391b3313a320b3c23 Author: Nathan Sidwell <nat...@acm.org> Date: Mon Mar 1 05:41:10 2021 -0800 c++: Completeness of typedef structs [PR 99294] When we read in a class definition, we use fixup_type_variants to propagate the now-completed fields of the class's TYPE to other variants. Unfortunately that doesn't propagate all of them, and in this case we had a typedef to an (incomplete) instantiation. That typedef ended up with a VOIDmode, which blew up gimple expansion as the type itself isn't VOID. Without modules, that information is propagated in finalize_type_size when laying out the class. But that doesn't happen with stream-in -- we already know the layout. There is already some overlap between the two functions, now there's a bit more. In fixup_type_variants, I pay attention to the TYPE_NAME to decide whether to override a user's TYPE_ALIGN -- variants of the main-variant typedef just copy the main-variant. Other variants recalculate. Overaligning is still permitted. I also added a TYPE_ALIGN_RAW accessor, and fixed a bug in the alignment streaming I noticed. I did not refactor TYPE_ALIGN beyond using the new accessor. (It could be written as ((1 << align_raw) >> 1), rather than use the conditional.) PR c++/99294 gcc/ * tree.h (TYPE_ALIGN_RAW): New accessor. (TYPE_ALIGN): Use it. gcc/cp/ * class.c (fixup_type_variants): Propagate mode, precision, alignment & emptiness. * module.cc (trees_out::type_node): Use TYPE_ALIGN_RAW. (trees_in::tree_node): Rematerialize alignment here. gcc/testsuite/ * g++.dg/modules/pr99294.h: New. * g++.dg/modules/pr99294_a.C: New. * g++.dg/modules/pr99294_b.C: New.
