https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113599
--- Comment #6 from GCC 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:fd620bd3351c6b9821c299035ed17e655d7954b5 commit r14-8439-gfd620bd3351c6b9821c299035ed17e655d7954b5 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Jan 26 00:08:36 2024 +0100 c++: Fix up build_m_component_ref [PR113599] The following testcase reduced from GDB is miscompiled starting with r14-5503 PR112427 change. The problem is in the build_m_component_ref hunk, which changed - datum = fold_build_pointer_plus (fold_convert (ptype, datum), component); + datum = cp_convert (ptype, datum, complain); + if (!processing_template_decl) + datum = build2 (POINTER_PLUS_EXPR, ptype, + datum, convert_to_ptrofftype (component)); + datum = cp_fully_fold (datum); Component is e, (sizetype) e is 16, offset of c inside of C. ptype is A *, pointer to type of C::c and datum is &d. Now, previously the above created ((A *) &d) p+ (sizetype) e which is correct, but in the new code cp_convert sees that C has A as base class and instead of returning (A *) &d, it returns &d.D.2800 where D.2800 is the FIELD_DECL for the A base at offset 8 into C. So, instead of computing ((A *) &d) p+ (sizetype) e it computes &d.D.2800 p+ (sizetype) e, which is ((A *) &d) p+ 24. The following patch fixes it by using convert instead of cp_convert which eventually calls build_nop (ptype, datum). 2024-01-26 Jakub Jelinek <ja...@redhat.com> PR c++/113599 * typeck2.cc (build_m_component_ref): Use convert instead of cp_convert for pointer conversion. * g++.dg/expr/ptrmem11.C: New test.
