https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95693
--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:4ccdb3fdbc14102c91b6148bcbe09d0763726ae0 commit r9-9408-g4ccdb3fdbc14102c91b6148bcbe09d0763726ae0 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Jan 22 19:03:23 2021 +0100 c++: Fix up ubsan false positives on references [PR95693] Alex' 2 years old change to build_zero_init_1 to return NULL pointer with reference type for references breaks the sanitizers, the assignment of NULL to a reference typed member is then instrumented before it is overwritten with a non-NULL address later on. That change has been done to fix error recovery ICE during process_init_constructor_record, where we: if (TYPE_REF_P (fldtype)) { if (complain & tf_error) error ("member %qD is uninitialized reference", field); else return PICFLAG_ERRONEOUS; } a few lines earlier, but then continue and ICE when build_zero_init returns NULL. The following patch reverts the build_zero_init_1 change and instead creates the NULL with reference type constants during the error recovery. The pr84593.C testcase Alex' change was fixing still works as before. 2021-01-22 Jakub Jelinek <ja...@redhat.com> PR sanitizer/95693 * init.c (build_zero_init_1): Revert the 2018-03-06 change to return build_zero_cst for reference types. * typeck2.c (process_init_constructor_record): Instead call build_zero_cst here during error recovery instead of build_zero_init. * g++.dg/ubsan/pr95693.C: New test. (cherry picked from commit e5750f847158e7f9bdab770fd9c5fff58c5074d3)
