re PR sanitizer/87095 (UndefinedBehaviorSanitizer vptr false positive with virtual inheritance only with -fno-sanitize-recover)
PR c++/87095
* decl.c (begin_destructor_body): If current_class_type has
virtual bases and the primary base is nearly empty virtual base,
voidify clearing of vptr and make it conditional on in-charge
argument.
* g++.dg/ubsan/vptr-13.C: New test.
From-SVN: r263967
