PR c++/83555
* typeck.c (build_static_cast_1): For static casts to reference types,
call build_base_path with flag_delete_null_pointer_checks as nonnull
instead of always false. When -fsanitize=null, call
ubsan_maybe_instrument_reference on the NULL reference INTEGER_CST.
* cp-gimplify.c (cp_genericize_r): Don't walk subtrees of UBSAN_NULL
call if the first argument is INTEGER_CST with REFERENCE_TYPE.
* g++.dg/opt/pr83555.C: New test.
* g++.dg/ubsan/pr83555.C: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@256186 138bc75d-0d04-0410-961f-82ee72b054a4