re PR sanitizer/65280 (-fsanitize=bounds does not detect out-of-bounds access)

re PR sanitizer/65280 (-fsanitize=bounds does not detect out-of-bounds access)

	PR sanitizer/65280
	* doc/invoke.texi: Update description of -fsanitize=bounds.

	* c-ubsan.c (ubsan_instrument_bounds): Check for COMPONENT_REF
	before trying to figure out whether we have a flexible array member.

	* c-c++-common/ubsan/bounds-1.c: Add testing of flexible array
	member-like arrays.
	* c-c++-common/ubsan/bounds-8.c: New test.
	* c-c++-common/ubsan/bounds-9.c: New test.
	* gcc.dg/ubsan/bounds-2.c: New test.

Co-Authored-By: Martin Uecker <uecker@eecs.berkeley.edu>
From-SVN: r221250