backport: re PR sanitizer/79944 (asan: incorrect instrumentation of atomic operations)

backport: re PR sanitizer/79944 (asan: incorrect instrumentation of atomic operations)

	Backported from mainline
	2017-03-09  Jakub Jelinek  <jakub@redhat.com>

	PR sanitizer/79944
	* asan.c (get_mem_refs_of_builtin_call): For BUILT_IN_ATOMIC* and
	BUILT_IN_SYNC*, determine the access type from the size suffix and
	always build a MEM_REF with that type.  Handle forgotten
	BUILT_IN_SYNC_FETCH_AND_NAND_16 and BUILT_IN_SYNC_NAND_AND_FETCH_16.

	* c-c++-common/asan/pr79944.c: New test.

From-SVN: r248658