re PR middle-end/63884 (ICE: SIGSEGV in is_sec_implicit_index_fn with -fcilkplus and __builtin_sadd_overflow())

	PR middle-end/63884
c-family/
	* array-notation-common.c (is_sec_implicit_index_fn): Return false
	for NULL fndecl.
	(extract_array_notation_exprs): Return for NULL node.
testsuite/
	* c-c++-common/cilk-plus/AN/pr63884.c: New test.

From-SVN: r217612