gcc/ChangeLog

	* input.c (location_get_source_line): Bail out on when line number
	is zero, and test the return value of
	lookup_or_add_file_to_cache_tab.

gcc/testsuite/ChangeLog

	* c-c++-common/cpp/warning-zero-location.c: New test.
	* c-c++-common/cpp/warning-zero-location-2.c: Likewise.

Signed-off-by: Dodji Seketeli <dodji@seketeli.org>

From-SVN: r207195