* jump.c (squeeze_notes): Return true if no real insns were found.
	* rtl.h (squeeze_notes): Adjust prototype.
	* cfgcleanup.c (merge_blocks_move_predecessor_nojumps): If
	squeeze_notes finds no real instructions, abort.
	(merge_blocks_move_successor_nojumps): Likewise.
	* loop.c (find_and_verify_loops): Likewise.
	* stmt.c (expand_end_case): Likewise.
	* ifcvt.c (dead_or_predicable): Return TRUE if squeeze_notes doesn't
	find any real instructions.

	* gcc.c-torture/compile/20011114-4.c: New test.

From-SVN: r47048