gcov.c (struct arc_info): Replace local_span with cycle.

gcov.c (struct arc_info): Replace local_span with cycle.

.	* gcov.c (struct arc_info): Replace local_span with cycle.
	(struct block_info): Replace u.span with u.cycle. Add is_call_return.
	(solve_flow_graph): Set is_call_return.
	(add_line_counts): Adjust. In block mode, blocks attach to last line.
	(accumulate_line_counts): Find graph cycles, not spanning tree.
	(output_branch_count): Adjust.
	(output_lines): Adjust.
	* doc/gcov.texi: Update.
testsuite:
	* gcc.misc-test/gcov-9.c: New test.
	* gcc.misc-test/gcov-10.c: New test
	* gcc.misc-test/gcov-11.c: New test.

From-SVN: r65299