The function bb_is_just_return finds if the BB it is asked about does
just a return and nothing else.  It currently does not allow clobbers
in the block either, which we of course can allow just fine.

This patch changes that.


	* cfgcleanup.c (bb_is_just_return): Allow CLOBBERs.

gcc/testsuite/

From-SVN: r248351