tree-optimization/116079 - store motion and clobbers

tree-optimization/116079 - store motion and clobbers

When we move a store out of an inner loop and remove a clobber in
the process, analysis of the inner loop can run into the clobber
via the meta-data and crash when accessing its basic-block.  The
following avoids this by clearing the VDEF which is how it identifies
already processed stores.

	PR tree-optimization/116079
	* tree-ssa-loop-im.cc (hoist_memory_references): Clear
	VDEF of elided clobbers.

	* gcc.dg/torture/pr116079.c: New testcase.