tree-optimization/111397 - missed copy propagation involving abnormal dest

tree-optimization/111397 - missed copy propagation involving abnormal dest

The following extends the previous enhancement to copy propagation
involving abnormals.  We can easily replace abnormal uses by not
abnormal uses and only need to preserve the abnormals in PHI arguments
flowing in from abnormal edges.  This changes the may_propagate_copy
argument indicating we are not propagating into a PHI node to indicate
whether we know we are not propagating into a PHI argument from an
abnormal PHI instead.

	PR tree-optimization/111397
	* tree-ssa-propagate.cc (may_propagate_copy): Change optional
	argument to specify whether the PHI destination doesn't flow in
	from an abnormal PHI.
	(propagate_value): Adjust.
	* tree-ssa-forwprop.cc (pass_forwprop::execute): Indicate abnormal
	PHI dest.
	* tree-ssa-sccvn.cc (eliminate_dom_walker::before_dom_children):
	Likewise.
	(process_bb): Likewise.

	* gcc.dg/uninit-pr111397.c: New testcase.