tree-ssa-sccvn.c (visit_reference_op_load): If the lookup found an expression with constants, note that in the VN for the lhs.

2008-03-18  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-sccvn.c (visit_reference_op_load): If the lookup
	found an expression with constants, note that in the VN for the lhs.
	* tree-ssa-pre.c (eliminate): Visit COND_EXPR statements and
	fold them to constants if possible.  Run cleanup_cfg if done so.
	(execute_pre): Return todo.
	(do_pre): Likewise.
	(execute_fre): Likewise.
	* tree-ssa-forwprop.c (can_propagate_from): Allow propagation
	of constants.
	(get_prop_source_stmt): Look through pointer conversions.

	* gcc.dg/tree-ssa/forwprop-4.c: New testcase.
	* gcc.dg/tree-ssa/ssa-fre-16.c: Likewise.

From-SVN: r133315