2008-11-05  Richard Guenther  <rguenther@suse.de>

	PR middle-end/37742
	* tree-ssa.c (useless_type_conversion_p_1): Check different restrict
	qualified pointer conversion before stripping qualifiers.
	* gimplify.c (create_tmp_from_val): Use correctly qualified type.
	* tree-flow.h (may_propagate_address_into_dereference): Declare.
	* tree-ssa-ccp.c (may_propagate_address_into_dereference): New function.
	(ccp_fold): Use it.
	* tree-ssa-forwprop.c (rhs_to_tree): Remove useless conversions,
	properly canonicalize binary ops.
	(forward_propagate_addr_expr_1): Use
	may_propagate_address_into_dereference.

	cp/
	* decl.c (start_preparsed_function): Use the correct type for
	building the RESULT_DECL.

	* gcc.c-torture/compile/pr37742.c: New testcase.
	* g++.dg/pr37742.C: Likewise.
	* gcc.dg/tree-ssa/forwprop-7.c: Check for two volatile loads.

From-SVN: r141606