re PR tree-optimization/49279 (Optimization incorrectly presuming constant variable inside loop in g++ 4.5 and 4.6 with -O2 and -O3 for x86_64 targets)

	PR tree-optimization/49279
	* tree-ssa-structalias.c (find_func_aliases): Don't handle
	CAST_RESTRICT.
	* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Allow
	restrict propagation.
	* tree-ssa.c (useless_type_conversion_p): Don't return false
	if TYPE_RESTRICT differs.

	* gcc.dg/tree-ssa/restrict-4.c: XFAIL.
	* gcc.c-torture/execute/pr49279.c: New test.

From-SVN: r179620