PR tree-optimization/51721
	* tree-vrp.c (register_edge_assert_for_2): If comparing
	lhs of right shift by constant with an integer constant,
	add ASSERT_EXPRs for the rhs1 of the right shift.

	* gcc.dg/tree-ssa/vrp63.c: New test.
	* gcc.dg/pr51721.c: New test.

From-SVN: r184927