* simplify-rtx.c (simplify_relational_operation_1): Optimize
	comparisons of POPCOUNT against zero.
	(simplify_const_relational_operation): Likewise.

	* gcc.target/ia64/builtin-popcount-1.c: New test case.
	* gcc.target/ia64/builtin-popcount-2.c: Likewise.

From-SVN: r121838