[arm] Handle immediate values in uaddvsi4

[arm] Handle immediate values in uaddvsi4

The uaddv patterns in the arm back-end do not currenty handle immediates
during expansion.  This patch adds this support for uaddvsi4.  It's really
a stepping-stone towards early expansion of uaddvdi4, but it complete and
a useful change in its own right.

Whilst making this change I also observed that we really had two patterns
that did exactly the same thing, but with slightly different properties;
consequently I've cleaned up all of the add-and-compare patterns to bring
some consistency.

	* config/arm/arm.md (adddi3): Call gen_addsi3_compare_op1.
	* (uaddv<mode>4): Delete expansion pattern.
	(uaddvsi4): New pattern.
	(uaddvdi4): Likewise.
	(addsi3_compareC): Delete pattern, change callers to use
	addsi3_compare_op1.
	(addsi3_compare_op1): No-longer anonymous.  Clean up constraints to
	reduce the number of alternatives and re-work type attribute handling.
	(addsi3_compare_op2): Clean up constraints to reduce the number of
	alternatives and re-work type attribute handling.
	(compare_addsi2_op0): Likewise.
	(compare_addsi2_op1): Likewise.

From-SVN: r277182