Add op_values() to iterate over the SDValue operands of an SDNode.

SDNode already had ops() which would iterate over the operands and return
SDUse*.  This version instead gets the SDValue's out of the SDUse's so that
we can use foreach in more places.

Reviewed by David Blaikie.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240805 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/SelectionDAGNodes.h

@@ -579,6 +579,23 @@ public:
   op_iterator op_end() const { return OperandList+NumOperands; }
   ArrayRef<SDUse> ops() const { return makeArrayRef(op_begin(), op_end()); }
 
+  /// Iterator for directly iterating over the operand SDValue's.
+  struct value_op_iterator
+      : iterator_adaptor_base<value_op_iterator, op_iterator,
+                              std::random_access_iterator_tag, SDValue,
+                              ptrdiff_t, value_op_iterator *,
+                              value_op_iterator *> {
+    explicit value_op_iterator(SDUse *U = nullptr)
+      : iterator_adaptor_base(U) {}
+
+    const SDValue &operator*() const { return I->get(); }
+  };
+
+  iterator_range<value_op_iterator> op_values() {
+    return iterator_range<value_op_iterator>(value_op_iterator(op_begin()),
+                                             value_op_iterator(op_end()));
+  }
+
   SDVTList getVTList() const {
     SDVTList X = { ValueList, NumValues };
     return X;