arg0.Uses++
	arg1.Uses++
	return v
}

// NewValue2A returns a new value in the block with two arguments and one aux values.
func (b *Block) NewValue2A(pos src.XPos, op Op, t *types.Type, aux Aux, arg0, arg1 *Value) *Value {
	v := b.Func.newValue(op, t, b, pos)
	v.AuxInt = 0
	v.Aux = aux
	v.Args = v.argstorage[:2]
	v.argstorage[0] = arg0
	v.argstorage[1] = arg1
	arg0.Uses++
	arg1.Uses++

		}

		// set up control flow for write barrier test
		// load word, test word, avoiding partial register write from load byte.
		cfgtypes := &f.Config.Types
		flag := b.NewValue2(pos, OpLoad, cfgtypes.UInt32, wbaddr, mem)
		flag = b.NewValue2(pos, OpNeq32, cfgtypes.Bool, flag, const0)
		b.Kind = BlockIf
		b.SetControl(flag)
		b.Likely = BranchUnlikely
		b.Succs = b.Succs[:0]
		b.AddEdgeTo(bThen)
		b.AddEdgeTo(bEnd)

	s := b.Func.ConstInt64(types.Types[types.TUINT64], shift)
	size := v.Type.Size()
	switch size {
	case 8:
		return b.NewValue2(pos, OpLsh64x64, v.Type, v, s)
	case 4:
		return b.NewValue2(pos, OpLsh32x64, v.Type, v, s)
	case 2:
		return b.NewValue2(pos, OpLsh16x64, v.Type, v, s)
	default:
		base.Fatalf("bad size %d\n", size)
		return nil
	}
}

            `),
			RootObject: mustUnstructured(`
                foo:
                - key: key1
                  bar: value1
                - key: key2
                  bar: newValue2
            `),
			RootOldObject: mustUnstructured(`
                foo:
                - key: key1
                  bar: value1
                - key: key2
                  bar: value2

		cmpOp := OpLess64U
		if pt.Size() == 4 {
			cmpOp = OpLess32U
		}
		limaddr := test.NewValue1I(bb.Pos, OpOffPtr, pt, 2*pt.Size(), g)
		lim := test.NewValue2(bb.Pos, OpLoad, pt, limaddr, mem0)
		cmp := test.NewValue2(bb.Pos, cmpOp, cfgtypes.Bool, sp, lim)
		test.SetControl(cmp)

		// if true, goto sched
		test.AddEdgeTo(sched)

		// if false, rewrite edge to header.

	var oldArgs []*Value
	argsWithoutMem := v.Args[:len(v.Args)-1]

	for j, a := range argsWithoutMem {
		oldArgs = append(oldArgs, a)
		i := int64(j)
		auxType := aux.TypeOfResult(i)
		auxBase := b.NewValue2A(v.Pos, OpLocalAddr, types.NewPtr(auxType), aux.NameOfResult(i), x.sp, mem)
		auxOffset := int64(0)
		aRegs := aux.RegsOfResult(int64(j))
		if a.Op == OpDereference {
			a.Op = OpLoad
		}
		var rc registerCursor