private DataType getInputDataType(PcodeOp op) {
		if (op == null) {
			return null;
		}

		Varnode[] inputs = op.getInputs();
		if (inputs.length == 2 && inputs[0].getHigh() != null) {
			return inputs[0].getHigh().getDataType();
		}

		return null;
	}
A base class that represents a variable from the decompiler.  This is either a variable
type or a variable with an optional field access.
Ghidra/Features/DecompilerDependent/src/main/java/ghidra/app/extension/datatype/finder/DecompilerVariable.java