- if (!InstOpRec->isSubClassOf("OptionalDefOperand"))
- throw TGError(Loc, "reg0 used for result that is not an "
- "OptionalDefOperand!");
+ // Tied operands where the source is a sub-operand of a complex operand
+ // need to represent both operands in the alias destination instruction.
+ // Allow zero_reg for the tied portion. This can and should go away once
+ // the MC representation of things doesn't use tied operands at all.
+ //if (!InstOpRec->isSubClassOf("OptionalDefOperand"))
+ // throw TGError(Loc, "reg0 used for result that is not an "
+ // "OptionalDefOperand!");