[llvm] [ARM] Add reference to `ARMAsmParser` in `ARMOperand` (PR #86110)

[Alfie Richards via llvm-commits]

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@@ -3378,7 +3387,21 @@ class ARMOperand : public MCParsedAsmOperand {
 
   void addVecListOperands(MCInst &Inst, unsigned N) const {
     assert(N == 1 && "Invalid number of operands!");
-    Inst.addOperand(MCOperand::createReg(VectorList.RegNum));
+
+    if (isAnyVectorList())
+      Inst.addOperand(MCOperand::createReg(VectorList.RegNum));
+    else if (isDReg() && !Parser->hasMVE()) {
+      Inst.addOperand(MCOperand::createReg(Reg.RegNum));
+    } else if (isQReg() && !Parser->hasMVE()) {
+      auto DPair = Parser->getDRegFromQReg(Reg.RegNum);
+      DPair = Parser->getMRI()->getMatchingSuperReg(
+          DPair, ARM::dsub_0, &ARMMCRegisterClasses[ARM::DPairRegClassID]);
+      Inst.addOperand(MCOperand::createReg(DPair));
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AlfieRichardsArm wrote:

For this code https://github.com/llvm/llvm-project/pull/83436#discussion_r1514421363 is somewhat helpful context if you are curious

https://github.com/llvm/llvm-project/pull/86110