Index: llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
===================================================================
--- llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
+++ llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
@@ -168,6 +168,12 @@
   return TSFlags & UsesMaskPolicyMask;
 }
 
+static inline unsigned getMergeOpNum(const MCInstrDesc &Desc) {
+  assert(hasMergeOp(Desc.TSFlags));
+  assert(!Desc.isVariadic());
+  return Desc.getNumDefs();
+}
+
 static inline unsigned getVLOpNum(const MCInstrDesc &Desc) {
   const uint64_t TSFlags = Desc.TSFlags;
   // This method is only called if we expect to have a VL operand, and all
Index: llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -1220,6 +1220,13 @@
   }
 
   const uint64_t TSFlags = Desc.TSFlags;
+  if (RISCVII::hasMergeOp(TSFlags)) {
+    unsigned OpIdx = RISCVII::getMergeOpNum(Desc);
+    if (MI.findTiedOperandIdx(0) != OpIdx) {
+      ErrInfo = "Merge op improperly tied";
+      return false;
+    }
+  }
   if (RISCVII::hasSEWOp(TSFlags)) {
     unsigned OpIdx = RISCVII::getSEWOpNum(Desc);
     uint64_t Log2SEW = MI.getOperand(OpIdx).getImm();