diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -394,6 +394,11 @@
       BaseOps.push_back(getNamedOperand(LdSt, AMDGPU::OpName::vaddr));
     }
     Offset = 0;
+    // Get appropriate operand, and compute width accordingly.
+    DataOpIdx = AMDGPU::getNamedOperandIdx(Opc, AMDGPU::OpName::vdst);
+    if (DataOpIdx == -1)
+      DataOpIdx = AMDGPU::getNamedOperandIdx(Opc, AMDGPU::OpName::vdata);
+    Width = getOpSize(LdSt, DataOpIdx);
     return true;
   }