diff --git a/include/llvm/MC/MCAssembler.h b/include/llvm/MC/MCAssembler.h
index 11c525116d0..57aa08a2d0f 100644
--- a/include/llvm/MC/MCAssembler.h
+++ b/include/llvm/MC/MCAssembler.h
@@ -235,7 +235,6 @@ public:
   virtual SmallVectorImpl<char> &getContents() { return Contents; }
   virtual const SmallVectorImpl<char> &getContents() const { return Contents; }
 
-  unsigned getInstSize() const { return Contents.size(); }
   const MCInst &getInst() const { return Inst; }
   void setInst(const MCInst& Value) { Inst = Value; }
 
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index ee5ac1d3c73..5fdc57ad309 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -387,11 +387,10 @@ uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
                                           const MCFragment &F) const {
   switch (F.getKind()) {
   case MCFragment::FT_Data:
-    return cast<MCDataFragment>(F).getContents().size();
+  case MCFragment::FT_Relaxable:
+    return cast<MCEncodedFragment>(F).getContents().size();
   case MCFragment::FT_Fill:
     return cast<MCFillFragment>(F).getSize();
-  case MCFragment::FT_Relaxable:
-    return cast<MCRelaxableFragment>(F).getInstSize();
 
   case MCFragment::FT_LEB:
     return cast<MCLEBFragment>(F).getContents().size();