diff --git a/include/llvm/Bitcode/ReaderWriter.h b/include/llvm/Bitcode/ReaderWriter.h
index 4c194a638d4..c44b084c34f 100644
--- a/include/llvm/Bitcode/ReaderWriter.h
+++ b/include/llvm/Bitcode/ReaderWriter.h
@@ -52,7 +52,7 @@ namespace llvm {
 
   /// Read the specified bitcode file, returning the module.
   /// This method *never* takes ownership of Buffer.
-  ErrorOr<Module *> parseBitcodeFile(MemoryBuffer *Buffer,
+  ErrorOr<Module *> parseBitcodeFile(const MemoryBuffer *Buffer,
                                      LLVMContext &Context);
 
   /// WriteBitcodeToFile - Write the specified module to the specified
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 4bbecfdb177..d763397e557 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -3406,9 +3406,10 @@ Module *llvm::getStreamedBitcodeModule(const std::string &name,
   return M;
 }
 
-ErrorOr<Module *> llvm::parseBitcodeFile(MemoryBuffer *Buffer,
+ErrorOr<Module *> llvm::parseBitcodeFile(const MemoryBuffer *Buffer,
                                          LLVMContext &Context) {
-  ErrorOr<Module *> ModuleOrErr = getLazyBitcodeModule(Buffer, Context);
+  ErrorOr<Module *> ModuleOrErr =
+      getLazyBitcodeModule(const_cast<MemoryBuffer *>(Buffer), Context);
   if (!ModuleOrErr)
     return ModuleOrErr;
   Module *M = ModuleOrErr.get();
diff --git a/lib/IRReader/IRReader.cpp b/lib/IRReader/IRReader.cpp
index 2bbe0753320..9d90324adf9 100644
--- a/lib/IRReader/IRReader.cpp
+++ b/lib/IRReader/IRReader.cpp
@@ -68,8 +68,7 @@ Module *llvm::ParseIR(const MemoryBuffer *Buffer, SMDiagnostic &Err,
                      TimePassesIsEnabled);
   if (isBitcode((const unsigned char *)Buffer->getBufferStart(),
                 (const unsigned char *)Buffer->getBufferEnd())) {
-    ErrorOr<Module *> ModuleOrErr =
-        parseBitcodeFile(const_cast<MemoryBuffer *>(Buffer), Context);
+    ErrorOr<Module *> ModuleOrErr = parseBitcodeFile(Buffer, Context);
     Module *M = nullptr;
     if (std::error_code EC = ModuleOrErr.getError())
       Err = SMDiagnostic(Buffer->getBufferIdentifier(), SourceMgr::DK_Error,