simplify code


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36837 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-dis/llvm-dis.cpp b/tools/llvm-dis/llvm-dis.cpp
index 6065e9b..12a5328 100644
--- a/tools/llvm-dis/llvm-dis.cpp
+++ b/tools/llvm-dis/llvm-dis.cpp
@@ -60,12 +60,8 @@
     std::auto_ptr<Module> M;
    
     if (Bitcode) {
-      MemoryBuffer *Buffer;
-      if (InputFilename == "-") {
-        Buffer = MemoryBuffer::getSTDIN();
-      } else {
-        Buffer = MemoryBuffer::getFile(&InputFilename[0], InputFilename.size());
-      }
+      MemoryBuffer *Buffer
+        = MemoryBuffer::getFileOrSTDIN(&InputFilename[0], InputFilename.size());
 
       if (Buffer == 0)
         ErrorMessage = "Error reading file '" + InputFilename + "'";