diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 2b25168..8bedf50 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -442,7 +442,7 @@
     }
   } else {
     llvm::MemoryBuffer *SB = llvm::MemoryBuffer::getSTDIN();
-    SourceMgr.createMainFileIDForMemBuffer(SB);
+    if (SB) SourceMgr.createMainFileIDForMemBuffer(SB);
     if (SourceMgr.getMainFileID().isInvalid()) {
       Diags.Report(diag::err_fe_error_reading_stdin);
       return false;