Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp
+++ lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -84,6 +84,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Format.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetLibraryInfo.h"
 #include "llvm/Transforms/Scalar.h"
@@ -493,8 +494,12 @@
   }
   const DILocation Loc(N);
   const unsigned LineNo = Loc.getLineNumber();
-  const char *DirName = Loc.getDirectory().data();
   const char *FileName = Loc.getFilename().data();
+  // Absolute path doesn't need DirName.
+  if (sys::path::is_absolute(FileName))
+    return format<const char *, const char *, unsigned>("%s%s:%u", "", FileName,
+                                                        LineNo);
+  const char *DirName = Loc.getDirectory().data();
   return format("%s/%s:%u", DirName, FileName, LineNo);
 }
 #endif