Index: lib/CodeGen/GlobalMerge.cpp
===================================================================
--- lib/CodeGen/GlobalMerge.cpp
+++ lib/CodeGen/GlobalMerge.cpp
@@ -616,8 +616,8 @@
     if (TM && !TM->shouldAssumeDSOLocal(M, &GV))
       continue;
 
-    if (!(MergeExternalGlobals && GV.hasExternalLinkage()) &&
-        !GV.hasInternalLinkage())
+    if (!(MergeExternalGlobals && GV.hasExternalLinkage())&&
+        !GV.hasInternalLinkage() && !GV.hasCommonLinkage())
       continue;
 
     PointerType *PT = dyn_cast<PointerType>(GV.getType());