Some optimizations done by globalopt are safe only for internal linkage, not
linkonce linkage. For example, it is not valid to add unnamed_addr.

This also fixes a crash in g++.dg/opt/static5.C.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158528 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 9e3b8c2..cca959b 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1729,6 +1729,9 @@
     return true;
   }
 
+  if (!GV->hasLocalLinkage())
+    return false;
+
   SmallPtrSet<const PHINode*, 16> PHIUsers;
   GlobalStatus GS;