Fix unused variable warning

llvm-svn: 239369
diff --git a/llvm/lib/Transforms/IPO/MergeFunctions.cpp b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
index 6ef1ac7..5acd8e2 100644
--- a/llvm/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
@@ -1437,6 +1437,7 @@
   assert((F->mayBeOverridden() && G->mayBeOverridden()) ||
          (!F->mayBeOverridden() && !G->mayBeOverridden()) &&
          "Only change functions if both are strong or both are weak");
+  (void)F;
 
   IterToF->replaceBy(G);
 }