Index: lib/Analysis/InlineCost.cpp
===================================================================
--- lib/Analysis/InlineCost.cpp
+++ lib/Analysis/InlineCost.cpp
@@ -602,6 +602,11 @@
     disableSROA(CostIt);
   }
 
+  // Implicit null checks act as unconditional branches, and
+  // they should be free. See the comments in visitBranchInst.
+  if (I.getMetadata(LLVMContext::MD_make_implicit))
+    return true;
+
   return false;
 }