Index: lib/Analysis/ValueTracking.cpp
===================================================================
--- lib/Analysis/ValueTracking.cpp
+++ lib/Analysis/ValueTracking.cpp
@@ -543,6 +543,11 @@
     return true;
   }
 
+  // If the context instruction is this assume, we shouldn't consider it valid.
+  // Otherwise the loops below will scan forward to the end of the block.
+  if (Inv == CxtI)
+    return false;
+
   // With or without a DT, the only remaining case we will check is if the
   // instructions are in the same BB.  Give up if that is not the case.
   if (Inv->getParent() != CxtI->getParent())