Index: lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- lib/Transforms/IPO/PassManagerBuilder.cpp
+++ lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -570,10 +570,15 @@
   // More loops are countable; try to optimize them.
   PM.add(createIndVarSimplifyPass());
   PM.add(createLoopDeletionPass());
+  if (!DisableUnrollLoops)
+    PM.add(createSimpleLoopUnrollPass());   // Unroll small loops
   if (EnableLoopInterchange)
     PM.add(createLoopInterchangePass());
 
   PM.add(createLoopVectorizePass(true, LoopVectorize));
+  // The vectorizer may have significantly shortened a loop body; unroll again.
+  if (!DisableUnrollLoops)
+    PM.add(createLoopUnrollPass());
 
   // Now that we've optimized loops (in particular loop induction variables),
   // we may have exposed more scalar opportunities. Run parts of the scalar