Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -325,6 +325,7 @@
   PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
+  PMBuilder.PrepareForThinLTO = CodeGenOpts.EmitFunctionSummary;
   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 
@@ -334,7 +335,7 @@
   // pipeline and pass down the in-memory function index.
   if (FunctionIndex) {
     PMBuilder.FunctionIndex = FunctionIndex;
-    PMBuilder.populateLTOPassManager(*MPM);
+    PMBuilder.populateThinLTOPassManager(*MPM);
     return;
   }