Count how many phis we are creating.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132748 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TailDuplication.cpp b/lib/CodeGen/TailDuplication.cpp
index 04d3d31..ea62b19 100644
--- a/lib/CodeGen/TailDuplication.cpp
+++ b/lib/CodeGen/TailDuplication.cpp
@@ -34,6 +34,7 @@
 STATISTIC(NumTailDups  , "Number of tail duplicated blocks");
 STATISTIC(NumInstrDups , "Additional instructions due to tail duplication");
 STATISTIC(NumDeadBlocks, "Number of dead blocks removed");
+STATISTIC(NumAddedPHIs , "Number of phis added");
 
 // Heuristic for tail duplication.
 static cl::opt<unsigned>
@@ -246,6 +247,7 @@
           }
         }
 
+        NumAddedPHIs += NewPHIs.size();
         SSAUpdateVRs.clear();
         SSAUpdateVals.clear();
       }