Add SlotIndex statistics.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127007 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SlotIndexes.cpp b/lib/CodeGen/SlotIndexes.cpp
index 73adb92..a495d1f 100644
--- a/lib/CodeGen/SlotIndexes.cpp
+++ b/lib/CodeGen/SlotIndexes.cpp
@@ -10,6 +10,7 @@
 #define DEBUG_TYPE "slotindexes"
 
 #include "llvm/CodeGen/SlotIndexes.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
@@ -21,6 +22,8 @@
 INITIALIZE_PASS(SlotIndexes, "slotindexes",
                 "Slot index numbering", false, false)
 
+STATISTIC(NumRenumPasses, "Number of slot index renumber passes");
+
 void SlotIndexes::getAnalysisUsage(AnalysisUsage &au) const {
   au.setPreservesAll();
   MachineFunctionPass::getAnalysisUsage(au);
@@ -128,6 +131,7 @@
   // pass during the initial numbering of the function if the new instructions
   // had been present.
   DEBUG(dbgs() << "\n*** Renumbering SlotIndexes ***\n");
+  ++NumRenumPasses;
 
   unsigned index = 0;