[ScheduleDAG] Add statistics for maintaining the topological order.

This is helpful to measure the impact of D60125 on maintaining
topological orders.

Reviewers: MatzeB, atrick, efriedma, niravd

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D60187

llvm-svn: 358058

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/ScheduleDAG.cpp b/llvm/lib/CodeGen/ScheduleDAG.cpp
index 8ebe8fa6bd6..5294c5b1c2c 100644
--- a/llvm/lib/CodeGen/ScheduleDAG.cpp
+++ b/llvm/lib/CodeGen/ScheduleDAG.cpp
@@ -14,6 +14,7 @@
 #include "llvm/CodeGen/ScheduleDAG.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
@@ -37,6 +38,10 @@ using namespace llvm;
 
 #define DEBUG_TYPE "pre-RA-sched"
 
+STATISTIC(NumNewPredsAdded, "Number of times a  single predecessor was added");
+STATISTIC(NumTopoInits,
+          "Number of times the topological order has been recomputed");
+
 #ifndef NDEBUG
 static cl::opt<bool> StressSchedOpt(
   "stress-sched", cl::Hidden, cl::init(false),
@@ -497,6 +502,7 @@ void ScheduleDAGTopologicalSort::InitDAGTopologicalSorting() {
   }
 
   Visited.resize(DAGSize);
+  NumTopoInits++;
 
 #ifndef NDEBUG
   // Check correctness of the ordering
@@ -523,6 +529,8 @@ void ScheduleDAGTopologicalSort::AddPred(SUnit *Y, SUnit *X) {
     // Recompute topological indexes.
     Shift(Visited, LowerBound, UpperBound);
   }
+
+  NumNewPredsAdded++;
 }
 
 void ScheduleDAGTopologicalSort::RemovePred(SUnit *M, SUnit *N) {