[ResetMachineFunction] Add statistic on the number of reset functions.

As the development of GlobalISel move forward, this statistic should
strictly decrease until it reaches zero. At this point, it would mean
GlobalISel can replace SDISel (at least on the tested inputs :P).

llvm-svn: 282275
diff --git a/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp b/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp
index 07a8259..554760ff 100644
--- a/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp
+++ b/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
@@ -19,6 +20,8 @@
 
 #define DEBUG_TYPE "reset-machine-function"
 
+STATISTIC(NumFunctionsReset, "Number of functions reset");
+
 namespace {
   class ResetMachineFunction : public MachineFunctionPass {
     /// Tells whether or not this pass should emit a fallback
@@ -38,6 +41,7 @@
       if (MF.getProperties().hasProperty(
               MachineFunctionProperties::Property::FailedISel)) {
         DEBUG(dbgs() << "Reseting: " << MF.getName() << '\n');
+        ++NumFunctionsReset;
         MF.reset();
         if (EmitFallbackDiag) {
           const Function &F = *MF.getFunction();