diff --git a/bolt/include/bolt/Passes/ZeroIdiom.h b/bolt/include/bolt/Passes/ZeroIdiom.h
--- a/bolt/include/bolt/Passes/ZeroIdiom.h
+++ b/bolt/include/bolt/Passes/ZeroIdiom.h
@@ -24,6 +24,11 @@
 class ZeroIdiomPass : public BinaryFunctionPass {
   void runOnFunction(BinaryFunction &Function, DataflowInfoManager &Info);
 
+  static std::atomic<std::uint64_t> ReplacedInsts;
+  static std::atomic<std::uint64_t> ModifiedFunctions;
+  static std::atomic<std::uint64_t> ReplacedDynamicCount;
+  static std::atomic<std::uint64_t> SavedBytes;
+
 public:
   explicit ZeroIdiomPass(const cl::opt<bool> &PrintPass)
       : BinaryFunctionPass(PrintPass) {}
diff --git a/bolt/lib/Passes/ZeroIdiom.cpp b/bolt/lib/Passes/ZeroIdiom.cpp
--- a/bolt/lib/Passes/ZeroIdiom.cpp
+++ b/bolt/lib/Passes/ZeroIdiom.cpp
@@ -20,18 +20,31 @@
 namespace llvm {
 namespace bolt {
 
+std::atomic<std::uint64_t> ZeroIdiomPass::ReplacedInsts{0};
+std::atomic<std::uint64_t> ZeroIdiomPass::ModifiedFunctions{0};
+std::atomic<std::uint64_t> ZeroIdiomPass::ReplacedDynamicCount{0};
+std::atomic<std::uint64_t> ZeroIdiomPass::SavedBytes{0};
+
 void ZeroIdiomPass::runOnFunction(BinaryFunction &BF,
                                   DataflowInfoManager &Info) {
   BinaryContext &BC = BF.getBinaryContext();
   LivenessAnalysis &LA = Info.getLivenessAnalysis();
 
+  bool Modified = false;
   for (BinaryBasicBlock &BB : BF) {
     for (MCInst &Inst : BB) {
       if (LA.isAlive(ProgramPoint(&Inst), BC.MIB->getFlagsReg()))
         continue;
-      BC.MIB->replaceZeroIdiom(Inst);
+      if (BC.MIB->replaceZeroIdiom(Inst)) {
+        Modified = true;
+        ++ReplacedInsts;
+        ReplacedDynamicCount += BB.getExecutionCount();
+        SavedBytes += 3; // FIXME
+      }
     }
   }
+  if (Modified)
+    ++ModifiedFunctions;
 }
 
 void ZeroIdiomPass::runOnFunctions(BinaryContext &BC) {
@@ -52,6 +65,14 @@
   ParallelUtilities::runOnEachFunctionWithUniqueAllocId(
       BC, ParallelUtilities::SchedulingPolicy::SP_INST_LINEAR, WorkFun, nullptr,
       "ZeroIdiom");
+
+  if (!ReplacedInsts)
+    return;
+
+  outs() << "BOLT-INFO: zero-idiom replaced " << ReplacedInsts
+         << " instructions (exec count " << ReplacedDynamicCount << ") in "
+         << ModifiedFunctions << " functions saving " << SavedBytes
+         << " bytes\n";
 }
 
 } // end namespace bolt