diff --git a/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp b/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp
--- a/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp
+++ b/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp
@@ -49,10 +49,6 @@
                                cl::value_desc("N"),
                                cl::desc("Function number to canonicalize."));
 
-static cl::opt<unsigned> CanonicalizeBasicBlockNumber(
-    "canon-nth-basicblock", cl::Hidden, cl::init(~0u), cl::value_desc("N"),
-    cl::desc("BasicBlock number to canonicalize."));
-
 namespace {
 
 class MIRCanonicalizer : public MachineFunctionPass {
@@ -375,15 +371,7 @@
 
 static bool runOnBasicBlock(MachineBasicBlock *MBB,
                             std::vector<StringRef> &bbNames,
-                            unsigned &basicBlockNum, VRegRenamer &Renamer) {
-
-  if (CanonicalizeBasicBlockNumber != ~0U) {
-    if (CanonicalizeBasicBlockNumber != basicBlockNum++)
-      return false;
-    LLVM_DEBUG(dbgs() << "\n Canonicalizing BasicBlock " << MBB->getName()
-                      << "\n";);
-  }
-
+                            unsigned BasicBlockNum, VRegRenamer &Renamer) {
   if (llvm::find(bbNames, MBB->getName()) != bbNames.end()) {
     LLVM_DEBUG({
       dbgs() << "Found potentially duplicate BasicBlocks: " << MBB->getName()
@@ -412,7 +400,7 @@
   Changed |= rescheduleCanonically(IdempotentInstCount, MBB);
   LLVM_DEBUG(dbgs() << "MBB After Scheduling:\n"; MBB->dump(););
 
-  Changed |= Renamer.renameVRegs(MBB);
+  Changed |= Renamer.renameVRegs(MBB, BasicBlockNum);
 
   Changed |= doDefKillClear(MBB);
 
@@ -454,7 +442,7 @@
   MachineRegisterInfo &MRI = MF.getRegInfo();
   VRegRenamer Renamer(MRI);
   for (auto MBB : RPOList)
-    Changed |= runOnBasicBlock(MBB, BBNames, BBNum, Renamer);
+    Changed |= runOnBasicBlock(MBB, BBNames, BBNum++, Renamer);
 
   return Changed;
 }
diff --git a/llvm/lib/CodeGen/MIRNamerPass.cpp b/llvm/lib/CodeGen/MIRNamerPass.cpp
--- a/llvm/lib/CodeGen/MIRNamerPass.cpp
+++ b/llvm/lib/CodeGen/MIRNamerPass.cpp
@@ -57,9 +57,10 @@
 
     VRegRenamer Renamer(MF.getRegInfo());
 
+    unsigned BBIndex = 0;
     ReversePostOrderTraversal<MachineBasicBlock *> RPOT(&*MF.begin());
     for (auto &MBB : RPOT)
-      Changed |= Renamer.renameVRegs(MBB);
+      Changed |= Renamer.renameVRegs(MBB, BBIndex++);
 
     return Changed;
   }
diff --git a/llvm/lib/CodeGen/MIRVRegNamerUtils.h b/llvm/lib/CodeGen/MIRVRegNamerUtils.h
--- a/llvm/lib/CodeGen/MIRVRegNamerUtils.h
+++ b/llvm/lib/CodeGen/MIRVRegNamerUtils.h
@@ -84,7 +84,7 @@
 
   /// Same as the above, but sets a BBNum depending on BB traversal that
   /// will be used as prefix for the vreg names.
-  bool renameVRegs(MachineBasicBlock *MBB, unsigned BBNum = 0);
+  bool renameVRegs(MachineBasicBlock *MBB, unsigned BBNum);
 
   unsigned getCurrentBBNumber() const { return CurrentBBNumber; }
 };