diff --git a/mlir/include/mlir/Pass/Pass.h b/mlir/include/mlir/Pass/Pass.h
--- a/mlir/include/mlir/Pass/Pass.h
+++ b/mlir/include/mlir/Pass/Pass.h
@@ -56,13 +56,12 @@
   TypeID getTypeID() const { return passID; }
 
   /// Returns the pass info for the specified pass class or null if unknown.
-  static const PassInfo *lookupPassInfo(TypeID passID);
-  template <typename PassT> static const PassInfo *lookupPassInfo() {
-    return lookupPassInfo(TypeID::get<PassT>());
-  }
+  static const PassInfo *lookupPassInfo(StringRef passArg);
 
-  /// Returns the pass info for this pass.
-  const PassInfo *lookupPassInfo() const { return lookupPassInfo(getTypeID()); }
+  /// Returns the pass info for this pass, or null if unknown.
+  const PassInfo *lookupPassInfo() const {
+    return lookupPassInfo(getArgument());
+  }
 
   /// Returns the derived pass name.
   virtual StringRef getName() const = 0;
@@ -76,11 +75,7 @@
 
   /// Returns the command line argument used when registering this pass. Return
   /// an empty string if one does not exist.
-  virtual StringRef getArgument() const {
-    if (const PassInfo *passInfo = lookupPassInfo())
-      return passInfo->getPassArgument();
-    return "";
-  }
+  virtual StringRef getArgument() const { return ""; }
 
   /// Returns the name of the operation that this pass operates on, or None if
   /// this is a generic OperationPass.
diff --git a/mlir/include/mlir/Pass/PassRegistry.h b/mlir/include/mlir/Pass/PassRegistry.h
--- a/mlir/include/mlir/Pass/PassRegistry.h
+++ b/mlir/include/mlir/Pass/PassRegistry.h
@@ -108,7 +108,7 @@
 public:
   /// PassInfo constructor should not be invoked directly, instead use
   /// PassRegistration or registerPass.
-  PassInfo(StringRef arg, StringRef description, TypeID passID,
+  PassInfo(StringRef arg, StringRef description,
            const PassAllocatorFunction &allocator);
 };
 
diff --git a/mlir/lib/Pass/PassRegistry.cpp b/mlir/lib/Pass/PassRegistry.cpp
--- a/mlir/lib/Pass/PassRegistry.cpp
+++ b/mlir/lib/Pass/PassRegistry.cpp
@@ -19,7 +19,7 @@
 using namespace detail;
 
 /// Static mapping of all of the registered passes.
-static llvm::ManagedStatic<DenseMap<TypeID, PassInfo>> passRegistry;
+static llvm::ManagedStatic<llvm::StringMap<PassInfo>> passRegistry;
 
 /// Static mapping of all of the registered pass pipelines.
 static llvm::ManagedStatic<llvm::StringMap<PassPipelineInfo>>
@@ -94,7 +94,7 @@
 // PassInfo
 //===----------------------------------------------------------------------===//
 
-PassInfo::PassInfo(StringRef arg, StringRef description, TypeID passID,
+PassInfo::PassInfo(StringRef arg, StringRef description,
                    const PassAllocatorFunction &allocator)
     : PassRegistryEntry(
           arg, description, buildDefaultRegistryFn(allocator),
@@ -105,18 +105,14 @@
 
 void mlir::registerPass(StringRef arg, StringRef description,
                         const PassAllocatorFunction &function) {
-  // TODO: We should use the 'arg' as the lookup key instead of the pass id.
-  TypeID passID = function()->getTypeID();
-  PassInfo passInfo(arg, description, passID, function);
-  passRegistry->try_emplace(passID, passInfo);
+  PassInfo passInfo(arg, description, function);
+  passRegistry->try_emplace(arg, passInfo);
 }
 
-/// Returns the pass info for the specified pass class or null if unknown.
-const PassInfo *mlir::Pass::lookupPassInfo(TypeID passID) {
-  auto it = passRegistry->find(passID);
-  if (it == passRegistry->end())
-    return nullptr;
-  return &it->getSecond();
+/// Returns the pass info for the specified pass argument or null if unknown.
+const PassInfo *mlir::Pass::lookupPassInfo(StringRef passArg) {
+  auto it = passRegistry->find(passArg);
+  return it == passRegistry->end() ? nullptr : &it->second;
 }
 
 //===----------------------------------------------------------------------===//
@@ -433,12 +429,8 @@
   }
 
   // If not, then this must be a specific pass name.
-  for (auto &passIt : *passRegistry) {
-    if (passIt.second.getPassArgument() == element.name) {
-      element.registryEntry = &passIt.second;
-      return success();
-    }
-  }
+  if ((element.registryEntry = Pass::lookupPassInfo(element.name)))
+    return success();
 
   // Emit an error for the unknown pass.
   auto *rawLoc = element.name.data();
diff --git a/mlir/test/lib/Pass/TestPassManager.cpp b/mlir/test/lib/Pass/TestPassManager.cpp
--- a/mlir/test/lib/Pass/TestPassManager.cpp
+++ b/mlir/test/lib/Pass/TestPassManager.cpp
@@ -16,9 +16,11 @@
 struct TestModulePass
     : public PassWrapper<TestModulePass, OperationPass<ModuleOp>> {
   void runOnOperation() final {}
+  StringRef getArgument() const final { return "test-module-pass"; }
 };
 struct TestFunctionPass : public PassWrapper<TestFunctionPass, FunctionPass> {
   void runOnFunction() final {}
+  StringRef getArgument() const final { return "test-function-pass"; }
 };
 class TestOptionsPass : public PassWrapper<TestOptionsPass, FunctionPass> {
 public:
@@ -41,6 +43,7 @@
   }
 
   void runOnFunction() final {}
+  StringRef getArgument() const final { return "test-options-pass"; }
 
   ListOption<int> listOption{*this, "list", llvm::cl::MiscFlags::CommaSeparated,
                              llvm::cl::desc("Example list option")};
@@ -56,6 +59,7 @@
 class TestCrashRecoveryPass
     : public PassWrapper<TestCrashRecoveryPass, OperationPass<>> {
   void runOnOperation() final { abort(); }
+  StringRef getArgument() const final { return "test-pass-crash"; }
 };
 
 /// A test pass that contains a statistic.