diff --git a/mlir/include/mlir/IR/Dialect.h b/mlir/include/mlir/IR/Dialect.h
--- a/mlir/include/mlir/IR/Dialect.h
+++ b/mlir/include/mlir/IR/Dialect.h
@@ -247,7 +247,10 @@
 
 /// Registers a specific dialect creation function with the system, typically
 /// used through the DialectRegistration template.
-void registerDialectAllocator(const DialectAllocatorFunction &function);
+/// Registrations are deduplicated by dialect ClassID and only the first
+/// registration will be used.
+void registerDialectAllocator(const ClassID *classId,
+                              const DialectAllocatorFunction &function);
 
 /// Registers all dialects with the specified MLIRContext.
 void registerAllDialects(MLIRContext *context);
@@ -255,10 +258,12 @@
 /// Utility to register a dialect. Client can register their dialect with the
 /// global registry by calling registerDialect<MyDialect>();
 template <typename ConcreteDialect> void registerDialect() {
-  registerDialectAllocator([](MLIRContext *ctx) {
-    // Just allocate the dialect, the context takes ownership of it.
-    new ConcreteDialect(ctx);
-  });
+  registerDialectAllocator(ClassID::getID<ConcreteDialect>(),
+                           [](MLIRContext *ctx) {
+                             // Just allocate the dialect, the context takes
+                             // ownership of it.
+                             new ConcreteDialect(ctx);
+                           });
 }
 
 /// DialectRegistration provides a global initializer that registers a Dialect
diff --git a/mlir/include/mlir/IR/DialectHooks.h b/mlir/include/mlir/IR/DialectHooks.h
--- a/mlir/include/mlir/IR/DialectHooks.h
+++ b/mlir/include/mlir/IR/DialectHooks.h
@@ -39,32 +39,36 @@
 
 /// Registers a function that will set hooks in the registered dialects
 /// based on information coming from DialectHooksRegistration.
-void registerDialectHooksSetter(const DialectHooksSetter &function);
+void registerDialectHooksSetter(const ClassID *classId,
+                                const DialectHooksSetter &function);
 
 /// DialectHooksRegistration provides a global initializer that registers
 /// a dialect hooks setter routine.
+/// Registrations are deduplicated by dialect ClassID and only the first
+/// registration will be used.
 /// Usage:
 ///
 ///   // At namespace scope.
-///   static DialectHooksRegistration<MyHooks, MyDialect> unused;
+///   static DialectHooksRegistration<MyHooks> unused("dialect_namespace");
 template <typename ConcreteHooks> struct DialectHooksRegistration {
   DialectHooksRegistration(StringRef dialectName) {
-    registerDialectHooksSetter([dialectName](MLIRContext *ctx) {
-      Dialect *dialect = ctx->getRegisteredDialect(dialectName);
-      if (!dialect) {
-        llvm::errs() << "error: cannot register hooks for unknown dialect '"
-                     << dialectName << "'\n";
-        abort();
-      }
-      // Set hooks.
-      ConcreteHooks hooks;
-      if (auto h = hooks.getConstantFoldHook())
-        dialect->constantFoldHook = h;
-      if (auto h = hooks.getDecodeHook())
-        dialect->decodeHook = h;
-      if (auto h = hooks.getExtractElementHook())
-        dialect->extractElementHook = h;
-    });
+    registerDialectHooksSetter(
+        ClassID::getID<ConcreteHooks>(), [dialectName](MLIRContext *ctx) {
+          Dialect *dialect = ctx->getRegisteredDialect(dialectName);
+          if (!dialect) {
+            llvm::errs() << "error: cannot register hooks for unknown dialect '"
+                         << dialectName << "'\n";
+            abort();
+          }
+          // Set hooks.
+          ConcreteHooks hooks;
+          if (auto h = hooks.getConstantFoldHook())
+            dialect->constantFoldHook = h;
+          if (auto h = hooks.getDecodeHook())
+            dialect->decodeHook = h;
+          if (auto h = hooks.getExtractElementHook())
+            dialect->extractElementHook = h;
+        });
   }
 };
 
diff --git a/mlir/lib/IR/Dialect.cpp b/mlir/lib/IR/Dialect.cpp
--- a/mlir/lib/IR/Dialect.cpp
+++ b/mlir/lib/IR/Dialect.cpp
@@ -27,38 +27,40 @@
 //===----------------------------------------------------------------------===//
 
 // Registry for all dialect allocation functions.
-static llvm::ManagedStatic<SmallVector<DialectAllocatorFunction, 8>>
+static llvm::ManagedStatic<DenseMap<const ClassID *, DialectAllocatorFunction>>
     dialectRegistry;
 
 // Registry for functions that set dialect hooks.
-static llvm::ManagedStatic<SmallVector<DialectHooksSetter, 8>>
+static llvm::ManagedStatic<DenseMap<const ClassID *, DialectHooksSetter>>
     dialectHooksRegistry;
 
 /// Registers a specific dialect creation function with the system, typically
 /// used through the DialectRegistration template.
-void mlir::registerDialectAllocator(const DialectAllocatorFunction &function) {
+void mlir::registerDialectAllocator(const ClassID *classId,
+                                    const DialectAllocatorFunction &function) {
   assert(function &&
          "Attempting to register an empty dialect initialize function");
-  dialectRegistry->push_back(function);
+  dialectRegistry->try_emplace(classId, function);
 }
 
 /// Registers a function to set specific hooks for a specific dialect, typically
 /// used through the DialectHooksRegistration template.
-void mlir::registerDialectHooksSetter(const DialectHooksSetter &function) {
+void mlir::registerDialectHooksSetter(const ClassID *classId,
+                                      const DialectHooksSetter &function) {
   assert(
       function &&
       "Attempting to register an empty dialect hooks initialization function");
 
-  dialectHooksRegistry->push_back(function);
+  dialectHooksRegistry->try_emplace(classId, function);
 }
 
 /// Registers all dialects and their const folding hooks with the specified
 /// MLIRContext.
 void mlir::registerAllDialects(MLIRContext *context) {
-  for (const auto &fn : *dialectRegistry)
-    fn(context);
-  for (const auto &fn : *dialectHooksRegistry) {
-    fn(context);
+  for (const auto &it : *dialectRegistry)
+    it.second(context);
+  for (const auto &it : *dialectHooksRegistry) {
+    it.second(context);
   }
 }