[mlir] Optimize getting properties on concrete ops (#88259)

This makes retrieving properties on concrete operations faster by
removing a branch when it is known that the operation must have
properties.

Author: Jeff Niu

mlir/include/mlir/IR/OpDefinition.h

@@ -1965,7 +1965,7 @@ class Op : public OpState, public Traits<ConcreteType>... {
     if constexpr (!hasProperties())
       return getEmptyProperties();
     return *getOperation()
-                ->getPropertiesStorage()
+                ->getPropertiesStorageUnsafe()
                 .template as<InferredProperties<T> *>();
   }
 

mlir/include/mlir/IR/Operation.h

@@ -895,8 +895,7 @@ class alignas(8) Operation final
   /// Returns the properties storage.
   OpaqueProperties getPropertiesStorage() {
     if (propertiesStorageSize)
-      return {
-          reinterpret_cast<void *>(getTrailingObjects<detail::OpProperties>())};
+      return getPropertiesStorageUnsafe();
     return {nullptr};
   }
   OpaqueProperties getPropertiesStorage() const {
@@ -905,6 +904,12 @@ class alignas(8) Operation final
           getTrailingObjects<detail::OpProperties>()))};
     return {nullptr};
   }
+  /// Returns the properties storage without checking whether properties are
+  /// present.
+  OpaqueProperties getPropertiesStorageUnsafe() {
+    return {
+        reinterpret_cast<void *>(getTrailingObjects<detail::OpProperties>())};
+  }
 
   /// Return the properties converted to an attribute.
   /// This is expensive, and mostly useful when dealing with unregistered