diff --git a/mlir/python/mlir/runtime/np_to_memref.py b/mlir/python/mlir/runtime/np_to_memref.py
--- a/mlir/python/mlir/runtime/np_to_memref.py
+++ b/mlir/python/mlir/runtime/np_to_memref.py
@@ -25,15 +25,16 @@
 
 def as_ctype(dtp):
   """Converts dtype to ctype."""
-  if dtp is np.dtype(np.complex128):
+  if dtp == np.dtype(np.complex128):
     return C128
-  if dtp is np.dtype(np.complex64):
+  if dtp == np.dtype(np.complex64):
     return C64
-  if dtp is np.dtype(np.float16):
+  if dtp == np.dtype(np.float16):
     return F16
   return np.ctypeslib.as_ctypes_type(dtp)
 
 
+# https://stackoverflow.com/questions/26921836/correct-way-to-test-for-numpy-dtype
 def to_numpy(array):
   """Converts ctypes array back to numpy dtype array."""
   if array.dtype == C128: