diff --git a/loopy/target/c/c_execution.py b/loopy/target/c/c_execution.py
index d73912460a2c99075c875375056be5922a98d692..f664e3ee1d1e8544edb218e93acc0b4ee32d1112 100644
--- a/loopy/target/c/c_execution.py
+++ b/loopy/target/c/c_execution.py
@@ -48,9 +48,12 @@ class CExecutionWrapperGenerator(ExecutionWrapperGeneratorBase):
         system_args = ["_lpy_c_kernels"]
         super().__init__(system_args)
 
-    def python_dtype_str(self, dtype):
+    def python_dtype_str_inner(self, dtype):
         if np.dtype(str(dtype)).isbuiltin:
-            return "_lpy_np."+dtype.name
+            name = dtype.name
+            if dtype.name == "bool":
+                name = "bool8"
+            return f"_lpy_np.dtype(_lpy_np.{name})"
         raise Exception(f"dtype: {dtype} not recognized")
 
     # {{{ handle non numpy arguements
@@ -100,7 +103,7 @@ class CExecutionWrapperGenerator(ExecutionWrapperGeneratorBase):
                     name=arg.name,
                     shape=strify(sym_shape),
                     dtype=self.python_dtype_str(
-                        kernel_arg.dtype.numpy_dtype),
+                        gen, kernel_arg.dtype.numpy_dtype),
                     order=order))
 
         expected_strides = tuple(
diff --git a/loopy/target/execution.py b/loopy/target/execution.py
index da5a54e6b4eafe39117b8b01bba2fdf570f3be8b..c00cc28d5fb58da7cc0ae6c1c0c58be048f546d4 100644
--- a/loopy/target/execution.py
+++ b/loopy/target/execution.py
@@ -22,6 +22,7 @@ THE SOFTWARE.
 
 
 import numpy as np
+from abc import ABC, abstractmethod
 from pytools import ImmutableRecord, memoize_method
 from loopy.diagnostic import LoopyError
 from pytools.py_codegen import (
@@ -119,7 +120,7 @@ class SeparateArrayPackingController:
 
 # {{{ ExecutionWrapperGeneratorBase
 
-class ExecutionWrapperGeneratorBase:
+class ExecutionWrapperGeneratorBase(ABC):
     """
     A set of common methods for generating a wrapper
     for execution
@@ -129,8 +130,25 @@ class ExecutionWrapperGeneratorBase:
     def __init__(self, system_args):
         self.system_args = system_args[:]
 
-    def python_dtype_str(self, dtype):
-        raise NotImplementedError()
+        from pytools import UniqueNameGenerator
+        self.dtype_name_generator = UniqueNameGenerator(forced_prefix="_lpy_dtype_")
+        self.dtype_str_to_name = {}
+
+    @abstractmethod
+    def python_dtype_str_inner(self, dtype):
+        pass
+
+    def python_dtype_str(self, gen, numpy_dtype):
+        dtype_str = self.python_dtype_str_inner(numpy_dtype)
+        try:
+            return self.dtype_str_to_name[dtype_str]
+        except KeyError:
+            pass
+
+        dtype_name = self.dtype_name_generator()
+        gen.add_to_preamble(f"{dtype_name} = _lpy_np.dtype({dtype_str})")
+        self.dtype_str_to_name[dtype_str] = dtype_name
+        return dtype_name
 
     # {{{ invoker generation
 
@@ -381,7 +399,7 @@ class ExecutionWrapperGeneratorBase:
 
         expect_no_more_arguments = False
 
-        for arg_idx, arg in enumerate(implemented_data_info):
+        for arg in implemented_data_info:
             is_written = arg.base_name in kernel.get_written_variables()
             kernel_arg = kernel.impl_arg_to_arg.get(arg.name)
 
@@ -463,7 +481,7 @@ class ExecutionWrapperGeneratorBase:
                 with Indentation(gen):
                     gen("if %s.dtype != %s:"
                             % (arg.name, self.python_dtype_str(
-                                kernel_arg.dtype.numpy_dtype)))
+                                gen, kernel_arg.dtype.numpy_dtype)))
                     with Indentation(gen):
                         gen("raise TypeError(\"dtype mismatch on argument '%s' "
                                 '(got: %%s, expected: %s)" %% %s.dtype)'
diff --git a/loopy/target/pyopencl_execution.py b/loopy/target/pyopencl_execution.py
index d23301077f1f14f85f93074f067b09acf1faa95a..0a9bafde9608624e7285363e4338f96b551307ea 100644
--- a/loopy/target/pyopencl_execution.py
+++ b/loopy/target/pyopencl_execution.py
@@ -48,13 +48,14 @@ class PyOpenCLExecutionWrapperGenerator(ExecutionWrapperGeneratorBase):
             "out_host=None"
             ]
         super().__init__(system_args)
-        from pytools import UniqueNameGenerator
-        self.dtype_name_generator = UniqueNameGenerator(forced_prefix="_lpy_dtype_")
 
-    def python_dtype_str(self, dtype):
+    def python_dtype_str_inner(self, dtype):
         import pyopencl.tools as cl_tools
         if dtype.isbuiltin:
-            return "_lpy_np."+dtype.name
+            name = dtype.name
+            if dtype.name == "bool":
+                name = "bool8"
+            return f"_lpy_np.dtype(_lpy_np.{name})"
         else:
             return ('_lpy_cl_tools.get_or_register_dtype("%s")'
                     % cl_tools.dtype_to_ctype(dtype))
@@ -117,10 +118,8 @@ class PyOpenCLExecutionWrapperGenerator(ExecutionWrapperGeneratorBase):
 
         gen("_lpy_size = %s" % strify(size_expr))
         sym_strides = tuple(itemsize*s_i for s_i in sym_ustrides)
-        dtype_str = self.python_dtype_str(kernel_arg.dtype.numpy_dtype)
 
-        dtype_name = self.dtype_name_generator()
-        gen.add_to_preamble(f"{dtype_name} = _lpy_np.dtype({dtype_str})")
+        dtype_name = self.python_dtype_str(gen, kernel_arg.dtype.numpy_dtype)
         gen(f"{arg.name} = _lpy_cl_array.Array(None, {strify(sym_shape)}, "
                 f"{dtype_name}, strides={strify(sym_strides)}, "
                 f"data=allocator({strify(itemsize * var('_lpy_size'))}), "