Fix KernelHasReturnValueError inside KernelDispatcher.

Author: Diptorup Deb

numba_dpex/kernel_api_impl/spirv/dispatcher.py

@@ -415,13 +415,6 @@ def cb_llvm(dur):
                     except ExecutionQueueInferenceError as eqie:
                         raise eqie
 
-                    # A function being compiled in the KERNEL compilation mode
-                    # cannot have a non-void return value
-                    if return_type and return_type != void:
-                        raise KernelHasReturnValueError(
-                            kernel_name=None, return_type=return_type, sig=sig
-                        )
-
                 # Don't recompile if signature already exists
                 existing = self.overloads.get(tuple(args))
                 if existing is not None:
@@ -444,6 +437,16 @@ def cb_llvm(dur):
                         kcres: _SPIRVKernelCompileResult = compiler.compile(
                             args, return_type
                         )
+                        if (
+                            self.targetoptions["_compilation_mode"]
+                            == CompilationMode.KERNEL
+                            and kcres.signature.return_type is not None
+                            and kcres.signature.return_type != types.void
+                        ):
+                            raise KernelHasReturnValueError(
+                                kernel_name=self.py_func.__name__,
+                                return_type=kcres.signature.return_type,
+                            )
                     except errors.ForceLiteralArg as err:
 
                         def folded(args, kws):

numba_dpex/tests/experimental/test_kernel_has_return_value_error.py

@@ -0,0 +1,41 @@
+# SPDX-FileCopyrightText: 2020 - 2024 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import dpnp
+import pytest
+from numba.core.errors import TypingError
+
+import numba_dpex.experimental as dpex
+from numba_dpex import int32, usm_ndarray
+from numba_dpex.core.exceptions import KernelHasReturnValueError
+from numba_dpex.core.types.kernel_api.index_space_ids import ItemType
+
+i32arrty = usm_ndarray(ndim=1, dtype=int32, layout="C")
+item_ty = ItemType(ndim=1)
+
+
+def f(item, a):
+    return a
+
+
+list_of_sig = [
+    None,
+    (i32arrty(item_ty, i32arrty)),
+]
+
+
+@pytest.fixture(params=list_of_sig)
+def sig(request):
+    return request.param
+
+
+def test_return(sig):
+    a = dpnp.arange(1024, dtype=dpnp.int32)
+
+    with pytest.raises((TypingError, KernelHasReturnValueError)) as excinfo:
+        kernel_fn = dpex.kernel(sig)(f)
+        dpex.call_kernel(kernel_fn, dpex.Range(a.size), a)
+
+    if isinstance(excinfo.type, TypingError):
+        assert "KernelHasReturnValueError" in excinfo.value.args[0]