Unit test checking if FlagEnum values are lowered as constants in LLV…

…M IR.

numba_dpex/tests/experimental/codegen/test_intenum_literal_codegen.py

@@ -0,0 +1,53 @@
+# SPDX-FileCopyrightText: 2023 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import re
+
+import dpctl
+from numba.core import types
+
+import numba_dpex.experimental as exp_dpex
+from numba_dpex import DpctlSyclQueue, DpnpNdArray, int64
+from numba_dpex.experimental.flag_enum import FlagEnum
+
+
+def test_compilation_as_literal_constant():
+    """Tests if FlagEnum objects are treaded as scalar constants inside
+    numba-dpex generated code.
+
+    The test case compiles the kernel `pass_flags_to_func` that includes a
+    call to the device_func `bitwise_or_flags`. The `bitwise_or_flags` function
+    is passed two FlagEnum arguments. The test case evaluates the generated
+    LLVM IR for `pass_flags_to_func` to see if the call to `bitwise_or_flags`
+    has the scalar arguments `i64 1` and `i64 2`.
+    """
+
+    class PseudoFlags(FlagEnum):
+        FLAG1 = 1
+        FLAG2 = 2
+
+    @exp_dpex.device_func
+    def bitwise_or_flags(flag1, flag2):
+        return flag1 | flag2
+
+    def pass_flags_to_func(a):
+        f1 = PseudoFlags.FLAG1
+        f2 = PseudoFlags.FLAG2
+        a[0] = bitwise_or_flags(f1, f2)
+
+    queue_ty = DpctlSyclQueue(dpctl.SyclQueue())
+    i64arr_ty = DpnpNdArray(ndim=1, dtype=int64, layout="C", queue=queue_ty)
+    kernel_sig = types.void(i64arr_ty)
+
+    disp = exp_dpex.kernel(pass_flags_to_func)
+    disp.compile(kernel_sig)
+    kcres = disp.overloads[kernel_sig.args]
+    llvm_ir_mod = kcres.library._final_module.__str__()
+
+    pattern = re.compile(
+        r"call spir_func i32 @\_Z.*bitwise\_or"
+        r"\_flags.*\(i64\* nonnull %.*, i64 1, i64 2\)"
+    )
+
+    assert re.search(pattern, llvm_ir_mod) is not None