Add tests for atomic APIs.

[neoblizz]

Notes:

• Triton doesn't support atomic_sub,
• Lots of types not officially supported by Triton, (int8 for add, floats for cas/xchg (except f32?)), weird coverage here. I just included the ones that passed.
• Iris doesn't support all atomics Triton supports: and, or, xor, min, max: https://triton-lang.org/main/python-api/triton.language.html#atomic-ops

============================= test session starts ==============================
platform linux -- Python 3.10.16, pytest-7.3.2, pluggy-1.5.0
rootdir: /workspace/iris
plugins: rerunfailures-14.0, xdoctest-1.1.0, cpp-2.3.0, flakefinder-1.1.0, hypothesis-5.35.1, xdist-3.3.1, anyio-4.9.0, typeguard-4.3.0
collected 540 items

tests/examples/test_load_bench.py ........                               [  1%]
tests/unittests/test_atomic_add.py ..................................... [  8%]
.......................................................................  [ 21%]
tests/unittests/test_atomic_cas.py ..................................... [ 28%]
.......................................................................  [ 41%]
tests/unittests/test_atomic_sub.py FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF [ 48%]
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF [ 61%]
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF                                      [ 68%]
tests/unittests/test_atomic_xchg.py .................................... [ 74%]
........................................................................ [ 88%]
                                                                         [ 88%]
tests/unittests/test_get.py ................                             [ 91%]
tests/unittests/test_load.py ................                            [ 94%]
tests/unittests/test_put.py ................                             [ 97%]
tests/unittests/test_store.py ................                           [100%]
...
FAILED tests/unittests/test_atomic_sub.py::test_atomic_sub_api[32-sys-acq_rel-dtype2] - AttributeError: module 'triton.language' has no attribute 'atomic_sub'. Did you mean: 'atomic_add'?
FAILED tests/unittests/test_atomic_sub.py::test_atomic_sub_api[32-sys-acq_rel-dtype3] - AttributeError: module 'triton.language' has no attribute 'atomic_sub'. Did you mean: 'atomic_add'?
================== 144 failed, 396 passed in 60.48s (0:01:00) ==================

[Copilot]

Pull Request Overview

Adds comprehensive unit tests for new atomic operations in the Iris library, covering add, sub, cas, and xchg across multiple data types, memory scopes, and cache‐ordering semantics.

• Introduces test_atomic_add.py, test_atomic_sub.py, test_atomic_cas.py, and test_atomic_xchg.py
• Parameterizes tests over data types, scopes (cta, gpu, sys), semaphores (acquire, release, acq_rel), and block sizes
• Validates correctness of each atomic operation against expected Torch tensors

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
tests/unittests/test_atomic_add.py	New parameterized tests for iris.atomic_add
tests/unittests/test_atomic_sub.py	New parameterized tests for iris.atomic_sub
tests/unittests/test_atomic_cas.py	New parameterized tests for iris.atomic_cas
tests/unittests/test_atomic_xchg.py	New parameterized tests for iris.atomic_xchg

Comments suppressed due to low confidence (2)

tests/unittests/test_atomic_cas.py:19

• [nitpick] Using the name cmp may be confusing (and shadows the old Python2 builtin). Consider renaming to cmp_val or compare_val for clarity.

    cmp = tl.full((), 0, dtype=dtype)  # scalar 0

tests/unittests/test_atomic_sub.py:1

• Triton does not support atomic_sub, causing these tests to fail with an AttributeError. Add a module‐level skip, e.g., pytest.skipif(not hasattr(iris, 'atomic_sub'), reason='atomic_sub not supported by Triton', allow_module_level=True).

import torch

[mawad-amd]

Looks good, modulo the Copilot comment and a question. Thanks!

[neoblizz]

Looks good, modulo the Copilot comment and a question. Thanks!

Copilot comments are not needed in this case.