xpu: support xpu backend from stock pytorch (>=2.4)

Fixes: huggingface#31237

XPU backend is available in the stock PyTorch starting from
version 2.4, see [1]. This commit extends huggingface transformers
to support XPU from both IPEX and the stock pytorch. IPEX is being
tried first.

See: pytorch/pytorch#114842
Requires: huggingface/accelerate#2825
Signed-off-by: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>

src/transformers/testing_utils.py

@@ -813,23 +813,24 @@ def require_torch_multi_npu(test_case):
 
 def require_torch_xpu(test_case):
     """
-    Decorator marking a test that requires XPU and IPEX.
+    Decorator marking a test that requires XPU (in PyTorch).
 
-    These tests are skipped when Intel Extension for PyTorch isn't installed or it does not match current PyTorch
-    version.
+    These tests are skipped when XPU backend is not available. XPU backend might be available either via stock
+    PyTorch (>=2.4) or via Intel Extension for PyTorch. In the latter case, if IPEX is installed, its version
+    must match match current PyTorch version.
     """
-    return unittest.skipUnless(is_torch_xpu_available(), "test requires IPEX and an XPU device")(test_case)
+    return unittest.skipUnless(is_torch_xpu_available(), "test requires XPU device")(test_case)
 
 
 def require_torch_multi_xpu(test_case):
     """
-    Decorator marking a test that requires a multi-XPU setup with IPEX and at least one XPU device. These tests are
-    skipped on a machine without IPEX or multiple XPUs.
+    Decorator marking a test that requires a multi-XPU setup (in PyTorch). These tests are skipped on a machine without
+    multiple XPUs.
 
     To run *only* the multi_xpu tests, assuming all test names contain multi_xpu: $ pytest -sv ./tests -k "multi_xpu"
     """
     if not is_torch_xpu_available():
-        return unittest.skip("test requires IPEX and at least one XPU device")(test_case)
+        return unittest.skip("test requires PyTorch XPU")(test_case)
 
     return unittest.skipUnless(torch.xpu.device_count() > 1, "test requires multiple XPUs")(test_case)
 

src/transformers/utils/import_utils.py

@@ -747,13 +747,18 @@ def get_major_and_minor_from_version(full_version):
 
 @lru_cache
 def is_torch_xpu_available(check_device=False):
-    "Checks if `intel_extension_for_pytorch` is installed and potentially if a XPU is in the environment"
-    if not is_ipex_available():
+    """
+    Checks if XPU acceleration is available either via `intel_extension_for_pytorch` or
+    via stock PyTorch (>=2.4) and potentially if a XPU is in the environment
+    """
+    if not is_torch_available():
         return False
 
-    import intel_extension_for_pytorch  # noqa: F401
     import torch
 
+    if is_ipex_available():
+        import intel_extension_for_pytorch  # noqa: F401
+
     if check_device:
         try:
             # Will raise a RuntimeError if no XPU  is found