Make Windows static library searches architecture-aware

cuda_pathfinder/cuda/pathfinder/_static_libs/find_static_lib.py

@@ -9,6 +9,7 @@
 from cuda.pathfinder._utils.env_vars import get_cuda_path_or_home
 from cuda.pathfinder._utils.find_sub_dirs import find_sub_dirs_all_sitepackages
 from cuda.pathfinder._utils.platform_aware import IS_WINDOWS
+from cuda.pathfinder._utils.windows_arch import windows_python_arch
 
 
 class StaticLibNotFoundError(RuntimeError):
@@ -32,17 +33,28 @@ class _StaticLibInfo(TypedDict):
     site_packages_dirs: tuple[str, ...]
 
 
+def _cudadevrt_info() -> _StaticLibInfo:
+    if not IS_WINDOWS:
+        return {
+            "filename": "libcudadevrt.a",
+            "ctk_rel_paths": ("lib64", "lib"),
+            "conda_rel_paths": ("lib",),
+            "site_packages_dirs": ("nvidia/cu13/lib", "nvidia/cuda_runtime/lib"),
+        }
+
+    arch_dir = windows_python_arch()
+    component_wheel_dirs = ("nvidia/cuda_runtime/lib/x64",) if arch_dir == "x64" else ()
+    conda_fallback_dirs = ("lib",) if arch_dir == "x64" else ()
+    return {
+        "filename": "cudadevrt.lib",
+        "ctk_rel_paths": (os.path.join("lib", arch_dir),),
+        "conda_rel_paths": (os.path.join("lib", arch_dir), *conda_fallback_dirs),
+        "site_packages_dirs": (f"nvidia/cu13/lib/{arch_dir}", *component_wheel_dirs),
+    }
+
+
 _SUPPORTED_STATIC_LIBS_INFO: dict[str, _StaticLibInfo] = {
-    "cudadevrt": {
-        "filename": "cudadevrt.lib" if IS_WINDOWS else "libcudadevrt.a",
-        "ctk_rel_paths": (os.path.join("lib", "x64"),) if IS_WINDOWS else ("lib64", "lib"),
-        "conda_rel_paths": ((os.path.join("lib", "x64"), "lib") if IS_WINDOWS else ("lib",)),
-        "site_packages_dirs": (
-            ("nvidia/cu13/lib/x64", "nvidia/cuda_runtime/lib/x64")
-            if IS_WINDOWS
-            else ("nvidia/cu13/lib", "nvidia/cuda_runtime/lib")
-        ),
-    },
+    "cudadevrt": _cudadevrt_info(),
 }
 
 SUPPORTED_STATIC_LIBS: tuple[str, ...] = tuple(sorted(_SUPPORTED_STATIC_LIBS_INFO.keys()))

cuda_pathfinder/docs/source/release/1.6.1-notes.rst

@@ -24,6 +24,11 @@ Highlights
 
 * Add ``UnsupportedArchError`` for unsupported Windows Python platform tags.
 
+* Make Windows static-library discovery architecture-aware. Searches now use
+  the current Python interpreter architecture to select the matching
+  ``lib/x64`` or ``lib/arm64`` CUDA Toolkit and wheel directories. CUDA 12
+  component-wheel and legacy Conda fallbacks remain x64-only.
+
 Internal maintenance
 --------------------
 

cuda_pathfinder/tests/test_find_static_lib.py

@@ -143,6 +143,41 @@ def test_locate_static_lib_conda_rel_path_fallback(monkeypatch, tmp_path):
     assert located_lib.found_via == "conda"
 
 
+@pytest.mark.parametrize(
+    ("target_arch", "expected_ctk_dirs", "expected_conda_dirs", "expected_site_packages_dirs"),
+    (
+        (
+            "x64",
+            (os.path.join("lib", "x64"),),
+            (os.path.join("lib", "x64"), "lib"),
+            ("nvidia/cu13/lib/x64", "nvidia/cuda_runtime/lib/x64"),
+        ),
+        (
+            "arm64",
+            (os.path.join("lib", "arm64"),),
+            (os.path.join("lib", "arm64"),),
+            ("nvidia/cu13/lib/arm64",),
+        ),
+    ),
+)
+@pytest.mark.agent_authored(model="gpt-5.6")
+def test_cudadevrt_windows_paths_follow_python_arch(
+    monkeypatch,
+    target_arch,
+    expected_ctk_dirs,
+    expected_conda_dirs,
+    expected_site_packages_dirs,
+):
+    monkeypatch.setattr(find_static_lib_module, "IS_WINDOWS", True)
+    monkeypatch.setattr(find_static_lib_module, "windows_python_arch", lambda: target_arch)
+
+    info = find_static_lib_module._cudadevrt_info()
+
+    assert info["ctk_rel_paths"] == expected_ctk_dirs
+    assert info["conda_rel_paths"] == expected_conda_dirs
+    assert info["site_packages_dirs"] == expected_site_packages_dirs
+
+
 @pytest.mark.usefixtures("clear_find_static_lib_cache")
 def test_find_static_lib_not_found_error_includes_cuda_home_directory_listing(monkeypatch, tmp_path):
     filename = CUDADEVRT_INFO["filename"]