[KernelGen][MThreads] Add square_ Moore Threads specialized operator

src/flag_gems/runtime/backend/_mthreads/ops/__init__.py

@@ -87,6 +87,7 @@
 from .softplus_backward import softplus_backward
 from .sort import sort, sort_stable
 from .special_gammainc import special_gammainc
+from .square_ import square_
 from .tile import tile
 from .trunc import trunc, trunc_
 from .unique import _unique2
@@ -183,6 +184,7 @@
     "sort",
     "sort_stable",
     "special_gammainc",
+    "square_",
     "tile",
     "true_divide",
     "true_divide_",

src/flag_gems/runtime/backend/_mthreads/ops/square_.py

@@ -0,0 +1,98 @@
+# Copyright 2026 FlagOS Contributors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+
+import torch
+import triton
+import triton.language as tl
+
+from flag_gems.ops.square import square_ as default_square_
+from flag_gems.runtime import torch_device_fn
+from flag_gems.utils import libentry
+
+logger = logging.getLogger(
+    f'flag_gems.runtime.backend._mthreads.ops.{__name__.split(".")[-1]}'
+)
+
+_SUPPORTED_DTYPES = {torch.float16, torch.bfloat16, torch.float32}
+
+
+@libentry()
+@triton.autotune(
+    configs=[
+        triton.Config({"BLOCK_SIZE": 256}, num_warps=1, num_stages=1),
+        triton.Config({"BLOCK_SIZE": 1024}, num_warps=2, num_stages=1),
+        triton.Config({"BLOCK_SIZE": 2048}, num_warps=2, num_stages=1),
+        triton.Config({"BLOCK_SIZE": 4096}, num_warps=2, num_stages=1),
+    ],
+    key=["n_elements"],
+    # Inplace: autotune reruns the kernel on the same buffer, so restore the
+    # input between trials to avoid squaring repeatedly in place.
+    restore_value=["x_ptr"],
+)
+@triton.jit
+def square_kernel_full(x_ptr, n_elements, BLOCK_SIZE: tl.constexpr):
+    pid = tl.program_id(0)
+    offsets = pid * BLOCK_SIZE + tl.arange(0, BLOCK_SIZE)
+    x = tl.load(x_ptr + offsets, eviction_policy="evict_first")
+    tl.store(x_ptr + offsets, x * x, eviction_policy="evict_first")
+
+
+@libentry()
+@triton.autotune(
+    configs=[
+        triton.Config({"BLOCK_SIZE": 256}, num_warps=1, num_stages=1),
+        triton.Config({"BLOCK_SIZE": 1024}, num_warps=2, num_stages=1),
+        triton.Config({"BLOCK_SIZE": 2048}, num_warps=2, num_stages=1),
+        triton.Config({"BLOCK_SIZE": 4096}, num_warps=2, num_stages=1),
+    ],
+    key=["n_elements"],
+    # Inplace: autotune reruns the kernel on the same buffer, so restore the
+    # input between trials to avoid squaring repeatedly in place.
+    restore_value=["x_ptr"],
+)
+@triton.jit
+def square_kernel_masked(x_ptr, n_elements, BLOCK_SIZE: tl.constexpr):
+    pid = tl.program_id(0)
+    offsets = pid * BLOCK_SIZE + tl.arange(0, BLOCK_SIZE)
+    mask = offsets < n_elements
+    x = tl.load(x_ptr + offsets, mask=mask, eviction_policy="evict_first")
+    tl.store(x_ptr + offsets, x * x, mask=mask, eviction_policy="evict_first")
+
+
+def _use_triton_kernel(x: torch.Tensor) -> bool:
+    if not isinstance(x, torch.Tensor):
+        return False
+    if x.device.type != "musa" or x.dtype not in _SUPPORTED_DTYPES:
+        return False
+    if not x.is_contiguous() or x.numel() == 0:
+        return False
+    return True
+
+
+def square_(x: torch.Tensor):
+    logger.debug("GEMS_MTHREADS SQUARE_")
+    if not _use_triton_kernel(x):
+        return default_square_(x)
+
+    n = x.numel()
+    with torch_device_fn.device(x.device):
+        if n % 4096 == 0:
+            grid = lambda META: (n // META["BLOCK_SIZE"],)
+            square_kernel_full[grid](x, n)
+        else:
+            grid = lambda META: (triton.cdiv(n, META["BLOCK_SIZE"]),)
+            square_kernel_masked[grid](x, n)
+    return x