[FRONTEND] make torch optional (#1604)

make torch optional to fix circular dependency issue

python/triton/__init__.py

@@ -4,10 +4,6 @@
 # ---------------------------------------
 # Note: import order is significant here.
 
-# TODO: torch needs to be imported first
-# or pybind11 shows `munmap_chunk(): invalid pointer`
-import torch  # noqa: F401
-
 # submodules
 from .runtime import (
     autotune,

python/triton/compiler/compiler.py

@@ -11,8 +11,6 @@
 from pathlib import Path
 from typing import Any, Tuple
 
-import torch
-
 import triton
 import triton._C.libtriton.triton as _triton
 from ..runtime import driver
@@ -324,6 +322,10 @@ def _is_cuda(arch):
 
 
 def get_architecture_descriptor(capability):
+    try:
+        import torch
+    except ImportError:
+        raise ImportError("Triton requires PyTorch to be installed")
     if capability is None:
         if torch.version.hip is None:
             device = triton.runtime.jit.get_current_device()

python/triton/language/semantic.py

@@ -3,8 +3,6 @@
 from functools import wraps
 from typing import List, Optional, Sequence, Tuple, TypeVar
 
-import torch
-
 import triton
 from . import core as tl
 from triton._C.libtriton.triton import ir
@@ -1183,6 +1181,10 @@ def dot(lhs: tl.tensor,
         allow_tf32: bool,
         out_dtype: tl.dtype,
         builder: ir.builder) -> tl.tensor:
+    try:
+        import torch
+    except ImportError:
+        raise ImportError("Triton requires PyTorch to be installed")
     if torch.version.hip is None:
         device = triton.runtime.jit.get_current_device()
         capability = triton.runtime.jit.get_device_capability(device)