Add check for QNN_SDK_ROOT in hadamard pass (pytorch#21815)

Differential Revision: D115881389

Pull Request resolved: pytorch#21815

Author: JakeStevens

backends/qualcomm/_passes/recompose_hadamard.py

@@ -3,6 +3,7 @@
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
+import os
 from operator import attrgetter
 
 import torch
@@ -156,7 +157,7 @@ def _is_hadamard_transform(self, graph_module, node):
     def call(self, graph_module: torch.fx.GraphModule):
         # HadamardTransform is only supported by QNN 2.47+. On older SDKs skip the
         # rewrite so the op keeps its normal lowering path.
-        if is_qnn_sdk_version_less_than("2.47"):
+        if not os.environ.get("QNN_SDK_ROOT") or is_qnn_sdk_version_less_than("2.47"):
             return PassResult(graph_module, False)
 
         graph = graph_module.graph