bug: WinMLSession silently drops provider_options in policy-based (default) compile path

[DingmaomaoBJTU]

Summary

WinMLSession._build_session_options takes provider_options from ep_config and passes them only in the explicit-EP path (add_provider_for_devices). In the policy-based path (the default for device="npu"/"auto"), they are silently ignored.

Affected code

src/winml/modelkit/session/session.py L387-L414

# Explicit EP path — provider_options correctly forwarded
opts.add_provider_for_devices([matched], self._provider_options)   # ✓

# Policy-based path (default) — provider_options silently dropped
opts.set_provider_selection_policy(policy)
return opts   # ✗ self._provider_options never used

Impact

Any option set via ep_config.provider_options is silently dropped during a normal winml compile run. Confirmed affected option: htp_performance_mode, set in:

• src/winml/modelkit/compiler/__init__.py L23: config.ep_config.provider_options["htp_performance_mode"] = "default"
• src/winml/modelkit/compiler/configs.py L75: docstring example sets htp_performance_mode = "default"

The compile pipeline (CompileStage) passes ep_config to WinMLSession, but the session never applies provider_options when using the standard policy path. As a result, QNN provider options (HTP performance mode, SOC model, etc.) have no effect.

Expected behavior

provider_options should be forwarded to ORT regardless of whether explicit-EP or policy-based selection is used.

Steps to reproduce

from winml.modelkit.compiler.configs import WinMLCompileConfig
config = WinMLCompileConfig.for_qnn()
config.ep_config.provider_options["htp_performance_mode"] = "burst"
# Compile a model — htp_performance_mode is silently ignored

Notes

• Discovered during investigation of QNN compilation behavior for deberta Slice ops.
• The policy-based path uses set_provider_selection_policy, which may have a different API for passing provider options — needs investigation.

[DingmaomaoBJTU]

Triage summary

• Component: Compile
• Priority: P1
• Owner(s): @zhenchaoni

WinMLSession silently drops provider_options (including htp_performance_mode) in the policy-based compile path; provider_options must be forwarded to ORT regardless of whether explicit-EP or policy-based selection is used.