[Akshay Sonawane (apsonawane)]

This pull request strengthens input validation for the Mixture-of-Experts (MoE) operator on CPU by ensuring that the hidden_size and inter_size parameters are positive. It also adds new unit tests to verify that invalid input shapes are correctly rejected and that valid, but edge-case, inputs remain supported.

Input Validation Improvements

• Added a check in moe_helper.h to ensure that hidden_size is positive; otherwise, an error is returned.
• Added a check in moe_helper.h to ensure that inter_size is positive; otherwise, an error is returned.

Unit Test Additions

• Added ZeroHiddenSizeRejectedOnCPU test in moe_test.cc to verify that MoE and QMoE operators reject inputs with zero hidden_size.
• Added ZeroRowsWithPositiveHiddenSizeRemainsSupportedOnCPU test in moe_test.cc to confirm that inputs with zero rows and positive hidden_size are still supported.

[Copilot]

🟡 Changes recommended

The QMoE test’s float32 scales are incompatible with its FP16 kernel, preventing it from reaching the intended validation, and the new zero-inter_size guard lacks regression coverage.

2 open issues

• Use FP16 scales in QMoE test to reach hidden-size validation · New
• Add regression tests for zero inter_size validation · New

What changed in this PR

This PR strengthens dimension validation in ONNX Runtime’s MoE input helper and adds CPU tests for invalid dimensions and empty inputs.

Changes:

• Reject non-positive hidden_size and inter_size.
• Add zero-hidden-size rejection cases for MoE and QMoE.
• Verify that MoE still supports zero rows with a positive hidden size.

File	Description
onnxruntime/​test/​contrib_ops/​moe_test.cc	Adds CPU rejection and empty-input regression tests.
onnxruntime/​contrib_ops/​cpu/​moe/​moe_helper.h	Adds positive hidden and intermediate dimension checks.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues were identified for the CPU MoE input-validation changes.

No open issues 🎉

2 resolved since last review

• Use FP16 scales in QMoE test to reach hidden-size validation
• Add regression tests for zero inter_size validation

_{Review effort: Max}

[Ti-Tai Wang (titaiwangms)]

No blocking issues found in a bounded static review of the diff, shared input validation, direct CPU MoE/QMoE consumers, and added tests. The hidden-size guard is before the intermediate-size modulo/division, and the tests distinguish zero hidden/intermediate dimensions from the supported zero-row case.

Validation scope: static inspection only; I did not build or run the tests or sanitizers.