[Enhancement] Remove RewriteUnsafeSelect Pass

[LJC00118]

Summary by CodeRabbit

• Chores

  • Removed an intermediate unsafe-select rewrite from the optimization pipeline to streamline compilation behavior.

• Tests

  • Added tests validating conditional selection correctness and ensuring generated kernels do not emit Python-level conditional statements.

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📝 Walkthrough

Walkthrough

Removed the RewriteUnsafeSelect pass from the OptimizeForTarget pipeline; added a new Python test module that exercises T.Select semantics and verifies generated kernel source contains no Python-level if statements.

Changes

Cohort / File(s)	Summary
Pass pipeline modification tilelang/engine/phase.py	Removed the RewriteUnsafeSelect invocation from the OptimizeForTarget optimization sequence; pipeline now flows from Simplify/RemoveNoOp to HoistIfThenElse and VerifyMemory without that pass.
Tests added testing/python/language/test_tilelang_language_select.py	New test module introducing two JIT-wrapped kernels using T.Select across operands/branches and tests for correctness against CUDA tensors and absence of Python-level if in generated kernel source.

Sequence Diagram(s)

(omitted — changes do not introduce a new multi-component control flow requiring visualization)

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• [Enhancement] Remove RewriteUnsafeSelect Pass #1705 — Removes RewriteUnsafeSelect from OptimizeForTarget and adds the same TileLang select tests (direct code-level overlap).

Poem

🐰 I hopped through passes, nibbled one away,

Now selects skip a step and romp in play,
I spun up tests, with kernels bold and spry,
No Python ifs in code — hops touch the sky! 🥕✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: removing the RewriteUnsafeSelect pass from the optimization pipeline, which is the primary modification in the changeset.

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✨ Finishing touches

• 📝 Generate docstrings

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