[MISC] fix import violations for re and triton modules

[llsj14]

Purpose

I found pre-commit hook errors during the merge process. To fix these violations, I updated the import statements.

Enforce import regex as re..........................................................................Failed
- hook id: enforce-import-regex-instead-of-re
- exit code: 1

❌ vllm/platforms/cpu.py:
  Line 7: import re

💡 Found 1 violation(s).
❌ Please replace 'import re' with 'import regex as re'
   Also replace 'from re import ...' with 'from regex import ...'
✅ Allowed imports:
   - import regex as re
   - import regex

Forbid direct 'import triton'.......................................................................Failed
- hook id: forbid-direct-triton-import
- exit code: 1

❌ Forbidden direct `import triton` detected. ➤ Use `from vllm.triton_utils import triton` instead.

❌ vllm/model_executor/layers/quantization/qutlass_utils.py:17: import triton
❌ vllm/model_executor/layers/quantization/qutlass_utils.py:18: import triton.language as tl

Test Plan

Test Result

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.
• (Optional) Release notes update. If your change is user facing, please update the release notes draft in the Google Doc.

[gemini-code-assist]

Code Review

This pull request aims to fix import violations for re and triton modules. The change to use regex instead of re is consistent with the project's conventions. However, the change to use a centralized triton import introduces a critical issue. It will cause a runtime AttributeError when Triton is not installed because the placeholder object is missing the cdiv method used in qutlass_utils.py. I've provided a comment with a suggested fix.

[gemini-code-assist]

This change to use the centralized triton import utility is a good step for consistency. However, it introduces a runtime error when Triton is not installed. The TritonPlaceholder object, which is used when Triton is unavailable, does not implement the cdiv method. This file calls triton.cdiv on lines 109, 110, 127, and 128, which will lead to an AttributeError.

To resolve this, please replace all calls to triton.cdiv with the locally defined ceil_div function (line 145), which provides the same ceiling division functionality.

[llsj14]

maybe this part should be reverted?

[DarkLight1337]

cc @mgoin @Isotr0py

[MengqingCao]

maybe this part should be reverted?

I think we should keep the current changes, as this could use TritonPlaceholder to avoid importing error. However, if the triton kernel is invoked at the runtime, we should keep the error to be raised, as that indicates we're using triton kernel in a scenario triton is not installed

[yewentao256]

LGTM, thanks for the work!