The GitHub Actions job "Lint" on tvm.git/main has failed.
Run started by GitHub user tlopex (triggered by tlopex).

Head commit for run:
b29b52fdf42e5dd792715e861dee80c6f26c731b / Igor Stadnyk 
<[email protected]>
[Fix][LLVM] Preserve 64-bit AllocBuffer extents (#20141)

Fixes #20125.

## What changed

LLVM CPU code generation now keeps constant `AllocBuffer` extents as
signed 64-bit values through stack allocation emission instead of
narrowing them to `int32_t`. The temporary-allocation alignment helper
accepts the same width and avoids multiplying when a large allocation
cannot reduce the requested alignment, preventing overflow in that
calculation.

This change is intentionally limited to the CPU `CodeGenLLVM` path. The
separate NVPTX and AMDGPU overrides described in the issue remain out of
scope.

## Why

An extent of `2**32 + 1` previously wrapped to one before
`CreateAlloca`, producing a one-element stack allocation followed by an
`i64 4294967296` element access in unoptimized TIR-X LLVM IR. The
generated module could therefore contain an out-of-bounds access even
though the original extent was valid as an `int64_t`.

The regression test only compiles and inspects LLVM IR; it does not
execute or materialize the very large allocation. It covers extents that
previously wrapped to one and four elements.

## Validation

- New regression on the unmodified base: 2 failures
- New regression after the fix: 2 passed
- `tests/python/codegen/test_target_codegen_llvm.py`: 380 passed
- Rebuilt all 65 affected C++ units, including the NVPTX and AMDGPU
callers of the alignment helper
- Changed-file pre-commit hooks and `git diff --check`: passed
- Compile-only boundary probes through `INT64_MAX - 3`: exact `i64`
allocation counts, with no allocation executed

## AI assistance

This PR was prepared with OpenAI Codex. The patch was derived from the
repository and the issue's documented failure mode; no external
third-party code was copied into the change.

Generated-by: OpenAI Codex

Co-authored-by: Igor Stadnyk <[email protected]>

Report URL: https://github.com/apache/tvm/actions/runs/34247794305

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