Landing: 0a970b270218
Project / Subsystem
gcc / tree-optimization
Date
2026-09-25
Author
Richard Biener
Commit
0a970b2702183d290df044858fd4df13ef698924
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- tree-optimization
- patch_id
- —
- commit_hash
- 0a970b2702183d290df044858fd4df13ef698924
- source_type
- github
- headline
- tree-optimization: Avoid overflow in vector loop epilog initialization
- tldr
- Prevents undefined behavior from integer overflow when calculating vector loop epilog start values.
- author
- Richard Biener
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • vectorization
- • loop analysis
- • undefined behavior
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-25T00:00:00.000Z
This commit resolves an undefined behavior issue in the vectorizer by using an unsigned type to compute the start value of loop epilogs. This prevents potential overflow during the calculation of init + step * vect-niters, ensuring more reliable loop transformations.