Landing: 097cd0ceee61
Project / Subsystem
gcc / tree-optimization
Date
2026-08-31
Author
Kyrylo Tkachov
Commit
097cd0ceee61aa4b5100931341e9c8642f060c0a
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- tree-optimization
- patch_id
- —
- commit_hash
- 097cd0ceee61aa4b5100931341e9c8642f060c0a
- source_type
- github
- headline
- Tighten matching for unsigned narrow clip patterns.
- tldr
- Refines pattern matching for unsigned integer narrow clips to correctly handle signed comparisons and unsigned right shifts.
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • compiler
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-31T00:00:00.000Z
This commit improves the unsigned_integer_narrow_clip pattern matching by requiring the comparison to be unsigned and the right shift to be signed. Previously, the pattern incorrectly assumed these conditions, potentially leading to incorrect transformations when a signed comparison preserved negative inputs or an unsigned right shift produced an incorrect result. The change captures both expressions and checks their result types before applying the transform, with new tests covering rejected forms.