Landing: fd1bc5303748
Project / Subsystem
gcc / match.pd
Date
2026-07-30
Author
Kyrylo Tkachov
Commit
fd1bc5303748a7b3b0a157a8688f3cb2af16abc6
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- match.pd
- patch_id
- —
- commit_hash
- fd1bc5303748a7b3b0a157a8688f3cb2af16abc6
- source_type
- github
- headline
- match.pd: Add rule for masked OR comparisons.
- tldr
- Adds a new pattern matching rule for optimizing masked OR comparisons.
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • match.pd
- • pattern matching
- • aarch64
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-30T00:00:00.000Z
This commit introduces a new optimization rule to GCC’s pattern matching system (match.pd) for simplifying masked OR comparisons. It addresses the dual of an existing rule: (X | C) == (Y | C) now folds to ((X ^ Y) & C) == 0. This optimization is demonstrated with an example of case-insensitive ASCII comparison, allowing for more efficient code generation on architectures like aarch64.