Landing: bbf1dfa9da86
Project / Subsystem
gcc / match.pd
Date
2026-07-29
Author
Kyrylo Tkachov
Commit
bbf1dfa9da862caadf97ebf9a21b877b1553dbf4
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- match.pd
- patch_id
- —
- commit_hash
- bbf1dfa9da862caadf97ebf9a21b877b1553dbf4
- source_type
- github
- headline
- Combine vector comparisons against zero
- tldr
- Optimizes vector comparisons by combining pairs of comparisons against zero.
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • vectorization
- • pattern matching
- • SIMD
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-29T00:00:00.000Z
This commit introduces optimizations for vector comparisons in GCC’s match.pd pattern matching system. It combines pairs of vector comparisons against zero, leveraging the identity (A == 0) & (B == 0) <=> (A | B) == 0. This applies to both equality and inequality, and handles cases where operands differ in signedness. The optimization is demonstrated with an aarch64 example and includes a new test case.