Landing: 23797f88d163
Project / Subsystem
gcc / gcc/match.pd
Date
2026-08-10
Author
Kyrylo Tkachov
Commit
23797f88d1635d38ce68c8d180a0f90a1ea34740
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc/match.pd
- patch_id
- —
- commit_hash
- 23797f88d1635d38ce68c8d180a0f90a1ea34740
- source_type
- github
- headline
- Fold inequality spelling of divisibility
- tldr
- Extends divisibility optimization to handle inequality conditions.
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • pattern-matching
- • aarch64
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-10T00:00:00.000Z
GCC now optimizes divisibility checks involving inequalities, similar to how it handles equalities. Previously, an expression like x / y * y == x could be simplified to x % y == 0. This change extends that optimization to also cover x / y * y != x, which simplifies to x % y != 0. This optimization can lead to more efficient code generation, as demonstrated by an example on AArch64.