Landing: 3791d1b507c5
Project / Subsystem
gcc / match
Date
2026-07-29
Author
Kyrylo Tkachov
Commit
3791d1b507c5715bc350d740dec70f4b06f19a96
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- match
- patch_id
- —
- commit_hash
- 3791d1b507c5715bc350d740dec70f4b06f19a96
- source_type
- github
- headline
- match: Fold sum of MIN/MAX pair into a single expression.
- tldr
- Optimizes expressions like (a + b) - MIN(a, b) to simplify to MAX(a, b).
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • algebraic simplification
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-29T00:00:00.000Z
This commit introduces a new simplification rule in match.pd that folds expressions of the form (x + y) - MIN(x, y) into MAX(x, y). This algebraic identity holds for both integers and floating-point numbers (under certain conditions like reassociation). The optimization simplifies code by reducing the number of operations required, as demonstrated by an example reducing four instructions to one on AArch64.