Landing: 7f02676a414e
Project / Subsystem
gcc / match-sat-alu.pd
Date
2026-09-14
Author
Kyrylo Tkachov
Commit
7f02676a414e4a96c498c0b3e58487aca3c45185
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- match-sat-alu.pd
- patch_id
- —
- commit_hash
- 7f02676a414e4a96c498c0b3e58487aca3c45185
- source_type
- github
- headline
- match-sat-alu.pd: Recognize signed constant-clamp truncation
- tldr
- GCC can now optimize signed saturating truncation that results from clamping a value to the bounds of a narrower signed type.
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • gcc
- • aarch64
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-14T00:00:00.000Z
GCC’s match-sat-alu.pd pattern matcher now recognizes signed saturating truncation that occurs when a value is clamped to the bounds of a narrower signed integer type. This optimization handles both orders of MIN and MAX operations used for clamping, enabling more efficient code generation. An AArch64 example shows a significant reduction from multiple instructions to a single sqxtn instruction.