Landing: dd682ea04149
Project / Subsystem
gcc / i386
Date
2026-05-28
Author
Kewen Lin
Commit
dd682ea04149261d27c871879c0c81a94ece8cd8
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- i386
- patch_id
- —
- commit_hash
- dd682ea04149261d27c871879c0c81a94ece8cd8
- source_type
- github
- headline
- i386: Refines c86-4g fdiv scheduling model
- tldr
- GCC's i386 backend now refines the scheduling model for floating-point division to better reflect hardware behavior.
- author
- Kewen Lin
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • i386
- • scheduling
- • fpu
- • optimization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-05-28T00:00:00.000Z
This commit refines the scheduling model for floating-point division on i386 architectures, specifically for the c86-4g model. It models a bounded part of the FPU pipe occupancy on a dedicated fdiv unit, improving the accuracy of instruction scheduling. The commit splits fpu0/fpu2 and fpu1/fpu3 into two paired automatons. It also corrects modelling omissions like a latency typo and adjustments to reservation units.