Landing: 2c1e97207485
Project / Subsystem
gcc / ivopts
Date
2026-08-29
Author
Jovan Dmitrovic
Commit
2c1e97207485e54ab6ae085f76c07e62a14440ae
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- ivopts
- patch_id
- —
- commit_hash
- 2c1e97207485e54ab6ae085f76c07e62a14440ae
- source_type
- github
- headline
- ivopts: Remove bias from register pressure cost calculation.
- tldr
- Loop invariant optimization pass removes a bias in register pressure cost that unfairly penalized larger candidate sets.
- author
- Jovan Dmitrovic
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- gcc:ivopts: remove bias from calculating reg pressure cost
- series_parts
- []
- tags
-
- • optimization
- • compiler
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-29T00:00:00.000Z
The ivopts_estimate_reg_pressure function was previously biased by the number of candidates in a set, making larger sets less likely to be chosen. This change removes that bias, allowing the optimizer to more fairly evaluate sets with varying numbers of loop-invariant candidates, improving the selection of optimal candidate sets.