Landing: 9eb8a18033a4
Project / Subsystem
gcc / gcc
Date
2026-04-28
Author
Vladimir N. Makarov
Commit
9eb8a18033a473b30559862b3ff6a1cac162759b
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc
- patch_id
- —
- commit_hash
- 9eb8a18033a473b30559862b3ff6a1cac162759b
- source_type
- github
- headline
- IRA: Fix implicit preference calculation for hard registers.
- tldr
- This patch corrects an issue in the IRA that could lead to suboptimal code generation by improving the hard register preference calculation.
- author
- Vladimir N. Makarov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • ira
- • register allocation
- • optimization
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-04-28T00:00:00.000Z
The IRA (Integrated Register Allocator) could ignore some valid register alternatives for subsequent operands when searching for preferred hard registers under strict constraints. This could result in suboptimal code generation because the allocator didn’t properly consider all options. This patch fixes the issue by ensuring that the same starting preference is used for all operands, leading to better register allocation decisions.