Landing: 55e9aef65b2d
Project / Subsystem
gcc / combine
Date
2026-09-16
Author
Yongqiang Tian
Commit
55e9aef65b2d3705089c2de601867aa6e7cc261d
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- combine
- patch_id
- —
- commit_hash
- 55e9aef65b2d3705089c2de601867aa6e7cc261d
- source_type
- github
- headline
- Combine: Ignore debug instructions in volatile checks
- tldr
- Debug instructions are ignored during volatile access checks in the combine pass.
- author
- Yongqiang Tian
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • combine
- • volatile
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-16T00:00:00.000Z
The combine pass in GCC now ignores DEBUG_INSNs when checking for intervening volatile memory accesses. Previously, a DEBUG_INSN could cause a non-executing memory access to be incorrectly treated as volatile, preventing valid instruction combinations. This change improves optimization opportunities by ensuring only actual volatile accesses are considered.