Landing: c8c3988ef66c
Project / Subsystem
gcc / xtensa
Date
2026-07-17
Author
Takayuki 'January June' Suwa
Commit
c8c3988ef66c112defe86dcd23e6679d39814587
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- xtensa
- patch_id
- —
- commit_hash
- c8c3988ef66c112defe86dcd23e6679d39814587
- source_type
- github
- headline
- Define LOCAL_REGNO() macro for Xtensa TARGET_WINDOWED_ABI.
- tldr
- Fixes phantom DF livenesses and improves optimization in Xtensa.
- author
- Takayuki 'January June' Suwa
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • xtensa
- • optimization
- • abi
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-17T00:00:00.000Z
This commit defines the LOCAL_REGNO() macro for the Xtensa target when the TARGET_WINDOWED_ABI option is enabled. Without this macro, the compiler incorrectly identifies phantom ‘DF’ (Data Flow) livenesses in the function epilogue. This incorrect liveness information hinders optimizations, such as low-overhead loop optimization, by causing the epilogue basic block to be incorrectly perceived as using loop variables. Defining LOCAL_REGNO() resolves this issue, enabling better optimization.