Landing: e7e488adc77b
Project / Subsystem
gcc / aarch64
Date
2026-08-11
Author
Kyrylo Tkachov
Commit
e7e488adc77b884f25e6ccf86d00abcb92df3346
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- aarch64
- patch_id
- —
- commit_hash
- e7e488adc77b884f25e6ccf86d00abcb92df3346
- source_type
- github
- headline
- aarch64: Use single FP condition mode when exceptions are unobservable.
- tldr
- Optimizes AArch64 floating-point comparisons by using a single condition mode when exceptions are not observable.
- author
- Kyrylo Tkachov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • aarch64
- • optimization
- • floating-point
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-11T00:00:00.000Z
This commit optimizes floating-point comparisons on AArch64 by using a single condition mode (CCFPmode) when exceptions like NaN-related invalid operations are unobservable, such as with -ffinite-math-only. Previously, both ordered and equality comparisons might emit separate instructions even when the exception difference was irrelevant. This change consolidates the instruction selection, potentially improving code density and performance. It also updates existing assembly scans and adds new tests.