Landing: dc65d88cdf15
Project / Subsystem
gcc / libstdc++
Date
2026-09-22
Author
Tamar Christina
Commit
dc65d88cdf15f3538fdcfd1d174c845474989533
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- libstdc++
- patch_id
- —
- commit_hash
- dc65d88cdf15f3538fdcfd1d174c845474989533
- source_type
- github
- headline
- libstdc++: Continue with regex DFS traversals without next frames
- tldr
- Optimized regex DFS execution in libstdc++ by avoiding unnecessary stack frame operations for repeated matches.
- author
- Tamar Christina
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • libstdc++
- • regex
- • optimization
- • performance
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-22T00:00:00.000Z
This patch revises the iterative DFS regex executor to avoid pushing and popping stack frames when a match is expected to continue. For repeated subexpressions, the executor now attempts to consume the state immediately, keeping values in registers to minimize memory accesses and function call overhead. This significantly improves performance for patterns involving repetitions, while maintaining the memory usage improvements of the original iterative approach.