Landing: 65814ca6027f
Project / Subsystem
gcc / forwprop
Date
2026-08-22
Author
Andrea Pinski
Commit
65814ca6027f373806edd21b0125f87359ebdcf2
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- forwprop
- patch_id
- —
- commit_hash
- 65814ca6027f373806edd21b0125f87359ebdcf2
- source_type
- github
- headline
- forwprop: Optimize `match_long_mul_phi` by reordering conditional checks.
- tldr
- forwprop: Reorders checks in `match_long_mul_phi` to prioritize cheaper conditions, improving performance.
- author
- Andrea Pinski
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • compiler
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-08-22T00:00:00.000Z
In tree-ssa-forwprop.cc, the match_long_mul_phi function has been updated to reorder its conditional checks. The check for the shift amount equality (shift_amt == halfwidth) is now performed before the more computationally expensive gimple_mul_low_sum and gimple_mul_cross_sum calls. This optimization can lead to faster compilation by avoiding unnecessary function calls when the shift amount condition is not met.