Landing: f6103f3a1e42
Project / Subsystem
gcc / gcc/internals
Date
2026-06-04
Author
Kevin Stefanov
Commit
f6103f3a1e42fe4db15f3c1d96847cd4a4829e4e
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc/internals
- patch_id
- —
- commit_hash
- f6103f3a1e42fe4db15f3c1d96847cd4a4829e4e
- source_type
- github
- headline
- GCC optimizes hard register set iteration by replacing `TEST_HARD_REG_BIT`.
- tldr
- GCC improves the efficiency of iterating over hard register sets by replacing `TEST_HARD_REG_BIT` with `hard_reg_set_iterator` and `hard_reg_set_popcount`.
- author
- Kevin Stefanov
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • optimization
- • register allocation
- • compiler internals
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-06-04T00:00:00.000Z
This GCC commit refactors internal loops that check individual bits in hard register sets, replacing inefficient TEST_HARD_REG_BIT calls within loops with the more efficient EXECUTE_IF_SET_IN_HARD_REG_SET macro. Additionally, direct calls to hard_reg_set_size are replaced with hard_reg_set_popcount, as the latter more accurately reflects the intended operation of counting set bits. These changes improve compiler performance by streamlining register set manipulations, primarily in architecture-specific code generation and optimization passes.