Landing: 82787e703f97
Project / Subsystem
gcc / gcc
Date
2026-09-18
Author
Richard Biener
Commit
82787e703f9782b113d0ddf6944b50814986205f
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc
- patch_id
- —
- commit_hash
- 82787e703f9782b113d0ddf6944b50814986205f
- source_type
- github
- headline
- Implement `umul<mode>3_highpart` for V2DI/V4DI using SSE2
- tldr
- Adds optimized hardware implementation for high-part multiplication of double-word vectors, improving performance on Zen4.
- author
- Richard Biener
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • i386
- • vectorization
- • optimization
- • performance
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-09-18T00:00:00.000Z
This commit implements the umul<mode>3_highpart intrinsic for V2DI, V4DI, and V8DI vector types using SSE2 instructions, specifically pmuludq. This provides a hardware-accelerated path for calculating the high-order part of unsigned integer multiplications on vectors of double-words. The implementation targets specific vector types and instruction sets (VI8_AVX2_AVX512F) and includes cost modeling for the new operation. This change is expected to significantly speed up workloads like 750.sealcrypto_r by approximately 20% on Zen4 processors, recovering performance lost in a previous revision.