Landing: 4c4933a4890c

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Project / Subsystem

gcc / risc-v

Date

2026-05-29

Author

Zhongyao Chen

Commit

4c4933a4890caf3973e1cff1d68371c545adb30b

Source

github

Perf win

Yes

Breaking

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All attributes

project: gcc
subsystem: risc-v
patch_id: —
commit_hash: 4c4933a4890caf3973e1cff1d68371c545adb30b
source_type: github
headline: RISC-V: Scale RVV integer vector body costs by unit ratio.
tldr: RISC-V vector cost model now scales integer vector operations based on scalar/vector unit ratios for better throughput prediction.
author: Zhongyao Chen
outcome: committed
performance_win: true
breaking_change: false
series_id: —
series_parts: []
tags: • risc-v
• vectorization
• cost-model
• performance
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/4c4933a4890caf3973e1cff1d68371c545adb30b
date: 2026-05-29T00:00:00.000Z

The RISC-V vector cost model has been updated to incorporate a scalar-to-vector unit ratio for integer vector operations. This change helps the cost model more accurately reflect actual hardware throughput, preventing vectorization from appearing overly cheap. The update introduces new fields for scalar and vector units in riscv_tune_param and applies the scaling to most vector body costs, excluding reductions and gather/scatter operations.