Landing: 1a29fdbdcb67

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Project / Subsystem

gcc / risc-v

Date

2026-08-18

Author

Jin Ma

Commit

1a29fdbdcb6775cd93bfc23426bf4e8b6b0475d2

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: risc-v
patch_id: —
commit_hash: 1a29fdbdcb6775cd93bfc23426bf4e8b6b0475d2
source_type: github
headline: RISC-V: Fix sub-Pmode index in vec_set/vec_extract
tldr: Fixes incorrect slide amount calculation for variable-indexed vector operations on RISC-V.
author: Jin Ma
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • risc-v
• vectorization
• compiler
• bugfix
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/1a29fdbdcb6775cd93bfc23426bf4e8b6b0475d2
date: 2026-08-18T00:00:00.000Z

This patch corrects an issue in RISC-V vector operations where variable-indexed element accesses were being mishandled. Previously, gen_lowpart incorrectly reinterpreted sub-Pmode indices, leading to wrong slide amounts in vslideup/vslidedown instructions. The fix uses convert_to_mode to zero-extend these indices, ensuring correct code generation.