About

Fixed vectors are currently passed using the same rules as structs. Sizes smaller than 2*XLEN are passed in scalar registers. Large sizes are passed in memory. This is not an efficient way to handle vectors.

Specifications:

PSABI https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/418

C-API https://github.com/riscv-non-isa/riscv-c-api-doc/pull/68

Stakeholders/Partners

RISE:

SiFive: Kito Cheng, Brandon Wu

Dependencies

Status

Development	COMPLETE
Development Timeline	2H2024
Upstreaming	COMPLETE
Upstream Version
Contacts	Kito Cheng (SiFive) Brandon Wu (SiFive)
Dependencies	PSABI and C-API specs

Updates

06 Mar 2025

https://github.com/llvm/llvm-project/pull/100346 was recently merged

12 Feb 2025

Moved to 20251H
Patch nearing completion https://github.com/llvm/llvm-project/pull/100346

12 Jul 2024

Created project

11 Jul 2024

Created project

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CT_01_018 - Fixed length vector calling convention(LLVM)