[PATCH] D40023: [RISCV] Implement ABI lowering

[Alex Bradbury via Phabricator via cfe-commits]

asb added a comment.

In https://reviews.llvm.org/D40023#933464, @majnemer wrote:

> So how does something like the following work:
>
>   union U { float f; int i; };
>   void f(union U u);
>   
>
> The flattening described in https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#hardware-floating-point-calling-convention makes sense for arrays and structs but I couldn't find where unions were described.


You're right that's not currently described - I have an issue tracking this here: https://github.com/riscv/riscv-elf-psabi-doc/issues/24. Last time I tried to check gcc behaviour it seemed that such cases would be passed according to the integer calling convention, but I'd be happier if one of the GCC devs would confirm.


https://reviews.llvm.org/D40023