Passing the complex args in the GPR's

[Andrew Pinski]

On Tue, Jun 6, 2023 at 7:50 AM Umesh Kalappa via Libc-alpha
<libc-alpha at sourceware.org> wrote:
>
> Hi all ,
>
> For the test case https://godbolt.org/z/vjs1vfs5W ,we see the mismatch
> in the ABI b/w gcc and clang .
>
> Do we have any supporting documents that second the GCC behaviour over CLANG ?
>
> EABI states like
>
> In the Power Architecture 64-Bit ELF V2 ABI Specification document
> (v1.1 from 16 July 2015)

You are looking at the wrong ABI document.
That is for the 64bit ABI.
The 32bit ABI document is located at:
http://refspecs.linux-foundation.org/elf/elfspec_ppc.pdf

Plus the 32bit ABI document does not document Complex argument passing
as it was written in 1995 and never updated.

https://www.nxp.com/docs/en/reference-manual/E500ABIUG.pdf does not
document it either.

Thanks,
Andrew Pinski

>
> Page 53:
>
> Map complex floating-point and complex integer types as if the
> argument was specified as separate real
> and imaginary parts.
>
> and in this case the double complexes are broken down with double real
> and double img and expected to pass in FPR not the GPR.
>
>
>
> Thank you
> ~Umesh