Passing the complex args in the GPR's

Segher Boessenkool segher at kernel.crashing.org
Wed Jun 7 02:42:56 AEST 2023


Hi!

On Tue, Jun 06, 2023 at 08:35:22PM +0530, Umesh Kalappa wrote:
> Hi Adnrew,
> Thank you for the quick response and for PPC64 too ,we do have
> mismatches in ABI b/w complex operations like
> https://godbolt.org/z/bjsYovx4c .
> 
> Any reason why GCC chose to use GPR 's here ?

What did you expect, what happened instead?  Why did you expect that,
and why then is it an error what did happen?

You used -O0.  As long as the code works, all is fine.  But unoptimised
code frequently is hard to read, please use -O2 instead?

As Andrew says, why did you use -m32 for GCC but -m64 for LLVM?  It is
hard to compare those at all!  32-bit PowerPC Linux ABI (based on 32-bit
PowerPC ELF ABI from 1995, BE version) vs. 64-bit ELFv2 ABI from 2015
(LE version).


Segher


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