[RFC] Exposing complex numbers to target backends

[Toon Moene]

On 7/5/23 17:12, Sylvain Noiry via Gcc wrote:

> Hi,
> 
> My name is Sylvain, I am an intern at Kalray and I work on improving the GCC backend for the KVX target.  The KVX ISA has dedicated instructions for the handling of complex numbers, which cannot be selected by GCC due to how complex numbers are handled internally.  My goal is to make GCC able to expose to machine description files new patterns dealing with complex numbers.  I already have a proof of concept which can increase performance even on other backends like x86 if the new patterns are implemented.

I do not have the expertise to evaluate if your approach is the way we 
want to go forward with the handling of complex numbers in the 
middle-/back-end(s) of GCC.

However, I *do* have a sizable amount of (Fortran) code over here that 
uses complex numbers in a day to day operation that I am willing to test 
(obviously, "day to day operation" is to be interpreted loosely here - 
what I do is following the *real* operation at my employer (KNMI) with 
my own weather forecasting computations at home, compiled with GCC).

I suppose that your patch is against the master branch of GCC's 
repository - so I'll have to test that first, cleanly.

Kind regards,

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands