How to use math functions in dcompute?

[Nicholas Wilson]

On Monday, 27 August 2018 at 09:57:18 UTC, Sobaya wrote:
> On Monday, 27 August 2018 at 09:41:34 UTC, 9il wrote:
>> On Monday, 27 August 2018 at 08:25:14 UTC, Sobaya wrote:
>>> I'm using dcompute(https://github.com/libmir/dcompute).
>>>
>>> In the development, I have got to use math functions such as 
>>> sqrt in @compute function.
>>>
>>> But LDC says "can only call functions from other @compute 
>>> modules in @compute code", so can't I call any math functions 
>>> with dcompute?
>>>
>>> Is there any way to use predefined math functions in dcompute?
>>>
>>> Thanks.
>>
>> You may want to try ldc.intrinsics / mir.math.common
>
> Do you mean llvm_sqrt in ldc.intrinsics?
>
> These functions are also not @compute code, so they cause the 
> same error.

Thanks for bringing this to my attention, will fix soon. In the 
meantime you may declare your own intrinsics in a @compute module 
and it should work. as in

@compute module mymath;

pragma(LDC_intrinsic, "llvm.sqrt.f#")
     T llvm_sqrt(T)(T val)
         if (__traits(isFloating, T));


This will work if you are targeting CUDA, SPIRV may not like it 
because the backend is less... mature.