[PATCH][RFC]Overloading intrinsics

[Martin Liška]

On 10/31/18 8:58 PM, Toon Moene wrote:
> On 10/30/2018 04:40 PM, Martin Liška wrote:
> 
> Did anyone ever helped you with this error message ? I haven't seen a reply to the list to that effect ...

Hello.

No, you're the first one who replied. Thanks for it.

> 
>> Now I've tried to separate real module and it's usage and I see strange error:
>>
>> $ cat ~/Programming/testcases/module.f90
>> module vector_math
>> Â Â  interface
>> Â Â Â Â  function sin(arg)
>> Â Â Â Â Â Â  !GCC$ attributes simd_notinbranch :: sin
>> Â Â Â Â Â Â  real, intent(in) :: arg
>> Â Â Â Â Â Â  real :: sin
>> Â Â Â Â  end function sin
>> Â Â  end interface
>> end module
>>
>> $ ./xgcc -B. -Ofast -c ~/Programming/testcases/module.f90
>>
>> $ cat ~/Programming/testcases/use.f90
>> program test_overloaded_intrinsic
>> Â Â  use vector_math
>> Â Â  real(4) :: x(3200), y(3200), z(3200)
>>
>> Â Â  ! this should be using simd clone
>> Â Â  y = sin(x)
>> Â Â  print *, y
>>
>> Â Â  ! this not
>> Â Â  z = cos(x)
>> Â Â  print *, z
>>
>> Â Â  z = sin (z)
>> Â Â  print *, z
>> end
>>
>> $ ./xgcc -B. -Ofast -c ~/Programming/testcases/use.f90
>> /home/marxin/Programming/testcases/use.f90:6:10:
>>
>> Â Â Â Â  6 |Â Â  y = sin(x)
>> Â Â Â Â Â Â  |Â Â Â Â Â Â Â Â Â  1
>> Error: Rank mismatch in argument ‘arg’ at (1) (scalar and rank-1)
>> /home/marxin/Programming/testcases/use.f90:13:11:
>>
>> Â Â Â  13 |Â Â  z = sin (z)
>> Â Â Â Â Â Â  |Â Â Â Â Â Â Â Â Â Â  1
>> Error: Rank mismatch in argument ‘arg’ at (1) (scalar and rank-1)
> 
> What is happening here is that you define an EXTERNAL function "sin" which, according to your declaration [ I left out the GCC attribute ]:
> 
>>Â Â Â Â Â  function sin(arg)
>>Â Â Â Â Â Â Â  real, intent(in) :: arg
>>Â Â Â Â Â Â Â  real :: sin
> 
> is a real function of a scalar argument returning a scalar result.
> 
> However, in using it, you pass it 32000 element arrays of reals (you don't need, and should omit, the (4) on the real declaration).
> 
> This works for the INTRINSIC functions "sin", "cos", etc., because the Fortran language declares them to be ELEMENTAL.

I see!

> 
> This means that, while you can pass them a scalar argument and get a scalar result, you can also pass them a rank-N array and get a rank-N array result OF THE SAME SHAPE.
> 
> I wonder if it works to change the declaration to:
> 
>>Â Â Â Â Â  elemental real function sin(arg)
>>Â Â Â Â Â Â Â  real, intent(in) :: arg
>>Â Â Â Â Â Â Â  real :: sin
> 
> which declares a user-defined, EXTERNAL, ELEMENTAL function called "sin".

I can confirm that adding ELEMENTAL removes the compilation error.

Now I slightly adjusted the 0001-Support-simd-attribute-propagation-for-a-vector_math.patch patch:
- I do not math match module by name
- I mark simd flag in mio_symbol, which is the place where a module symbol is created.

Now I'm able to add 'use vector_math' directive to my test:

module vector_math
  interface
    elemental function sin(arg)
      !GCC$ attributes simd_notinbranch :: sin
      real, intent(in) :: arg
      real :: sin
    end function sin
  end interface
end module

program test_overloaded_intrinsic
  use vector_math
  real :: x(3200), y(3200), z(3200)

  ! this should be using simd clone
  y = sin(x)
  print *, y

  ! this not
  z = cos(x)
  print *, z

  z = sin (z)
  print *, z
end

However, now I need significant hacking in resolve.c in order to persuade Fortran FE
that my "sin" function (being external module function)
can really be seen as intrinsic (please see 0002-* patch).
Any ideas how to make the resolution working without hacking?

Thank you,
Martin

> 
> Hope this helps,
> 

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