PGCC-S-0155-Accelerator region ignored around unsigned long

Accelerated Computing HPC Compilers Legacy PGI Compilers
1

Hi,

I have a compilation error on pgc++.
pgc++ says “unsupported operation”.
But, I could not find out which description is unsupported.

more sample.cpp

int main( ) {
        #pragma acc parallel loop
        for(int i=0;i<10;i++){
                bool vv ;
                bool *val=&vv ;
                unsigned long tmp = 0u;
                unsigned long tmp2 = (~tmp) ;
                *val = tmp2 != 0;
        }
}



$ pgc++ -acc -Minfo=accel sample.cpp
PGCC-S-0155-Accelerator region ignored; see -Minfo messages (sample.cpp: 1)
main:
1, Accelerator region ignored
3, Accelerator restriction: an unsupported operation was found
7, Accelerator restriction: unsupported operation: UKNOT
PGCC/x86 Linux 17.4-0: compilation completed with severe errors

If we modify a datatype for tmp and tmp2 to unsigned int, this error doesn’t occur.

more sample2.cpp

int main( ) {
        #pragma acc parallel loop
        for(int i=0;i<10;i++){
                bool vv ;
                bool *val=&vv ;
                unsigned int tmp = 0u;
                unsigned int tmp2 = (~tmp) ;
                *val = tmp2 != 0;
        }
}



$ pgc++ -acc -Minfo=accel sample2.cpp
main:
1, Accelerator kernel generated
Generating Tesla code
3, #pragma acc loop gang, vector(10) /* blockIdx.x threadIdx.x */

So, “unsigned long” seems to be related to this issue.
But, I’m not sure which my description is not suitable for pgc++.

Did I miss my bug on sample.cpp?

Thanks,
Hideki

2

Hi Hideki,

It’s actually not the unsigned long that’s the problem but rather using the bitwise not operator on an unsigned long. I’m not sure if our engineers just missed this case or if there’s a hardware limitation.

Either way, I added a request for enhancement (TPR#24692) to engineering to see if we can add this support.

Thanks,
Mat

3

Hi Mat,

Thank you for adding the request.

Hideki