Re: [Patch] nvptx: Add -mptx=6.0 + -misa=sm_70

[Tobias Burnus <tobias@codesourcery.com>]

Hi Tom,

On 22.02.22 15:43, Tom de Vries wrote:
> On 2/17/22 18:24, Tobias Burnus wrote:
>> --- a/gcc/config/nvptx/t-omp-device
>> +++ b/gcc/config/nvptx/t-omp-device
>> @@ -1,4 +1,4 @@
>>      echo kind: gpu > $@
>>      echo arch: nvptx >> $@
>> -    echo isa: sm_30 sm_35 >> $@
>> +    echo isa: sm_30 sm_35 sm_53 sm_70 sm_75 sm_80 >> $@
>
> I'm not sure I understand how this is used.  Is this user-visible?  Is
> there a libgomp test-case where we can observe a difference?

That's used for OpenMP context selectors like; that way, one can generate,
e.g. one code used with nvptx and one with gcn as with:

#pragma omp declare variant (on_nvptx) match(construct={target},device={arch(nvptx)})
#pragma omp declare variant (on_gcn) match(construct={target},device={arch(gcn)})
...
   #pragma omp target map(from:v)
   v = on ();
which then either calls 'on' or 'on_nvptx' or 'on_gcn'
(from libgomp/testsuite/libgomp.c/target-42.c)


The following testcases use 'arch(nvptx)':

libgomp/testsuite/libgomp.c-c++-common/on_device_arch.h
libgomp/testsuite/libgomp.c/target-42.c
libgomp/testsuite/libgomp.c/usleep.h
libgomp/testsuite/libgomp.fortran/declare-variant-1.f90

For ISA, there is only one run-time test:

libgomp/testsuite/libgomp.c/declare-variant-1.c

but only for x86-64: match (device={isa("avx512f")})

The sm_35 also appears, but only in the compile-time tests:
gcc/testsuite/{c-c++-common,gfortran.dg}/gomp/declare-variant-{9,10}.*

Tobias

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