On 6/23/20 6:44 PM, Thomas Schwinge wrote:
> Per the PTX 3.1 manual that I looked into, I see for CAS it supports:
> '.b32', '.b64'. We've got:
>
> $ build-gcc-offload-nvptx-none/gcc/xgcc
> -Bbuild-gcc-offload-nvptx-none/gcc -dM -E -x c /dev/null | grep -i
> compare.and.swap
> #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
> #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
>
> ..., so that would match the PTX 3.1 manual. GCC also seems to know
> about 16-byte ("'.b128'", which doesn't exist in PTX). A quick run of
> your testcase with 'GENERATE_TEST(__int128)' seems to just work, but I
> haven't verified why/how.
In this case, we hit the critical section strategy and use
expand_omp_atomic_mutex.
Thanks,
- Tom
