On 5/17/21 10:49 AM, Tobias Burnus wrote:
> Early *PING*  - and I fixed a wording issue in my patch.
> 
> OK? Suggestions?
> 

LGTM, thanks.
- Tom

> Tobias
> 
> On 14.05.21 00:06, Tobias Burnus wrote:
>> Document this new flag, added in
>> https://gcc.gnu.org/g:2a1586401a21dcd43e0f904bb6eec26c8b2f366b
>> + https://gcc.gnu.org/onlinedocs/gcc/Nvidia-PTX-Options.html#index-mptx
>>
>> Any wording suggestions?
>>
>> Tobias
>>
>> PS: Some background remarks:
>>
>> (PTX ISA 3.1 is supported since NVidia's CUDA 5 while 6.3 is supported
>> since
>> CUDA 10.0 - and adds very useful new features; current is PTX ISA 7.3
>> (CUDA 11.3),* but on the PTX side, 6.3 adds a lot, >6.3 only few
>> features,
>> we still may want to support sometime in the future.)
>>
>> (The new flag paves the way for additional -misa= flags
>> (i.e. newer hardware, relevant for enabling ptx instructions which only
>> newer GPUs support) and newer GPU-hardware-independent PTX ISA features;
>> hence, either permitting better code generation or for be used to fix
>> bugs.
>> While this will change during GCC 12, currently, the generated code is
>> effectively the same with either -mptx= value.)
>>
>> (Regarding the produced instructions, the installed CUDA will JIT
>> (and then cache) the GCC-generated nvptx in the binary at startup,
>> optimizing for the available hardware - i.e. the chosen -mptx and
>> available -misa do not restrict the hardware ability, just that
>> PTX instructions which is only available in newer PTX / for newer
>> hardware may not be generated.)
>>
>> (* Cf.
>> https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#release-notes__ptx-release-history
>>
>> )
>>
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