Early *PING* - and I fixed a wording issue in my patch.
OK? Suggestions? 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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diff --git a/htdocs/gcc-12/changes.html b/htdocs/gcc-12/changes.html index 23f71411..53abf9ed 100644 --- a/htdocs/gcc-12/changes.html +++ b/htdocs/gcc-12/changes.html @@ -101,8 +101,13 @@ a work-in-progress.</p> <!-- <h3 id="nios2">Nios II</h3> --> -<!-- <h3 id="nvptx">NVPTX</h3> --> - +<h3 id="nvptx">NVPTX</h3> +<ul> + <li>The <code>-mptx</code> flag has been added to specify the PTX ISA version + for the generated code; permitted values are <code>3.1</code> + (default, matches previous GCC versions) and <code>6.3</code>. + </li> +</ul> <!-- <h3 id="hppa">PA-RISC</h3> --> <!-- <h3 id="powerpc">PowerPC / PowerPC64 / RS6000</h3> -->
