On Tue, 4 Jun 2024, Andre Vieira (lists) wrote: > Hi, > > We got a question as to whether GCC had something similar to llvm's pragma > clang loop interleave_count(N), see > https://clang.llvm.org/docs/LanguageExtensions.html#extensions-for-loop-hint-optimizations > > I did a quick hack, using 'GCC interleaves N', just as a proof of concept, to > see whether we could connect this to the suggested_unroll_factor in the > vectorizer and to test the waters regarding having something like this > upstream. > > For the real thing I'd suggest we use the same pragma syntax as clang's so its > easier to port code. It is my understanding that the main use for this is for > doing performance tuning of HPC kernels and performance tuning of CPU's cost > models. > > This seems to work (TM), though with the move to slp-only I guess this will > stop working? Though I suspect we will want to have similar capabilities in > SLP, or maybe we have already and I didn't look hard enough.
suggested-unroll-factor also works with SLP, at least I don't see a reason why it should not. > Also only implemented it for C and C++, have not looked at Fortran. > > WDYT? > > Kind regards, > Andre
