On 27/09/2019 20:23, GT wrote: > I am attempting to create a vector version of sincos for PPC64. > The relevant discussion thread is on the GLIBC libc-alpha mailing list. > Navigate it beginning at > https://sourceware.org/ml/libc-alpha/2019-09/msg00334.html > > The intention is to reuse as much as possible from the existing GCC > implementation of other libmvec functions. > My questions are: Which function(s) in GCC; > > 1. Gather scalar function input arguments, from multiple loop iterations, > into a single vector input argument for the vector function version? > 2. Distribute scalar function outputs, to appropriate loop iteration result, > from the single vector function output result? > > I am referring especially to vectorization of sin and cos.
i wonder if gcc can auto-vectorize scalar sincos calls, the vectorizer seems to want the calls to have no side-effect, but attribute pure or const is not appropriate for sincos (which has no return value but takes writable pointer args) "#pragma omp simd" on a loop seems to work but i could not get unannotated sincos loops to vectorize. it seems it would be nice if we could add pure/const somehow (maybe to the simd variant only? afaik openmp requires no sideeffects for simd variants, but that's probably only for explicitly marked loops?)
