https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82449
--- Comment #3 from rguenther at suse dot de <rguenther at suse dot de> --- On Fri, 6 Oct 2017, spop at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82449 > > --- Comment #2 from Sebastian Pop <spop at gcc dot gnu.org> --- > This part is not affine: {0, +, {1, +, 1}_1}_1 > This is a polynomial of degree 2. > Are you sure the scev analysis reports this as affine? Yes: /* Determine whether CHREC is an affine evolution function or not. */ static inline bool evolution_function_is_affine_p (const_tree chrec) { return chrec && TREE_CODE (chrec) == POLYNOMIAL_CHREC && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), CHREC_VARIABLE (chrec)) && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC || evolution_function_is_affine_p (CHREC_RIGHT (chrec))); } this doesn't look at CHREC_LEFT at all (because technically CHREC_LEFT is not part of the evolution of CHREC). > I was trying to understand from the fortran code which part this scev comes > from... > and I think it comes from the NKL counter that gets incremented in the inner > loop, > counting the number of iterations of both loops, so it has a quadratic > evolution. Yes. I guess we should still be able to generate an expression for it somehow...
