https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97832
--- Comment #25 from rguenther at suse dot de <rguenther at suse dot de> --- On Mon, 28 Nov 2022, crazylht at gmail dot com wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97832 > > --- Comment #24 from Hongtao.liu <crazylht at gmail dot com> --- > _233 = {f_im_36, f_re_35, f_re_35, f_re_35}; > _217 = {f_re_35, f_im_36, f_im_36, f_im_36}; > ... > vect_x_re_55.15_227 = VEC_PERM_EXPR <vect_x_im_61.14_228, vect_x_im_61.13_230, > { 0, 5, 6, 7 }>; > vect_x_re_55.23_211 = VEC_PERM_EXPR <vect_x_im_61.13_230, > vect_x_im_61.14_228, { 0, 5, 6, 7 }>; > ... > vect_y_re_69.17_224 = .FNMA (vect_x_re_55.15_227, _233, vect_y_re_63.9_237); > vect_y_re_69.25_208 = .FNMA (vect_x_re_55.23_211, _217, > vect_y_re_69.17_224); > > is equal to > > _233 = {f_im_36,f_im_36, f_im_36, f_im_36} > _217 = {f_re_35, f_re_35, f_re_35, f_re_35}; > ... > vect_y_re_69.17_224 = .FNMA (vect_x_im_61.14_228, _233, vect_y_re_63.9_237) > vect_y_re_69.25_208 = .FNMA (vect_x_im_61.13_230, _217, vect_y_re_69.17_224) > > A simplication in match.pd? I guess that's possible but the SLP vectorizer has a permute optimization phase (and SLP discovery itself), it would be nice to see why the former doesn't elide the permutes here.
