https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121925
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Tamar Christina from comment #0) > Given the following vectors > > a = [A1 A0] > b = [C D ] b = [C B] I suppose? > c = [E D ] [..] > rot0 = [E + A0 * C, D + A0 * B] > rot90 = [E + A1 * B, D - A1 * C] > rot180 = [E - A0 * C, D - A0 * B] > rot270 = [E + A1 * B, D - A1 * C] so that's all c + mul-with-rot (a, b), I guess fmrot0a fmrot90a fmrot180a fmrot270a? That is, do the instructions also avoid the extra rounding for the add?
