https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113441
--- Comment #13 from rguenther at suse dot de <rguenther at suse dot de> --- On Tue, 23 Jan 2024, juzhe.zhong at rivai dot ai wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113441 > > --- Comment #12 from JuzheZhong <juzhe.zhong at rivai dot ai> --- > (In reply to Richard Biener from comment #11) > > (In reply to Tamar Christina from comment #9) > > > There is a weird costing going on in the PHI nodes though: > > > > > > m_108 = PHI <m_92(16), m_111(5)> 1 times vector_stmt costs 0 in body > > > m_108 = PHI <m_92(16), m_111(5)> 2 times scalar_to_vec costs 0 in prologue > > > > > > they have collapsed to 0. which can't be right.. > > > > Note this is likely because of the backend going wrong. > > > > bool > > vectorizable_phi (vec_info *, > > stmt_vec_info stmt_info, gimple **vec_stmt, > > slp_tree slp_node, stmt_vector_for_cost *cost_vec) > > { > > .. > > > > /* For single-argument PHIs assume coalescing which means zero cost > > for the scalar and the vector PHIs. This avoids artificially > > favoring the vector path (but may pessimize it in some cases). */ > > if (gimple_phi_num_args (as_a <gphi *> (stmt_info->stmt)) > 1) > > record_stmt_cost (cost_vec, SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node), > > vector_stmt, stmt_info, vectype, 0, vect_body); > > > > You could check if we call this with sane values. > > Do you mean it's RISC-V backend cost model issue ? I responded to Tamar which means a aarch64 cost model issue - the specific issue that the PHIs appear to have no cost. I didn't look at any of the rest.
