> I have no idea. Is the Gimple basic block of S_3 never set, or is it set and > deleted on the way?
I think, that it is deleted on the way. I've found out, that the Gimple basic block will be set, if we add the following code to the generate_isl_schedule: bb_schedule = isl_map_set_tuple_id (bb_schedule, isl_dim_in, isl_id_for_pbb (scop, pbb)); where isl_id_for_pbb is static isl_id * isl_id_for_pbb (scop_p s, poly_bb_p pbb) { char name[50]; snprintf (name, sizeof (name), "S_%d", pbb_index (pbb)); return isl_id_alloc (s->ctx, name, pbb); } > What code does S_3 correspond to? If I'm not mistaken, it is corresponds to: res_18 = Cross_BB_scalar_dependence.7[0]; phi_out_of_ssa.4[0] = res_18; I used the following code from https://gcc.gnu.org/onlinedocs/gccint/Basic-Blocks.html to dump basic block of the Gimple basic block: gimple_stmt_iterator si; for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) { gimple phi = gsi_stmt (si); print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); } for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) { gimple stmt = gsi_stmt (si); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } Could you please advise me possible functions from graphite-sese-to-poly.c, which can delete this? P.S.: Only S_3 has this problem in the example. -- Cheers, Roman Gareev.