https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115602
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rsandifo at gcc dot gnu.org Keywords| |missed-optimization --- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> --- Ah, interesting - somehow we managed to create a self-referencing cycle!? t.c:13:6: note: node 0x4ab34e0 (max_nunits=1, refcnt=3) vector(2) double t.c:13:6: note: op: VEC_PERM_EXPR t.c:13:6: note: stmt 0 _11 = gvevent_motion_job.zoom; t.c:13:6: note: stmt 1 _11 = gvevent_motion_job.zoom; t.c:13:6: note: lane permutation { 0[1] 0[0] } t.c:13:6: note: children 0x4ab34e0 that's because this permute is the same as the load that was originally feeding it: t.c:13:6: note: node 0x4ab3690 (max_nunits=2, refcnt=1) vector(2) double t.c:13:6: note: op template: _11 = gvevent_motion_job.zoom; t.c:13:6: note: stmt 0 _11 = gvevent_motion_job.zoom; t.c:13:6: note: stmt 1 _11 = gvevent_motion_job.zoom; t.c:13:6: note: load permutation { 2 2 } that's a missed optimization caused by the SLP optimize pass which inserts this permute as compensation. Richard - can you look where to best see that uniform nodes (through a uniform load permute) do not require a permute? I'll see to somehow make CSE robust against this.