https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117738
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Last reconfirmed| |2024-11-25 Status|UNCONFIRMED |NEW --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- One of the implementation reasons is that we do not support niter peeling for the outer loop at this point. The other reason is that sum[j] in the inner loop conflicts with different iterations in the outer loop - we do not currently handle this situation specially. Then there's the issue that with constant outer bound we apply unroll-and-jam and that confuses us with a duplicate store to sum[j]. So the biggest roadblock is to incrementally relax the restrictions on grouped accesses for outer loop vect in vect_analyze_data_ref_access. IIRC the actual issues are subtle.