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.

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