[Bug tree-optimization/37698] New: [alias-improvements-branch] pre makes latech-block non-empty

["dorit at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

This happens in testcase gcc.dg/vect/vect-62.c:

looks like on the alias branch pre is more powerful, as it moves the load into
the latch block; as a result the latch block is not empty, and we fail to
vectorize (with -fno-tree-pre vectorization succeeds).

Related non-empty-latch PRs that prevernt vectorization: PR28643, PR33447


-- 
           Summary: [alias-improvements-branch] pre makes latech-block non-
                    empty
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dorit at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37698