[Bug tree-optimization/41879] New: [4.5 Regression] 172.mgrid regression, vectorizer prevents predictive commoning

[rguenth at gcc dot gnu dot org]

The fix for PR41783 causes us to vectorize RESID and PSINV where we only
predictive common the epilogue loop now.  This causes mgrid score to drop
by almost 40% on x86_64 and the vectorized code is pretty bad because it
uses unaligned accesses.


-- 
           Summary: [4.5 Regression] 172.mgrid regression, vectorizer
                    prevents predictive commoning
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org
OtherBugsDependingO 41783
             nThis:


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41879