The cs elim pass introduces a conditional store, but does not remove the original one. If the former is not removed by DSE, this results in worse code.
original thread: http://gcc.gnu.org/ml/gcc-patches/2009-09/msg01955.html. on machines with no predicated stores, disabling this optimization is generally a win, but only as a workaround. -- Summary: cselim is not dse aware Product: gcc Version: tree-ssa Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: chrbr at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41486
