There is a huge regression of gcc 4.3 performance detected on cpu2006/454.calculix benchmark at -O2 optimization level on x86_64-redhat-linux.
Regression is caused by mem-ssa merge 12/12/2006 (revision 119760). http://gcc.gnu.org/viewcvs?view=rev&revision=119760 mem-ssa merge may introduce unnecessary memory <-> register moves. -- Summary: 50% slow down due to mem-ssa merge Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: hjl at lucon dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30735
