On Core 2, I am using gcc 4.4 revision 139589 as baseline. On 64bit, I compare
O2: -O2 -ffast-math O3: -O3 -ffast-math -funroll-loops On 32bit, I compare O2: -O2 -msse2 -mfpmath=sse -ffast-math O3: -O3 -msse2 -mfpmath=sse -ffast-math -funroll-loops -- Summary: IRA performance impact on SPEC CPU 2K/2006 Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: hjl dot tools at gmail dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37397