Basic block re-ordering appears to be unconditionally disabled when optimizing for size, irrespective of whether -freorder-blocks was specified on command line. This is applicable to all versions 4.4.1 - 4.5.
As suggested in the following discussion this is incorrect behaviour http://gcc.gnu.org/ml/gcc/2010-03/msg00365.html -- Summary: Basic block re-ordering unconditionally disabled for Os Product: gcc Version: 4.4.1 Status: UNCONFIRMED Severity: enhancement Priority: P3 Component: rtl-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rahul at icerasemi dot com GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43515
