I noticed that the amount of RAM used, compared to the code generated by gcc 4.1.1, is increased by 256 bytes and found that this it's due to the __clz_tab array linked in at RAM start.
-- Summary: Too much RAM used: __clz_tab[] linked Product: gcc Version: 4.2.0 Status: UNCONFIRMED Severity: major Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: batt at develer dot com GCC build triplet: 20061014 GCC host triplet: i686-pc-linux-gnu GCC target triplet: avr-*-* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29524