Heyu Zhu <zhu.heyu@xxxxxxxxx> writes: > I configure gcc as below > > ../gcc-4.2.4(or gcc-3.4.4)/configure > --target=arm-elf > --prefix=/usr/local/arm > --enable-languages=c > --without-headers > --with-gnu-ld > --with-gnu-as > --disable-shared > --disable-threads > --disable-libssp > > Executable binary file generated by gcc-3.4.4 is 15% faster than by > gcc-4.2.4 for some test programs, for example, Dhrystone. > > Need i configure gcc-4.2.4 with special options to get a good > performace as gcc-3.4.4 does? There are no configure options which will make a difference here. There may be some runtime options which will help. In particular, make sure you use -O2 and use a -march option appropriate for your target. It is of course entirely possible that there has been some optimization regression in gcc. If you can pin down the code which is slower, please open a bug report with a test case as described at http://gcc.gnu.org/bugs/ . Thanks. Ian
