Hi, I would like to mention a couple unfixed optimizer bugs: 1) -O and higher keeps volatiles in registers: http://gcc.gnu.org/ml/gcc-bugs/2000-08/msg00038.html 2) A strength-reduction bug (-O -fstrength-reduce, or -O2 and higher): http://gcc.gnu.org/ml/gcc-bugs/2000-08/msg00303.html Tom Truscott