On OSX -fomit-frame-pointer is turned off if you use -O2, or other levels. In fact, if you turn it on, the compiled ruby crashes. OSX has an addition to gcc - a "-fast" option that turns on the following flags: -O3 -fomit-frame-pointer -fstrict-aliasing -momit-leaf-frame-pointer -fno-tree-pre -falign-loops But as both -fomit-frame-pointer and -momit-leaf-frame-pointer cause the compiled ruby to crash, I have been using these options to compile ruby with MBARI7: -O3 -fstrict-aliasing -fno-tree-pre -falign-loops Also with these options I have not had any problems setting STACK_WIPE_SITES to 0x4370 -Stephen On Tue, Jan 13, 2009 at 12:49 AM, Hongli Lai <hongli / plan99.net> wrote: > Brent Roman wrote: >> >> That's not the way the gcc behaves in my experience with the 32-bit x86 >> machines.