Greg Schafer wrote: > PS - According to my build logs, GCC-4.2 takes almost *double* the amount > of time of GCC-4.1 for a 3-stage bootstrap. This doesn't matter much on a > modern dual-core system (16m 45s vs 8m 41s) but it's very noticeable on an > older ppc mac mini (91m vs 43m). So maybe there *is* merit in skipping the > bootstrap after all? :-) But seriously, I suspect the reason is some extra > checking is switched on in the stage1 4.2 compiler (I managed to hac^H^H^H > switch it off in the 4.1 series). Will investigate...
Ok, it appears the GCC devs conveniently added a new (undocumented?) configure switch in 4.2 `--disable-stage1-checking' which does the right thing. Times for GCC-4.2.1 bootstraps without and with the switch are below: real 18m54.421s user 32m55.131s sys 1m46.275s real 13m0.254s user 22m24.004s sys 1m47.959s Amount of time saved will obviously increase the slower the hardware. If bootstrap times are a concern then I would recommend LFS use this switch when upgrading to GCC-4.2.x. I'll be adding it to my Refbuild ASAP. Regards Greg -- http://www.diy-linux.org/ -- http://linuxfromscratch.org/mailman/listinfo/lfs-dev FAQ: http://www.linuxfromscratch.org/faq/ Unsubscribe: See the above information page
