------- Comment #9 from anirkko at insel dot ch 2007-04-23 11:35 ------- (In reply to comment #8) > > The bootstrap works fine with all flags equal to '-O2' > > Great, thanks for the confirmation. > > > Still worrysome, because somewhere in the installation instructions, it is > > recommended to bootstrap the compiler with the flags one intends to later > > use it with. > > Please point me to this and I'll immediately propose to delete it. 99% of > the testing of the compiler is done with the default bootstrap settings. > > > Does it mean the offending flag is broken and should never be used at all? > > -mcpu=supersparc is totally untested these days so bugs can be expected, yes. >
> Please point me to this... It is in the main directory, file FAQ, section "Optimizing the compiler itself": If you want to test a particular optimization option, it's useful to try bootstrapping the compiler with that option turned on. But please don't let this be removed, because 1) I find the suggestion useful, and it seems to somewhat parallel the reason why you want the compiler bootstrap itself through all stages in the first place: to make sure it can compile itself. Likewise, if it can compile itself reproducibly through the bootstrap using different options, you have made sure these options are pretty well tested for real code by the time you have the compiler finished 2) You closed this bug on the premises that -mcpu=supersparc is the culprit. Well, it isn't: I now bootstrapped with '-O2 -mcpu=supersparc' and everything went fine! Therefore, I still think there is a bug in -O3. (alternatively, in the combination of the two). Would you consider reopening this bug if it was -O3? (In this case, I might re-run the bootstrap with only '-O3', next weekend). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31523
