Messages in this thread |  | | From | Allan Sandfeld <> | Subject | Re: kernel compiler | Date | Fri, 26 Oct 2001 11:18:46 +0200 |
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On Friday 26 October 2001 00:13, J . A . Magallon wrote: > On 20011025 Lost Logic wrote: > >GCC 3.0 Produces slower code, eh? I was of the understanding that it > >contained many more optimizations than previous versions...??? > > > >Any way, I've been able to run my system based entirely on a fairly > >recent GCC CVS-3.02 snapshot, including kernels, and everything EXCEPT > >for glibc which is specifically incompatible according to the GNU folks. > > > >By way of information however, neither of the GCC 3.0 releases (3.0.0 or > >3.0.1) work at all on my system, and I cannot get a kernel to function > >at better than -O2 (not that I could get that to work in 2.95.* or > >2.96.* either). > > -O3 activates -finline-functions: > `-finline-functions' > Integrate all simple functions into their callers. The compiler > heuristically decides which functions are simple enough to be worth > integrating in this way. > > If all calls to a given function are integrated, and the function > is declared `static', then the function is normally not output as > assembler code in its own right. > > Last paragraph is the key. Perhaps previous gcc'd did not all his work > as the manual says (ie, did not kill the non-inline version, bug), > but people has got used to the bug, and see it as a feature.
I believe '-fkeep-inline-functions' is your friend in this case. I haven't tested it though on the kernel.
regards `Allan
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