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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.mira.net.au!vic.news.telstra.net!act.news.telstra.net!nsw.news.telstra.net!asstdc.scgt.oz.au!walkabout!imb From: imb@walkabout.asstdc.com.au (michael butler) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: gcc optimizations for kernel Date: 15 Sep 1996 14:54:51 GMT Organization: Assorted C Software Lines: 14 Message-ID: <51h5br$sop@asstdc.scgt.oz.au> References: <51d0eg$9uf@usenet4.interramp.com> <323A693E.7B4C@OntheNet.com.au> Reply-To: imb@asstdc.com.au NNTP-Posting-Host: walkabout.asstdc.com.au X-Newsreader: TIN [version 1.2 PL2] Tony Griffiths (tonyg@OntheNet.com.au) wrote: : The higher levels of optimisation are "probably" OK for non-device : driver code, but would almost certainly bring you undone in a driver. : Re-arranging the order of 'bashing' device registers is generally not a : good thing. Local testing shows that "-O2 -m486 -pipe" are relatively safe where "-O3" introduces other problems .. like the removal of apparently unreferenced static structures which are used by the linker and not obvious to the compiler (it optimises them away). However, YMMV .. michael