Date: Sat, 3 Jul 2004 20:21:39 -0700 From: David Schultz <das@FreeBSD.ORG> To: Dag-Erling Smorgrav <des@FreeBSD.ORG> Cc: cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/share/examples/etc make.conf Message-ID: <20040704032139.GA93138@VARK.homeunix.com> In-Reply-To: <200407030941.i639fwt8078389@repoman.freebsd.org> References: <200407030941.i639fwt8078389@repoman.freebsd.org>
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On Sat, Jul 03, 2004, Dag-Erling Smorgrav wrote: > des 2004-07-03 09:41:58 UTC > > FreeBSD src repository > > Modified files: > share/examples/etc make.conf > Log: > The -O2 bugs are in libalias(3), not ppp(8). FWIW, I've been compiling most things with -O2 for a while (to find -O2 bugs, not for speed) and haven't noticed many problems. The only significant one I know of is that -O2 breaks floating-point exceptions in libm because gcc doesn't support the FENV_ACCESS pragma. I think for some routines like rint(3), it may even give the wrong answer due to incorrect optimizations, but I'd have to check that again. AFAIK, the necessary functionality to make gcc's optimizer treat floating-point code in a sane manner isn't on the horizon, so maybe -O2 should be automatically turned off while compiling libm (and perhaps libalias as well). That would make it more easily justifiable to make -O2 the default at some future point.
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