Date: Thu, 22 May 2003 12:08:17 -0700 From: David Schultz <das@FreeBSD.ORG> To: Anti <fearow@attbi.com> Cc: freebsd-current@FreeBSD.ORG Subject: Re: gcc/libm floating-point bug? Message-ID: <20030522190817.GB2295@HAL9000.homeunix.com> In-Reply-To: <20030522093623.30915ed0.fearow@attbi.com> References: <200305201025.30296.jlido@goof.com> <200305201512.27174.jlido@goof.com> <20030522011014.GC27806@dragon.nuxi.com> <200305221010.59718.jlido@goof.com> <20030522093623.30915ed0.fearow@attbi.com>
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On Thu, May 22, 2003, Anti wrote: > > > > I feel some will screem if we take away the ability to use > > > -march=pentium4 in places they know for sure will work. Unix is about > > > mechanisms, not policy. > > > > Well, we've got a compiler here with a broken mechanism. Deciding whether or > > not to act on it sounds like a policy decision to me. I just hope 5.1 > > doesn't get shipped with such an easy way to break stuff. > > > p4 should expand to "-march=pentium4 -mno-sse2" (could set it to pentium3, but > then people would see pentium3 being used when they specified p4 and think it's > a bug)... > > any educated person with a legit reason to use -march=pentium4 without disabling > sse2 can always add it to CFLAGS instead of setting it in CPUTYPE... > > don't see why anyone wouldn't want to put an end to all the breakage and bug > reports due to this when the fix is so simple and of no real harm... When I last checked, -march=pentium4 was slower than -march=pentium3, and -msse2 was pretty much a wash in terms of performance, even though SSE2 shaved a few bytes off of FP code size. This implies that downgrading to -march=pentium3 is the better option, unless our goal is to dupe people who don't know well enough to read the documentation.
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