Date: Wed, 15 Mar 2000 23:01:22 -0500 From: Donn Miller <dmmiller@cvzoom.net> To: "Jeffrey J. Mountin" <jeff@mountin.net> Cc: current@FreeBSD.ORG Subject: Re: panic during make depend Message-ID: <38D05C92.4F85C798@cvzoom.net> References: <4.3.2.20000315172056.00bf7740@mixcom.com>
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"Jeffrey J. Mountin" wrote: > Successfully did a buildworld with -O -pipe -march=pentiumpro, installworld > was good, remade /dev and built a generic kernel. Config'd my local kernel > and within the first few lines of 'make depend' it bombed: Sounds like one of those nasty gcc optimization bugs. I generally build my kernel and world with -mpentium -O3 -pipe, and I haven't seen any bugs at all. I build everything with these flags without problems. The only problems I've see, as mentioned previously, was in building Qt. I've gotten an "Internal compiler error" with those flags, but reverting to what Troll put in qt/configs solved the problems. Apparently, there's both compile-time and run-time bugs with gcc's opt. code. I think there are some bugs with the pentium-specific flags in gcc, excluding the generic-pentium flag of -mpentium. I would try using -mpentium -O3 -pipe --- I'm pretty confident that will solve your problems, and you can still get generic pentium optimization levels. Of course, I don't really know if there's anything to be gained by using these flags over the stock -O -pipe -- but I do it anyways for the psychological reassurance (placebo effect). I definitely think building XFree86 with pentium opt. is a great idea. But with buildworld and buildkernel, my advice would be to just use -mpentium, as it's probably the "happiest medium" between pentium opt. and stability. From what I've heard, compiling mission critical stuff with -mpentiumpro is a bad idea. Hmmm... didn't -mpentiumpro come from pgcc? I think the best place to use -mpentiumpro is in compiling multimedia type stuff, where stability isn't important but speed is. Basically, gcc is a very good compiler. But, it isn't exactly the best compiler to use for optimization. Someone told me that Sun's and DEC's compilers, for example, blow away gcc in terms of speed. But, they aren't portable. - Donn To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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