Re: Possible GCC contamination of Linux

Artur Skawina (
Wed, 22 Sep 1999 18:59:34 +0200

Richard B. Johnson wrote:
> > > The machine does 'Uncompressing Linux', 'Booting...' Screen-flash crash
> > > reboot. There is no way in hell I can find the instruction(s) causing
> > > the problem(s).
> >
> > Could you run 'objdump -d --no-show-raw-insn vmlinux | grep -3 cmov'
> > on the nonbooting kernel? If the problem is indeed abs() you will
> > probably see a few od these (a 486 can't handle conditional moves so
> > if gcc generates them then that is a problem).
> Nope. The instruction is not being used. However, there are a lot
> of coprocessor instructions and if any of these are encountered
> before the emulator handler is in place, I'm in trouble. The '486
> doesn't have a coprocessor.

odd. (i'm assuming your objdump knows about cmovs)
Then it's probably some other builtin that is the problem
(the compiler doesn't emit fpu memcpy etc, i hope)

It still looks to me like a compiler bug; unless this happens with
either gcc2.7 or gcc2.95, it should probably be ignored.

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