On Wed, Oct 03, 2001 at 04:39:59PM -0400, Todd Vierling wrote:
> On Wed, 3 Oct 2001, Arto Huusko wrote:
> 
> : Is there any reason what would prevent me to tweak my local kernel
> : makefiles and set -march=pentium or -march=pentiumpro. Would it break
> : anything, or is it safe to just do.
> 
> -march=pentiumpro is not safe in current generations of gcc, from
> experience.  It tends to produce very buggy code above -O1.

I don't know about anything newer than 2.91, but with the ECGS that's
in our tree if you don't have USE_NEW_TOOLCHAIN set, a gcc built with
-march=pentiumpro -mcpu=pentiumpro has the really EXCELLENT property
that it cannot build NetBSD kernels; they always seem to either 
triple-fault the machine very early in the boot process or hang just
after printing out the interrupt masks.

-mcpu=pentiumpro -march=pentium seems to be safe, though; as is
-mcpu=pentiumpro -march=pentiumpro in a kernel build *so long as gcc
itself was not built that way*.

-- 
Thor Lancelot Simon	                                      tls@rek.tjls.com
    And now he couldn't remember when this passion had flown, leaving him so
  foolish and bewildered and astray: can any man?
						   William Styron