On Tue, Nov 11, 2003 at 09:24:35PM +1100, Hamish Moffatt wrote: > On Mon, Nov 10, 2003 at 05:08:48PM -0600, Joe Wreschnig wrote: > > Of course, I'm far from a compiler and chip design expert (or even > > novice); this is what I remember from my classes last year. :) But it > > shows how complicated optimizing compilers can get, and why you can't > > say any optimization is always good/safe/faster/etc. The only truly safe > > way to tell is extensive, controlled benchmarking. > > An optimisation that makes things unsafe or slower isn't an > optimisation. The compiler shouldn't produce any code that is incorrect > or slower. Of course, it can't stop you from taking a P4-optimised > binary and running it on an Athlon. > > I think you could say that any optimisation is safe and not slower; > otherwise it's not an optimisation. Mmm. -ffast-math and -funsafe-math-optimizations, off the top of my head. -- .''`. ** Debian GNU/Linux ** | Andrew Suffield : :' : http://www.debian.org/ | `. `' | `- -><- |
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