Author: Jeremiah Penery
Date: 12:22:45 10/01/02
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On October 01, 2002 at 09:21:35, Vincent Diepeveen wrote: >On September 30, 2002 at 00:09:28, Jeremiah Penery wrote: > >>On September 29, 2002 at 23:31:36, Robert Hyatt wrote: >> >>>I don't know what this means. I have several dozen programs (Crafty >>>is only one) that we have run using intel's compiler and gcc, and in >>>_every_ case, Intel's compiler is faster. On P2's, on P3's and on >>>P4's... Of course I wouldn't use intel's compiler for an AMD chip, >>>why would they want to optimize for a competitor's chip??? >> >>They don't have to optimize specifically for the competitor's chip, as Intel >>compiler still produces probably the fastest binaries for AMD machines. Any >>general optimizations (P2, P3, and even P4 optimizations (excluding SSE2 stuff >>or whatever)) are just as helpful for AMD processors as they are for Intel ones. > >Oh well very old intel c++ compilers i already found out i couldn't >use P4 optimizations. I never would *assume* in fact that P4 optimizations >are downwards compatible. > >So i never went further than P3 optimizations for all other hardware than >P4. > >And it's definitely *not* the case that optimizations that work for P3 >also are fast for AMD. A good example is doing 2 vector instructions >after each other at the AMD, which is very bad for it. There are of course >thousands of other combinations which hurt AMD more than P3 or P2. And there are thousands of combinations that probably help AMD more than P3/P2, but they still help P3/P2(P4), so the Intel compiler may be doing them. >I hope you realize a chip is a very complex thing. It's millions of >transistors, so there is plenty of combinations to execute instructions >which are getting some kind of penalty on cpu A and not on cpu I. >In short there is plenty of room to make your own cpu look better >than a competing cpu. So please tell me why Intel compiler is still the fastest one for AMD processors. :)
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