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Re: g77 performance on ALPHA
Richard Henderson wrote:
> On Sat, Aug 28, 1999 at 09:25:21PM +0200, Toon Moene wrote:
> > Huh? Then there must be something pretty wrong with the alpha port -
> > this is the inner loop I get with g77 -O3 -funroll-loops, using
> > gcc-2.95.1 on Linux/Intel:
> ] Loop unrolling: Not basic or general induction var.
> Use -fno-rerun-loop-opt. We're somehow losing iteration
> information that the unroller needs.
[ Assuming this advice is directed at Martin ]
Just to be sure: You've found that on the Alpha -fno-rerun-loop-opt
gets an unrolled loop when specifying -funroll-loops where on the ix86
it doesn't matter ? Strange ....
However, you should realize that rerunning loop optimization is a
cop-out I thought up three years ago when giv-finding and -reducing in
loop.c was far less sophisticated than it is now [due to your own and
Joern's work]. It might simply be counterproductive at these modern
times ...
HTH,
--
Toon Moene (toon@moene.indiv.nluug.nl)
Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
Phone: +31 346 214290; Fax: +31 346 214286
GNU Fortran: http://world.std.com/~burley/g77.html