Re: Similar systems, different performance of fortran code

[Victor Munoz <vmunoz@macul.ciencias.uchile.cl>]

On Sat, Apr 23, 2005 at 10:58:56AM -0400, Johan Kullstam wrote:
> Why are you not using optimization?  It is possible that g77-3.3
> generates very inefficient code without optimization.  A plausible
> (but could be highly wrong) explaination is that different compiler
> versions generate different basic code representations.  The 3.3
> representation may be highly inefficient in and of itself, but also be
> amenable to its optimization routines.

Sure, but I was only doing a simple test to see if the code compiled and
gave the expected results when run in both machines. The code isn't mine, so
I had to check. And this strange behavior came out. And although it's not a
problem of life and death (after all I can optimize as you say, or use
g77-3.4), I'd like to know what kind of code-compiler interaction is
producing this. It could help in the future.

Regards,
					Victor