Re: Value Range Propagation Patch (Version 4)

[Toon Moene <toon at moene dot indiv dot nluug dot nl>]

John Wehle wrote:

> [ In addition to the usual improvements redundant bounds
>   checking is removed from:
> 
>       PARAMETER (N=10)
>       DIMENSION A(N)
>       DO I = 1, N
>          A(I) = I
>          A(I) = A(I) + 3
>       ENDDO
>       PRINT*,A
>       END
> 
>   when compiled on the Alpha.                            ]

Yep - it works !  Thanks a lot !

Did my suggestion about zero-extended variables on Alpha have any merit,
or was it just a complete miss ?

There is a interesting irony about value range propagation:  It tends to
spend most of its time on routines/code that ultimately will take the
least time to execute anyway ;-)
[ Mainly because, as the human programmer knows - they won't take long
  to execute, so why should _he_ spend any time to optimize them ? ]

I just saw it spend 5:26 minutes on a routine that will take care of the
initialisation of some arrays in a split second when executing :-)
[ That 5+ minutes is without array bounds checking ]

How do you get it to focus its efforts on code that really matters ?

Cheers,

-- 
Toon Moene - mailto:toon@moene.indiv.nluug.nl - phoneto: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
GNU Fortran 77: http://gcc.gnu.org/onlinedocs/g77_news.html
GNU Fortran 95: http://g95.sourceforge.net/ (under construction)

PS: Unfortunately, due to the large memory requirements, some of my
    compilations ended with a Segmentation Fault.  I'll retry shortly
    with only one compilation thread instead of four.