Re: ADA on the super

[mfb@mbunix.mitre.org (Michael F Brenner)]

    > Yes, Robert I agree, but ... [it] shares the back end of GCC,
    > which isn't famous for its optimization.

Robert >  ... the backend of GCC, actually it is well known for high 
       > code quality and extensive optimization. On a number of machines, 
       > GCC is the most efficient code generator available. ...
       > A number of customers chose gnat ... after extensive benchmarking
       > *because* it was the most effective compiler *for their application*.
           
I would like to confirm what Robert says in the following cases:
   (a) tsgreat, an extensive arithmetic with no I/O, is timed as follows:
       (first run tsgreat 1001 and tsgreat 1, then subtract the two numbers to
       get the time for 1000 iterations):
       
       90 MHz Pentium DOS     Alsys-83 32-bit Compiler:          25 sec 
       90 MHZ Pentium DOS     Meridian-83 32 bit Compiler:       49 sec
       90 MHz Pentium DOS     Janus-83 16 bit Compiler:          39 sec
       90 MHz Pentium DOS     gnat-95 3.10 from GWU:             21 sec
       90 MHz Pentium DOS     Turbo Pascal 7.0 32 bit Compiler:  78 sec

   (b) Lighting up things dot by dot on the SVGA memory mapped screen goes
       about twice as fast in gnat3.10 than in Alsys-83.

   (c) Lighting up things by moving large blocks or whole lines at a 
       time to the SVGA memory mapped screen goes about twice as fast in
       Alsys-83 than in gnat3.10. 

CONCLUSION: Gnat has good optimization. Gnat has good code generation
            except for packed arrays. Robert is right about bench
            marking your application with ALL of your data before 
            deciding what is fast and what is slow. 

Mike Brenner