EGCS performance ?

["Sergio Ruocco" <ruoccos at comm2000 dot it>]

 RL> to anything else.  This is meant only to be a relative performance
 RL> indicator.  Arguments about dhrystone being obsolete or a piece of crap
 RL> are beyond the scope of the immediate discussion. ;-)
 
Ok, I agree that Dhry. is a quasi-meaningless test, and as far as the
topic of my posting is concerned, performance is only a component of
the overall quality of compiler, however...
 
 RL> # GCC = egcs 1.1b                              781860.8
 RL> # This is EGCS as of this morning.             829875.5
 RL> # This is the SVR5 compiler from SCO.         1086956.5
 RL> # This is Intel's Optimizing Compiler 2.1.4.  1582278.5
 RL> # Same compiler without the i/p analysis.     1088139.2

...I was surprised to see a large performance gulf (?) in such a
simple test among EGCS and other "proprietary" compilers, and I'm
wondering what is causing these gaps:

- better intermediate optimizations (see the 50% improvement due
  only to i/p analysis)
...
- dedicated x86 schedulers
- embedded-auto-recognition of Drystone benchmark code... :-)

If someone could test with a better benchmark EGCS vs. other
compilers on different (RISC) architectures we could determine this
performance gap still exists, and how much is due to x86 scheduling
arcana (if they come on par) vs to machine-independent optimizations
(if the 30-200% performance gulf stays).

	Sergio Ruocco - ruoccos@comm2000.it