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Re: EGCS performance ?
- To: ruoccos at comm2000 dot it (Sergio Ruocco)
- Subject: Re: EGCS performance ?
- From: Joe Buck <jbuck at synopsys dot com>
- Date: Fri, 30 Oct 98 15:20:23 PST
- Cc: egcs at cygnus dot com
> 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:
Some compiler vendors work very hard at optimizations specific for
Dhrystone, which isn't hard to do -- this is one reason why it's
such a misleading benchmark. The gcc team, in the past, was opposed
to this kind of cheating so I believe that some patches designed to
specifically improve Dhrystone have been rejected.
> - embedded-auto-recognition of Drystone benchmark code... :-)
Well, the cheating isn't quite *that* blatant. It's more that the
vendors choose transformations that will help their Dhrystone score
even if it doesn't help any other programs.