[LLVMdev] [llvm-announce] llvm and simplescalar

David Greene dag at cray.com
Tue Jun 17 07:26:37 PDT 2008

On Monday 16 June 2008 20:19, 左琦 wrote:
> Thank you for your answers and suggestions!
> Well, I want to do some experiments about the compiler optimization in llvm
> under SPM and I need performance evaluation. As I know, alpha is a
> general-purpose CPU, so I consider that arm may be an alternative.
> Simplesim-arm is able to do performance simulation while m5-arm is still
> under development. Then, what should I do? Do the experiment under m5-alpha
> or use simplesim-arm? And if I choose to use m5-alpha, can I use llvm as
> the compiler for this simulator?

LLVM has an Alpha target but I don't know how well it's maintained.

SimpleScalar is simply not a good performance simulator.  It does not model
the complex interactions that happen in today's processors.  It's memory model
is particularly bad.

I'm not familiar with SimpleScalar's ARM model.  As that's a relatively simple
CPU, it may be adequate depending on what you want to do.  But I do not trust
any studies, papers, etc. that are published with SimpleScalar results and I
take studies published using ANY simulator with a very large grain of salt.


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