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Odd performance result with HLVM
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Date: 2009-02-28 (01:07)
From: Jon Harrop <jon@f...>
Subject: Odd performance result with HLVM

I am developing a high-level virtual machine built upon LLVM and written in 
OCaml that uses JIT compilation to execute OCaml-like code at break-neck 

I just stumbled upon a weird performance result: compiling my VM with ocamlc 
and ocamlopt produces very different benchmark results for the performance of 
the generated code (which should be identical). For example, my float-based 
Fibonacci function becomes 70% slower if I use ocamlopt and some other 
float-based functions also see big performance drops.

What is ocamlopt doing that might explain this? I assume it is fiddling with 
the floating point state somehow...

Dr Jon Harrop, Flying Frog Consultancy Ltd.