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[Benchmark] NBody
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Date: 2005-02-26 (16:09)
From: John Carr <jfc@M...>
Subject: Re: [Caml-list] NBody (one more question)

> > Optimizations in gcc -O1 compared to gcc -O0 include register
> > allocation, dead code elimination, branch straightening, common
> > subexpression elimination, instruction combining, and instruction
> > scheduling.
> Ok, but do you know which one(s) account for the speedup observed in
> this particular case?

There is no way to be sure without careful analysis of generated
code and possibly the state of gcc's internal representation at
intermediate steps.  Most of the optimizations at -O1 can not be
turned on or off independently of the general optimization level.