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Re: -fmove-all-movables and -freduce-all-givs
- From: Joern Rennecke <joern dot rennecke at superh dot com>
- To: mstephen at MIT dot EDU (Mark Stephenson)
- Cc: gcc at gcc dot gnu dot org, fortran at gnu dot org
- Date: Mon, 26 Apr 2004 22:41:19 +0100 (BST)
- Subject: Re: -fmove-all-movables and -freduce-all-givs
> I'm currently researching how machine learning algorithms can be
> employed to discover effective compiler heuristics. I see from your
> online documentation that -fmove-all-movables and -freduce-all-givs can
> sometimes generate slower code.
>
> These optimizations seem like prime candidates for machine learning
> because the tradeoffs are not clear (in my mind it seems like the
> optimizations should always yield speedups).
Only if your processor has an infinite number of registers what can
be addressed with equal cost.