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Re: loop hoisting fails

From: "Paulo J. Matos" <pocmatos at gmail dot com>
To: gcc at gcc dot gnu dot org
Date: Thu, 10 Feb 2011 10:59:32 +0000
Subject: Re: loop hoisting fails
References: <iiu0pq$ioe$1@dough.gmane.org> <mcrd3n1p7pi.fsf@google.com> <iiubpk$ie4$1@dough.gmane.org> <mcrzkq5nqtl.fsf@google.com>

On 09/02/11 15:57, Ian Lance Taylor wrote:

For your processor it sounds like you should make a constant more
expensive than a register for an outer code of SET.  You're right that
the cost should really depend on the destination of the set but
unfortunately I don't know if you will see that.

I agree that costs are unfortunately not very well documented and the
middle-end does not use them in the most effective manner.  It's still
normally the right mechanism to use to control what combine does.


Thanks for the help.
Is there any bug open or anyone working to improve handling of costs?

References:
- loop hoisting fails
  - From: Paulo J. Matos
- Re: loop hoisting fails
  - From: Ian Lance Taylor
- Re: loop hoisting fails
  - From: Paulo J. Matos
- Re: loop hoisting fails
  - From: Ian Lance Taylor

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