[Bug tree-optimization/31756] Doesn't optimize the following (obvious) sequence

[spop at gcc dot gnu dot org]

------- Comment #2 from spop at gcc dot gnu dot org  2007-04-29 16:21 -------
Subject: Re:  Doesn't optimize the following (obvious) sequence

> PRE optimized the "offset" and "stride" variables.
> SCEV doesn't know how to create an offset or step out of these optimized
> operations.

I remember another bug report like this one, and the solution was to tweak
PRE not to peel linear sequences.

> We used to at some point, but I believe these are "peeled_chrec's"
> that we removed support for before merge.
>

Yes, I had another solution for transforming back the simple peeled chrecs
to linear ones.

> I think it's time we add back support for these chrec's.  I can't block PRE
> from optimizing these variables easily.
>

agreed, I'll send a patch for this.

Sebastian


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31756