[Bug tree-optimization/25371] -ftree-vectorize results in internal compiler error on AMD64

["Jan dot Sjodin at amd dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #8 from Jan dot Sjodin at amd dot com  2007-05-08 21:30 -------
Subject: RE:  -ftree-vectorize results in
 internal compiler error on AMD64

I would prefer to make it work instead of disabling the vectorizer for
these cases.

- Jan

> -----Original Message-----
> From: sebpop@gmail.com [mailto:sebpop@gmail.com] On Behalf Of
Sebastian
> Pop
> Sent: Tuesday, May 08, 2007 3:19 PM
> To: gcc-bugzilla@gcc.gnu.org
> Cc: Sjodin, Jan
> Subject: Re: [Bug tree-optimization/25371] -ftree-vectorize results in
> internal compiler error on AMD64
> 
> On 5/8/07, Sjodin, Jan <Jan.Sjodin@amd.com> wrote:
> > > Okay, I looked at the code, and the problem is that we have to
pass to
> > > force_gimple_operand an expression that is not a chain of
recurrence,
> > > ie. a real expression that can be used to be decomposed in 3 addr
code
> > > by the gimplifier.
> >
> > Thanks! That was the answer I was looking for. Sounds like the
> > vectorizer is biting off more than it can chew :) Perhaps there is a
> > check missing for chrecs somewhere.
> 
> Yes, I also think that the quick fix is to add to the vectorizer the
> missing
> checks for simple enough expressions.
> 
> I went back to look at the testcase, and I saw these nested loops,
> and we are trying to vectorize the innermost ones.  So for avoiding a
> failed vectorization, and making the vectorizer to produce the right
code,
> we want to generate some code for the base address in the outer loop.
> 
> Sebastian
> 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25371