Re: How to access structure information from "pass_vectorize"

[Swati Rathi <swatirathi at cse dot iitb dot ac dot in>]

On Monday 20 January 2014 02:20 PM, Richard Biener wrote:
> On Sun, Jan 19, 2014 at 6:01 PM, Swati Rathi <swatirathi@cse.iitb.ac.in> wrote:
> > We are writing a GIMPLE pass and would like to use some information computed
> > in
> > pass_vectorize. However, we are not able to use the data structures which
> > gets populated in pass_vectorize
> > because the information is not made available across passes.
> >
> > In particular, we wish to access the structures "stmt_vec_info" and
> > "data_reference".
> >
> > How do we access this information? Should we invoke pass_vectorize as a
> > sub-pass of our pass? Should
> > we explicitly call the execute function of pass_vectorize in our pass? Or
> > should we modify pass_vectorize
> > code and make a deep copy in a global variable? Is there any other way of
> > getting this information?
> It really depends on what kind of information you want to access.  You can
> re-compute things in your pass, or you can make your pass part of the
> vectorizer (thus, modify the vectorizer pass).  In particular data_reference
> is just what the data-reference analysis usable from any pass (tree-data-ref.h)
> produces.
>
> But without more information on what information exactly you want to access
> (and where - where is your pass placed compared to the vectorizer?) it is
> hard to suggest anything.
>
> Richard.

We wish to access the chain of recurrence (chrecs) which is being 
populated in the below structure.

struct indices
{
  /* The object.  */
  tree base_object;

  /* A list of chrecs.  Access functions of the indices.  */
  VEC(tree,heap) *access_fns;

  /* Whether BASE_OBJECT is an access representing the whole object
     or whether the access could not be constrained.  */
  bool unconstrained_base;
};


Our pass is placed after "pass_ipa_pta".
However, we even tried placing the pass after pass_vectorize to access 
this information.

Can we use the chain of recurrence computed by the pass_vectorize or do 
we have to recompute it?
Is there any other pass which is also computing this information and can 
we access it?