[Bug tree-optimization/20165] Pointer does not really escape with write

["rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #7 from rguenther at suse dot de  2009-07-02 15:46 -------
Subject: Re:  Pointer does not really escape
 with write

On Thu, 2 Jul 2009, steven at gcc dot gnu dot org wrote:

> ------- Comment #6 from steven at gcc dot gnu dot org  2009-07-02 15:40 -------
> Dan, you mentioned a "pointer_no_escape" attribute.  What was that about?  I've
> never seen that mentioned before (or a patch to implement it).  Sounds like a
> cool attribute to have (and not just for Fortran, too).

There are several useful things to specify per pointer argument:

 1) whether it escapes
 2) whether pointed-to memory is read
 3) whether pointed-to memory is written to
 4) whether memory reachable from it is read
 5) whether memory reachable form it is written to
 6) whether addresses to pointed-to memory may be returned
 7) whether addresses to reachable memory may be returned

in addition to, of course, if the function reads from / writes to
global memory.

Zdenek hat a patch with some fancy attribute at some point, and
implementation-wise I'd like to have something that shares
representation with IPA-PTA results.

We do have tasks to do both IPA-PTA and the above attribute btw.

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20165