[Bug tree-optimization/24694] Address taken and addressable variables and call clobber

[pinskia at gcc dot gnu dot org]

--- Comment #5 from pinskia at gcc dot gnu dot org  2009-04-22 23:09 ---
This problem is harder than what is mentioned, I am going to close this as
won't fix.


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pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution||WONTFIX


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24694

[Bug tree-optimization/24694] Address taken and addressable variables and call clobber

[pinskia at gcc dot gnu dot org]

--- Comment #4 from pinskia at gcc dot gnu dot org  2005-12-30 18:28 ---
And there is a fixme in the source for this problem:
  /* FIXME: LHS is not an SSA_NAME.  Even if it's an assignment to a
 local variables we cannot be sure if it will escape, because we
 don't have information about objects not in SSA form.  Need to
 implement something along the lines of

 J.-D. Choi, M. Gupta, M. J. Serrano, V. C. Sreedhar, and S. P.
 Midkiff, ``Escape analysis for java,'' in Proceedings of the
 Conference on Object-Oriented Programming Systems, Languages, and
 Applications (OOPSLA), pp. 1-19, 1999.  */

So confirming.


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pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Keywords||FIXME
   Last reconfirmed|-00-00 00:00:00 |2005-12-30 18:28:19
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24694

[Bug tree-optimization/24694] Address taken and addressable variables and call clobber

[dberlin at dberlin dot org]

--- Comment #3 from dberlin at gcc dot gnu dot org  2005-11-06 23:59 ---
Subject: Re:   New: Address taken and
addressable variables and call clobber

On Sun, 2005-11-06 at 15:46 +, pinskia at gcc dot gnu dot org wrote:
> Take the following code:
> int f(int);
> int g(void)
> {
>   int i;
>   int *iptr = &i;
>   int **ipp = &iptr;
>   **ipp = 1;
>   f(i);
>   return **ipp;
> }
> --
> Here we consider i being call clobber because we lose the fact that iptr is
> addressable 

> but we don't look to see if its address escapes at all (which in
> this case it does not).
No, we don't actually.
In fact, that's not even close to what happens.

iptr isn't renamed, and thus, we assume the address taking of i and storage
into iptr is the same as a global store, 
because we know nothing about unrenamed variables.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24694

[Bug tree-optimization/24694] Address taken and addressable variables and call clobber

[pinskia at gcc dot gnu dot org]

--- Comment #2 from pinskia at gcc dot gnu dot org  2005-11-06 16:08 ---
Note this is not fixed on the iab.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24694

[Bug tree-optimization/24694] Address taken and addressable variables and call clobber

[pinskia at gcc dot gnu dot org]

--- Comment #1 from pinskia at gcc dot gnu dot org  2005-11-06 15:47 ---
Found this while looking a little into PR 24689.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24694