[Bug c++/47611] New: [trans-mem] memory allocated by default new/new_vec operator can be considered as transaction local

[Bug c++/47611] New: [trans-mem] memory allocated by default new/new_vec operator can be considered as transaction local

[patrick.marlier at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47611

           Summary: [trans-mem] memory allocated by default new/new_vec
                    operator can be considered as transaction local
           Product: gcc
           Version: trans-mem
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: patrick.marlier@gmail.com
                CC: rth@gcc.gnu.org, aldyh@gcc.gnu.org


This is an improvement with a *LOW* priority. Only if spare time (hey could be
a nice homework).

See comments in 
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46941

[Bug c++/47611] [trans-mem] memory allocated by default new/new_vec operator can be considered as transaction local

[aldyh at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47611

Aldy Hernandez <aldyh at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P5
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.02.04 21:11:43
     Ever Confirmed|0                           |1

--- Comment #1 from Aldy Hernandez <aldyh at gcc dot gnu.org> 2011-02-04 21:11:43 UTC ---
Bringing in a note from the other PR...

The reason memory allocated by the C++ new operator does not get
optimized by the TM-memopt pass is not because of a missing ECF_MALLOC
attribute, but because the alias oracle in GCC considers the chunk of memory as
possibly able to escape from the current function.

That is, the following hunk of code returns true in the TM-memopt pass:

      if (ptr_deref_may_alias_global_p (x))

Apparently, since new/delete operators may be overridden by class specific
hooks, the memory must be considered escaped.

[Bug c++/47611] [trans-mem] memory allocated by default new/new_vec operator can be considered as transaction local

[torvald at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47611

torvald at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |torvald at gcc dot gnu.org
         Resolution|                            |INVALID

--- Comment #2 from torvald at gcc dot gnu.org 2011-11-21 16:39:40 UTC ---
If the alias oracle considers the memory region returned from new/delete to be
potentially escaping to code outside of the transaction, then I think we need
to respect this.  If you think this should not be possible, please file another
bug against the alias oracle.