[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[rguenth at gcc dot gnu dot org]

------- Comment #12 from rguenth at gcc dot gnu dot org  2006-03-06 14:41 -------
In principle this blocks optimization of tramp3d domain operations (if it were
not structure-aliasing fixing most of the problems).


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |22501
              nThis|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[rguenth at gcc dot gnu dot org]

------- Comment #13 from rguenth at gcc dot gnu dot org  2006-10-24 12:34 -------
We now get

<bb 2>:
  #   param_2 = V_MAY_DEF <param_1>;
  param.f1 = 0;
  #   param_6 = V_MAY_DEF <param_2>;
  #   SFT.0_7 = V_MAY_DEF <SFT.0_3>;
  #   NONLOCAL.6_8 = V_MAY_DEF <NONLOCAL.6_5>;
  #   NONLOCAL.12_13 = V_MAY_DEF <NONLOCAL.12_12>;
  #   NONLOCAL.18_16 = V_MAY_DEF <NONLOCAL.18_15>;
  #   NONLOCAL.24_19 = V_MAY_DEF <NONLOCAL.24_18>;
  #   NONLOCAL.30_22 = V_MAY_DEF <NONLOCAL.30_21>;
  #   NONLOCAL.36_25 = V_MAY_DEF <NONLOCAL.36_24>;
  __builtin_memcpy (&local, &param, 9);
  #   VUSE <SFT.0_7>;
  D.2668_4 = local.f1;
  if (D.2668_4 != 0) goto <L0>; else goto <L1>;

<L0>:;
  #   param_9 = V_MAY_DEF <param_6>;
  #   SFT.0_10 = V_MAY_DEF <SFT.0_7>;
  #   NONLOCAL.6_11 = V_MAY_DEF <NONLOCAL.6_8>;
  #   NONLOCAL.12_14 = V_MAY_DEF <NONLOCAL.12_13>;
  #   NONLOCAL.18_17 = V_MAY_DEF <NONLOCAL.18_16>;
  #   NONLOCAL.24_20 = V_MAY_DEF <NONLOCAL.24_19>;
  #   NONLOCAL.30_23 = V_MAY_DEF <NONLOCAL.30_22>;
  #   NONLOCAL.36_26 = V_MAY_DEF <NONLOCAL.36_25>;
  link_error ();

<L1>:;
  return;


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2005-12-09 04:36:34         |2006-10-24 12:34:46
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[dberlin at gcc dot gnu dot org]

------- Comment #14 from dberlin at gcc dot gnu dot org  2006-10-24 18:31 -------
(In reply to comment #13)
> We now get
> 
> <bb 2>:
>   #   param_2 = V_MAY_DEF <param_1>;
>   param.f1 = 0;
>   #   param_6 = V_MAY_DEF <param_2>;
>   #   SFT.0_7 = V_MAY_DEF <SFT.0_3>;
>   #   NONLOCAL.6_8 = V_MAY_DEF <NONLOCAL.6_5>;
>   #   NONLOCAL.12_13 = V_MAY_DEF <NONLOCAL.12_12>;
>   #   NONLOCAL.18_16 = V_MAY_DEF <NONLOCAL.18_15>;
>   #   NONLOCAL.24_19 = V_MAY_DEF <NONLOCAL.24_18>;
>   #   NONLOCAL.30_22 = V_MAY_DEF <NONLOCAL.30_21>;
>   #   NONLOCAL.36_25 = V_MAY_DEF <NONLOCAL.36_24>;
>   __builtin_memcpy (&local, &param, 9);
>   #   VUSE <SFT.0_7>;
>   D.2668_4 = local.f1;
>   if (D.2668_4 != 0) goto <L0>; else goto <L1>;
> 
> <L0>:;
>   #   param_9 = V_MAY_DEF <param_6>;
>   #   SFT.0_10 = V_MAY_DEF <SFT.0_7>;
>   #   NONLOCAL.6_11 = V_MAY_DEF <NONLOCAL.6_8>;
>   #   NONLOCAL.12_14 = V_MAY_DEF <NONLOCAL.12_13>;
>   #   NONLOCAL.18_17 = V_MAY_DEF <NONLOCAL.18_16>;
>   #   NONLOCAL.24_20 = V_MAY_DEF <NONLOCAL.24_19>;
>   #   NONLOCAL.30_23 = V_MAY_DEF <NONLOCAL.30_22>;
>   #   NONLOCAL.36_26 = V_MAY_DEF <NONLOCAL.36_25>;
>   link_error ();
> 
> <L1>:;
>   return;
> 

Uh, there should only ever be one non-local var per function, and referenced
vars should be reset at the end of each function so why do you have multiple
NONLOCAL's here?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[rguenth at gcc dot gnu dot org]

------- Comment #15 from rguenth at gcc dot gnu dot org  2009-09-26 15:30 -------
On trunk we get

<bb 2>:
  # .MEM_3 = VDEF <.MEM_2(D)>
  param.f1 = 0;
  # .MEM_4 = VDEF <.MEM_3>
  memcpy (&local, &param, 9);
  # VUSE <.MEM_4>
  D.1743_1 = local.f1;
  if (D.1743_1 != 0)
    goto <bb 3>;
  else
    goto <bb 4>;

<bb 3>:
  # .MEM_5 = VDEF <.MEM_4>
  link_error ();

<bb 4>:
  return;

which shows this is an issue of value-numbering not looking through
memcpy.  SRA obviously does not work here because both vars have their
address taken.  The issue in the summary should have been fixed by the
SRA rewrite.

I'm looking at the VN issue.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rguenth at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-10-24 12:34:46         |2009-09-26 15:30:16
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[rguenth at gcc dot gnu dot org]

------- Comment #16 from rguenth at gcc dot gnu dot org  2010-08-11 12:33 -------
We can also expand

  __builtin_memcpy (&local, &param, 9);

to multiple copies based on src/dest alignment and size (similar to
store_by_pieces)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #19 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-03-15 13:41:43 UTC ---
Fixed.

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

--- Comment #18 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-03-15 13:37:42 UTC ---
Author: rguenth
Date: Tue Mar 15 13:37:23 2011
New Revision: 170994

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=170994
Log:
2011-03-15  Richard Guenther  <rguenther@suse.de>

    PR tree-optimization/13954
    * tree-ssa-sccvn.c (vn_reference_lookup_3): Look through memcpy
    and friends.

    * g++.dg/tree-ssa/pr13954.C: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/tree-ssa/pr13954.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-sccvn.c

[Bug c++/13954] [tree-ssa] SRA does not work for classes that use inheritance with an empty base

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13954

--- Comment #17 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-03-08 15:50:59 UTC ---
I have a patch, queued for 4.7.