[Bug tree-optimization/27084] New: Does not propagate memory load base through useless type conversion

[Bug tree-optimization/27084] New: Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

Consider

struct Data {
  int get() const { return value; }
  int value;
};

struct Object {
  int operator[](int i) const { return data_m->get(); }
  Data *data_m;
};

int foo(Object&o)
{
  return o[0];
}

here we have after forwprop

int foo(Object&) (o)
{
  struct Object * const this;
  struct Data * D.20003;
  int D.20005;
  struct Data * const this;

<bb 2>:
  this_2 = o_1;
  D.20003_4 = this_2->data_m;
  this_5 = D.20003_4;
  D.20005_6 = this_5->value;
  D.20005_7 = D.20005_6;
  D.20005_8 = D.20005_7;
  D.20005_9 = D.20005_8;
  D.20005_10 = D.20005_9;
  return D.20005_10;

}

both memory loads could load from o_1 and D.20003_4 respectively.


-- 
           Summary: Does not propagate memory load base through useless type
                    conversion
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug tree-optimization/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2006-04-08 17:09 -------
Created an attachment (id=11227)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11227&action=view)
prototype patch

I have a prototype patch for forwprop that handles this, but somehow messes up
virtual operands.  We get a non-ssaname VUSE:

#   VUSE <opD.8355>;
D.6255_561 = D.6253_558->typeD.4890

during build of libcpp.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug tree-optimization/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2006-04-08 17:21 -------
Hm, we have from DCE to forwprop

  struct cpp_token * D.6254;
  struct cpp_token * D.6253;

   #   temp_1334 = V_MAY_DEF <temp_330>;
   #   unsignedp_1335 = V_MAY_DEF <unsignedp_333>;
   #   op_1336 = V_MAY_DEF <op_351>;
   #   SMT.698_1337 = V_MAY_DEF <SMT.698_1262>;
   #   SMT.700_1338 = V_MAY_DEF <SMT.700_1287>;
   #   SMT.703_1339 = V_MAY_DEF <SMT.703_1307>;
   D.6253_558 = cpp_get_token (pfile_475);
   D.6254_560 = D.6253_558;
-  #   VUSE <op_1336>;
-  D.6255_561 = D.6254_560->type;
+  D.6255_561 = D.6253_558->type;
   D.6256_562 = (cpp_ttype) D.6255_561;
   #   SFT.637_563 = V_MUST_DEF <SFT.637_360>;
   op.op = D.6256_562;


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug tree-optimization/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2006-04-08 18:31 -------
Of course this is from tramp3d, and I hope fixing it would enable the hoisting
of more invariant loads out of the inner loops.


-- 

rguenth at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug tree-optimization/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2006-04-08 18:58 -------
hmhm, merge_alias_info seems to fix it


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug tree-optimization/27084] Does not propagate memory load base through useless type conversion

[pinskia at gcc dot gnu dot org]

------- Comment #5 from pinskia at gcc dot gnu dot org  2006-04-08 19:09 -------
forwrop when propragating better be using merge_ssa_info anyways, just like
copy prop and such.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2006-04-08 23:11 -------
Here is the patch which fixes this issue for me:
Index: cp-objcp-common.c
===================================================================
--- cp-objcp-common.c   (revision 112789)
+++ cp-objcp-common.c   (working copy)
@@ -179,7 +179,7 @@ cxx_types_compatible_p (tree x, tree y)
   if (POINTER_TYPE_P (x) && POINTER_TYPE_P (y)
       && TYPE_MODE (x) == TYPE_MODE (y)
       && TYPE_REF_CAN_ALIAS_ALL (x) == TYPE_REF_CAN_ALIAS_ALL (y)
-      && same_type_p (TREE_TYPE (x), TREE_TYPE (y)))
+      && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (x), TREE_TYPE
(y)))
     return 1;

   return 0;


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|tree-optimization           |c++


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[pinskia at gcc dot gnu dot org]

------- Comment #7 from pinskia at gcc dot gnu dot org  2006-04-08 23:28 -------
I am testing the C++ patch right now.  It is always a better idea to fix a pass
to do what it should be doing instead of hacking another one to do the same.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[pinskia at gcc dot gnu dot org]

------- Comment #8 from pinskia at gcc dot gnu dot org  2006-04-12 01:20 -------
The C++ patch fixes the problem with this code and it also finished
bootstrapping without any regression so please test it fully and submit it
instead of your hack.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-04-12 01:20:10
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2006-04-12 13:35 -------
PASS: g++.old-deja/g++.mike/dyncast7.C (test for excess errors)
FAIL: g++.old-deja/g++.mike/dyncast7.C execution test

const Foo* and Foo* are really not compatible.  We can just exchange Foo* for
const Foo* for loads.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #10 from rguenth at gcc dot gnu dot org  2006-04-12 13:37 -------
Created an attachment (id=11250)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11250&action=view)
updated patch

Patch I will clean and test instead.  Also fixes 27090.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #11227|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[pinskia at gcc dot gnu dot org]

------- Comment #11 from pinskia at gcc dot gnu dot org  2006-04-12 17:40 -------
(In reply to comment #9)
> PASS: g++.old-deja/g++.mike/dyncast7.C (test for excess errors)
> FAIL: g++.old-deja/g++.mike/dyncast7.C execution test

I did not get that failure.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[patchapp at dberlin dot org]

------- Comment #12 from patchapp at dberlin dot org  2006-04-20 11:45 -------
Subject: Bug number PR27084

A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-04/msg00750.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #13 from rguenth at gcc dot gnu dot org  2006-07-05 10:54 -------
Subject: Bug 27084

Author: rguenth
Date: Wed Jul  5 10:54:17 2006
New Revision: 115200

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=115200
Log:
2006-07-05  Richard Guenther  <rguenther@suse.de>
        Andrew Pinski  <pinskia@gcc.gnu.org>

        PR c++/27084
        * cp-objcp-common.c (cxx_types_compatible_p): Ignore
        top level qualifiers for pointer type comparisons.

        * g++.dg/tree-ssa/copyprop-1.C: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/tree-ssa/copyprop-1.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-objcp-common.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #14 from rguenth at gcc dot gnu dot org  2006-07-05 10:58 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #15 from rguenth at gcc dot gnu dot org  2006-08-02 20:49 -------
Subject: Bug 27084

Author: rguenth
Date: Wed Aug  2 20:48:59 2006
New Revision: 115887

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=115887
Log:
2006-08-02  Richard Guenther  <rguenther@suse.de>

      PR c++/28479
      Revert
      2006-07-05  Richard Guenther  <rguenther@suse.de>
      Andrew Pinski  <pinskia@gcc.gnu.org>

      PR c++/27084
      * cp-objcp-common.c (cxx_types_compatible_p): Ignore
      top level qualifiers for pointer type comparisons.

      * g++.dg/tree-ssa/copyprop-1.C: XFAIL.

Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-objcp-common.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/tree-ssa/copyprop-1.C


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #16 from rguenth at gcc dot gnu dot org  2006-08-02 20:50 -------
Patch was reverted.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[mmitchel at gcc dot gnu dot org]

------- Comment #17 from mmitchel at gcc dot gnu dot org  2007-05-14 22:26 -------
Will not be fixed in 4.2.0; retargeting at 4.2.1.


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.2.0                       |4.2.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.2.1                       |4.2.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug c++/27084] Does not propagate memory load base through useless type conversion

[mmitchel at gcc dot gnu dot org]

------- Comment #18 from mmitchel at gcc dot gnu dot org  2007-10-09 19:21 -------
Change target milestone to 4.2.3, as 4.2.2 has been released.


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.2.2                       |4.2.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084

[Bug middle-end/27084] Does not propagate memory load base through useless type conversion

[rguenth at gcc dot gnu dot org]

------- Comment #19 from rguenth at gcc dot gnu dot org  2007-10-29 22:12 -------
This is fixed on the mainline by the middle-end type-system and the first
forwprop pass.  cxx_types_compatible_p is no longer involved for pointer types.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
          Component|c++                         |middle-end
         Resolution|                            |FIXED
   Target Milestone|4.2.3                       |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27084