[Bug middle-end/36227] New: [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[Bug middle-end/36227] New: [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

unsigned long * sat_add(unsigned long *ptr, unsigned long i, unsigned long
*end)
{
  if ((unsigned long)ptr + i * sizeof(*ptr) > (unsigned long)ptr)
    return ptr + i;
  else
    return end;
}

is folded to

  if (ptr + (long unsigned int) (i * 8) > ptr)
    {
      return ptr + (long unsigned int) (i * 8);
    }
  else
    {
      return end;
    }


-- 
           Summary: [4.3/4.4 Regression] POINTER_PLUS folding introduces
                    undefined overflow
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
        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=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2008-05-13 12:43 -------
Err - only with volatiles ... !?

volatile unsigned long * sat_add(volatile unsigned long *ptr, unsigned long i,
volatile unsigned long *end)
{
  if ((unsigned long)ptr + i * sizeof(*ptr) > (unsigned long)ptr)
    return ptr + i;
  else
    return end;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2008-05-13 12:54 -------
Part of the fix is

Index: fold-const.c
===================================================================
--- fold-const.c        (revision 135255)
+++ fold-const.c        (working copy)
@@ -6831,7 +6831,8 @@ fold_sign_changed_comparison (enum tree_
           && TREE_TYPE (TREE_OPERAND (arg1, 0)) == inner_type))
     return NULL_TREE;

-  if (TYPE_UNSIGNED (inner_type) != TYPE_UNSIGNED (outer_type)
+  if ((TYPE_UNSIGNED (inner_type) != TYPE_UNSIGNED (outer_type)
+       || POINTER_TYPE_P (inner_type) != POINTER_TYPE_P (outer_type))
       && code != NE_EXPR
       && code != EQ_EXPR)
     return NULL_TREE;


but the question is if the folding to POINTER_PLUS is correct at all.


-- 

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|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-05-13 12:54:21
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2008-05-13 14:02 -------
Subject: Bug 36227

Author: rguenth
Date: Tue May 13 14:01:53 2008
New Revision: 135260

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=135260
Log:
2008-05-13  Richard Guenther  <rguenther@suse.de>

        PR middle-end/36227
        * fold-const.c (fold_sign_changed_comparison): Do not allow
        changes in pointer-ness.

        * gcc.dg/pr36227.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/pr36227.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2008-05-13 14:05 -------
Subject: Bug 36227

Author: rguenth
Date: Tue May 13 14:04:40 2008
New Revision: 135261

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=135261
Log:
2008-05-13  Richard Guenther  <rguenther@suse.de>

        PR middle-end/36227
        * fold-const.c (fold_sign_changed_comparison): Do not allow
        changes in pointer-ness.

        * gcc.dg/pr36227.c: New testcase.

Added:
    branches/gcc-4_3-branch/gcc/testsuite/gcc.dg/pr36227.c
      - copied unchanged from r135260, trunk/gcc/testsuite/gcc.dg/pr36227.c
Modified:
    branches/gcc-4_3-branch/gcc/ChangeLog
    branches/gcc-4_3-branch/gcc/fold-const.c
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.3.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2008-05-13 14:13 -------
Only the theoretical problem remains.  We still fold

  (unsigned long)ptr + (unsigned long)i

to

  (unsigned long)(ptr + (unsigned long)i)

where the inner POINTER_PLUS_EXPR now may invoke undefined behavior on
overflow.

No testcase is known where that results in a wrong-code bug.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|rguenth at gcc dot gnu dot  |unassigned at gcc dot gnu
                   |org                         |dot org
             Status|ASSIGNED                    |NEW


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2008-06-06 14:59 -------
4.3.1 is being released, adjusting target milestone.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.1                       |4.3.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[jsm28 at gcc dot gnu dot org]

------- Comment #7 from jsm28 at gcc dot gnu dot org  2008-08-27 22:04 -------
4.3.2 is released, changing milestones to 4.3.3.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.2                       |4.3.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #8 from rguenth at gcc dot gnu dot org  2009-01-16 13:20 -------
Now it does.  See PR38835.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |38835
              nThis|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2009-01-16 13:35 -------
Mine.


-- 

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|2008-05-13 12:54:21         |2009-01-16 13:35:48
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #11 from rguenth at gcc dot gnu dot org  2009-01-16 18:57 -------
*** Bug 38835 has been marked as a duplicate of this bug. ***


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #10 from rguenth at gcc dot gnu dot org  2009-01-16 18:56 -------
C testcase, fails with 4.3 and 4.4 with -O2 --param
max-fields-for-field-sensitive=0

#include <stdint.h>
extern void abort (void);
int main()
{
  int i = 1;
  int *p = &i;
  uintptr_t iptr;

  iptr = (uintptr_t)p - (uintptr_t)&iptr;
  p = (int *)((uintptr_t)&iptr + iptr);
  if (*p != 1)
    abort ();
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3/4.4 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #12 from rguenth at gcc dot gnu dot org  2009-01-16 19:18 -------
Subject: Bug 36227

Author: rguenth
Date: Fri Jan 16 19:18:18 2009
New Revision: 143442

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=143442
Log:
2009-01-16  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/38835
        PR middle-end/36227
        * fold-const.c (fold_binary): Remove PTR + INT -> (INT)(PTR p+ INT)
        and INT + PTR -> (INT)(PTR p+ INT) folding.
        * tree-ssa-address.c (create_mem_ref): Properly use POINTER_PLUS_EXPR.

        java/
        * builtins.c (build_addr_sum): Use POINTER_PLUS_EXPR.

        * gcc.c-torture/execute/pr36227.c: New testcase.
        * gcc.dg/tree-ssa/foldaddr-1.c: XFAIL.
        * g++.dg/init/const7.C: Likewise.

Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr36227.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/java/ChangeLog
    trunk/gcc/java/builtins.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/init/const7.C
    trunk/gcc/testsuite/gcc.dg/tree-ssa/foldaddr-1.c
    trunk/gcc/tree-ssa-address.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #13 from rguenth at gcc dot gnu dot org  2009-01-16 19:22 -------
Fixed on the trunk.  Also fails with plain -O for 4.3.2.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |4.3.2
      Known to work|                            |4.2.4 4.4.0
            Summary|[4.3/4.4 Regression]        |[4.3 Regression]
                   |POINTER_PLUS folding        |POINTER_PLUS folding
                   |introduces undefined        |introduces undefined
                   |overflow                    |overflow


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3 Regression] POINTER_PLUS folding introduces undefined overflow

[danglin at gcc dot gnu dot org]

------- Comment #14 from danglin at gcc dot gnu dot org  2009-01-19 16:14 -------
New test fails on hpux:

Executing on host: /test/gnu/gcc/objdir/gcc/xgcc -B/test/gnu/gcc/objdir/gcc/
/te
st/gnu/gcc/gcc/gcc/testsuite/gcc.c-torture/execute/pr36227.c  -w  -O0   -lm  
-o
 /test/gnu/gcc/objdir/gcc/testsuite/gcc/pr36227.x0    (timeout = 300)
/test/gnu/gcc/gcc/gcc/testsuite/gcc.c-torture/execute/pr36227.c:1:20: error:
std
int.h: No such file or directory


-- 

danglin at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |danglin at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenther at suse dot de]

------- Comment #15 from rguenther at suse dot de  2009-01-19 16:22 -------
Subject: Re:  [4.3 Regression] POINTER_PLUS folding
 introduces undefined overflow

On Mon, 19 Jan 2009, danglin at gcc dot gnu dot org wrote:

> ------- Comment #14 from danglin at gcc dot gnu dot org  2009-01-19 16:14 -------
> New test fails on hpux:
> 
> Executing on host: /test/gnu/gcc/objdir/gcc/xgcc -B/test/gnu/gcc/objdir/gcc/
> /te
> st/gnu/gcc/gcc/gcc/testsuite/gcc.c-torture/execute/pr36227.c  -w  -O0   -lm  
> -o
>  /test/gnu/gcc/objdir/gcc/testsuite/gcc/pr36227.x0    (timeout = 300)
> /test/gnu/gcc/gcc/gcc/testsuite/gcc.c-torture/execute/pr36227.c:1:20: error:
> std
> int.h: No such file or directory

Ah, needs

{ target { stdint_types } }

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #16 from rguenth at gcc dot gnu dot org  2009-01-20 09:21 -------
Should be fixed now.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #17 from rguenth at gcc dot gnu dot org  2009-01-24 10:20 -------
GCC 4.3.3 is being released, adjusting target milestone.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.3                       |4.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #18 from rguenth at gcc dot gnu dot org  2009-01-24 23:34 -------
Backporting requires revs 143442, 143455 and 143509 and then still regresses

gcc.target/i386/pr37101.c
gfortran.dg/array_constructor_12.f90

all pointer-plus ICEs.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227

[Bug middle-end/36227] [4.3 Regression] POINTER_PLUS folding introduces undefined overflow

[rguenth at gcc dot gnu dot org]

------- Comment #19 from rguenth at gcc dot gnu dot org  2009-06-17 12:35 -------
WONTFIX for 4.3.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to fail|4.3.2                       |4.3.2 4.3.3 4.3.4
         Resolution|                            |FIXED
   Target Milestone|4.3.4                       |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36227