[Bug c++/36607] New: Incorrect type diagnostic on substracting casted char pointers

[Bug c++/36607] New: Incorrect type diagnostic on substracting casted char pointers

[rschiele at gmail dot com]

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The following little code sample does no longer compile with 4.3 or higher:

struct a {};
void b() {
    int a::*m;
    a *c;
    int p = reinterpret_cast<char*>(&(c->*m)) - reinterpret_cast<char*>(c);
}

Instead the compiler emits the error message:

bad.cc: In function ‘void b()’:
bad.cc:5: error: aggregate value used where an integer was expected

Though it is clear that this code sample is not perfectly valid according to
the C++ standard since "reinterpret_cast<char*>(&(c->*m))" and
"reinterpret_cast<char*>(c)" are not part of the same array I would not expect
this kind of behavior since the claim of the compiler that there is something
wrong with types is completely bogus.

Rewriting the code like the following makes the compiler accepting it again:

struct a {};
void b() {
    int a::*m;
    a *c;
    char* d = reinterpret_cast<char*>(&(c->*m));
    char* e = reinterpret_cast<char*>(c);
    int p = d - e;
}


-- 
           Summary: Incorrect type diagnostic on substracting casted char
                    pointers
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rschiele at gmail dot com
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] Incorrect type diagnostic on substracting casted char pointers

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2008-12-28 00:40 -------
This works for me with 4.3.2 and the current trunk.

Does it work for you?


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] Incorrect type diagnostic on substracting casted char pointers

[rschiele at gmail dot com]

------- Comment #2 from rschiele at gmail dot com  2008-12-30 06:07 -------
It works for you? This is weired!

Just tried it with current trunk again and it does still show exactly the same
error there.


-- 

rschiele at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |UNCONFIRMED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2008-12-30 06:14 -------
Ok, it fails with -m64, looking into it.

Confirmed.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
  GCC build triplet|x86_64-unknown-linux-gnu    |
   GCC host triplet|x86_64-unknown-linux-gnu    |
 GCC target triplet|x86_64-unknown-linux-gnu    |PTR == 64 bits
           Keywords|                            |rejects-valid
      Known to fail|                            |4.3.3 4.4.0
      Known to work|                            |4.0.1 4.1.1
   Last reconfirmed|0000-00-00 00:00:00         |2008-12-30 06:14:14
               date|                            |
            Summary|Incorrect type diagnostic on|[4.3/4.4 Regression]
                   |substracting casted char    |Incorrect type diagnostic on
                   |pointers                    |substracting casted char
                   |                            |pointers
   Target Milestone|---                         |4.3.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[pinskia at gcc dot gnu dot org]

------- Comment #5 from pinskia at gcc dot gnu dot org  2008-12-30 17:13 -------
I have a simple fix, the front-end should have already warned about the
conversion from a pointer to a member object to an integer type.  Therefor
convert can handle OFFSET_TYPE just like INTEGER_TYPE and such.


-- 

pinskia at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[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=36607

[Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[rguenth at gcc dot gnu dot org]

------- Comment #6 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=36607

[Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[bonzini at gnu dot org]

------- Comment #7 from bonzini at gnu dot org  2009-02-03 13:56 -------
ping?


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bonzini at gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini at gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

Re: [Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[Andrew Thomas Pinski]

Sent from my iPhone

On Feb 3, 2009, at 5:56 AM, "bonzini at gnu dot org" <gcc-bugzilla@gcc.gnu.org 
 > wrote:

>
>
> ------- Comment #7 from bonzini at gnu dot org  2009-02-03 13:56  
> -------
> ping?

The patch was just approved last night and I will be applying it when  
I get into work today.

>
>
>
> -- 
>
> bonzini at gnu dot org changed:
>
>           What    |Removed                     |Added
> --- 
> --- 
> ----------------------------------------------------------------------
>                 CC|                            |bonzini at gnu dot org
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607
>

[Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[pinskia at gmail dot com]

------- Comment #8 from pinskia at gmail dot com  2009-02-03 15:44 -------
Subject: Re:  [4.3/4.4 Regression] Incorrect type diagnostic on substracting
casted char pointers



Sent from my iPhone

On Feb 3, 2009, at 5:56 AM, "bonzini at gnu dot org" <gcc-bugzilla@gcc.gnu.org 
 > wrote:

>
>
> ------- Comment #7 from bonzini at gnu dot org  2009-02-03 13:56  
> -------
> ping?

The patch was just approved last night and I will be applying it when  
I get into work today.

>
>
>
> -- 
>
> bonzini at gnu dot org changed:
>
>           What    |Removed                     |Added
> --- 
> --- 
> ----------------------------------------------------------------------
>                 CC|                            |bonzini at gnu dot org
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607
>


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3/4.4 Regression] Incorrect type diagnostic on substracting casted char pointers

[pinskia at gcc dot gnu dot org]

------- Comment #9 from pinskia at gcc dot gnu dot org  2009-02-03 22:38 -------
Subject: Bug 36607

Author: pinskia
Date: Tue Feb  3 22:38:16 2009
New Revision: 143909

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=143909
Log:
2009-02-03  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR C++/36607
        * convert.c (convert_to_integer): Treat OFFSET_TYPE like INTEGER_TYPE.

2009-02-03  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR C++/36607
        * g++.dg/expr/cast10.C: New test.



Added:
    trunk/gcc/testsuite/g++.dg/expr/cast10.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/convert.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3 Regression] Incorrect type diagnostic on substracting casted char pointers

[pinskia at gcc dot gnu dot org]

------- Comment #10 from pinskia at gcc dot gnu dot org  2009-02-03 22:39 -------
Fixed on the trunk at least.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.3/4.4 Regression]        |[4.3 Regression] Incorrect
                   |Incorrect type diagnostic on|type diagnostic on
                   |substracting casted char    |substracting casted char
                   |pointers                    |pointers


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3 Regression] Incorrect type diagnostic on substracting casted char pointers

[pinskia at gcc dot gnu dot org]

------- Comment #11 from pinskia at gcc dot gnu dot org  2009-04-16 15:43 -------
I am no longer working on this one.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|pinskia 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=36607

[Bug c++/36607] [4.3 Regression] Incorrect type diagnostic on substracting casted char pointers

[rguenth at gcc dot gnu dot org]

------- Comment #12 from rguenth at gcc dot gnu dot org  2009-06-19 16:51 -------
Testing a backport.


-- 

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3 Regression] Incorrect type diagnostic on substracting casted char pointers

[rguenth at gcc dot gnu dot org]

------- Comment #13 from rguenth at gcc dot gnu dot org  2009-06-19 21:44 -------
Subject: Bug 36607

Author: rguenth
Date: Fri Jun 19 21:44:24 2009
New Revision: 148730

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=148730
Log:
2009-06-19  Richard Guenther  <rguenther@suse.de>

        Backport from mainline:
        2009-02-03  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR C++/36607
        * convert.c (convert_to_integer): Treat OFFSET_TYPE like INTEGER_TYPE.

        * g++.dg/expr/cast10.C: New test.

        2009-02-03  Jakub Jelinek  <jakub@redhat.com>

        PR target/35318
        * function.c (match_asm_constraints_1): Skip over
        initial optional % in the constraint.

        * gcc.c-torture/compile/pr35318.c: New test.

        2009-05-20  Jakub Jelinek  <jakub@redhat.com>

        PR middle-end/40204
        * fold-const.c (fold_binary) <case BIT_AND_EXPR>: Avoid infinite
        recursion if build_int_cst_type returns the same INTEGER_CST as
        arg1.

        * gcc.c-torture/compile/pr40204.c: New test.

Added:
    branches/gcc-4_3-branch/gcc/testsuite/g++.dg/expr/cast10.C
    branches/gcc-4_3-branch/gcc/testsuite/gcc.c-torture/compile/pr35318.c
    branches/gcc-4_3-branch/gcc/testsuite/gcc.c-torture/compile/pr40204.c
Modified:
    branches/gcc-4_3-branch/gcc/ChangeLog
    branches/gcc-4_3-branch/gcc/convert.c
    branches/gcc-4_3-branch/gcc/fold-const.c
    branches/gcc-4_3-branch/gcc/function.c
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607

[Bug c++/36607] [4.3 Regression] Incorrect type diagnostic on substracting casted char pointers

[rguenth at gcc dot gnu dot org]

------- Comment #14 from rguenth at gcc dot gnu dot org  2009-06-19 21:46 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to fail|4.3.3 4.4.0                 |4.3.3
      Known to work|4.0.1 4.1.1                 |4.0.1 4.1.1 4.3.4 4.4.0
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36607