[Bug c/35616] New: Incorrect code while O2 compling

[Bug c/35616] New: Incorrect code while O2 compling

[J dot Gorka at osmosys dot tv]

While compling program below (3 files) with O2 or O3 option, code is generated
not properly (SF).


/******************************************************************************/

file 1:
gcc_bug.c

#include <stdio.h>
#include "function.h"

static void my_listener(
        int a,
        int b,
        int c)
{
  printf("It works!!!\n");
}

static struct data_t data;

int main()
{
  data.listener = my_listener;

  data.a = 11;
  data.b = 22;
  data.c = 33; /* with O2 compiling, function_calling_listener try call
function with address 33,
                  not my_listener address */
  data.d = 44;

  function_calling_listener(data);

  return 0;
}

/******************************************************************************/

file 2:
function.h

typedef void (*listener_fun)(
        int a,
        int b,
        int c);

struct data_t
{
  int a;

  listener_fun listener;

  int b;
  int c;
  int d;
};

void function_calling_listener (struct data_t data);

/******************************************************************************/

file 3:
function.c

#include "function.h"

void function_calling_listener (struct data_t data)
{
  data.listener(data.a, data.c, data.d);
}

/******************************************************************************/

GCC VERSION:
gcc --version
gcc (GCC) 4.1.2 20070626 (Red Hat 4.1.2-13)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


-- 
           Summary: Incorrect code while O2 compling
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: J dot Gorka at osmosys dot tv


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] Incorrect code while O2 compling

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2008-03-17 16:40 -------
> gcc (GCC) 4.1.2 20070626 (Red Hat 4.1.2-13)

Please try 4.2.3 or 4.3.0.  Also you should have reported this to RedHat first
as it is their modified compiler.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |middle-end


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] Incorrect code while O2 compling

[J dot Gorka at osmosys dot tv]

------- Comment #2 from J dot Gorka at osmosys dot tv  2008-03-17 17:12 -------
The same problem on that version. I don't think that is Red Hat specific
problem...

Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr
--enable-shared --
Thread model: posix
gcc version 4.1.2 20061028 (prerelease) (Debian 4.1.1-19)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] Incorrect code while O2 compling

[J dot Gorka at osmosys dot tv]

------- Comment #3 from J dot Gorka at osmosys dot tv  2008-03-18 07:57 -------
Ok. Now version 4.3.0 from Debian. The same problem....

gcc-4.3 --version
gcc-4.3 (Debian 4.3.0-1) 4.3.1 20080309 (prerelease)
Copyright (C) 2008 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] Incorrect code while O2 compling

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2008-03-18 08:01 -------
Can you include the contents of function.h, it seems to be missing ?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] Incorrect code while O2 compling

[J dot Gorka at osmosys dot tv]

------- Comment #5 from J dot Gorka at osmosys dot tv  2008-03-18 08:17 -------
All is fine. My friend copy that program from here, compile on gcc-4.3 and give
me result that is in comment #3.... But ok, i copy one more time what is in
function.h file:

typedef void (*listener_fun)(
        int a,
        int b,
        int c);

struct data_t
{
  int a;

  listener_fun listener;

  int b;
  int c;
  int d;
};

void function_calling_listener (struct data_t data);


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2008-03-18 10:51 -------
This looks like a target issue.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |matz at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
          Component|middle-end                  |target
     Ever Confirmed|0                           |1
 GCC target triplet|                            |i?86-*-*
           Keywords|                            |wrong-code
      Known to fail|                            |3.4.0 4.0.4 4.1.3 4.4.0
      Known to work|                            |3.3.6
   Last reconfirmed|0000-00-00 00:00:00         |2008-03-18 10:51:19
               date|                            |
            Summary|Incorrect code while O2     |[4.1/4.2/4.3/4.4 Regression]
                   |compling                    |Incorrect code while O2
                   |                            |compling
   Target Milestone|---                         |4.1.3
            Version|unknown                     |4.1.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[ubizjak at gmail dot com]

------- Comment #7 from ubizjak at gmail dot com  2008-03-18 14:34 -------
asm dump with GCC: (GNU) 4.4.0 20080318 (experimental) and -O2
-fomit-frame-pointer:

function_calling_listener:
        movl    20(%esp), %eax  # data.d, data.d
        movl    16(%esp), %ecx  # data.c, data.c
        movl    %eax, 12(%esp)  # data.d,
        movl    %ecx, 8(%esp)   # data.c,
        jmp     *%ecx   # data.c

-O0:

function_calling_listener:
        pushl   %ebx    #
        subl    $24, %esp       #,
        movl    36(%esp), %ebx  # data.listener, D.1190
        movl    48(%esp), %eax  # data.d, D.1191
        movl    44(%esp), %edx  # data.c, D.1192
        movl    32(%esp), %ecx  # data.a, D.1193
        movl    %eax, 8(%esp)   # D.1191,
        movl    %edx, 4(%esp)   # D.1192,
        movl    %ecx, (%esp)    # D.1193,
        call    *%ebx   # D.1190
        addl    $24, %esp       #,
        popl    %ebx    #
        ret


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[ubizjak at gmail dot com]

------- Comment #8 from ubizjak at gmail dot com  2008-03-18 14:45 -------
It works when function.c is compiled with -O2 -fno-optimize-sibling-calls.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2008-03-18 14:53 -------
The stack modifications before the sibcall look indeed interesting.  Micha,
maybe you want to poke into this somewhat?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[matz at gcc dot gnu dot org]

------- Comment #10 from matz at gcc dot gnu dot org  2008-03-18 14:55 -------
The tree dumps already look wrong.  from .130t.final_cleanup:

function_calling_listener (data)
{
<bb 2>:
  data (data.a, data.c, data.d) [tail call];
  return;
}

Note how the function pointer is replaced with the whole "data" object.  Huh?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[ubizjak at gmail dot com]

------- Comment #11 from ubizjak at gmail dot com  2008-03-18 15:01 -------
cse1 pass somehow figures out that:

(insn 11 10 12 2 function.c:5 (set (reg/f:SI 61)
        (mem/s/f/c:SI (plus:SI (reg/f:SI 16 argp)
                (const_int 4 [0x4])) [4 data.listener+0 S4 A32])) 41 {*movsi_1} 
(nil))

(call_insn/j 12 11 0 2 function.c:5 (call (mem:QI (reg/f:SI 61) [0 S1 A8])
        (const_int 12 [0xc])) 423 {*sibcall_1} (nil)
    (nil))

can be substituted with:

(insn 11 10 12 2 function.c:5 (set (reg/f:SI 61 [ data.listener ])
        (reg:SI 59 [ data.c ])) 41 {*movsi_1} (nil))

(call_insn/j 12 11 0 2 function.c:5 (call (mem:QI (reg:SI 59 [ data.c ]) [0 S1
A
8])
        (const_int 12 [0xc])) 423 {*sibcall_1} (nil)
    (nil))


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[matz at gcc dot gnu dot org]

------- Comment #12 from matz at gcc dot gnu dot org  2008-03-18 15:03 -------
Uros: the problem isn't cse.  It's already expand which creates broken code
(it reads from and writes to (mem (plus (virtual-incoming-regs) (4)).
But it does that only because the input tree is completely wrong (TER breaks
this).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[rguenth at gcc dot gnu dot org]

------- Comment #13 from rguenth at gcc dot gnu dot org  2008-03-18 15:25 -------
Actually the trees are correct, just the dumping of function names in call
exprs
is "interesting".  Still expand is the primary suspect here.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[ubizjak at gmail dot com]

------- Comment #14 from ubizjak at gmail dot com  2008-03-18 15:30 -------
(In reply to comment #12)
> Uros: the problem isn't cse.  It's already expand which creates broken code
> (it reads from and writes to (mem (plus (virtual-incoming-regs) (4)).
> But it does that only because the input tree is completely wrong (TER breaks
> this).

Yes, looking a bit more into the expand dump, it looks that gcc tries to fix
outgoing call stack by copying 'c' and 'd' into the position of 'listener' and
'b'. It accidentally overwrites 'listener' (and 'b', but this isn't used
anywhere). The code would work OK if 'listener' would be copied to a temporary
first.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug target/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[matz at gcc dot gnu dot org]

------- Comment #15 from matz at gcc dot gnu dot org  2008-03-18 15:37 -------
We can either force expanding the call address before the arguments (if
it overlaps with them) or simply validate the thing after the fact. 
Validating seems a bit easier (and is in line with what is done already for
the expansion of overlapping arguments).  Proof of concept patch:

Index: calls.c
===================================================================
--- calls.c     (revision 133304)
+++ calls.c     (working copy)
@@ -2756,8 +2756,15 @@ expand_call (tree exp, rtx target, int i
            use_reg (&call_fusage, struct_value);
        }

-      funexp = prepare_call_address (funexp, static_chain_value,
+       {
+         rtx before_arg = get_last_insn ();
+
+         funexp = prepare_call_address (funexp, static_chain_value,
                                     &call_fusage, reg_parm_seen, pass == 0);
+         if (pass == 0
+             && check_sibcall_argument_overlap (before_arg, 0, 0))
+           sibcall_failure = 1;
+       }

       load_register_parameters (args, num_actuals, &call_fusage, flags,
                                pass == 0, &sibcall_failure);


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[matz at gcc dot gnu dot org]

-- 

matz at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |matz at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
          Component|target                      |middle-end
   Last reconfirmed|2008-03-18 10:51:19         |2008-03-18 16:00:52
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[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=35616

[Bug middle-end/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[matz at gcc dot gnu dot org]

------- Comment #16 from matz at gcc dot gnu dot org  2008-03-19 19:15 -------
Subject: Bug 35616

Author: matz
Date: Wed Mar 19 19:15:03 2008
New Revision: 133348

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=133348
Log:
        PR middle-end/35616
        * calls.c (expand_call): Check overlap of arguments with call
        address for sibcalls.

        * gcc.dg/pr35616.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr35616.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/calls.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] [4.1/4.2/4.3/4.4 Regression] Incorrect code while O2 compling

[matz at gcc dot gnu dot org]

------- Comment #17 from matz at gcc dot gnu dot org  2008-03-19 19:38 -------
Subject: Bug 35616

Author: matz
Date: Wed Mar 19 19:37:48 2008
New Revision: 133350

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=133350
Log:
Backport from mainline:
        PR middle-end/35616
        * calls.c (expand_call): Check overlap of arguments with call
        address for sibcalls.

        * gcc.dg/pr35616.c: New test.

Added:
    branches/gcc-4_3-branch/gcc/testsuite/gcc.dg/pr35616.c
      - copied unchanged from r133348, trunk/gcc/testsuite/gcc.dg/pr35616.c
Modified:
    branches/gcc-4_3-branch/gcc/ChangeLog
    branches/gcc-4_3-branch/gcc/calls.c
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] [4.1/4.2 Regression] Incorrect code while O2 compling

[matz at gcc dot gnu dot org]

------- Comment #18 from matz at gcc dot gnu dot org  2008-03-19 19:40 -------
trunk and 4.3 are fixed.


-- 

matz at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|matz at gcc dot gnu dot org |unassigned at gcc dot gnu
                   |                            |dot org
             Status|ASSIGNED                    |NEW
      Known to fail|3.4.0 4.0.4 4.1.3 4.4.0     |3.4.0 4.0.4 4.1.3
           Priority|P2                          |P4
            Summary|[4.1/4.2/4.3/4.4 Regression]|[4.1/4.2 Regression]
                   |Incorrect code while O2     |Incorrect code while O2
                   |compling                    |compling


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] [4.2 Regression] Incorrect code while O2 compling

[jsm28 at gcc dot gnu dot org]

------- Comment #19 from jsm28 at gcc dot gnu dot org  2008-07-04 22:40 -------
Closing 4.1 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.1/4.2 Regression]        |[4.2 Regression] Incorrect
                   |Incorrect code while O2     |code while O2 compling
                   |compling                    |
   Target Milestone|4.1.3                       |4.2.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616

[Bug middle-end/35616] [4.2 Regression] Incorrect code while O2 compling

[jsm28 at gcc dot gnu dot org]

------- Comment #20 from jsm28 at gcc dot gnu dot org  2009-03-31 15:26 -------
Closing 4.2 branch, fixed for 4.3.1 and 4.4.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
      Known to fail|3.4.0 4.0.4 4.1.3 4.3.0     |3.4.0 4.0.4 4.1.3 4.3.0
                   |                            |4.2.5
         Resolution|                            |FIXED
   Target Milestone|4.2.5                       |4.3.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35616