[Bug c++/28553] New: string processing -O3 optimization bug under GCC 4.1.1

[Bug c++/28553] New: string processing -O3 optimization bug under GCC 4.1.1

[peter at chocky dot org]

Note, the following is in reference to this Debian version of GCC:

gcc version 4.1.2 20060729 (prerelease) (Debian 4.1.1-10)

However, it also occurs under a version I have built myself:

Target: i686-pc-linux-gnu
Configured with: ../configure --prefix=/usr/local/gcc-4.1
--enable-languages=c,c++,java
Thread model: posix
gcc version 4.1.1


My C++ knowledge isn't extensive enough to give further details of this other
than it's related to string handling, or guess if it's already been reported,
but the following preprocessed code reproduces the problem under -O3, but not
-O2.  The code performs correctly under GCC 3.4.6 and -O3

Here is the expected output:

op [0]: "A"
op [1]: "B"
op [2]: "C"
op [3]: "D"
op [4]: "E"
op [5]: "F"

Here is a crash caught by GDB:

CfgSchema (this=0xbfd0a400, schema_str=@0xbfd0a40c) at
/usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../include/c++/4.1.2/bits/stl_algo.h:260
260               if (__pred(*__first))
(gdb) bt
#0  CfgSchema (this=0xbfd0a400, schema_str=@0xbfd0a40c) at
/usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../include/c++/4.1.2/bits/stl_algo.h:260
#1  0x08048ebe in main () at cfgtblopt.cpp:36


-- 
           Summary: string processing -O3 optimization bug under GCC 4.1.1
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: peter at chocky dot org
  GCC host triplet: i486-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] string processing -O3 optimization bug under GCC 4.1.1

[peter at chocky dot org]

------- Comment #1 from peter at chocky dot org  2006-07-31 17:56 -------
Created an attachment (id=11981)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11981&action=view)
Preprocessed C++ demonstrating problem


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] string processing -O3 optimization bug under GCC 4.1.1

[pcarlini at suse dot de]

------- Comment #2 from pcarlini at suse dot de  2006-08-01 12:02 -------
The problem cannot be reproduced in mainline, only in 4_1-branch. Seems an
rtl-optimization bug: for the below slightly reduced testcase t97.final_cleanup
is identical in mainline and 4_1-branch:

#include <string>
#include <algorithm>

template<typename InputIter, typename SplitPred>
  inline
  void
  SplitTo(InputIter b, InputIter e, SplitPred sp)
  {
    InputIter p = std::find_if(b, e, sp);

    while (p != e)
      {
        b = p;
        p = std::find_if(b, e, sp);
      }
  }

template<typename InputIter>
  inline
  void
  SplitTo(InputIter b, InputIter e)
  { SplitTo(b, e, std::bind2nd(std::equal_to<char>(), ';')); }

int
main(void)
{
  const std::string& src = "";
  SplitTo(src.begin(), src.end());
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2006-08-01 12:18 -------
-O2 -finline-functions is sufficient to reproduce the problem on the branch, or
if you mark CfgSchema::CfgSchema(const std::string &) 'inline'.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org
           Keywords|                            |wrong-code
      Known to fail|                            |4.1.0 4.1.1
      Known to work|                            |4.0.3 4.2.0
            Summary|string processing -O3       |[4.1 Regression] string
                   |optimization bug under GCC  |processing -O3 optimization
                   |4.1.1                       |bug under GCC 4.1.1
   Target Milestone|---                         |4.1.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[bangerth at dealii dot org]

------- Comment #4 from bangerth at dealii dot org  2006-08-24 01:52 -------
Paolo has already confirmed this one.


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-08-24 01:52:50
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2006-10-27 09:41 -------
I cannot reproduce this with 4.1.2 20061024 anymore.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[mmitchel at gcc dot gnu dot org]

------- Comment #6 from mmitchel at gcc dot gnu dot org  2006-11-01 18:16 -------
Can the original submitter still reproduce this problem?


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[peter at chocky dot org]

------- Comment #7 from peter at chocky dot org  2006-11-02 16:34 -------
I can confirm that this is fixed with the GCC 4.1 now in Debian unstable.


-- 

peter at chocky dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[peter at chocky dot org]

------- Comment #8 from peter at chocky dot org  2006-12-06 17:37 -------
And it's back, at least in this version:

Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../configure --prefix=/usr/local/gcc-4.1
--enable-languages=c,c++,java
Thread model: posix
gcc version 4.1.2 20061204 (prerelease)


-- 

peter at chocky dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.1.2                       |4.1.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553

[Bug c++/28553] [4.1 Regression] string processing -O3 optimization bug under GCC 4.1.1

[jsm28 at gcc dot gnu dot org]

------- Comment #9 from jsm28 at gcc dot gnu dot org  2008-07-04 15:46 -------
Closing 4.1 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
      Known to fail|4.1.0 4.1.1 4.1.2           |4.1.0 4.1.1 4.1.2 4.1.3
         Resolution|                            |FIXED
   Target Milestone|4.1.3                       |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28553