[Bug c/39433] New: gcc core dumping for unnecessary header file conflict

["nmdilipsimha at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

I created a small dummy program with a dedicated insignificant bug.
But gcc throws an error and then core dumps, which is abnormal.

Here is the output:
gcc -v -save-temps 1.c >& log.txt

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 --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--with-gxx-include-dir=/usr/include/c++/4.1.3 --program-suffix=-4.1
--enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug
--enable-mpfr --enable-checking=release i486-linux-gnu
Thread model: posix
gcc version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)
 /usr/lib/gcc/i486-linux-gnu/4.1.3/cc1 -E -quiet -v 1.c -mtune=generic
-fpch-preprocess -o 1.i
ignoring nonexistent directory "/usr/local/include/i486-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/i486-linux-gnu/4.1.3/../../../../i486-linux-gnu/include"
ignoring nonexistent directory "/usr/include/i486-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc/i486-linux-gnu/4.1.3/include
 /usr/include
End of search list.
 /usr/lib/gcc/i486-linux-gnu/4.1.3/cc1 -fpreprocessed 1.i -quiet -dumpbase 1.c
-mtune=generic -auxbase 1 -version -fstack-protector -fstack-protector -o 1.s
GNU C version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)
(i486-linux-gnu)
        compiled by GNU C version 4.1.3 20070929 (prerelease) (Ubuntu
4.1.2-16ubuntu2).
GGC heuristics: --param ggc-min-expand=47 --param ggc-min-heapsize=31866
Compiler executable checksum: caf034d6752b947185f431aa3e927159
In file included from 3.h:6,
                 from 2.h:6,
                 from 1.h:5,
                 from 1.c:2:
1.h:3: error: redefinition of typedef ?F1?
1.h:3: error: previous declaration of ?F1? was here
In file included from 3.h:6,
                 from 2.h:6,
                 from 1.h:5,
                 from 1.c:2:
1.h:9: error: field ?a2? has incomplete type
In file included from 1.c:2:
1.h:7: error: redefinition of ?struct f1?
gcc: Internal error: Segmentation fault (program cc1)
Please submit a full bug report.

Since test program is very small, I am pasting it here:
source files:
simha@home_pc:~/test/header_file$ cat 1.c
#include "1.h"

int main()
{
        F1 a;
        a.a = 1;
        return 0;
}

---------------------------------------------
simha@home_pc:~/test/header_file$ cat 1.h
#ifndef F1_H

typedef struct f1 F1;
#include "2.h"

struct f1
{
        int a;
        F2 a2;
};

#define F1_H
#endif

---------------------------------------------
simha@home_pc:~/test/header_file$ cat 2.h
#ifndef F2_H
#define F2_H

typedef struct f2 F2;
#include "3.h"

struct f2
{
        int a;
        F3 a3;
};

#endif

---------------------------------------------
simha@home_pc:~/test/header_file$ cat 3.h
#ifndef F3_H
#define F3_H

typedef struct f3 F3;
#include "1.h"

struct f3
{
        int a;
        F1 a1;
};

#endif

---------------------------------------------

Finally 1.i:
simha@home_pc:~/test/header_file$ cat 1.i
# 1 "1.c"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "1.c"
# 1 "1.h" 1


typedef struct f1 F1;
# 1 "2.h" 1



typedef struct f2 F2;
# 1 "3.h" 1



typedef struct f3 F3;
# 1 "1.h" 1


typedef struct f1 F1;
# 1 "2.h" 1
# 5 "1.h" 2

struct f1
{
 int a;
 F2 a2;
};
# 6 "3.h" 2

struct f3
{
 int a;
 F1 a1;
};
# 6 "2.h" 2

struct f2
{
 int a;
 F3 a3;
};
# 5 "1.h" 2

struct f1
{
 int a;
 F2 a2;
};
# 2 "1.c" 2

int main()
{
 F1 a;
 a.a = 1;
 return 0;
}


-- 
           Summary: gcc core dumping for unnecessary header file conflict
           Product: gcc
           Version: 4.1.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: nmdilipsimha at gmail dot com
 GCC build triplet:  i486-linux-gnu
  GCC host triplet:  i486-linux-gnu
GCC target triplet:  i486-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39433