[Bug c++/55366] New: g++ segfault; see also Bug 55365

["jasongross9+bugzilla at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55366

             Bug #: 55366
           Summary: g++ segfault; see also Bug 55365
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jasongross9+bugzilla@gmail.com


A slight modification of the code of Bug 55365 causes g++ to segfault:

$ /afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/g++ -std=c++11 -c
free_list.cpp  -v -save-temps
Using built-in specs.
COLLECT_GCC=/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/g++
Target: x86_64-unknown-linux-gnu
Configured with: ./configure
--prefix=/afs/csail/proj/courses/6.172/gcc-cilkplus --enable-languages=c,c++
Thread model: posix
gcc version 4.8.0 20120618 (experimental) (GCC)
COLLECT_GCC_OPTIONS='-std=c++11' '-c' '-v' '-save-temps' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.8.0/cc1plus
-E -quiet -v -iprefix
/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/
-D_GNU_SOURCE free_list.cpp -mtune=generic -march=x86-64 -std=c++11
-fpch-preprocess -o free_list.ii
ignoring nonexistent directory
"/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../x86_64-unknown-linux-gnu/include"
ignoring duplicate directory
"/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../include/c++/4.8.0"
ignoring duplicate directory
"/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../include/c++/4.8.0/x86_64-unknown-linux-gnu"
ignoring duplicate directory
"/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../include/c++/4.8.0/backward"
ignoring duplicate directory
"/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/include"
ignoring duplicate directory
"/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/include-fixed"
ignoring nonexistent directory
"/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /opt/intel/composer_xe_2013.0.079/mkl/include
 /opt/intel/composer_xe_2013.0.079/tbb/include

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../include/c++/4.8.0

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../include/c++/4.8.0/x86_64-unknown-linux-gnu

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/../../../../include/c++/4.8.0/backward

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/include

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.0/include-fixed
 /usr/local/include

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../lib/gcc/../../include
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-std=c++11' '-c' '-v' '-save-temps' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'

/afs/csail.mit.edu/proj/courses/6.172/gcc-cilkplus/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.8.0/cc1plus
-fpreprocessed free_list.ii -quiet -dumpbase free_list.cpp -mtune=generic
-march=x86-64 -auxbase free_list -std=c++11 -version -o free_list.s
GNU C++ (GCC) version 4.8.0 20120618 (experimental) (x86_64-unknown-linux-gnu)
        compiled by GNU C version 4.8.0 20120618 (experimental), GMP version
5.0.2, MPFR version 3.1.0, MPC version 0.9
warning: GMP header version 5.0.2 differs from library version 4.3.2.
warning: MPFR header version 3.1.0 differs from library version 3.0.0-p3.
warning: MPC header version 0.9 differs from library version 0.8.2.
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
GNU C++ (GCC) version 4.8.0 20120618 (experimental) (x86_64-unknown-linux-gnu)
        compiled by GNU C version 4.8.0 20120618 (experimental), GMP version
5.0.2, MPFR version 3.1.0, MPC version 0.9
warning: GMP header version 5.0.2 differs from library version 4.3.2.
warning: MPFR header version 3.1.0 differs from library version 3.0.0-p3.
warning: MPC header version 0.9 differs from library version 0.8.2.
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: 9140df29c77763bd28b47359117a6952
free_list.cpp:6:9: error: field âbâ has incomplete type
     Bar b;
         ^
â
In constructor âFoo::Foo(Bar&&)â:
Segmentation fault
       : _data{ .b = c } { }
                       ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

$ cat free_list.ii
# 1 "free_list.cpp"
# 1 "<command-line>"
# 1 "free_list.cpp"
struct Bar;

class Foo {
 private:
  union arr_or_b {
    Bar b;
    char arr[];
  };

  arr_or_b _data;

 public:
  Foo(Bar &&c)
      : _data{ .b = c } { }
};

struct Bar {
  Foo *foo;
};

void quz() {
  Foo *foo = new Foo(Bar());
}