[Bug tree-optimization/56501] New: gcc 4.6 ICE on noreturn function at -Os and above

[dhazeghi at yahoo dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56501

             Bug #: 56501
           Summary: gcc 4.6 ICE on noreturn function at -Os and above
    Classification: Unclassified
           Product: gcc
           Version: 4.6.3
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: dhaze...@yahoo.com


The following testcase (derived from gzip) triggers an internal compiler error
with gcc 4.6, 4.5 and 4.4 when compiled at -Os or higher on x86_64-linux.  The
problem does not occur with 4.7 or newer, or with 4.3 or older.

$ gcc-4.6 --version
gcc-4.6 (GCC) 4.6.3
$ gcc-4.6 -O1 -w small.c
$ gcc-4.6 -Os -w small.c
small.c: In function ‘main’:
small.c:24:1: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ cat small.c

int a;
void try_help () __attribute__ ((__noreturn__));
void try_help ()
{
}

int main ()
{
    switch (a)
    {
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
    case '8':
    case '9':
        break;
    default:
        try_help ();
    }
}