[Bug c/49413] New: over-optimization that causes valid code to segfault

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49413

           Summary: over-optimization that causes valid code to segfault
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: gattis@gmail.com


Created attachment 24529
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24529
source code

The attached short .c code compiles without warnings and segfaults when -O3 is
used.  The code runs fine with -O1 or if I declare v as "volatile double *"
instead of just "double *".  This was triggered in a much larger code base. 
I've managed to strip everything else out and reduce it to this.  I'm pretty
sure the code left is correct, so I think it's a GCC bug.

GCC Version: 4.6.0 w/ gmp-5.0.2, mpc-0.9, mpfr-3.0.1
System: CentOS 5 x86_64 (AMD Istanbull)
GCC ./configure flags: --enable-languages=c,c++,fortran
Source compilation command: gcc -O3 volatile.c -o volatile