[Bug rtl-optimization/61047] New: wrong code at -O1 on x86_64-linux

[su at cs dot ucdavis.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61047

            Bug ID: 61047
           Summary: wrong code at -O1 on x86_64-linux
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu

The current gcc trunk and 4.9.0 mis-compile the following code on x86_64-linux
at -O1 in both 32-bit and 64-bit modes. 

This is a regression from 4.8.x and seems related to
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60452. 

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/4.10.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 4.10.0 20140503 (experimental) [trunk revision 210026] (GCC) 
$ 
$ gcc-trunk -O0 small.c; a.out
$ gcc-trunk -Os small.c; a.out
$ gcc-4.8.2 -O1 small.c; a.out
$ 
$ gcc-trunk -O1 small.c
$ a.out
Segmentation fault (core dumped)
$ gcc-4.9.0 -O1 small.c
$ a.out
Segmentation fault (core dumped)
$ 

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

int a, c, d;
short b;

int
main ()
{
  int e[1];
  for (; b < 2; b++)
    {
      a = 0;
      if (b == 2837)
        a = e[b];
      if (!(d || b))
        for (; c;)
          ;
    }
  return 0;
}