[Bug tree-optimization/64494] New: ICE at -Os and above on x86_64-linux-gnu in duplicate_ssa_name_range_info, at tree-ssanames.c:499

["su at cs dot ucdavis.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64494

            Bug ID: 64494
           Summary: ICE at -Os and above on x86_64-linux-gnu in
                    duplicate_ssa_name_range_info, at tree-ssanames.c:499
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu

The following code causes an ICE when compiled with the current gcc trunk at
-Os and above on x86_64-linux-gnu in both 32-bit and 64-bit modes. 

It is a regression from 4.9.x.

$ 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/5.0.0/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 5.0.0 20150104 (experimental) [trunk revision 219172] (GCC) 

$ 
$ gcc-trunk -O1 small.c; a.out
$ gcc-4.9 -Os small.c; a.out
$ 
$ gcc-trunk -Os small.c
small.c: In function âmainâ:
small.c:5:1: internal compiler error: in duplicate_ssa_name_range_info, at
tree-ssanames.c:499
 main ()
 ^
0xc90af5 duplicate_ssa_name_range_info(tree_node*, value_range_type,
range_info_def*)
        ../../gcc-trunk/gcc/tree-ssanames.c:499
0xba9f24 fini_copy_prop
        ../../gcc-trunk/gcc/tree-ssa-copy.c:572
0xba9f24 execute_copy_prop
        ../../gcc-trunk/gcc/tree-ssa-copy.c:628
0xba9f24 execute
        ../../gcc-trunk/gcc/tree-ssa-copy.c:658
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 


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


int a, b;
char c;

int
main ()
{
  int d = 0;
  a = 0;
  for (; d < 2; d++)
    {
      a &= (b >= 1);
      c = (204 > (255 >> a)) ? 0 : 204 << a;
      b = 0;
    }
  return 0;
}