[Bug tree-optimization/67827] New: ICE on valid code at -O2 and -O3 on x86_64-linux-gnu in duplicate_ssa_name_range_info, at tree-ssanames.c:506

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67827

            Bug ID: 67827
           Summary: ICE on valid code at -O2 and -O3 on x86_64-linux-gnu
                    in duplicate_ssa_name_range_info, at
                    tree-ssanames.c:506
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

The following code causes an ICE when compiled with the current gcc trunk at
-O2 and -O3 on x86_64-linux-gnu in both 32-bit and 64-bit modes.

It is a regression from 5.2.x.


$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-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 6.0.0 20151002 (experimental) [trunk revision 228389] (GCC) 
$ 
$ gcc-trunk -Os -c small.c
$ gcc-5.2 -O2 -c small.c
$ 
$ gcc-trunk -O2 -c small.c
small.c: In function ‘fn1’:
small.c:5:1: internal compiler error: in duplicate_ssa_name_range_info, at
tree-ssanames.c:506
 fn1 ()
 ^
0xcb0f15 duplicate_ssa_name_range_info(tree_node*, value_range_type,
range_info_def*)
        ../../gcc-trunk/gcc/tree-ssanames.c:506
0xc37f3d eliminate_dom_walker::before_dom_children(basic_block_def*)
        ../../gcc-trunk/gcc/tree-ssa-pre.c:4127
0x10e9c5e dom_walker::walk(basic_block_def*)
        ../../gcc-trunk/gcc/domwalk.c:177
0xc3689b eliminate
        ../../gcc-trunk/gcc/tree-ssa-pre.c:4540
0xc3ffd7 execute
        ../../gcc-trunk/gcc/tree-ssa-pre.c:4890
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, c, d, e, g;
short f;

void
fn1 ()
{
  int i;
  f = a - b;
  e = (c && (i = d = (unsigned) f - 1)) || i;
  g = (unsigned) f - 1;
  c && (d = 0);
}