[Bug middle-end/68570] New: ICE on valid code at -O1, -O2 and -O3 on x86_64-linux-gnu

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68570

            Bug ID: 68570
           Summary: ICE on valid code at -O1, -O2 and -O3 on
                    x86_64-linux-gnu
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          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
-O1, -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 20151125 (experimental) [trunk revision 230867] (GCC)
$
$ gcc-trunk -O0 -c small.c
$ gcc-5.2 -O1 -c small.c
$
$ gcc-trunk -O1 -c small.c
small.c: In function ‘fn1’:
small.c:4:1: internal compiler error: Segmentation fault
 fn1 ()
 ^~~

0xaf378f crash_signal
        ../../gcc-trunk/gcc/toplev.c:334
0xe4db44 gimple_truth_valued_p(tree_node*, tree_node* (*)(tree_node*))
        /tmp/objdir/gcc/gimple-match.c:162
0xec0d99 gimple_simplify_NE_EXPR
        /tmp/objdir/gcc/gimple-match.c:47863
0xe53881 gimple_simplify
        /tmp/objdir/gcc/gimple-match.c:52160
0xe5610d gimple_resimplify2(gimple**, code_helper*, tree_node*, tree_node**,
tree_node* (*)(tree_node*))
        ../../gcc-trunk/gcc/gimple-match-head.c:159
0xebebf0 gimple_simplify(gimple*, code_helper*, tree_node**, gimple**,
tree_node* (*)(tree_node*), tree_node* (*)(tree_node*))
        ../../gcc-trunk/gcc/gimple-match-head.c:748
0xb3b20f cleanup_control_expr_graph
        ../../gcc-trunk/gcc/tree-cfgcleanup.c:101
0xb3b20f cleanup_control_flow_bb
        ../../gcc-trunk/gcc/tree-cfgcleanup.c:200
0xb3b20f cleanup_tree_cfg_bb
        ../../gcc-trunk/gcc/tree-cfgcleanup.c:617
0xb3b878 cleanup_tree_cfg_1
        ../../gcc-trunk/gcc/tree-cfgcleanup.c:670
0xb3b878 cleanup_tree_cfg_noloop
        ../../gcc-trunk/gcc/tree-cfgcleanup.c:720
0xb3b878 cleanup_tree_cfg()
        ../../gcc-trunk/gcc/tree-cfgcleanup.c:771
0xa27ce4 execute_function_todo
        ../../gcc-trunk/gcc/passes.c:1911
0xa2873b execute_todo
        ../../gcc-trunk/gcc/passes.c:2010
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, d, e, f, h, i, k;

void
fn1 ()
{ 
  char m;
  for (;;)
    { 
      for (;;)
        { 
          e = f = 1;
          if (i)
            d = h = 0;
          else
            a = 0;
          break;
        }
      k = 0;
      if (f)
        a = 3;
      if (d)
        f = 0;
      if (a > (i < 1))
        { 
          if (e)
            break;
        }
      else
        i = m;
      k = i ? a : i;
    }
}