[Bug tree-optimization/63941] New: ICE on valid code at -O3 and above on x86_64-linux-gnu

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63941

            Bug ID: 63941
           Summary: ICE on valid code at -O3 and above on x86_64-linux-gnu
           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
-O3 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 20141117 (experimental) [trunk revision 217671] (GCC) 

$ gcc-trunk -O2 -c small.c
$ gcc-4.9 -O3 -c small.c
$ 
$ gcc-trunk -O3 -c small.c
small.c: In function ‘fn1’:
small.c:4:1: internal compiler error: in add_to_predicate_list, at
tree-if-conv.c:438
 fn1 ()
 ^
0xb11044 add_to_predicate_list
    ../../gcc-trunk/gcc/tree-if-conv.c:438
0xb11044 add_to_dst_predicate_list
    ../../gcc-trunk/gcc/tree-if-conv.c:488
0xb11564 predicate_bbs
    ../../gcc-trunk/gcc/tree-if-conv.c:1155
0xb11c7a combine_blocks
    ../../gcc-trunk/gcc/tree-if-conv.c:2005
0xb13c06 tree_if_conversion
    ../../gcc-trunk/gcc/tree-if-conv.c:2162
0xb13c06 execute
    ../../gcc-trunk/gcc/tree-if-conv.c:2240
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[1], e, f, g, h;

void
fn1 ()
{
  char i = 0;
  for (b = 0; b >= 0;)
    for (b = 0; b < 2; b++)
      {
    d[f] && (e = 0);
    h = 1 & a - i ? 0 : a;
    c = i = h;
    char j = c;
    int k = 0;
    g = j || j > k;
    d[0] = 0;
      }
}