[Bug tree-optimization/64326] New: ICE at -O3 on x86_64-linux-gnu in check_probability, at basic-block.h:581

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64326

            Bug ID: 64326
           Summary: ICE at -O3 on x86_64-linux-gnu in check_probability,
                    at basic-block.h:581
           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 20141215 (experimental) [trunk revision 218731] (GCC) 

$ 
$ gcc-trunk -O2 -c small.c
$ gcc-4.9 -O3 -c small.c
$ 
$ gcc-trunk -O3 -c small.c
small.c: In function ‘fn2’:
small.c:11:1: internal compiler error: in check_probability, at
basic-block.h:581
 fn2 ()
 ^
0xc9da16 check_probability
    ../../gcc-trunk/gcc/basic-block.h:581
0xc9b165 check_probability
    ../../gcc-trunk/gcc/tree.h:2893
0xc9b165 combine_probabilities
    ../../gcc-trunk/gcc/basic-block.h:590
0xc9b165 slpeel_tree_peel_loop_to_edge
    ../../gcc-trunk/gcc/tree-vect-loop-manip.c:1382
0xc9b504 vect_do_peeling_for_loop_bound(_loop_vec_info*, tree_node*,
tree_node*, unsigned int, bool)
    ../../gcc-trunk/gcc/tree-vect-loop-manip.c:1773
0xc8bef7 vect_transform_loop(_loop_vec_info*)
    ../../gcc-trunk/gcc/tree-vect-loop.c:5907
0xcaa3f7 vectorize_loops()
    ../../gcc-trunk/gcc/tree-vectorizer.c:491
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, f[5][2];
char g;

int
fn1 ()
{
  return d && c ? 0 : 1;
}

int
fn2 ()
{
  int h;
  for (;;)
    for (; e;)
      {
    int i, j;
    h = a ? 1 : b;
    if (h || fn1 () ^ g - 682)
      {
        for (i = 0; i < 5; i++)
          for (j = 0; j < 2; j++)
        f[i][j] = 0;
        return 0;
      }
      }
}