[Bug tree-optimization/60382] New: ICE on valid code at -O3 on x86_64-linux-gnu (in vect_create_epilog_for_reduction, at tree-vect-loop.c:4352)

[su at cs dot ucdavis.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60382

            Bug ID: 60382
           Summary: ICE on valid code at -O3 on x86_64-linux-gnu (in
                    vect_create_epilog_for_reduction, at
                    tree-vect-loop.c:4352)
           Product: gcc
           Version: unknown
            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 also seems to affect the current 4.8 branch, but not GCC 4.8.2. 

$ 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/4.9.0/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 4.9.0 20140301 (experimental) [trunk revision 208241] (GCC) 
$ 
$ gcc-trunk -O2 small.c; a.out
$ gcc-4.8.2 -O3 small.c; a.out
$ 
$ gcc-trunk -O3 small.c
small.c: In function ‘foo’:
small.c:4:1: internal compiler error: in vect_create_epilog_for_reduction, at
tree-vect-loop.c:4495
 foo ()
 ^
0xb66aa1 vect_create_epilog_for_reduction
    ../../gcc-trunk/gcc/tree-vect-loop.c:4493
0xb64c04 vectorizable_reduction(gimple_statement_base*, gimple_stmt_iterator*,
gimple_statement_base**, _slp_tree*)
    ../../gcc-trunk/gcc/tree-vect-loop.c:5344
0xb5656a vect_transform_stmt(gimple_statement_base*, gimple_stmt_iterator*,
bool*, _slp_tree*, _slp_instance*)
    ../../gcc-trunk/gcc/tree-vect-stmts.c:7226
0xb5acee vect_transform_loop(_loop_vec_info*)
    ../../gcc-trunk/gcc/tree-vect-loop.c:6054
0xb78f6b vectorize_loops()
    ../../gcc-trunk/gcc/tree-vectorizer.c:476
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, e, f; 

void
foo ()
{
  for (b = 0; b < 3; b++)
    if (e)
      {
    for (c = 0; c < 4; c++)
      {
        if (b)
          continue;
        f = 1;
        for (a = 0; a < 2; a++)
          f |= 1; 
      }
    for (;;) 
      ;
      }
}

int
main ()
{
  foo (); 
  return 0;
}