[Bug tree-optimization/68305] New: ICE on valid code at -O3 on x86_64-linux-gnu: tree check: expected class ‘expression’, have ‘exceptional’ (ssa_name) in tree_operand_check, at tree.h:3436

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68305

            Bug ID: 68305
           Summary: ICE on valid code at -O3 on x86_64-linux-gnu: tree
                    check: expected class ‘expression’, have ‘exceptional’
                    (ssa_name) in tree_operand_check, at tree.h:3436
           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
-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 20151110 (experimental) [trunk revision 230107] (GCC) 
$ 
$ gcc-trunk -O2 -c small.c
$ gcc-5.2 -O3 -c small.c
$ 
$ gcc-trunk -O3 -c small.c
small.c: In function ‘fn1’:
small.c:4:1: internal compiler error: tree check: expected class ‘expression’,
have ‘exceptional’ (ssa_name) in tree_operand_check, at tree.h:3436
 fn1 ()
 ^

0xd66987 tree_class_check_failed(tree_node const*, tree_code_class, char
const*, int, char const*)
        ../../gcc-trunk/gcc/tree.c:9638
0xd3f9c3 expr_check(tree_node*, char const*, int, char const*)
        ../../gcc-trunk/gcc/tree.h:3107
0xd3f9c3 tree_operand_check(tree_node*, int, char const*, int, char const*)
        ../../gcc-trunk/gcc/tree.h:3436
0xd3f9c3 vect_get_constant_vectors
        ../../gcc-trunk/gcc/tree-vect-slp.c:2744
0xd3fce1 vect_get_slp_defs(vec<tree_node*, va_heap, vl_ptr>, _slp_tree*,
vec<vec<tree_node*, va_heap, vl_ptr>, va_heap, vl_ptr>*, int)
        ../../gcc-trunk/gcc/tree-vect-slp.c:3025
0xd0e5f9 vectorizable_condition(gimple*, gimple_stmt_iterator*, gimple**,
tree_node*, int, _slp_tree*)
        ../../gcc-trunk/gcc/tree-vect-stmts.c:7389
0xd2137e vect_transform_stmt(gimple*, gimple_stmt_iterator*, bool*, _slp_tree*,
_slp_instance*)
        ../../gcc-trunk/gcc/tree-vect-stmts.c:8020
0xd38ce4 vect_schedule_slp_instance
        ../../gcc-trunk/gcc/tree-vect-slp.c:3482
0xd38b39 vect_schedule_slp_instance
        ../../gcc-trunk/gcc/tree-vect-slp.c:3363
0xd3a8d6 vect_schedule_slp(vec_info*)
        ../../gcc-trunk/gcc/tree-vect-slp.c:3547
0xd275c5 vect_transform_loop(_loop_vec_info*)
        ../../gcc-trunk/gcc/tree-vect-loop.c:6619
0xd4254b vectorize_loops()
        ../../gcc-trunk/gcc/tree-vectorizer.c:533
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;

void
fn1 ()
{
  int c, d; 
  for (; b; b++)
    a = a ^ !c ^ !d; 
}