[Bug c/68951] New: ICE on x86_64-pc-linux-gnu at -O3 in both 32-bit and 64-bit modes (in vect_update_misalignment_for_peel, at tree-vect-data-refs.c:889)

[chengniansun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68951

            Bug ID: 68951
           Summary: ICE on x86_64-pc-linux-gnu at -O3 in both 32-bit and
                    64-bit modes (in vect_update_misalignment_for_peel, at
                    tree-vect-data-refs.c:889)
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chengniansun at gmail dot com
  Target Milestone: ---

The following code crashes the gcc trunk at -O3 in both 32-bit and 64-bit modes
on x86_64-pc-linux-gnu. 


$: 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 20151216 (experimental) [trunk revision 231674] (GCC) 
$: 
$: gcc-trunk -w -c small.c -O3 -m32
small.c: In function ‘fn1’:
small.c:2:5: internal compiler error: in vect_update_misalignment_for_peel, at
tree-vect-data-refs.c:889
 int fn1() {
     ^~~

0x1230002 vect_update_misalignment_for_peel
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:888
0x1232cb5 vect_peeling_hash_get_lowest_cost(_vect_peel_info**,
_vect_peel_extended_info*)
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:1219
0x123e603 void hash_table<peel_info_hasher,
xcallocator>::traverse_noresize<_vect_peel_extended_info*,
&(vect_peeling_hash_get_lowest_cost(_vect_peel_info**,
_vect_peel_extended_info*))>(_vect_peel_extended_info*)
        ../../gcc-trunk/gcc/hash-table.h:946
0x123e603 void hash_table<peel_info_hasher,
xcallocator>::traverse<_vect_peel_extended_info*,
&(vect_peeling_hash_get_lowest_cost(_vect_peel_info**,
_vect_peel_extended_info*))>(_vect_peel_extended_info*)
        ../../gcc-trunk/gcc/hash-table.h:968
0x123e603 vect_peeling_hash_choose_best_peeling
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:1274
0x123e603 vect_enhance_data_refs_alignment(_loop_vec_info*)
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:1686
0xd307ed vect_analyze_loop_2
        ../../gcc-trunk/gcc/tree-vect-loop.c:1975
0xd307ed vect_analyze_loop(loop*)
        ../../gcc-trunk/gcc/tree-vect-loop.c:2251
0xd4678f vectorize_loops()
        ../../gcc-trunk/gcc/tree-vectorizer.c:532
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.

$: 
$: gcc-trunk -w -c small.c -O3 -m64
small.c: In function ‘fn1’:
small.c:2:5: internal compiler error: in vect_update_misalignment_for_peel, at
tree-vect-data-refs.c:889
 int fn1() {
     ^~~

0x1230002 vect_update_misalignment_for_peel
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:888
0x1232cb5 vect_peeling_hash_get_lowest_cost(_vect_peel_info**,
_vect_peel_extended_info*)
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:1219
0x123e603 void hash_table<peel_info_hasher,
xcallocator>::traverse_noresize<_vect_peel_extended_info*,
&(vect_peeling_hash_get_lowest_cost(_vect_peel_info**,
_vect_peel_extended_info*))>(_vect_peel_extended_info*)
        ../../gcc-trunk/gcc/hash-table.h:946
0x123e603 void hash_table<peel_info_hasher,
xcallocator>::traverse<_vect_peel_extended_info*,
&(vect_peeling_hash_get_lowest_cost(_vect_peel_info**,
_vect_peel_extended_info*))>(_vect_peel_extended_info*)
        ../../gcc-trunk/gcc/hash-table.h:968
0x123e603 vect_peeling_hash_choose_best_peeling
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:1274
0x123e603 vect_enhance_data_refs_alignment(_loop_vec_info*)
        ../../gcc-trunk/gcc/tree-vect-data-refs.c:1686
0xd307ed vect_analyze_loop_2
        ../../gcc-trunk/gcc/tree-vect-loop.c:1975
0xd307ed vect_analyze_loop(loop*)
        ../../gcc-trunk/gcc/tree-vect-loop.c:2251
0xd4678f vectorize_loops()
        ../../gcc-trunk/gcc/tree-vectorizer.c:532
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.
$: 
$: cat small.c
static int g_534[1][1];
int fn1() {
  int i;
  for (i = 0; i < 4; i++)
    g_534[i + 2][i] ^= 3;
  for (;;)
    ;
}