[Bug c/68104] New: ice in vect_update_misalignment_for_peel with -O3

["dcb314 at hotmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68104

            Bug ID: 68104
           Summary: ice in vect_update_misalignment_for_peel with -O3
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 36592
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36592&action=edit
C source code

For trunk dated 20151025 on x86_64, the attached code crashes as follows
when compiled with -O3

osm_qos.c: In function âvlarb_update_table_blockâ:
osm_qos.c:146:24: internal compiler error: in
vect_update_misalignment_for_peel, at tree-vect-data-refs.c:850
0x138e609 vect_update_misalignment_for_peel
        ../../src/trunk/gcc/tree-vect-data-refs.c:849
0x138f2a5 vect_peeling_hash_get_lowest_cost(_vect_peel_info**,
_vect_peel_extended_info*)
        ../../src/trunk/gcc/tree-vect-data-refs.c:1167
0x139bd9a 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*)
        ../../src/trunk/gcc/hash-table.h:915
0x139bd9a 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*)
        ../../src/trunk/gcc/hash-table.h:937
0x139bd9a vect_peeling_hash_choose_best_peeling
        ../../src/trunk/gcc/tree-vect-data-refs.c:1222
0x139bd9a vect_enhance_data_refs_alignment(_loop_vec_info*)
        ../../src/trunk/gcc/tree-vect-data-refs.c:1636
0xe0547f vect_analyze_loop_2
        ../../src/trunk/gcc/tree-vect-loop.c:1748
0xe0547f vect_analyze_loop(loop*)
        ../../src/trunk/gcc/tree-vect-loop.c:1934
0xe1a81f vectorize_loops()
        ../../src/trunk/gcc/tree-vectorizer.c:496
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