[Bug c/83914] New: ice in vect_is_simple_use with -O3

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83914

            Bug ID: 83914
           Summary: ice in vect_is_simple_use with -O3
           Product: gcc
           Version: 8.0
            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 43160
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43160&action=edit
C source code

The attached C code, when compiled by recent gcc trunk and flag -O3,
does this:

./src/regex/regcomp.c:284:1: internal compiler error: Segmentation fault
0xda679f crash_signal
        ../../trunk/gcc/toplev.c:325
0x10876e0 vect_is_simple_use(tree_node*, vec_info*, gimple**, vect_def_type*)
        ../../trunk/gcc/tree-vect-stmts.c:9927
0x1088745 vect_get_vec_def_for_operand(tree_node*, gimple*, tree_node*)
        ../../trunk/gcc/tree-vect-stmts.c:1434
0x10abebd vectorizable_induction(gimple*, gimple_stmt_iterator*, gimple**,
_slp_tree*)

I have a go at reducing the code and finding a range of revisions
where the problem seems to exist.