[Bug middle-end/70240] New: [6 Regression] ICE: in gimplify_modify_expr, at gimplify.c:4854 with -ftree-vectorize

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70240

            Bug ID: 70240
           Summary: [6 Regression] ICE: in gimplify_modify_expr, at
                    gimplify.c:4854 with -ftree-vectorize
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
            Target: i686-pc-linux-gnu, armv7a-hardfloat-linux-gnueabi,
                    powerpc-unknown-linux-gnu

Created attachment 37970
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37970&action=edit
reduced testcase

Compiler output:
$ i686-pc-linux-gnu-gcc -O3 testcase.c 
In function 'foo':
cc1: internal compiler error: in gimplify_modify_expr, at gimplify.c:4854
0x8fcc0e gimplify_modify_expr
        /repo/gcc-trunk/gcc/gimplify.c:4854
0x8f182d gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        /repo/gcc-trunk/gcc/gimplify.c:10186
0x8f4356 gimplify_stmt(tree_node**, gimple**)
        /repo/gcc-trunk/gcc/gimplify.c:5652
0x8f811b gimplify_cond_expr
        /repo/gcc-trunk/gcc/gimplify.c:3247
0x8f17b6 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        /repo/gcc-trunk/gcc/gimplify.c:10142
0x8f4356 gimplify_stmt(tree_node**, gimple**)
        /repo/gcc-trunk/gcc/gimplify.c:5652
0x8f7e4c gimplify_cond_expr
        /repo/gcc-trunk/gcc/gimplify.c:3140
0x8f17b6 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        /repo/gcc-trunk/gcc/gimplify.c:10142
0x90afec force_gimple_operand_1(tree_node*, gimple**, bool (*)(tree_node*),
tree_node*)
        /repo/gcc-trunk/gcc/gimplify-me.c:78
0x90b11f force_gimple_operand_gsi_1(gimple_stmt_iterator*, tree_node*, bool
(*)(tree_node*), tree_node*, bool, gsi_iterator_update)
        /repo/gcc-trunk/gcc/gimplify-me.c:115
0xde0728 expand_vector_piecewise
        /repo/gcc-trunk/gcc/tree-vect-generic.c:272
0xde0ada expand_vector_parallel
        /repo/gcc-trunk/gcc/tree-vect-generic.c:306
0xde238b expand_vector_scalar_condition
        /repo/gcc-trunk/gcc/tree-vect-generic.c:1482
0xde238b expand_vector_operations_1
        /repo/gcc-trunk/gcc/tree-vect-generic.c:1533
0xde238b expand_vector_operations
        /repo/gcc-trunk/gcc/tree-vect-generic.c:1768
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.

Tested revisions:
trunk r234183 - FAIL
5-branch r234179 - OK