[Bug tree-optimization/69157] New: [6 Regression] ICE in vect_transform_stmt, at tree-vect-stmts.c:8176

[doko at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69157

            Bug ID: 69157
           Summary: [6 Regression] ICE in vect_transform_stmt, at
                    tree-vect-stmts.c:8176
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: doko at gcc dot gnu.org
  Target Milestone: ---

seen with trunk r232040, x86_64-linux-gnu, -O2 avoids the issue.

reduced test case:

typedef struct {
  float *data_normal3f;
  float *data_texcoordtexture2f;
  float *data_texcoordlightmap2f;
  float *data_color4f;
} dp_model_t;
dp_model_t a;
float *b;
void fn1() {
  int c;
  a.data_normal3f = b + c * 3;
  a.data_texcoordtexture2f = a.data_normal3f + c * 3;
  a.data_texcoordlightmap2f = a.data_color4f =
      a.data_texcoordlightmap2f + c * 2;
}

$ gcc -c -g -O3 model_brush.i
model_brush.i: In function 'fn1':
model_brush.i:9:6: internal compiler error: in vect_transform_stmt, at
tree-vect-stmts.c:8176
 void fn1() {
      ^~~

0xb5a9b2 vect_transform_stmt(gimple*, gimple_stmt_iterator*, bool*, _slp_tree*,
_slp_instance*)
        ../../src/gcc/tree-vect-stmts.c:8176
0xb716b6 vect_schedule_slp_instance
        ../../src/gcc/tree-vect-slp.c:3537
0xb713ce vect_schedule_slp_instance
        ../../src/gcc/tree-vect-slp.c:3412
0xb74325 vect_schedule_slp(vec_info*)
        ../../src/gcc/tree-vect-slp.c:3609
0xb74b0c vect_slp_bb(basic_block_def*)
        ../../src/gcc/tree-vect-slp.c:2633
0xb76605 execute
        ../../src/gcc/tree-vectorizer.c:759
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