[Bug tree-optimization/105173] [10/11/12 Regression] ICE: during GIMPLE pass: reassoc: verify_ssa failed (definition in block 2 follows the use) at -Ofast with decimals since r7-950-g8a85cee26eabf5cf

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105173

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
  <bb 2> [local count: 1073741824]:
  i.0_1 = i;
  _2 = (_Decimal32) i.0_1;
  _12 = (_Decimal64) _2;
  _13 = (_Decimal64) d_8(D);
  _3 = _12 * _13;
  _4 = (_Decimal64) c_9(D);
  _5 = -_4;
  _6 = _3 * _5;
  d_10 = (_Decimal32) _6;
  _11 = (int) d_10;

Transforming _12 = (_Decimal64) _2;
 into _14 = _12 * -1.0e+0;
Transforming _3 = _12 * _13;
 into _15 = _14 * _4;
Transforming _6 = _3 * _5;
 into _6 = _15 * _13;

  <bb 2> [local count: 1073741824]:
  i.0_1 = i;
  _2 = (_Decimal32) i.0_1;
  _14 = _12 * -1.0e+0;
  _12 = (_Decimal64) _2;
  _13 = (_Decimal64) d_8(D);
  _4 = (_Decimal64) c_9(D);
  _15 = _14 * _4;
  _6 = _15 * _13;
  d_10 = (_Decimal32) _6;
  _11 = (int) d_10;
  return _11;

and the logic wrt

              gimple *insert_point
                = find_insert_point (stmt, oe1->op, oe2->op);
...
              if (insert_point == gsi_stmt (gsi))
                gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
              else
                insert_stmt_after (stmt, insert_point);

does not work for

(gdb) p debug_gimple_stmt (stmt)
_12 = (_Decimal64) _2;
$4 = void
(gdb) p oe1->op
$5 = <ssa_name 0x7ffff667e120 12>
(gdb) p oe2->op
$6 = <real_cst 0x7ffff6681540>

testing a fix.