[Bug tree-optimization/91616] Incorrect data address computation in very simple code

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91616

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2019-09-02
     Ever confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
I don't see anything "incorrect" either - GCC optimizes this down to the
single IV 'seed', eliding 'i' by expressing data_array[i] in terms of 'seed':

  <bb 3> [local count: 955630224]:
  # seed_14 = PHI <14627338366734941935(2), seed_7(3)>
  seed_7 = seed_14 + 1;
  MEM[symbol: data_array, index: seed_7, step: 8, offset:
-6338242491622225792B] = seed_14;
  if (seed_7 != 14627338366734941951)
    goto <bb 3>; [89.00%]