[Bug tree-optimization/128267] [15/16/17 Regression] wrong code at -O2 with -march=x86-64-v4: a signed char shift induction is 64 again instead of 0 after 256 iterations

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128267

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot 
gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
  ivtmp_40 = ivtmp_39 + 1;
  if (ivtmp_40 < 8192)
    goto <bb 5>; [98.99%]
  else
    goto <bb 7>; [1.01%]

  <bb 5> [local count: 1052266995]:
  goto <bb 3>; [100.00%]

  <bb 7> [local count: 10737416]:
  # b_30 = PHI <b_10(3)>
  # i_31 = PHI <i_11(3)>
  # ivtmp_32 = PHI <ivtmp_5(3)>

  <bb 8> [local count: 75161909]:
  # b_13 = PHI <b_26(9), 64(OVF)(7)>
  # i_19 = PHI <i_27(9), 65536(7)>
  # ivtmp_21 = PHI <ivtmp_28(9), 1(7)>
  _22 = (long unsigned int) i_19;
  _23 = _22 * 2;