[Bug tree-optimization/70310] [6 Regression] wrong code with vector compare at -O0

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70310

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot 
gnu.org

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Ick.  The IL is quite "interesting", including some "dead" _4 = {_3}

  <bb 2>:
  _2 = (unsigned char) u_1(D);
  _3 = -_2;
  _4 = {_3};
  _16 = 0;
  _5 = {_16, -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF),
-1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF),
-1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF),
-1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF), -1(OVF)};
  v32u8_0.0_6 = VIEW_CONVERT_EXPR<v32u8>(_5);
  v32u8_0 = v32u8_0.0_6;
  _9 = BIT_FIELD_REF <v32u8_0, 8, 248>;
  _10 = (int) _9;
  _11 = BIT_FIELD_REF <v32u8_0, 8, 0>;
  _12 = (int) _11;
  _13 = _10 + _12;
  _14 = (unsigned int) _13;
  v32u8_0 ={v} {CLOBBER};