[Bug tree-optimization/81083] [7/8 Regression] ICE: Unable to coalesce ssa_names 4 and 13 which are marked as MUST COALESCE

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81083

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2017-06-13
      Known to work|                            |6.3.1
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot 
gnu.org
   Target Milestone|---                         |7.2
            Summary|[7 Regression] ICE: Unable  |[7/8 Regression] ICE:
                   |to coalesce ssa_names 4 and |Unable to coalesce
                   |13 which are marked as MUST |ssa_names 4 and 13 which
                   |COALESCE                    |are marked as MUST COALESCE
     Ever confirmed|0                           |1
      Known to fail|                            |7.1.1, 8.0

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

  <bb 4> [99.96%]:
  obj.x = arg_3(ab);
  arg_13(ab) = arg_9(D);
  _1 = obj.x;
  if (_1 != 0)
    goto <bb 5>; [33.00%]
  else
    goto <bb 7>; [67.00%]

  <bb 5> [32.99%]:
  func ();

  <bb 6> [32.98%]:
  pretmp_17 = obj.x;

  <bb 7> [99.95%]:
  # prephitmp_18 = PHI <arg_3(ab)(4), pretmp_17(6)>

caused by PRE.

Mine.