[Bug tree-optimization/71020] [6/7 Regression] SSA corruption: Unable to coalesce ssa_names 2 and 13 which are marked as MUST COALESCE.

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71020

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
                 CC|                            |rsandifo at gcc dot gnu.org

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
  b_13(ab) = SQRT (b_1(ab));
  DCE_COND_LB.2_15 = b_1(ab);
  if (DCE_COND_LB.2_15 u>= 0.0)

introduced by cdce.  Likely triggered by Richards changes.  We have

  <bb 4>:
  # b_1(ab) = PHI <b_9(3), b_2(ab)(5)>
  _setjmp ();
  b_13(ab) = sqrt (b_1(ab));
  err_logo ();
  goto <bb 6>;

where one way to fix this is push b_1(ab) to a non-abnormal temporary
before the call and re-use that.  Or simply give up for example
via checking for abnormal SSA call arguments in an appropriate place.