[Bug tree-optimization/38819] [4.2/4.3/4.4 Regression] trapping expression wrongly hoisted out of loop

["rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #5 from rguenth at gcc dot gnu dot org  2009-01-16 20:04 -------
PRE shouldn't cause new evaluations - the issue here is that the CFG

  # BLOCK 2 freq:900
  # PRED: ENTRY [100.0%]  (fallthru,exec)
  si1_3 ={v} a;
  si2_4 ={v} b;
  # SUCC: 3 [100.0%]  (fallthru,exec)

  # BLOCK 3 freq:9100
  # PRED: 8 [100.0%]  (fallthru) 2 [100.0%]  (fallthru,exec)
  # i_31 = PHI <i_12(8), 0(2)>
  foo ();
  x.0_6 ={v} x;
  if (x.0_6 == 8)
    goto <bb 4>;
  else
    goto <bb 7>;
  # SUCC: 4 [28.0%]  (true,exec) 7 [72.0%]  (false,exec)


  # BLOCK 7 freq:6552
  # PRED: 3 [72.0%]  (false,exec)
  goto <bb 5>;
  # SUCC: 5 [100.0%]  (fallthru)

  # BLOCK 4 freq:2548
  # PRED: 3 [28.0%]  (true,exec)
  i_7 = i_31 + 1;
  # SUCC: 5 [100.0%]  (fallthru,exec)

  # BLOCK 5 freq:9100
  # PRED: 7 [100.0%]  (fallthru) 4 [100.0%]  (fallthru,exec)
  # i_1 = PHI <i_31(7), i_7(4)>
  D.1253_8 = si1_3 % si2_4;
  r.1_10 ={v} r;
  D.1254_9 = D.1253_8 + r.1_10;
  r.2_11 = D.1254_9 + i_1;
  r ={v} r.2_11;
  i_12 = i_1 + 1;
  if (i_12 <= 99)
    goto <bb 8>;
  else
    goto <bb 6>;
  # SUCC: 8 [90.1%]  (true,exec) 6 [9.9%]  (false,exec)

  # BLOCK 8 freq:8200
  # PRED: 5 [90.1%]  (true,exec)
  goto <bb 3>;
  # SUCC: 3 [100.0%]  (fallthru)

  # BLOCK 6 freq:900
  # PRED: 5 [9.9%]  (false,exec)
  abort ();
  # SUCC:

does not model the fact that foo () does not return.

Danny, do you have any suggestion (besides to try to avoid trapping stuff
somehow) to model this?


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dberlin at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38819