[Bug tree-optimization/110628] [14 regression] gcc.dg/tree-ssa/update-threading.c fails after r14-2383-g768f00e3e84123

["hubicka at ucw dot cz" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110628

--- Comment #6 from Jan Hubicka <hubicka at ucw dot cz> ---
The mismatch happens on:
void foo (unsigned int x)
{
  if (x != 0x800 && x != 0x810)
    abort ();
}

It is bug in reassoc turning:

void foo (unsigned int x)
{  
;;   basic block 2, loop depth 0, count 1073741824 (estimated locally, freq
1.0000), maybe hot
;;    prev block 0, next block 3, flags: (NEW, REACHABLE, VISITED)
;;    pred:       ENTRY [always]  count:1073741824 (estimated locally, freq
1.0000) (FALLTHRU,EXECUTABLE)
  if (x_1(D) != 2048)
    goto <bb 3>; [66.00%]
  else
    goto <bb 5>; [34.00%]
;;    succ:       3 [66.0% (guessed)]  count:708669600 (estimated locally, freq
0.6600) (TRUE_VALUE,EXECUTABLE)
;;                5 [34.0% (guessed)]  count:365072224 (estimated locally, freq
0.3400) (FALSE_VALUE,EXECUTABLE)

;;   basic block 3, loop depth 0, count 708669600 (estimated locally, freq
0.6600), maybe hot
;;    prev block 2, next block 4, flags: (NEW, REACHABLE, VISITED)
;;    pred:       2 [66.0% (guessed)]  count:708669600 (estimated locally, freq
0.6600) (TRUE_VALUE,EXECUTABLE)
  if (x_1(D) != 2064)
    goto <bb 4>; [0.00%]
  else
    goto <bb 5>; [100.00%] 
;;    succ:       4 [never]  count:0 (precise, freq 0.0000)
(TRUE_VALUE,EXECUTABLE)
;;                5 [always]  count:708669600 (estimated locally, freq 0.6600)
(FALSE_VALUE,EXECUTABLE)

;;   basic block 4, loop depth 0, count 0 (precise, freq 0.0000), probably
never executed
;;    prev block 3, next block 5, flags: (NEW, REACHABLE, VISITED)
;;    pred:       3 [never]  count:0 (precise, freq 0.0000)
(TRUE_VALUE,EXECUTABLE)
  abort ();
;;    succ:       



to:


void foo (unsigned int x)
{
  unsigned int _4;
  _Bool _5;

;;   basic block 2, loop depth 0, count 1073741824 (estimated locally, freq
1.0000), maybe hot
;;    prev block 0, next block 3, flags: (NEW, REACHABLE, VISITED)
;;    pred:       ENTRY [always]  count:1073741824 (estimated locally, freq
1.0000) (FALLTHRU,EXECUTABLE)
  _4 = x_1(D) & 4294967279;
  _5 = _4 != 2048;
  if (_5 != 0)
    goto <bb 3>; [66.00%]
  else
    goto <bb 4>; [34.00%]
;;    succ:       3 [66.0% (guessed)]  count:708669600 (estimated locally, freq
0.6600) (TRUE_VALUE,EXECUTABLE)
;;                4 [34.0% (guessed)]  count:365072224 (estimated locally, freq
0.3400) (FALSE_VALUE,EXECUTABLE)

;;   basic block 3, loop depth 0, count 0 (precise, freq 0.0000), probably
never executed
;;   Invalid sum of incoming counts 708669600 (estimated locally, freq 0.6600),
should be 0 (precise, freq 0.0000)
;;    prev block 2, next block 4, flags: (NEW, REACHABLE, VISITED)
;;    pred:       2 [66.0% (guessed)]  count:708669600 (estimated locally, freq
0.6600) (TRUE_VALUE,EXECUTABLE)
  abort ();
;;    succ:

;;   basic block 4, loop depth 0, count 1073741824 (estimated locally, freq
1.0000), maybe hot
;;   Invalid sum of incoming counts 365072224 (estimated locally, freq 0.3400),
should be 1073741824 (estimated locally, freq 1.0000)
;;    prev block 3, next block 1, flags: (NEW, REACHABLE, VISITED)
;;    pred:       2 [34.0% (guessed)]  count:365072224 (estimated locally, freq
0.3400) (FALSE_VALUE,EXECUTABLE)
  return;

So it combines two conditionals together but does not update the
outgoing probabilitis of the conditional.
On x86-64 we have already in cfg dump:

  _1 = x != 2048;
  _2 = x != 2064;
  _3 = _1 & _2;
  if (_3 != 0)
    goto <bb 3>; [INV]
  else

I wonder why optimization diverges here?