[Bug tree-optimization/37810] Bad store sinking job

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37810

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2009-04-03 12:34:44         |2021-7-25

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
For the reduced testcase in comment #2 I get now:
4.8.0+:
.L4:
        addl    $1, %eax
        movl    %eax, (%rbx)
        cmpl    4(%rbx), %eax
        je      .L8
.L3:
        testl   %eax, %eax
        jne     .L4

4.7.4 and before:
.L3:
        testl   %eax, %eax
        je      .L8
        addl    $1, %eax
        cmpl    4(%rbx), %eax
        movl    %eax, (%rbx)
        jne     .L3

Or on the trunk at the gimple level:
  <bb 3> [local count: 1014686025]:
  _1 = prephitmp_10 + 1;
  iter_6(D)->n = _1;
  _2 = iter_6(D)->m;
  if (_1 == _2)
    goto <bb 4>; [5.50%]
  else
    goto <bb 6>; [94.50%]

  <bb 4> [local count: 55807731]:
  g ();

  <bb 5> [local count: 114863530]:
  pretmp_11 = iter_6(D)->n;

  <bb 6> [local count: 1073741824]:
  # prephitmp_10 = PHI <pretmp_11(5), _1(3)>
  if (prephitmp_10 != 0)
    goto <bb 3>; [94.50%]
  else
    goto <bb 7>; [5.50%]

Aka the store still happens inside the loop unconditionally.