[Bug tree-optimization/105832] [13 Regression] Dead Code Elimination Regression at -O3 (trunk vs. 12.1.0)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105832

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-bisection             |

--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> ---
With r13-3897-gbe2c74fdcd0e8d66 get:
gcc pr105832.c -c -O3 -fdump-tree-optimized=/dev/stdout --param
max-jump-thread-duplication-stmts=17


;; Function main (main, funcdef_no=0, decl_uid=2741, cgraph_uid=1,
symbol_order=2) (executed once)

int main ()
{
  <bb 2> [local count: 178992760]:
  c.a = 0;
  return 0;

}

before the revision I was:

;; Function main (main, funcdef_no=0, decl_uid=2741, cgraph_uid=1,
symbol_order=2) (executed once)

Removing basic block 5
int main ()
{
  char _1;
  unsigned char _2;
  char iftmp.0_11;

  <bb 2> [local count: 178992758]:
  _1 = c.b;
  _2 = (unsigned char) _1;
  if (_2 > 4)
    goto <bb 4>; [50.00%]
  else
    goto <bb 3>; [50.00%]

  <bb 3> [local count: 89496379]:
  iftmp.0_11 = _1 << 2;

  <bb 4> [local count: 178992760]:
  c.a = 0;
  return 0;

}