[Bug tree-optimization/38785] [4.5/4.6/4.7/4.8 Regression] huge performance regression on EEMBC bitmnp01

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38785

--- Comment #38 from Jan Hubicka <hubicka at gcc dot gnu.org> 2012-11-22 13:05:38 UTC ---
yet another variant...
void
f (int i, long *a, long *b)
{
  int sum = 0;
  for (; --i >=  0; a++, b++)
    {
  b[i] = 0;
#define PART(I) if (t()) sum+=100+I;
  PART (1);
  PART (2);
  PART (3);
  PART (4);
  PART (5);
  PART (6);
  tt (sum);
    }
}
leads to...
Starting insert iteration 1
Could not find SSA_NAME representative for expression:{plus_expr,sum_8,101}
Created SSA_NAME representative pretmp_98 for expression:{plus_expr,sum_8,101}
Could not find SSA_NAME representative for expression:{plus_expr,pretmp_98,102}
Created SSA_NAME representative pretmp_99 for
expression:{plus_expr,pretmp_98,102}
Could not find SSA_NAME representative for expression:{plus_expr,pretmp_99,103}
Created SSA_NAME representative pretmp_100 for
expression:{plus_expr,pretmp_99,103}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_100,104}
Created SSA_NAME representative pretmp_101 for
expression:{plus_expr,pretmp_100,104}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_101,105}
Created SSA_NAME representative pretmp_102 for
expression:{plus_expr,pretmp_101,105}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_100,105}
Created SSA_NAME representative pretmp_103 for
expression:{plus_expr,pretmp_100,105}
Could not find SSA_NAME representative for expression:{plus_expr,pretmp_99,104}
Created SSA_NAME representative pretmp_104 for
expression:{plus_expr,pretmp_99,104}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_104,105}
Created SSA_NAME representative pretmp_105 for
expression:{plus_expr,pretmp_104,105}
Could not find SSA_NAME representative for expression:{plus_expr,pretmp_99,105}
Created SSA_NAME representative pretmp_106 for
expression:{plus_expr,pretmp_99,105}
Could not find SSA_NAME representative for expression:{plus_expr,pretmp_98,103}
Created SSA_NAME representative pretmp_107 for
expression:{plus_expr,pretmp_98,103}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_107,104}
Created SSA_NAME representative pretmp_108 for
expression:{plus_expr,pretmp_107,104}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_108,105}
Created SSA_NAME representative pretmp_109 for
expression:{plus_expr,pretmp_108,105}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_107,105}
Created SSA_NAME representative pretmp_110 for
expression:{plus_expr,pretmp_107,105}
Could not find SSA_NAME representative for expression:{plus_expr,pretmp_98,104}
Created SSA_NAME representative pretmp_111 for
expression:{plus_expr,pretmp_98,104}
Could not find SSA_NAME representative for
expression:{plus_expr,pretmp_111,105}

that eventually leads to a lot of unused pretmp vars.