[Bug rtl-optimization/21617] [4.4/4.5/4.6/4.7 Regression] CRC64 algorithm optimization problem on Intel 32-bit

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21617

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-12-08 
03:37:28 UTC ---
-O1:

<bb 5>:
  # __crc0_73 = PHI <__crc0_35(5), __crc0_54(7)>
  # __data_75 = PHI <__data_32(5), data_7(7)>
  D.1900_26 = __crc0_73 >> 56;
  D.1901_27 = (int) D.1900_26;
  D.1902_28 = MEM[base: __data_75, offset: 0B];
  D.1903_29 = (int) D.1902_28;
  D.1904_30 = D.1903_29 ^ D.1901_27;
  __tab_index_31 = D.1904_30 & 255;
  __data_32 = __data_75 + 1;
  D.1905_33 = crc_table[__tab_index_31];
  D.1906_34 = __crc0_73 << 8;
  __crc0_35 = D.1905_33 ^ D.1906_34;
  if (__data_32 != D.1928_55)
    goto <bb 5>;
  else
    goto <bb 6>;

-O2:
<bb 5>:
  # __crc0_1 = PHI <__crc0_35(5), __crc0_54(7)>
  # __data_67 = PHI <__data_32(5), data_7(7)>
  D.1900_26 = __crc0_1 >> 56;
  D.1901_27 = (int) D.1900_26;
  D.1902_28 = MEM[base: __data_67, offset: 0B];
  D.1903_29 = (int) D.1902_28;
  D.1904_30 = D.1903_29 ^ D.1901_27;
  __tab_index_31 = D.1904_30 & 255;
  __data_32 = __data_67 + 1;
  D.1905_33 = crc_table[__tab_index_31];
  D.1906_34 = __crc0_1 << 8;
  __crc0_35 = D.1905_33 ^ D.1906_34;
  if (__data_32 != D.1955_86)
    goto <bb 5>;
  else
    goto <bb 6>;

Aka nothing on the tree level causes the issue.