[Bug middle-end/25248] [4.1/4.2 Regression] 2.6.15-rc4 arch/powerpc/mm/hash_utils_64.c miscompiled

[rguenth at gcc dot gnu dot org]

------- Comment #17 from rguenth at gcc dot gnu dot org  2005-12-06 13:59 
-------
IVOPTs truncates pstartD.1866_10 down to int, which is wrong:

htab_bolt_mapping (pstartD.1866, cntD.1867)
{
  unsigned intD.3 D.1959;
  long unsigned intD.4 D.1960;
  long unsigned intD.4 ivtmp.50D.1954;
  unsigned intD.3 stepD.1871;
  long unsigned intD.4 iD.1870;
  intD.0 D.1881;
  long unsigned intD.4 D.1880;
  long unsigned intD.4 D.1879;
  unsigned intD.3 cond.12D.1878;
  intD.0 D.1877;
  intD.0 shift.11D.1876;
  unsigned intD.3 shift.10D.1875;

<bb 0>:
  shift.10D.1875_5 = shiftD.1865;
  shift.11D.1876_6 = (intD.0) shift.10D.1875_5;
  D.1877_7 = 1 << shift.11D.1876_6;
  stepD.1871_8 = (unsigned intD.3) D.1877_7;
  if (cntD.1867_11 != 0) goto <L9>; else goto <L4>;

<L9>:;
  ivtmp.50D.1954_21 = (long unsigned intD.4) stepD.1871_8;
  D.1959_23 = (unsigned intD.3) pstartD.1866_10;
  D.1960_26 = (long unsigned intD.4) D.1959_23;
  ivtmp.50D.1954_3 = D.1960_26 - 000000000;

  # ivtmp.50D.1954_1 = PHI <ivtmp.50D.1954_2(5), ivtmp.50D.1954_3(1)>;
  # iD.1870_28 = PHI <iD.1870_18(5), 0(1)>;
<L0>:;
  cond.12D.1878_15 = condD.1864;
  if (cond.12D.1878_15 != 0) goto <L1>; else goto <L2>;


before we have (cunroll):

<bb 0>:
  shift.10D.1875_5 = shiftD.1865;
  shift.11D.1876_6 = (intD.0) shift.10D.1875_5;
  D.1877_7 = 1 << shift.11D.1876_6;
  stepD.1871_8 = (unsigned intD.3) D.1877_7;
  if (cntD.1867_11 != 0) goto <L9>; else goto <L4>;

<L9>:;

  # iD.1870_28 = PHI <iD.1870_18(5), 0(1)>;
  # pstartD.1866_27 = PHI <pstartD.1866_17(5), pstartD.1866_10(1)>;
<L0>:;
  cond.12D.1878_15 = condD.1864;
  if (cond.12D.1878_15 != 0) goto <L1>; else goto <L2>;


Zdenek surely knows where this happens and how to best fix it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25248