[Bug tree-optimization/43017] New: [4.5 Regression] VRP miscompiles python with -fwrapv, II

[rguenth at gcc dot gnu dot org]

Another one.

signed char foo(unsigned char c2)
{
  signed char c2_22;

  if (c2 <= 63 || c2 == 127)
    goto bb43;
  else
    goto bb20;

bb20:
  if (c2 > 252)
    goto bb43;
  else
    goto bb21;

bb21:
  /*...*/;

bb24:
  c2_22 = (signed char)c2;
  if (c2_22 >= 0)
    goto bb25;
  else
    goto bb26;

bb25:
  c2 = (unsigned char)(c2_22 - 64);
  goto bb27;

bb26:
  c2 = (unsigned char)(c2_22 - 65);

bb27:
  if (c2 <= 93)
    goto bb28;
  else
    goto bb29;

bb28:
  c2 = c2 + 33;
  goto bb30;

bb29:
  c2 = (unsigned char)((signed char)c2 - 61);

bb30:
  return c2;

bb43:
  return -1;
}
extern void abort (void);
int main()
{
  signed char res[256] = {
      -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1,
      33, 34, 35, 36, 37, 38, 39, 40,
      41, 42, 43, 44, 45, 46, 47, 48,
      49, 50, 51, 52, 53, 54, 55, 56,
      57, 58, 59, 60, 61, 62, 63, 64,
      65, 66, 67, 68, 69, 70, 71, 72,
      73, 74, 75, 76, 77, 78, 79, 80,
      81, 82, 83, 84, 85, 86, 87, 88,
      89, 90, 91, 92, 93, 94, 95, -1,
      96, 97, 98, 99, 100, 101, 102, 103,
      104, 105, 106, 107, 108, 109, 110, 111,
      112, 113, 114, 115, 116, 117, 118, 119,
      120, 121, 122, 123, 124, 125, 126, 33,
      34, 35, 36, 37, 38, 39, 40, 41,
      42, 43, 44, 45, 46, 47, 48, 49,
      50, 51, 52, 53, 54, 55, 56, 57,
      58, 59, 60, 61, 62, 63, 64, 65,
      66, 67, 68, 69, 70, 71, 72, 73,
      74, 75, 76, 77, 78, 79, 80, 81,
      82, 83, 84, 85, 86, 87, 88, 89,
      90, 91, 92, 93, 94, 95, 96, 97,
      98, 99, 100, 101, 102, 103, 104, 105,
      106, 107, 108, 109, 110, 111, 112, 113,
      114, 115, 116, 117, 118, 119, 120, 121,
      122, 123, 124, 125, 126, -1, -1, -1
  };
  unsigned int c;
  for (c = 0; c <= 255; ++c)
    {
      if (foo (c) != res[c])
        abort ();
    }
  return 0;
}


-- 
           Summary: [4.5 Regression] VRP miscompiles python with -fwrapv, II
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43017