V6034. Shift by N bits is inconsistent with the size of type.


Analyzer detected a likely error that has to do with shifting a value of integer number by 'N' bits, 'N' being greater than the length of this type in bits.

Consider the following example:

long convert(int x, int y, int shift)
{
  if (shift < 0 || shift > 32) {
    return -1;
  }
  return (x << shift) + y;
}

In this case, a developer wanted to get the 64-bit number from two 32-bit ones, having shifted 'x' for some number of bits 'shift' and having merged the small and the great part. It is possible that 'shift' may have the value equal to 32. As 'x' is 32-bit number at the moment of shifting, then a shift for 32 bits is equal to a shift for 0 bit, which will lead to incorrect result.

This is what the fixed version of the code could look like:

long convert(int x, int y, int shift)
{
  if (shift < 0 || shift > 32) {
    return -1;
  }
  return ((long)x << shift) + y;
}

Bugs Found

Checked Projects
346
Collected Errors
13 188