[Bug 37117] New: PVS-Studio Error: Shifting a negative number

[wine-bugs at winehq.org]

https://bugs.winehq.org/show_bug.cgi?id=37117

            Bug ID: 37117
           Summary: PVS-Studio Error: Shifting a negative number
           Product: Wine
           Version: 1.7.22
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: wine-bugs at winehq.org
          Reporter: lukebenes at hotmail.com

PVS-Studio Error: V610 Undefined behavior. Check the shift operator '<<. The
left operand '(LONGLONG) - 1' is negative. propvar.c 127

...
if (*res >= ((LONGLONG)1 << (dest_bits-1)) ||
  *res < ((LONGLONG)-1 << (dest_bits-1)))
  return HRESULT_FROM_WIN32(ERROR_ARITHMETIC_OVERFLOW);
...

The LONGLONG type is declared as 'typedef signed __int64 LONGLONG;', i.e. it is
a signed type. According to the new standard, shifting negative numbers leads
to undefined or unspecified behavior. To find out why such code still may work
and how to fix it best, see the article Wade not in unknown waters - part
three.

details on the V610 error here: http://www.viva64.com/en/d/0225/

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