PVS-Studio warning V684 for V8

U_CFUNC int32_t U_CALLCONV
ucol_calcSortKey(....)
{
  ....
  if((caseBits & 0xC0) == 0) {
    *(cases-1) |= 1 << (--caseShift);
  } else {
    *(cases-1) |= 0 << (--caseShift);
  ....
}

This suspicious code was found in V8 project by PVS-Studio static code analyzer.
Warning message is:
V684 A value of the variable '* (cases - 1)' is not modified. Consider inspecting the expression. It is possible that '1' should be present instead of '0'. ucol.cpp 4941

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