The Clang scanbuild tool warns:

    Utilities/cmliblzma/liblzma/simple/x86.c:106:23: warning:
    The result of the '<<' expression is undefined
      src = dest ^ ((1u << (32 - i * 8)) - 1);
                     ~~~^~~~~~~~~~~~~~~

AFAIK overflow of a left shift on an unsigned type is well-defined.