fixed clang warning about shifting negative values
fixed clang warning about shifting negative values

rzinsly/gperftools,gperftools/gperftools,alk/gperftools,gperftools/gperftools,romange/gperftools,xiaoyur347/gperftools,gperftools/gperftools,rzinsly/gperftools,gperftools/gperftools,alk/gperftools,gshirishfree/gperftools,romange/gperftools,alk/gperftools,rzinsly/gperftools,rzinsly/gperftools,chencl/gperftools,acmorrow/gperftools,gshirishfree/gperftools,acmorrow/gperftools,acmorrow/gperftools,chencl/gperftools,alk/gperftools,romange/gperftools,gshirishfree/gperftools,chencl/gperftools,acmorrow/gperftools,gshirishfree/gperftools,romange/gperftools,xiaoyur347/gperftools,chencl/gperftools,xiaoyur347/gperftools,xiaoyur347/gperftools