Re: clang memory sanitizer report unsigned int overflow

[Roberto Ierusalimschy <roberto@...>]

> For reference that is this line marked with **:
> 
>    |  unsigned int luaS_hash (const char *str, size_t l, unsigned int seed)
> {
>    |    unsigned int h = seed ^ cast_uint(l);
>    |    for (; l > 0; l--)
> **|       h ^= ((h<<5) + (h>>2) + cast_byte(str[l - 1]));
>    |    return h;
>    |  }
> 
> Though not sure which part of that would be causing an add overflow because
> h is an unsigned int which I believe should not trigger UB when it
> overflows.

The 'reason' itself states "Unsigned integer overflow", which does not
exist in ISO C...

    Process 626150 stopped
    * thread #1, name = 'ufsrv', stop reason = Unsigned integer overflow
                                      ??????????????????????????????????

-- Roberto