[PATCH 0/7] Fix invalid left shift of negative value.

[Andreas Schwab]

DJ Delorie <dj@redhat.com> writes:

> -  return ((size + (1 << align) - 1) & (-1 << align));
> +  return ((size + (1 << align) - 1) & -(1 << align));
>
> This is an annoying new rule to remember.  Would this be a valid substitution?
>
>    return ((size + (1 << align) - 1) & (~0 << align));
>
> In cases where we're forming bitmasks, a mathematical negation doesn't
> "fit" as well as logical operations.

~0 is still a negative number.

Andreas.

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Andreas Schwab, schwab@linux-m68k.org
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