RFC: Simplify rules for ctz/clz patterns and RTL

[Andrew Pinski]

On 8/15/07, Zack Weinberg <zack@codesourcery.com> wrote:
> Is popcount really slow on PowerPC?  (Compared to clz?)
popcount is really popcount in bytes and then you do a multiple to get
the real popcount.  This is why it is slower than count leading zeros.
 Also popcount does not exist in most powerpc's while count leading
zeros exist in all.

Thanks,
Andrew Pinski