ARM patch: Fix PR 40697

[Richard Earnshaw]

On Fri, 2010-03-19 at 12:33 +0100, Bernd Schmidt wrote:
> On 03/19/2010 11:15 AM, Richard Earnshaw wrote:
> 
> > +             return COSTS_N_INSNS (1);
> > 
> > Surely doing the AND with shifts costs two insns, not one.  Could you
> > also add a comment.
> 
> Like so?

Well the comment is fine, but why do we have to lie to the front end to
get it to do the right thing?  Bosscher has been jumping up and down
recently because other parts of the ARM back-end aren't giving the true
costs of things and this would be yet another case.

R.