Fix disable-checking bootstrap problem on ppc-darwin

[Andrew MacLeod]

On Tue, 2004-08-10 at 14:12, Daniel Berlin wrote:
> 
> On Aug 10, 2004, at 1:56 PM, Geoffrey Keating wrote:
> 
>
> > +
> > +  for (i = 0; i < NUM_VUSES (ve1->vuses); i++)
> > +    if (! expressions_equal_p (VUSE_OP (ve1->vuses, i),
> > +			       VUSE_OP (ve2->vuses, i)))
> > +      return false;
> >
> 
> My only concern is here:
> Diego, are the vuse lists sorted, such that we can simply compare them 
> in order and get the right result for equality testing?
> If not, can we make them so, so that we can do something like the above?
> 

They aren't sorted. Some stmts can have a lot of vuses, and since the
virtual operands are rebuilt every time the stmt is modified, you might
see some unpleasant time increases as we sort these over and over.

The above code snippet is likely done far less often then the operand
building, so you'd be better off doing it there.  probably :-)

That being said, I will look into sorting them, since there might be an
opportunity to do that cheaply with some of the new operand work I have
in progress... I might be able to offset the cost of sorting them during
insertion with some lookups that need to be done... 

Andrew