[aarch64-port-dev ] RFR: 8221658: aarch64: add necessary predicate for ubfx patterns

[Yangfei (Felix)]

Updated webrev: http://cr.openjdk.java.net/~fyang/8221658/webrev.01 
Is this one better? 

Still some constraints can be removed from predicate by using a match operand for other patterns, say ubfizwI/ubfiz. 
I can propose a separate patch to handle that if you want. 

Thanks,
Felix

> 
> On 4/1/19 2:19 AM, Yangfei (Felix) wrote:
> > The patch adds the following three constraints for 'rshift' and 'mask' operands:
> >
> >     1. 0 <= rshift <=31/63
> >     2. mask != 0
> >     3. rshift + width <= 32/64  (width = exact_log2(mask+1))
> >
> >     Constraint 3 needs to be implemented by adding a predicate as we are
> checking both 'rshift' and 'mask' operands.
> >
> >     Do you want me to implement constraint 1 & 2 using a match operand?
> 
> Yes. Please do so wherever possible.