misc VRP cleanups for value_range API

[Aldy Hernandez]

On 11/8/18 9:31 AM, Richard Biener wrote:
> On Thu, Nov 8, 2018 at 1:42 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>>
>> Stupid boring changes.
>>
>> OK?
> 
> Well, IMHO using m_min is making clear you are accessing a member
> while using min () does not.

There is already prior art here.  I believe I discussed this before and 
committed some bits like this.

> 
> So no, please do not make this kind of changes?

It also makes it easier for my work going forward.  So not technically 
needed, but it would make my life easier as I change the min/max 
implementation in the distant future.  Please?

Aldy