This is a fresh re-post of:

https://gcc.gnu.org/ml/gcc-patches/2019-07/msg00006.html

Andrew gave me some feedback a week ago, and I obviously don't remember 
what it was because I was about to leave on PTO.  However, I do remember 
I addressed his concerns before getting drunk on rum in tropical islands.

This patch adds MIN/MAX values for VR_VARYING.  As was discussed 
earlier, we are only changing VR_VARYING, not VR_UNDEFINED as was the 
original plan.

As I mentioned earlier, I am tired of re-doing ChangeLogs, so I'll whip 
up the changelog when the review starts.

Tested on x86-64 Linux.

OK?

Aldy