Dump LIS before regalloc. MI sched changes them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187107 91177308-0d34-0410-b5e6-96231b3b80d8
RegPressure: Order the "pressure sets" by number of regunits per set.

This lets heuristics easily pick the most important set to follow.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187108 91177308-0d34-0410-b5e6-96231b3b80d8
MI Sched: track register pressure by importance of the set, not weight of the units.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187109 91177308-0d34-0410-b5e6-96231b3b80d8
MI Sched: Register pressure heuristics.

Consider which set is being increased or decreased before comparing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187110 91177308-0d34-0410-b5e6-96231b3b80d8