mi-sched: Don't call MBB.size() in initSUnits. The driver already has instr count.

This fixes a pathological compile time problem with very large blocks
and lots of scheduling boundaries.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189116 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused field.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189117 91177308-0d34-0410-b5e6-96231b3b80d8
MI Sched: record local vreg uses.

This will be used to compute the cyclic critical path and to
update precomputed per-node pressure differences.
In the longer term, it could also be used to speed up LiveInterval
update by avoiding visiting all global vreg users.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189118 91177308-0d34-0410-b5e6-96231b3b80d8
Adds cyclic critical path computation and heuristics, temporarily disabled.

Estimate the cyclic critical path within a single block loop. If the
acyclic critical path is longer, then the loop will exhaust OOO
resources after some number of iterations. If lag between the acyclic
critical path and cyclic critical path is longer the the time it takes
to issue those loop iterations, then aggressively schedule for
latency.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189120 91177308-0d34-0410-b5e6-96231b3b80d8
Add a convenient PSetIterator for visiting pressure sets affected by a register.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189121 91177308-0d34-0410-b5e6-96231b3b80d8
Simplify RegPressure helpers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189122 91177308-0d34-0410-b5e6-96231b3b80d8
Rename to RegPressure API parameters RegUnits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189123 91177308-0d34-0410-b5e6-96231b3b80d8
PrintVRegOrUnit

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189124 91177308-0d34-0410-b5e6-96231b3b80d8