Comment a strange field in ScheduleDAG.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180159 91177308-0d34-0410-b5e6-96231b3b80d8
Machine model: rewrite a tablegen loop to avoid comparing record pointers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180160 91177308-0d34-0410-b5e6-96231b3b80d8
Machine model: verify well-formed processor resource groups.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180161 91177308-0d34-0410-b5e6-96231b3b80d8
Machine model: Generate table entries for super-resources.

Super-resources and resource groups are two ways of expressing
overlapping sets of processor resources. Now we generate table entries
the same way for both so the scheduler never needs to explicitly check
for super-resources.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180162 91177308-0d34-0410-b5e6-96231b3b80d8