Add an ILP scheduler. This is a register pressure aware scheduler that's
appropriate for targets without detailed instruction iterineries.
The scheduler schedules for increased instruction level parallelism in
low register pressure situation; it schedules to reduce register pressure
when the register pressure becomes high.
On x86_64, this is a win for all tests in CFP2000. It also sped up 256.bzip2
by 16%.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109300
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