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%.

llvm-svn: 109300
6 files changed
tree: f904cf94fcb05e176dac04012da8c1ff956b38c9
  1. clang/
  2. compiler-rt/
  3. libcxx/
  4. lldb/
  5. llvm/