Adds initial support for spill/reload estimation. Currently, it just
runs the operands and calculates number of registers, used by the
operands. If this number greater than the number of total available
registers, it consider the first (full) groups as the candidates for the spills/reloads.
Reviewers: hiraditya, RKSimon, bababuck
Pull Request: https://github.com/llvm/llvm-project/pull/187594
d9a44c818f