[PATCH] D54367: RegAllocFast: Improve hinting heuristic

[Matthias Braun via Phabricator via llvm-commits]

MatzeB created this revision.
MatzeB added reviewers: qcolombet, wmi, kparzysz, myatsina, javed.absar, arsenm.
Herald added subscribers: wdng, mcrosier.

- Trace through multiple COPYs when looking for a physreg source.
- Add hinting for vregs that will be copied into physregs (we only hinted for vregs getting copied to a physreg previously).
- Give hinted a register a bonus when deciding which value to spill.

This is part of my rewrite regallocfast series. In fact this one doesn't even have an effect unless you also flip the allocation to happen from back to front of a basic block. Nonetheless it helps to split this up to ease review of https://reviews.llvm.org/D52010


Repository:
  rL LLVM

https://reviews.llvm.org/D54367

Files:
  lib/CodeGen/RegAllocFast.cpp

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