[PATCH] D152026: [AMDGPU] WIP: Use implicit operands instead of RegScavenger for AGPR copy lowering on gfx908

[Jeffrey Byrnes via Phabricator via llvm-commits]

jrbyrnes planned changes to this revision.
jrbyrnes added a comment.

Per offline discussion -- we need to avoid adding new virt regs during live range splitting.

Tentative plan involves a two-part approach:

1. Rework RA prioritization s.t. AGPR live-range splitting (and copy emission) is reasonably rare on gfx908.
2. Attach as many implicit vgprs as reasonably possible (i.e. the PreRAOptimizations functionality here), and rely on VGPRForAGPRCopy in the rare copies in which no implicit operand is available.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D152026/new/

https://reviews.llvm.org/D152026