[PATCH] D135693: [WIP][RegisterScavenger][RISCV] Don't search for FrameSetup instrs if we were searching from Non-FrameSetup instrs

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

If I understand correctly, the use of a vreg in the frame-setup allowed findSurvivorBackward to trigger this code

  // Keep searching when we find a vreg since the spilled register will
  // be usefull for this other vreg as well later.
  bool FoundVReg = false;
  for (const MachineOperand &MO : MI.operands()) {
    if (MO.isReg() && Register::isVirtualRegister(MO.getReg())) {
      FoundVReg = true;
      break;
    }
  }
  if (FoundVReg) {
    InstrCountDown = InstrLimit;
    Pos = I;
  }

which caused the search to stop above the frame-setup. So another option might be to use T1 as the scratch register in frame-setup as was once proposed in an earlier revision of https://reviews.llvm.org/D61884


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D135693/new/

https://reviews.llvm.org/D135693