[PATCH] D105019: [RegisterCoalescer] Avoid coalescing erased Copy

[guopeilin via Phabricator via llvm-commits]

guopeilin added a comment.

Sometimes the `CurrList` may have two identical instructions that will be coalesced later. Once the first one coalesced, it will be removed from its parent, this will make the second identical instruction become illegal which `getParent` will be a nullptr. In this case, we should avoid coalescing erased instruction.<br>
The test case will trigger an Assertion like the following:

  llvm-project/llvm/include/llvm/CodeGen/MachineOperand.h:359: llvm::Register llvm::MachineOperand::getReg() const: Assertion `isReg() && "This is not a register operand!"' failed.

Also recorded in Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=50919


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D105019/new/

https://reviews.llvm.org/D105019