[PATCH] D78440: [PowerPC] Fix the liveins for ppc-early-ret pass

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

A physical register is "livein" when on entry to that block, the register contains some meaningful value, and that value is used in that block or one of its successors.  Moving an instruction at the end of a block can't affect the liveness at the beginning of that block.  If the register didn't contain a meaningful value before, it still won't contain a meaningful value afterwards.

Please take another look at the input and output to ppc-early-ret, and try to figure out what the correct liveness actually looks like.  Blindly calling addLiveIn might satisfy the verifier, but it won't make the result correct.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D78440/new/

https://reviews.llvm.org/D78440