[PATCH] D111035: [AArch64] Fix incorrect removal of COPYs in AArch64RedundantCopyElimination

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

OK. This does alter codegen without changed to the register allocator, and I wanted to look into why.

What would happen if we had this? We should still know that the top bits are 0:

    $w8 = ...
    CBNZW $w8, %bb.2
  bb.1:
    $w8 = COPY $wzr, implicit-def $x8
    ...


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D111035/new/

https://reviews.llvm.org/D111035