[PATCH] D152502: [MCP] Do not remove redundant copy for COPY from undef

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


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Comment at: llvm/test/CodeGen/X86/machine-copy-prop.mir:232
+    NOOP implicit killed $rax
+    $rax = COPY $rdi
+    NOOP implicit $rax, implicit $rdi
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I don’t see why this test isn’t failing the verifier. There’s no def of rdi, so the second and third uses should also be undef.

For the one read is undef and later are not, there still needs to be a live in of some kind 


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D152502/new/

https://reviews.llvm.org/D152502