[PATCH] D83163: [DAGCombiner] visitSIGN_EXTEND_INREG should fold sext_vector_inreg(undef) to 0 not undef.

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri accepted this revision.
lebedev.ri added a comment.
This revision is now accepted and ready to land.

Would be good to have a test case, but it's obviously broken, yes.

  ----------------------------------------
  Name: zz
    %r = sext i8 undef to i32
    ret i32 %r
  =>
    %r = i32 undef
    ret i32 %r
  
  ERROR: Value mismatch for i32 %r
  
  Example:
  Source value: #x00000000 (0)    [based on undef value]
  Target value: #x00008000 (32768)


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D83163/new/

https://reviews.llvm.org/D83163