[PATCH] D32892: Handle a COPY with undef source operand in LowerCopy().

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added a comment.

I was thinking more about a minimal test that just focused on that one transformation that postrapseudos should do. Whether you also run the verifier or not shouldn't matter at that point. Should look something like this (I haven't actually tested this though, so you may need some tweaks):

  # RUN: llc -mtriple=s390x-linux-gnu -mcpu=z13 -verify-machineinstrs -run-pass=postrapseudos -o - %s | FileCheck %s
  ---
  # CHECK-LABEL: name: undef_copy
  # CHECK: %r13d = KILL undef %r0d, implicit killed %r12q, implicit-def %r12q
  name: undef_copy
  tracksRegLiveness: true
  body: |
    bb.0:
      liveins: %r12q
      %r13d = COPY undef %r0d, implicit killed %r12q, implicit-def %r12q


https://reviews.llvm.org/D32892