[PATCH] D101523: [DebugInfo] Fix updateDbgUsersToReg to support DBG_VALUE_LIST

[Jeremy Morse via Phabricator via llvm-commits]

jmorse added a comment.

Hmmmmm. What if we have:

  $rax = COPY $rcx
  DBG_VALUE $ax

And the copy to $rax is copy-prop'd? As I understand it, the DBG_VALUE will appear on the MaybeDeadDbgUsers list, and its operand $ax will be detected as being affected by the copy propagation. But because we use:

  Op.setReg(NewReg);

In updateDbgUsersToReg, doesn't this then produce:

  DBG_VALUE $rcx

i.e., widens what was a 16 bit register to a 64 bit one?

Another question is what the old implementation of this did. Was it similarly borken?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101523/new/

https://reviews.llvm.org/D101523