[PATCH] D150606: [RegisterCoalescer] Remove DbgMergedVRegNums (NFC)

[Jeremy Morse via Phabricator via llvm-commits]

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

/me squints -- hmmm, maybe this is why there were still false variable locations after register coalescing when I tried to fix them up, ouch.

The intention behind this was detecting when the repeated merging of virtual registers led to variable locations getting the wrong value -- which can happen transitively, hence there was a map for tracking which VRegs were now "in" other VRegs. The compile-time performance of this was bad, and it just didn't work properly in general, hence instr-ref recomputes SSA in full.

Seeing how nothing ever adds anything to `DbgMergedVRegNums`, it's clearly dead code and can be deleted.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150606/new/

https://reviews.llvm.org/D150606