[PATCH] D89800: [ARM][LowOverheadLoops] Don't generate a LOL if lr is redefined after the start

[Sam Tebbs via Phabricator via llvm-commits]

samtebbs created this revision.
samtebbs added reviewers: samparker, SjoerdMeijer, dmgreen.
Herald added subscribers: llvm-commits, danielkiss, hiraditya, kristof.beyls.
Herald added a project: LLVM.
samtebbs requested review of this revision.

Low-overhead loops are created even if the LR is redefined after the loop start instruction, causing the loop decrement and loop end to use different values to the loop start. This patch makes sure that the LR definition at the loop start is the same as the live-out def.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D89800

Files:
  llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
  llvm/test/CodeGen/Thumb2/LowOverheadLoops/lr-def-after-start.mir

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