[PATCH] D89048: [ARM][LowOverheadLoops] Insert loop start at end of block in more cases

[Sam Parker via Phabricator via llvm-commits]

samparker added inline comments.


================
Comment at: llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp:1086
         InsertPt = FirstNonTerminator;
+      else {
+        // Try putting the loop start at the end of the block even if the count or lr are live-out.
----------------
Can this logic be simplified? I don't think we should need to be concerned with LR, or at least the top-level conditional block should be guard with:

```
if (FirstNonTerminator == MBB->end() && RDA.isReachingDefLiveOut(Start, ARM::LR)
```
Then it looks like what we just need to check whether InsertPt kills CountReg?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D89048/new/

https://reviews.llvm.org/D89048