[llvm] [RemoveDIs] Replicate dbg intrinsic movement pattern in SelectOptimize (PR #81737)

[Paul T Robinson via llvm-commits]

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@@ -621,6 +621,12 @@ void SelectOptimizeImpl::convertProfitableSIGroups(SelectGroups &ProfSIGroups) {
     SelectLike LastSI = ASI.back();
     BasicBlock *StartBlock = SI.getI()->getParent();
     BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(LastSI.getI()));
+    // With RemoveDIs turned off, SplitPt can be a dbg.* intrinsic. With
+    // RemoveDIs turned on, SplitPt would instead point to the next
+    // instruction. To match existing behaviour dbg.* intrinsic behaviour
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pogo59 wrote:

```suggestion
    // instruction. To match existing dbg.* intrinsic behaviour
```

https://github.com/llvm/llvm-project/pull/81737