[llvm-branch-commits] LiveRangeShrink: Early exit when encountering a code motion barrier. (PR #136806)

[Matt Arsenault via llvm-branch-commits]

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@@ -95,14 +95,24 @@ static MachineInstr *FindDominatedInstruction(MachineInstr &New,
   return Old;
 }
 
+static bool isCodeMotionBarrier(MachineInstr &MI) {
+  return MI.hasUnmodeledSideEffects() && !MI.isPseudoProbe();
+}
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arsenm wrote:

Document this? What is the exact problematic condition? We have several different barrier concepts already spread in MachineInstr and TargetInstrInfo, can we use one of those 

https://github.com/llvm/llvm-project/pull/136806