[llvm] [NewPM] LiveIntervals: Check dependencies for invalidation (PR #123563)

[via llvm-commits]

================
@@ -127,6 +127,20 @@ LiveIntervalsWrapperPass::LiveIntervalsWrapperPass() : MachineFunctionPass(ID) {
 
 LiveIntervals::~LiveIntervals() { clear(); }
 
+bool LiveIntervals::invalidate(
+    MachineFunction &MF, const PreservedAnalyses &PA,
+    MachineFunctionAnalysisManager::Invalidator &Inv) {
+  auto PAC = PA.getChecker<LiveIntervalsAnalysis>();
+
+  if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<MachineFunction>>())
+    return true;
+
+  // LiveIntervals holds pointers to these results, so check for their
+  // invalidation.
+  return (Inv.invalidate<SlotIndexesAnalysis>(MF, PA) ||
+          Inv.invalidate<MachineDominatorTreeAnalysis>(MF, PA));
+}
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paperchalice wrote:

Then
```c++
PreservedAnalyses SomePass::run(IRUnitT &, AnalysisManager &) {
  PreservedAnalyses PA;
  PA.preserve<LiveIntervals>();
  return PA;
}
```
will no longer work, which is counter-intuitive... because it doesn't preserve `SlotIndexes` explicitly.

https://github.com/llvm/llvm-project/pull/123563