[llvm] [AArch64][SME] Exclude runtime defined liveins when computing liveouts (PR #154325)

[Benjamin Maxwell via llvm-commits]

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@@ -135,14 +142,25 @@ void LiveRegUnits::addPristines(const MachineFunction &MF) {
   addUnits(Pristine.getBitVector());
 }
 
-void LiveRegUnits::addLiveOuts(const MachineBasicBlock &MBB) {
+void LiveRegUnits::addLiveOuts(const MachineBasicBlock &MBB,
+                               const TargetLowering *TLI) {
   const MachineFunction &MF = *MBB.getParent();
 
   addPristines(MF);
 
+  MCPhysReg ExceptionPointer;
+  MCPhysReg ExceptionSelector;
+
+  // Remove live-ins from successors that are defined by the runtime.
+  if (TLI && MF.getFunction().hasPersonalityFn()) {
+    auto PersonalityFn = MF.getFunction().getPersonalityFn();
+    ExceptionPointer = TLI->getExceptionPointerRegister(PersonalityFn);
+    ExceptionSelector = TLI->getExceptionSelectorRegister(PersonalityFn);
+  }
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MacDue wrote:

I'm not sure what your suggesting the solution should be? Why does this have to be different from how the `liveout_iterator` handles this? 

https://github.com/llvm/llvm-project/pull/154325