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

[Matt Arsenault 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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arsenm wrote:

This doesn't belong here. These should have had explicit uses already in the MIR such that it doesn't require special casing. The live outs list is supposed to be consistent with the state of the underlying instruction liveness, it isn't really supposed to have standalone meaning

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