[llvm] [llvm] Support multiple save/restore points in mir (PR #119357)

[Matt Arsenault via llvm-commits]

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@@ -651,6 +679,67 @@ static void insertCSRRestores(MachineBasicBlock &RestoreBlock,
   }
 }
 
+static void fillCSInfoPerBB(MachineFrameInfo &MFI,
+                            DenseMap<Register, CalleeSavedInfo *> &RegToInfo,
+                            MBBVector &PrologEpilogBlocks, bool isSave) {
+  // Global CalleeSavedInfo list aggregating CSIVs for all points
+  std::vector<CalleeSavedInfo> GCSIV;
+  const SaveRestorePoints::PointsMap &SRPoints =
+      isSave ? MFI.getSavePoints() : MFI.getRestorePoints();
+  SaveRestorePoints::PointsMap Inner;
+  for (auto [BB, Regs] : SRPoints) {
+    // CalleeSavedInfo list for each point
+    std::vector<CalleeSavedInfo> CSIV;
+    for (auto &Reg : Regs) {
+      auto It = RegToInfo.find(Reg.getReg());
+      if (It == RegToInfo.end())
+        continue;
+      CSIV.push_back(*RegToInfo.at(Reg.getReg()));
+      GCSIV.push_back(*RegToInfo.at(Reg.getReg()));
+    }
+    // We need to sort CSIV, because Aarch64 expect CSI list to come sorted by
+    // frame index
+    std::sort(CSIV.begin(), CSIV.end(),
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arsenm wrote:

```suggestion
    sort(CSIV,
```

https://github.com/llvm/llvm-project/pull/119357