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

[Philip Reames via llvm-commits]

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@@ -332,10 +332,10 @@ class MachineFrameInfo {
   /// stack objects like arguments so we can't treat them as immutable.
   bool HasTailCall = false;
 
-  /// Not null, if shrink-wrapping found a better place for the prologue.
-  MachineBasicBlock *Save = nullptr;
-  /// Not null, if shrink-wrapping found a better place for the epilogue.
-  MachineBasicBlock *Restore = nullptr;
+  /// Not empty, if shrink-wrapping found a better place for the prologue.
+  std::vector<MachineBasicBlock *> SavePoints;
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preames wrote:

Why not SmallVector?  This seems like a classic use case.

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