[llvm] [CodeGen] Distinguish zero-sized call frames from no call frame in MachineBB (PR #106964)

[Matt Arsenault via llvm-commits]

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@@ -282,6 +284,10 @@ class MachineFrameInfo {
   /// It is only valid during and after prolog/epilog code insertion.
   uint64_t MaxCallFrameSize = ~UINT64_C(0);
 
+  /// Call frame sizes for the MachineFunction's MachineBasicBlocks. This is set
+  /// by the MachineFrameSizeInfo constructor and cleared by its destructor.
+  MachineFrameSizeInfo *SizeInfo = nullptr;
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arsenm wrote:

I don't think this type of ownership makes sense. MachineFrameInfo should be a compilation wide state as the function is processed. This shouldn't be set for one function in one pass that happens to compute it 

https://github.com/llvm/llvm-project/pull/106964