[llvm] [CodeGen] Fix lpad padding at section start after empty block (PR #112595)

[Fabian Parzefall via llvm-commits]

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@@ -673,10 +677,17 @@ class MachineBasicBlock
   /// Returns true if this block ends any section.
   bool isEndSection() const { return IsEndSection; }
 
+  /// Returns true if this block contains the first instruction of its section.
+  bool isFirstNonEmptyBBInSection() const { return IsFirstNonEmptyBBInSection; }
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pzfl wrote:

That's fair. The intuition was that we track very similar properties already there, and that we get this value for free when iterating over the blocks anyways. But less state is good, so if you prefer computing it locally, I will move it.

https://github.com/llvm/llvm-project/pull/112595