[llvm] [mlir] Number MLIR blocks; require GraphHasNodeNumbers in llvm::LoopInfoBase (PR #207617)

[Fangrui Song via llvm-commits]

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@@ -422,6 +435,11 @@ class alignas(8) Block : public IRObjectWithUseList<BlockOperand>,
   /// the operations within this block have a valid ordering.
   llvm::PointerIntPair<Region *, /*IntBits=*/1, bool> parentValidOpOrderPair;
 
+  /// Unique number of this block within its parent region, assigned when the
+  /// block is added to a region; -1u while the block has no parent. See
+  /// getNumber().
+  unsigned blockNumber = -1u;
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MaskRay wrote:

On int nit: LLVM's BasicBlock uses unsigned, and the API returns unsigned.

https://github.com/llvm/llvm-project/pull/207617