[Mlir-commits] [mlir] [mlir][IR] Adjust insertion block when splitting blocks / moving ops (PR #150819)

[Markus Böck]

================
@@ -576,24 +576,39 @@ class RewriterBase : public OpBuilder {
 
   /// Split the operations starting at "before" (inclusive) out of the given
   /// block into a new block, and return it.
+  ///
+  /// If the current insertion point is before the split point, the insertion
+  /// point is adjusted to the new block.
   Block *splitBlock(Block *block, Block::iterator before);
 
   /// Unlink this operation from its current block and insert it right before
   /// `existingOp` which may be in the same or another block in the same
   /// function.
+  ///
+  /// If the insertion point is before the moved operation, the insertion block
+  /// is adjusted to the block of `existingOp`.
   void moveOpBefore(Operation *op, Operation *existingOp);
 
   /// Unlink this operation from its current block and insert it right before
   /// `iterator` in the specified block.
+  ///
+  /// If the insertion point is before the moved operation, the insertion block
+  /// is adjusted to the specified block.
   void moveOpBefore(Operation *op, Block *block, Block::iterator iterator);
 
   /// Unlink this operation from its current block and insert it right after
   /// `existingOp` which may be in the same or another block in the same
   /// function.
+  ///
+  /// If the insertion point is before the moved operation, the insertion block
+  /// is adjusted to the block of `existingOp`.
   void moveOpAfter(Operation *op, Operation *existingOp);
 
   /// Unlink this operation from its current block and insert it right after
   /// `iterator` in the specified block.
+  ///
+  /// If the insertion point is before the moved operation, the insertion block
+  /// is adjusted to the specified block.
----------------
zero9178 wrote:

I am not fully confident this is the best behaviour for these operations but I fear this depends on ones iternal model of the insertion point.

In my mind, erasing an operation and moving an operation from the POV of the current insertion point are not much different: In both cases the erased/moved op disappears from the current insertion point and arguably the insertion point shouldn't care what happens to it after.

My expected behaviour would then be similar to `eraseOp`, which is that the insertion point remains exactly where it was, relatively speaking, and doesn't magically "travel" with the operation.

https://github.com/llvm/llvm-project/pull/150819