diff --git a/mlir/include/mlir/IR/Builders.h b/mlir/include/mlir/IR/Builders.h
--- a/mlir/include/mlir/IR/Builders.h
+++ b/mlir/include/mlir/IR/Builders.h
@@ -188,7 +188,8 @@
     setInsertionPoint(op);
   }
 
-  explicit OpBuilder(Block *block) : OpBuilder(block, block->end()) {}
+  /// Create a builder and set the insertion point to the start of the Block.
+  explicit OpBuilder(Block *block) : OpBuilder(block, block->begin()) {}
 
   OpBuilder(Block *block, Block::iterator insertPoint)
       : OpBuilder(block->getParent()) {