Index: mlir/include/mlir/Dialect/ControlFlow/IR/ControlFlowOps.td
===================================================================
--- mlir/include/mlir/Dialect/ControlFlow/IR/ControlFlowOps.td
+++ mlir/include/mlir/Dialect/ControlFlow/IR/ControlFlowOps.td
@@ -162,7 +162,7 @@
 
   let extraClassDeclaration = [{
     // These are the indices into the dests list.
-    enum { trueIndex = 0, falseIndex = 1 };
+    enum { trueIndex = 0, falseIndex = 1, trueODSIndex = 1, falseODSIndex = 2 };
 
     // Accessors for operands to the 'true' destination.
     Value getTrueOperand(unsigned idx) {
@@ -192,6 +192,26 @@
       setOperand(getFalseDestOperandIndex() + idx, value);
     }
 
+    /// Replace the operands of a branch beginning at 'start' and
+    /// ending at 'start' + 'length' with the ones provided in 'operands'.
+    /// 'operands' may be smaller or larger than the range pointed to by
+    /// 'start'+'length'.
+    void setTrueOperands(unsigned start, unsigned int length, ValueRange values) {
+      setBranchOperands(trueODSIndex, start, length, values);
+    }
+    void setFalseOperands(unsigned start, unsigned int length, ValueRange values) {
+      setBranchOperands(falseODSIndex, start, length, values);
+    }
+
+    /// Insert the given operands into the operand list of a branch at
+    /// the given 'index'.
+    void insertTrueOperands(unsigned start, ValueRange values) {
+      setTrueOperands(start, 0, values);
+    }
+    void insertFalseOperands(unsigned start, ValueRange values) {
+      setFalseOperands(start, 0, values);
+    }
+
     operand_range getTrueOperands() { return getTrueDestOperands(); }
     operand_range getFalseOperands() { return getFalseDestOperands(); }
 
@@ -210,6 +230,9 @@
     unsigned getFalseDestOperandIndex() {
       return getTrueDestOperandIndex() + getNumTrueOperands();
     }
+    /// Insert operands values on branch brIndex starting from operandIdx
+    void setBranchOperands(unsigned brODSIndex, unsigned int startIdx,
+                           unsigned int length, ValueRange values);
   }];
 
   let hasCanonicalizer = 1;
Index: mlir/lib/Dialect/ControlFlow/IR/ControlFlowOps.cpp
===================================================================
--- mlir/lib/Dialect/ControlFlow/IR/ControlFlowOps.cpp
+++ mlir/lib/Dialect/ControlFlow/IR/ControlFlowOps.cpp
@@ -450,6 +450,29 @@
   return nullptr;
 }
 
+/// Replace the operands of a branch beginning at 'start' and
+/// ending at 'start' + 'length' with the ones provided in 'operands'.
+/// 'operands' may be smaller or larger than the range pointed to by
+/// 'start'+'length'.
+void CondBranchOp::setBranchOperands(unsigned brODSIndex, unsigned int startIdx,
+                                     unsigned int length, ValueRange values) {
+  auto range = getODSOperandIndexAndLength(brODSIndex);
+  assert(startIdx <= range.second && "insertion out of range");
+  auto sizeAttr = (*this)
+                      ->getAttr(getOperandSegmentSizesAttrName())
+                      .cast<::mlir::DenseIntElementsAttr>();
+
+  /// Update sizes
+  llvm::SmallVector<uint32_t> sizes(sizeAttr.value_begin<uint32_t>(),
+                                    sizeAttr.value_end<uint32_t>());
+  sizes[brODSIndex] += values.size() - length;
+  auto newAttr = DenseIntElementsAttr::get(sizeAttr.getType(), sizes);
+  (*this)->setAttr(getOperandSegmentSizesAttrName(), newAttr);
+
+  /// Update operands
+  (*this)->setOperands(range.first + startIdx, length, values);
+}
+
 //===----------------------------------------------------------------------===//
 // SwitchOp
 //===----------------------------------------------------------------------===//