From 1a934bc4cc9094fa8a7fea3814791924da9699cc Mon Sep 17 00:00:00 2001
From: Murat Toprak <murattoprak2004@gmail.com>
Date: Wed, 15 Jul 2026 18:44:42 +0300
Subject: [PATCH] Fix aliasing bug in OpenFHE emitter for InsertOp with shared
 buffers

---
 lib/Target/OpenFhePke/OpenFhePkeEmitter.cpp | 19 ++++++++++++----
 tests/Emitter/Openfhe/emit_insert_copy.mlir | 25 +++++++++++++++++++++
 2 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 tests/Emitter/Openfhe/emit_insert_copy.mlir

diff --git a/lib/Target/OpenFhePke/OpenFhePkeEmitter.cpp b/lib/Target/OpenFhePke/OpenFhePkeEmitter.cpp
index 5ddcea7b1f..26b932c2b5 100644
--- a/lib/Target/OpenFhePke/OpenFhePkeEmitter.cpp
+++ b/lib/Target/OpenFhePke/OpenFhePkeEmitter.cpp
@@ -1707,11 +1707,19 @@ LogicalResult OpenFhePkeEmitter::printOperation(
 
 LogicalResult OpenFhePkeEmitter::printOperation(tensor::InsertOp op) {
   // For a tensor.insert MLIR statement, we assign the destination vector and
-  // then map the result value to the destination value.
+  // then map the result value to the destination value if they are equal.
   // %result = tensor.insert %scalar into %dest[%idx]
   // dest[idx] = scalar;
-  os << variableNames->getNameForValue(op.getDest());
-  os << "[";
+  std::string destName = variableNames->getNameForValue(op.getDest());
+  std::string resultName = variableNames->getNameForValue(op.getResult());
+  if (destName != resultName) {
+    if (failed(emitType(op.getResult().getType(), op->getLoc()))) {
+      return failure();
+    }
+    os << " " << resultName << "(" << destName << ");\n";
+  }
+
+  os << resultName << "[";
   if (op.getIndices().empty()) {
     os << "0";
   } else {
@@ -1724,7 +1732,10 @@ LogicalResult OpenFhePkeEmitter::printOperation(tensor::InsertOp op) {
   os << "]";
   os << " = " << variableNames->getNameForValue(op.getScalar()) << ";\n";
 
-  variableNames->mapValueNameToValue(op.getResult(), op.getDest());
+  if (destName == resultName) {
+    variableNames->mapValueNameToValue(op.getResult(), op.getDest());
+  }
+
   return success();
 }
 
diff --git a/tests/Emitter/Openfhe/emit_insert_copy.mlir b/tests/Emitter/Openfhe/emit_insert_copy.mlir
new file mode 100644
index 0000000000..cb2b7750ce
--- /dev/null
+++ b/tests/Emitter/Openfhe/emit_insert_copy.mlir
@@ -0,0 +1,25 @@
+// RUN: heir-translate %s --emit-openfhe-pke | FileCheck %s
+
+!cc = !openfhe.crypto_context
+!ct = !openfhe.ciphertext
+
+module attributes {scheme.bgv} {
+  // Two tensor.insert ops sharing the same tensor.empty buffer must produce
+  // distinct C++ vectors (copy-on-write), not alias both results to the same
+  // destination variable.
+
+  // CHECK: mm_bug_two_wraps
+  // CHECK: std::vector<{{.*}}> [[V1:v[0-9]+]](
+  // CHECK: [[V1]][0] = %arg1
+  // CHECK: std::vector<{{.*}}> [[V2:v[0-9]+]](
+  // CHECK: [[V2]][0] = %arg2
+  // CHECK: return {[[V1]], [[V2]]};
+  func.func @mm_bug_two_wraps(%arg0: !cc, %arg1: !ct, %arg2: !ct)
+      -> (tensor<1x!ct>, tensor<1x!ct>) {
+    %c0 = arith.constant 0 : index
+    %buf = tensor.empty() : tensor<1x!ct>
+    %wrap1 = tensor.insert %arg1 into %buf[%c0] : tensor<1x!ct>
+    %wrap2 = tensor.insert %arg2 into %buf[%c0] : tensor<1x!ct>
+    return %wrap1, %wrap2 : tensor<1x!ct>, tensor<1x!ct>
+  }
+}