Express ownership transfer in PassManager API through std::unique_ptr (NFC)

Since raw pointers are always passed around for IR construct without
implying any ownership transfer, it can be error prone to have implicit
ownership transferred the same way.
For example this code can seem harmless:

  Pass *pass = ....
  pm.addPass(pass);
  pm.addPass(pass);
  pm.run(module);

PiperOrigin-RevId: 263053082

1 files changed, 2 insertions, 2 deletions

diff --git a/mlir/lib/Transforms/LoopInvariantCodeMotion.cpp b/mlir/lib/Transforms/LoopInvariantCodeMotion.cpp
index d8b5b2d8b2c..09fe9afe808 100644
--- a/mlir/lib/Transforms/LoopInvariantCodeMotion.cpp
+++ b/mlir/lib/Transforms/LoopInvariantCodeMotion.cpp
@@ -76,8 +76,8 @@ static bool isMemRefDereferencingOp(Operation &op) {
   return false;
 }
 
-FunctionPassBase *mlir::createLoopInvariantCodeMotionPass() {
-  return new LoopInvariantCodeMotion();
+std::unique_ptr<FunctionPassBase> mlir::createLoopInvariantCodeMotionPass() {
+  return llvm::make_unique<LoopInvariantCodeMotion>();
 }
 
 // Returns true if the individual op is loop invariant.