Walk in pre-order. Rebase to clean-up windows build issue.

Author: jeanPerier

mlir/lib/IR/Builders.cpp

@@ -528,15 +528,15 @@ LogicalResult OpBuilder::tryFold(Operation *op,
 Operation *OpBuilder::clone(Operation &op, IRMapping &mapper) {
   Operation *newOp = op.clone(mapper);
   newOp = insert(newOp);
-  // The `insert` call below handles the notification for inserting `newOp`
+  // The `insert` call above handles the notification for inserting `newOp`
   // itself. But if `newOp` has any regions, we need to notify the listener
   // about any ops that got inserted inside those regions as part of cloning.
   if (listener) {
     auto walkFn = [&](Operation *walkedOp) {
       listener->notifyOperationInserted(walkedOp);
     };
     for (Region &region : newOp->getRegions())
-      region.walk(walkFn);
+      region.walk<WalkOrder::PreOrder>(walkFn);
   }
   return newOp;
 }

mlir/test/IR/test-clone.mlir

@@ -3,22 +3,33 @@
 module {
   func.func @fixpoint(%arg1 : i32) -> i32 {
     %r = "test.use"(%arg1) ({
-       "test.yield"(%arg1) : (i32) -> ()
+      %r2 = "test.use2"(%arg1) ({
+         "test.yield2"(%arg1) : (i32) -> ()
+      }) : (i32) -> i32
+      "test.yield"(%r2) : (i32) -> ()
     }) : (i32) -> i32
     return %r : i32
   }
 }
 
 // CHECK: notifyOperationInserted: test.use
+// CHECK-NEXT: notifyOperationInserted: test.use2
+// CHECK-NEXT: notifyOperationInserted: test.yield2
 // CHECK-NEXT: notifyOperationInserted: test.yield
 // CHECK-NEXT: notifyOperationInserted: func.return
 
 // CHECK:   func @fixpoint(%[[arg0:.+]]: i32) -> i32 {
 // CHECK-NEXT:     %[[i0:.+]] = "test.use"(%[[arg0]]) ({
-// CHECK-NEXT:       "test.yield"(%arg0) : (i32) -> ()
+// CHECK-NEXT:       %[[r2:.+]] = "test.use2"(%[[arg0]]) ({
+// CHECK-NEXT:         "test.yield2"(%[[arg0]]) : (i32) -> ()
+// CHECK-NEXT:       }) : (i32) -> i32
+// CHECK-NEXT:       "test.yield"(%[[r2]]) : (i32) -> ()
 // CHECK-NEXT:     }) : (i32) -> i32
 // CHECK-NEXT:     %[[i1:.+]] = "test.use"(%[[i0]]) ({
-// CHECK-NEXT:       "test.yield"(%[[i0]]) : (i32) -> ()
+// CHECK-NEXT:       %[[r2:.+]] = "test.use2"(%[[i0]]) ({
+// CHECK-NEXT:         "test.yield2"(%[[i0]]) : (i32) -> ()
+// CHECK-NEXT:       }) : (i32) -> i32
+// CHECK-NEXT:       "test.yield"(%[[r2]]) : (i32) -> ()
 // CHECK-NEXT:     }) : (i32) -> i32
 // CHECK-NEXT:     return %[[i1]] : i32
 // CHECK-NEXT:   }