diff --git a/mlir/include/mlir-c/Pass.h b/mlir/include/mlir-c/Pass.h
--- a/mlir/include/mlir-c/Pass.h
+++ b/mlir/include/mlir-c/Pass.h
@@ -51,8 +51,9 @@
 // PassManager/OpPassManager APIs.
 //===----------------------------------------------------------------------===//
 
-/// Create a new top-level PassManager.
-MLIR_CAPI_EXPORTED MlirPassManager mlirPassManagerCreate(MlirContext ctx);
+/// Create a new top-level PassManager anchored on `anchorOp`.
+MLIR_CAPI_EXPORTED MlirPassManager
+mlirPassManagerCreate(MlirContext ctx, MlirStringRef anchorOp);
 
 /// Destroy the provided PassManager.
 MLIR_CAPI_EXPORTED void mlirPassManagerDestroy(MlirPassManager passManager);
diff --git a/mlir/lib/Bindings/Python/Pass.cpp b/mlir/lib/Bindings/Python/Pass.cpp
--- a/mlir/lib/Bindings/Python/Pass.cpp
+++ b/mlir/lib/Bindings/Python/Pass.cpp
@@ -57,8 +57,9 @@
   //----------------------------------------------------------------------------
   py::class_<PyPassManager>(m, "PassManager", py::module_local())
       .def(py::init<>([](DefaultingPyMlirContext context) {
-             MlirPassManager passManager =
-                 mlirPassManagerCreate(context->get());
+             MlirPassManager passManager = mlirPassManagerCreate(
+                 context->get(),
+                 mlirStringRefCreateFromCString("builtin.module"));
              return new PyPassManager(passManager);
            }),
            py::arg("context") = py::none(),
@@ -83,7 +84,9 @@
       .def_static(
           "parse",
           [](const std::string &pipeline, DefaultingPyMlirContext context) {
-            MlirPassManager passManager = mlirPassManagerCreate(context->get());
+            MlirPassManager passManager = mlirPassManagerCreate(
+                context->get(),
+                mlirStringRefCreateFromCString("builtin.module"));
             PyPrintAccumulator errorMsg;
             MlirLogicalResult status = mlirOpPassManagerAddPipeline(
                 mlirPassManagerGetAsOpPassManager(passManager),
diff --git a/mlir/lib/CAPI/IR/Pass.cpp b/mlir/lib/CAPI/IR/Pass.cpp
--- a/mlir/lib/CAPI/IR/Pass.cpp
+++ b/mlir/lib/CAPI/IR/Pass.cpp
@@ -20,8 +20,8 @@
 // PassManager/OpPassManager APIs.
 //===----------------------------------------------------------------------===//
 
-MlirPassManager mlirPassManagerCreate(MlirContext ctx) {
-  return wrap(new PassManager(unwrap(ctx)));
+MlirPassManager mlirPassManagerCreate(MlirContext ctx, MlirStringRef anchorOp) {
+  return wrap(new PassManager(unwrap(ctx), unwrap(anchorOp)));
 }
 
 void mlirPassManagerDestroy(MlirPassManager passManager) {
diff --git a/mlir/test/CAPI/execution_engine.c b/mlir/test/CAPI/execution_engine.c
--- a/mlir/test/CAPI/execution_engine.c
+++ b/mlir/test/CAPI/execution_engine.c
@@ -31,7 +31,8 @@
 }
 
 void lowerModuleToLLVM(MlirContext ctx, MlirModule module) {
-  MlirPassManager pm = mlirPassManagerCreate(ctx);
+  MlirPassManager pm = mlirPassManagerCreate(
+      ctx, mlirStringRefCreateFromCString("builtin.module"));
   MlirOpPassManager opm = mlirPassManagerGetNestedUnder(
       pm, mlirStringRefCreateFromCString("func.func"));
   mlirPassManagerAddOwnedPass(pm, mlirCreateConversionConvertFuncToLLVM());
diff --git a/mlir/test/CAPI/pass.c b/mlir/test/CAPI/pass.c
--- a/mlir/test/CAPI/pass.c
+++ b/mlir/test/CAPI/pass.c
@@ -53,7 +53,8 @@
   // CHECK: func.func      , 1
   // CHECK: func.return        , 1
   {
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     MlirPass printOpStatPass = mlirCreateTransformsPrintOpStats();
     mlirPassManagerAddOwnedPass(pm, printOpStatPass);
     MlirLogicalResult success = mlirPassManagerRun(pm, module);
@@ -95,7 +96,8 @@
   // CHECK: func.func      , 1
   // CHECK: func.return        , 1
   {
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     MlirOpPassManager nestedFuncPm = mlirPassManagerGetNestedUnder(
         pm, mlirStringRefCreateFromCString("func.func"));
     MlirPass printOpStatPass = mlirCreateTransformsPrintOpStats();
@@ -111,7 +113,8 @@
   // CHECK: func.func      , 1
   // CHECK: func.return        , 1
   {
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     MlirOpPassManager nestedModulePm = mlirPassManagerGetNestedUnder(
         pm, mlirStringRefCreateFromCString("builtin.module"));
     MlirOpPassManager nestedFuncPm = mlirOpPassManagerGetNestedUnder(
@@ -135,7 +138,8 @@
 
 void testPrintPassPipeline() {
   MlirContext ctx = mlirContextCreate();
-  MlirPassManager pm = mlirPassManagerCreate(ctx);
+  MlirPassManager pm = mlirPassManagerCreate(
+      ctx, mlirStringRefCreateFromCString("builtin.module"));
   // Populate the pass-manager
   MlirOpPassManager nestedModulePm = mlirPassManagerGetNestedUnder(
       pm, mlirStringRefCreateFromCString("builtin.module"));
@@ -171,7 +175,8 @@
 
 void testParsePassPipeline() {
   MlirContext ctx = mlirContextCreate();
-  MlirPassManager pm = mlirPassManagerCreate(ctx);
+  MlirPassManager pm = mlirPassManagerCreate(
+      ctx, mlirStringRefCreateFromCString("builtin.module"));
   // Try parse a pipeline.
   MlirLogicalResult status = mlirParsePassPipeline(
       mlirPassManagerGetAsOpPassManager(pm),
@@ -329,7 +334,8 @@
       exit(EXIT_FAILURE);
     }
 
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     mlirPassManagerAddOwnedPass(pm, externalPass);
     MlirLogicalResult success = mlirPassManagerRun(pm, module);
     if (mlirLogicalResultIsFailure(success)) {
@@ -371,7 +377,8 @@
       exit(EXIT_FAILURE);
     }
 
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     MlirOpPassManager nestedFuncPm =
         mlirPassManagerGetNestedUnder(pm, funcOpName);
     mlirOpPassManagerAddOwnedPass(nestedFuncPm, externalPass);
@@ -421,7 +428,8 @@
       exit(EXIT_FAILURE);
     }
 
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     mlirPassManagerAddOwnedPass(pm, externalPass);
     MlirLogicalResult success = mlirPassManagerRun(pm, module);
     if (mlirLogicalResultIsFailure(success)) {
@@ -468,7 +476,8 @@
       exit(EXIT_FAILURE);
     }
 
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     mlirPassManagerAddOwnedPass(pm, externalPass);
     MlirLogicalResult success = mlirPassManagerRun(pm, module);
     if (mlirLogicalResultIsSuccess(success)) {
@@ -516,7 +525,8 @@
       exit(EXIT_FAILURE);
     }
 
-    MlirPassManager pm = mlirPassManagerCreate(ctx);
+    MlirPassManager pm = mlirPassManagerCreate(
+        ctx, mlirStringRefCreateFromCString("builtin.module"));
     mlirPassManagerAddOwnedPass(pm, externalPass);
     MlirLogicalResult success = mlirPassManagerRun(pm, module);
     if (mlirLogicalResultIsSuccess(success)) {