diff --git a/mlir/lib/Dialect/Linalg/EDSC/Builders.cpp b/mlir/lib/Dialect/Linalg/EDSC/Builders.cpp
--- a/mlir/lib/Dialect/Linalg/EDSC/Builders.cpp
+++ b/mlir/lib/Dialect/Linalg/EDSC/Builders.cpp
@@ -90,14 +90,19 @@
                              ? getElementTypeOrSelf(it.value())
                              : it.value().getType());
 
-  assert(op->getRegions().front().empty());
-  op->getRegions().front().push_front(new Block);
+  assert(op->getNumRegions() == 1);
+  assert(op->getRegion(0).empty());
+  auto &region = op->getRegion(0);
+  region.push_front(new Block);
   OpBuilder bb(op->getRegions().front());
   ScopedContext scope(bb, op->getLoc());
   BlockHandle b;
   auto handles = makeValueHandles(blockTypes);
   BlockBuilder(&b, makeHandlePointers(MutableArrayRef<ValueHandle>(handles)))(
       [&] { regionBuilder(b.getBlock()->getArguments()); });
+  region.getBlocks().erase(region.begin());
+  assert(op->getNumRegions() == 1);
+  assert(op->getRegion(0).getBlocks().size() == 1);
   return op;
 }
 
diff --git a/mlir/test/EDSC/builder-api-test.cpp b/mlir/test/EDSC/builder-api-test.cpp
--- a/mlir/test/EDSC/builder-api-test.cpp
+++ b/mlir/test/EDSC/builder-api-test.cpp
@@ -876,7 +876,7 @@
 //       CHECK:   linalg.generic {args_in = 2 : i64, args_out = 1 : i64,
 // CHECK-SAME: indexing_maps = [affine_map<(d0, d1, d2) -> (d0, d2)>, affine_map<(d0, d1, d2) -> (d2, d1)>, affine_map<(d0, d1, d2) -> (d0, d1)>],
 // CHECK-SAME: iterator_types = ["parallel", "parallel", "reduction"]}
-///      CHECK:   ^bb1(%[[a0:.*]]: f32, %[[a1:.*]]: f32, %[[a2:.*]]: f32):
+///      CHECK:   ^bb0(%[[a0:.*]]: f32, %[[a1:.*]]: f32, %[[a2:.*]]: f32):
 //       CHECK:     %[[a3:.*]] = mulf %[[a0]], %[[a1]] : f32
 //       CHECK:     %[[a4:.*]] = addf %[[a2]], %[[a3]] : f32
 //       CHECK:     linalg.yield %[[a4]] : f32
@@ -906,7 +906,7 @@
 // CHECK-SAME: affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d4, d5, d6, d1)>,
 // CHECK-SAME: affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d0, d2, d3, d1)>],
 // CHECK-SAME: iterator_types = ["parallel", "parallel", "parallel", "parallel", "reduction", "reduction", "reduction"]}
-///      CHECK:   ^bb1(%[[a0:.*]]: f32, %[[a1:.*]]: f32, %[[a2:.*]]: f32):
+///      CHECK:   ^bb0(%[[a0:.*]]: f32, %[[a1:.*]]: f32, %[[a2:.*]]: f32):
 //       CHECK:     %[[a3:.*]] = mulf %[[a0]], %[[a1]] : f32
 //       CHECK:     %[[a4:.*]] = addf %[[a2]], %[[a3]] : f32
 //       CHECK:     linalg.yield %[[a4]] : f32
@@ -937,7 +937,7 @@
 // CHECK-SAME: affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d5, d6, d2, d1)>,
 // CHECK-SAME: affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d0, d3, d4, d1 + d2 * 7)>],
 // CHECK-SAME: iterator_types = ["parallel", "parallel", "parallel", "parallel", "parallel", "reduction", "reduction"]}
-//       CHECK:   ^bb1(%[[a0:.*]]: f32, %[[a1:.*]]: f32, %[[a2:.*]]: f32):
+//       CHECK:   ^bb0(%[[a0:.*]]: f32, %[[a1:.*]]: f32, %[[a2:.*]]: f32):
 //       CHECK:     %[[a3:.*]] = mulf %[[a0]], %[[a1]] : f32
 //       CHECK:     %[[a4:.*]] = addf %[[a2]], %[[a3]] : f32
 //       CHECK:     linalg.yield %[[a4]] : f32