diff --git a/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp b/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp
--- a/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp
+++ b/mlir/lib/Dialect/GPU/IR/GPUDialect.cpp
@@ -218,25 +218,25 @@
 }
 
 KernelDim3 LaunchOp::getBlockIds() {
-  assert(!body().getBlocks().empty() && "FuncOp body must not be empty.");
+  assert(!body().empty() && "LaunchOp body must not be empty.");
   auto args = body().getBlocks().front().getArguments();
   return KernelDim3{args[0], args[1], args[2]};
 }
 
 KernelDim3 LaunchOp::getThreadIds() {
-  assert(!body().getBlocks().empty() && "FuncOp body must not be empty.");
+  assert(!body().empty() && "LaunchOp body must not be empty.");
   auto args = body().getBlocks().front().getArguments();
   return KernelDim3{args[3], args[4], args[5]};
 }
 
 KernelDim3 LaunchOp::getGridSize() {
-  assert(!body().getBlocks().empty() && "FuncOp body must not be empty.");
+  assert(!body().empty() && "LaunchOp body must not be empty.");
   auto args = body().getBlocks().front().getArguments();
   return KernelDim3{args[6], args[7], args[8]};
 }
 
 KernelDim3 LaunchOp::getBlockSize() {
-  assert(!body().getBlocks().empty() && "FuncOp body must not be empty.");
+  assert(!body().empty() && "LaunchOp body must not be empty.");
   auto args = body().getBlocks().front().getArguments();
   return KernelDim3{args[9], args[10], args[11]};
 }
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
@@ -140,7 +140,7 @@
   SmallVector<Value, 8> handles(blockTypes.size());
   BlockBuilder(&b, op->getRegion(0), blockTypes,
                handles)([&] { regionBuilder(b.getBlock()->getArguments()); });
-  assert(op->getRegion(0).getBlocks().size() == 1);
+  assert(llvm::hasSingleElement(op->getRegion(0)));
   return op;
 }
 
diff --git a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
--- a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
+++ b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
@@ -202,7 +202,7 @@
            << " inputs (tensor or buffer) and output buffer operands";
 
   auto &region = op.region();
-  if (region.getBlocks().size() != 1)
+  if (!llvm::hasSingleElement(region))
     return op.emitOpError("expected region with 1 block");
   if (failed(BlockArgsVerifier<GenericOpType>::verify(op, region.front())))
     return failure();
diff --git a/mlir/lib/Dialect/Linalg/Transforms/Tiling.cpp b/mlir/lib/Dialect/Linalg/Transforms/Tiling.cpp
--- a/mlir/lib/Dialect/Linalg/Transforms/Tiling.cpp
+++ b/mlir/lib/Dialect/Linalg/Transforms/Tiling.cpp
@@ -182,7 +182,7 @@
     indexedGenericOp.emitOpError("expected a region");
     return;
   }
-  auto &block = region.getBlocks().front();
+  auto &block = region.front();
 
   OpBuilder::InsertionGuard g(b);
   b.setInsertionPointToStart(&block);
diff --git a/mlir/lib/Transforms/LoopFusion.cpp b/mlir/lib/Transforms/LoopFusion.cpp
--- a/mlir/lib/Transforms/LoopFusion.cpp
+++ b/mlir/lib/Transforms/LoopFusion.cpp
@@ -636,7 +636,7 @@
   DenseMap<Value, SetVector<unsigned>> memrefAccesses;
 
   // TODO: support multi-block functions.
-  if (f.getBlocks().size() != 1)
+  if (!llvm::hasSingleElement(f))
     return false;
 
   DenseMap<Operation *, unsigned> forToNodeMap;
diff --git a/mlir/lib/Transforms/MemRefDataFlowOpt.cpp b/mlir/lib/Transforms/MemRefDataFlowOpt.cpp
--- a/mlir/lib/Transforms/MemRefDataFlowOpt.cpp
+++ b/mlir/lib/Transforms/MemRefDataFlowOpt.cpp
@@ -178,7 +178,7 @@
 void MemRefDataFlowOpt::runOnFunction() {
   // Only supports single block functions at the moment.
   FuncOp f = getFunction();
-  if (f.getBlocks().size() != 1) {
+  if (!llvm::hasSingleElement(f)) {
     markAllAnalysesPreserved();
     return;
   }
diff --git a/mlir/lib/Transforms/ViewOpGraph.cpp b/mlir/lib/Transforms/ViewOpGraph.cpp
--- a/mlir/lib/Transforms/ViewOpGraph.cpp
+++ b/mlir/lib/Transforms/ViewOpGraph.cpp
@@ -130,7 +130,7 @@
       for (Region &region : op.getRegions()) {
         for (auto indexed_block : llvm::enumerate(region)) {
           // Suffix block number if there are more than 1 block.
-          auto blockName = region.getBlocks().size() == 1
+          auto blockName = llvm::hasSingleElement(region)
                                ? ""
                                : ("__" + llvm::utostr(indexed_block.index()));
           llvm::WriteGraph(os, &indexed_block.value(), short_names,
diff --git a/mlir/test/lib/Dialect/Affine/TestVectorizationUtils.cpp b/mlir/test/lib/Dialect/Affine/TestVectorizationUtils.cpp
--- a/mlir/test/lib/Dialect/Affine/TestVectorizationUtils.cpp
+++ b/mlir/test/lib/Dialect/Affine/TestVectorizationUtils.cpp
@@ -248,7 +248,7 @@
 
   // Only support single block functions at this point.
   FuncOp f = getFunction();
-  if (f.getBlocks().size() != 1)
+  if (!llvm::hasSingleElement(f))
     return;
 
   std::string str;