[mlir] Use llvm::is_contained (NFC)

mlir/include/mlir/Dialect/Bufferization/IR/UnstructuredControlFlow.h

@@ -54,8 +54,7 @@ struct OpWithUnstructuredControlFlowBufferizableOpInterfaceExternalModel
       // If the forwarded operand is already on the invocation stack, we ran
       // into a loop and this operand cannot be used to compute the bufferized
       // type.
-      if (llvm::find(invocationStack, opOperand->get()) !=
-          invocationStack.end())
+      if (llvm::is_contained(invocationStack, opOperand->get()))
         continue;
 
       // Compute the bufferized type of the forwarded operand.

mlir/lib/Dialect/Transform/Interfaces/TransformInterfaces.cpp

@@ -807,8 +807,7 @@ void transform::TransformState::compactOpHandles() {
   for (Value handle : opHandlesToCompact) {
     Mappings &mappings = getMapping(handle, /*allowOutOfScope=*/true);
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
-    if (llvm::find(mappings.direct[handle], nullptr) !=
-        mappings.direct[handle].end())
+    if (llvm::is_contained(mappings.direct[handle], nullptr))
       // Payload IR is removed from the mapping. This invalidates the respective
       // iterators.
       mappings.incrementTimestamp(handle);

mlir/test/lib/Analysis/TestTopologicalSort.cpp

@@ -53,7 +53,7 @@ struct TestTopologicalSortAnalysisPass
         return WalkResult::advance();
       });
 
-      if (llvm::find(selectedOps, nullptr) != selectedOps.end()) {
+      if (llvm::is_contained(selectedOps, nullptr)) {
         root->emitError("invalid test case: some indices are missing among the "
                         "selected ops");
         return WalkResult::skip();