diff --git a/mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td b/mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td
--- a/mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td
+++ b/mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td
@@ -58,12 +58,12 @@
     should be used to execute the parallel region.
 
     The optional $default_val attribute specifies the default data sharing attribute
-    of variables used in the parallel region that are not passed explicitly as parameters
+    of values used in the parallel region that are not passed explicitly as parameters
     to the operation.
 
     The $private_vars, $firstprivate_vars, $shared_vars and $copyin_vars parameters
-    are a variadic list of variables that specify the data sharing attribute of
-    those variables.
+    are a variadic list of values that specify the data sharing attribute of
+    those values.
 
     The optional $proc_bind_val attribute controls the thread affinity for the execution
     of the parallel region.
diff --git a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
--- a/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
+++ b/mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp
@@ -227,38 +227,44 @@
   }
 
   // Add if parameter
-  if (segments[ifClausePos]) {
+  if (segments[ifClausePos])
     parser.resolveOperand(ifCond.first, ifCond.second, result.operands);
-  }
+  else
+    return failure();
 
   // Add num_threads parameter
-  if (segments[numThreadsClausePos]) {
+  if (segments[numThreadsClausePos])
     parser.resolveOperand(numThreads.first, numThreads.second, result.operands);
-  }
+  else
+    return failure();
 
   // Add private parameters
-  if (segments[privateClausePos]) {
+  if (segments[privateClausePos])
     parser.resolveOperands(privates, privateTypes, privates[0].location,
                            result.operands);
-  }
+  else
+    return failure();
 
   // Add firstprivate parameters
-  if (segments[firstprivateClausePos]) {
+  if (segments[firstprivateClausePos])
     parser.resolveOperands(firstprivates, firstprivateTypes,
                            firstprivates[0].location, result.operands);
-  }
+  else
+    return failure();
 
   // Add shared parameters
-  if (segments[sharedClausePos]) {
+  if (segments[sharedClausePos])
     parser.resolveOperands(shareds, sharedTypes, shareds[0].location,
                            result.operands);
-  }
+  else
+    return failure();
 
   // Add copyin parameters
-  if (segments[copyinClausePos]) {
+  if (segments[copyinClausePos])
     parser.resolveOperands(copyins, copyinTypes, copyins[0].location,
                            result.operands);
-  }
+  else
+    return failure();
 
   result.addAttribute("operand_segment_sizes",
                       parser.getBuilder().getI32VectorAttr(segments));