diff --git a/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c b/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c
--- a/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c
+++ b/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c
@@ -1,17 +1,17 @@
 // Check that the CHECK lines are generated before the definition and not the declaration
 // RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -emit-llvm -o - | FileCheck %s
 
-int foo();
+int foo(int arg);
 
-void empty_function();
+void empty_function(void);
 
 int main() {
   empty_function();
-  return foo();
+  return foo(1);
 }
 
-int foo() {
-  return 1;
+int foo(int arg) {
+  return arg;
 }
 
-void empty_function() {}
+void empty_function(void) {}
diff --git a/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c.expected b/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c.expected
--- a/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c.expected
+++ b/clang/test/utils/update_cc_test_checks/Inputs/def-and-decl.c.expected
@@ -2,33 +2,36 @@
 // Check that the CHECK lines are generated before the definition and not the declaration
 // RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -emit-llvm -o - | FileCheck %s
 
-int foo();
+int foo(int arg);
 
-void empty_function();
+void empty_function(void);
 
 // CHECK-LABEL: @main(
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    [[RETVAL:%.*]] = alloca i32, align 4
 // CHECK-NEXT:    store i32 0, i32* [[RETVAL]], align 4
 // CHECK-NEXT:    call void @empty_function()
-// CHECK-NEXT:    [[CALL:%.*]] = call i32 @foo()
+// CHECK-NEXT:    [[CALL:%.*]] = call i32 @foo(i32 1)
 // CHECK-NEXT:    ret i32 [[CALL]]
 //
 int main() {
   empty_function();
-  return foo();
+  return foo(1);
 }
 
 // CHECK-LABEL: @foo(
 // CHECK-NEXT:  entry:
-// CHECK-NEXT:    ret i32 1
+// CHECK-NEXT:    [[ARG_ADDR:%.*]] = alloca i32, align 4
+// CHECK-NEXT:    store i32 [[ARG:%.*]], i32* [[ARG_ADDR]], align 4
+// CHECK-NEXT:    [[TMP0:%.*]] = load i32, i32* [[ARG_ADDR]], align 4
+// CHECK-NEXT:    ret i32 [[TMP0]]
 //
-int foo() {
-  return 1;
+int foo(int arg) {
+  return arg;
 }
 
 // CHECK-LABEL: @empty_function(
 // CHECK-NEXT:  entry:
 // CHECK-NEXT:    ret void
 //
-void empty_function() {}
+void empty_function(void) {}
diff --git a/llvm/utils/update_cc_test_checks.py b/llvm/utils/update_cc_test_checks.py
--- a/llvm/utils/update_cc_test_checks.py
+++ b/llvm/utils/update_cc_test_checks.py
@@ -76,8 +76,18 @@
     if line is None:
       common.debug('Skipping function without line number:', node['name'], '@', node['loc'])
       return
-    # If there is no 'inner' object, it is a function declaration -> skip
-    if 'inner' not in node:
+
+    # If there is no 'inner' object, it is a function declaration and we can
+    # skip it. However, function declarations may also contain an 'inner' list,
+    # but in that case it will only contains ParmVarDecls. If we find an entry
+    # that is not a ParmVarDecl, we know that this is a function definition.
+    has_body = False
+    if 'inner' in node:
+      for i in node['inner']:
+        if i.get('kind', 'ParmVarDecl') != 'ParmVarDecl':
+          has_body = True
+          break
+    if not has_body:
       common.debug('Skipping function without body:', node['name'], '@', node['loc'])
       return
     spell = node['name']