diff --git a/compiler-rt/test/xray/TestCases/Linux/func-id-utils.cc b/compiler-rt/test/xray/TestCases/Linux/func-id-utils.cc
index 834e7b4999f6..1183d01c79eb 100644
--- a/compiler-rt/test/xray/TestCases/Linux/func-id-utils.cc
+++ b/compiler-rt/test/xray/TestCases/Linux/func-id-utils.cc
@@ -2,45 +2,41 @@
 // maximum function id for the current binary.
 //
 // RUN: %clangxx_xray -std=c++11 %s -o %t
-// RUN: XRAY_OPTIONS="patch_premain=false xray_naive_log=false" %run %t | FileCheck %s
+// RUN: XRAY_OPTIONS="patch_premain=false xray_naive_log=false" %run %t
 
 #include "xray/xray_interface.h"
 #include <algorithm>
+#include <cassert>
 #include <cstdio>
-#include <set>
 #include <iterator>
+#include <set>
 
-[[clang::xray_always_instrument]] void bar(){
-    // do nothing!
-}
+[[clang::xray_always_instrument]] void bar(){}
 
-    [[clang::xray_always_instrument]] void foo() {
+[[clang::xray_always_instrument]] void foo() {
   bar();
 }
 
 [[clang::xray_always_instrument]] int main(int argc, char *argv[]) {
-  printf("max function id: %zu\n", __xray_max_function_id());
-  // CHECK: max function id: [[MAX:.*]]
-
-  std::set<void *> must_be_instrumented;
-  must_be_instrumented.insert(reinterpret_cast<void*>(&foo));
-  must_be_instrumented.insert(reinterpret_cast<void*>(&bar));
-  printf("addresses:\n");
+  assert(__xray_max_function_id() != 0 && "we need xray instrumentation!");
+  std::set<void *> must_be_instrumented = {reinterpret_cast<void *>(&foo),
+                                           reinterpret_cast<void *>(&bar),
+                                           reinterpret_cast<void *>(&main)};
   std::set<void *> all_instrumented;
   for (auto i = __xray_max_function_id(); i != 0; --i) {
     auto addr = __xray_function_address(i);
-    printf("#%lu -> @%04lx\n", i, addr);
     all_instrumented.insert(reinterpret_cast<void *>(addr));
   }
+  assert(all_instrumented.size() == __xray_max_function_id() &&
+         "each function id must be assigned to a unique function");
 
-  // CHECK-LABEL: addresses:
-  // CHECK: #[[MAX]] -> @[[ADDR:.*]]
-  // CHECK-NOT: #0 -> @{{.*}}
   std::set<void *> common;
-
   std::set_intersection(all_instrumented.begin(), all_instrumented.end(),
                         must_be_instrumented.begin(),
                         must_be_instrumented.end(),
                         std::inserter(common, common.begin()));
+  assert(
+      common == must_be_instrumented &&
+      "we should see all explicitly instrumented functions with function ids");
   return common == must_be_instrumented ? 0 : 1;
 }