diff --git a/llvm/tools/llvm-profgen/ProfileGenerator.cpp b/llvm/tools/llvm-profgen/ProfileGenerator.cpp
--- a/llvm/tools/llvm-profgen/ProfileGenerator.cpp
+++ b/llvm/tools/llvm-profgen/ProfileGenerator.cpp
@@ -383,6 +383,7 @@
 void ProfileGenerator::generateProfile() {
   if (Binary->usePseudoProbes()) {
     // TODO: Support probe based profile generation
+    exitWithError("Probe based profile generation not supported for AutoFDO.");
   } else {
     generateLineNumBasedProfile();
   }