Index: lib/Basic/Targets.cpp
===================================================================
--- lib/Basic/Targets.cpp
+++ lib/Basic/Targets.cpp
@@ -3862,6 +3862,7 @@
   MCUX86_32TargetInfo(const llvm::Triple &Triple) : X86_32TargetInfo(Triple) {
     LongDoubleWidth = 64;
     LongDoubleFormat = &llvm::APFloat::IEEEdouble;
+    UserLabelPrefix = "";
   }
 
   CallingConvCheckResult checkCallingConvention(CallingConv CC) const override {
Index: test/Preprocessor/elfiamcu-predefines.c
===================================================================
--- test/Preprocessor/elfiamcu-predefines.c
+++ test/Preprocessor/elfiamcu-predefines.c
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 -E -dM -triple i586-intel-elfiamcu | FileCheck %s
 
+// CHECK: #define __USER_LABEL_PREFIX__ {{$}}
 // CHECK: #define __iamcu
 // CHECK: #define __iamcu__