diff --git a/llvm/include/llvm/MC/MCContext.h b/llvm/include/llvm/MC/MCContext.h
index e74e592b41d863d062f320406753495ff2fc57ff..b42b1d6a397c860976fa980bf3c8e2a01ef70185 100644
--- a/llvm/include/llvm/MC/MCContext.h
+++ b/llvm/include/llvm/MC/MCContext.h
@@ -104,10 +104,10 @@ namespace llvm {
     DenseMap<unsigned, MCLabel *> Instances;
     /// NextInstance() creates the next instance of the directional local label
     /// for the LocalLabelVal and adds it to the map if needed.
-    unsigned NextInstance(unsigned LocalLabelVal);
+    unsigned NextInstance(unsigned LocalLabelVal, bool &valid);
     /// GetInstance() gets the current instance of the directional local label
     /// for the LocalLabelVal and adds it to the map if needed.
-    unsigned GetInstance(unsigned LocalLabelVal);
+    unsigned GetInstance(unsigned LocalLabelVal, bool &valid);
 
     /// The file name of the log file from the environment variable
     /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
@@ -275,11 +275,11 @@ namespace llvm {
 
     /// Create the definition of a directional local symbol for numbered label
     /// (used for "1:" definitions).
-    MCSymbol *createDirectionalLocalSymbol(unsigned LocalLabelVal);
+    MCSymbol *createDirectionalLocalSymbol(unsigned LocalLabelVal, bool &valid);
 
     /// Create and return a directional local symbol for numbered label (used
     /// for "1b" or 1f" references).
-    MCSymbol *getDirectionalLocalSymbol(unsigned LocalLabelVal, bool Before);
+    MCSymbol *getDirectionalLocalSymbol(unsigned LocalLabelVal, bool Before, bool &valid);
 
     /// Lookup the symbol inside with the specified \p Name.  If it exists,
     /// return it.  If not, create a forward reference and return it.
diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index 9ff66e48824684eb5f7c610de6b5cc85a1945838..dbaa5df1cd4617f04ce329bb42ad8d72e06a5848 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -222,14 +222,24 @@ MCSymbol *MCContext::createTempSymbol(bool CanBeUnnamed) {
   return createTempSymbol("tmp", true, CanBeUnnamed);
 }
 
-unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
+unsigned MCContext::NextInstance(unsigned LocalLabelVal, bool &valid)
+{
+  if (LocalLabelVal > Instances.size()) {
+      valid = false;
+      return 0;
+  }
   MCLabel *&Label = Instances[LocalLabelVal];
   if (!Label)
     Label = new (*this) MCLabel(0);
   return Label->incInstance();
 }
 
-unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
+unsigned MCContext::GetInstance(unsigned LocalLabelVal, bool &valid)
+{
+  if (LocalLabelVal > Instances.size()) {
+      valid = false;
+      return 0;
+  }
   MCLabel *&Label = Instances[LocalLabelVal];
   if (!Label)
     Label = new (*this) MCLabel(0);
@@ -244,14 +254,22 @@ MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
   return Sym;
 }
 
-MCSymbol *MCContext::createDirectionalLocalSymbol(unsigned LocalLabelVal) {
-  unsigned Instance = NextInstance(LocalLabelVal);
+MCSymbol *MCContext::createDirectionalLocalSymbol(unsigned LocalLabelVal, bool &valid)
+{
+  valid = true;
+  unsigned Instance = NextInstance(LocalLabelVal, valid);
+  if (!valid)
+      return nullptr;
   return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
 }
 
 MCSymbol *MCContext::getDirectionalLocalSymbol(unsigned LocalLabelVal,
-                                               bool Before) {
-  unsigned Instance = GetInstance(LocalLabelVal);
+                                               bool Before, bool &valid)
+{
+  valid = true;
+  unsigned Instance = GetInstance(LocalLabelVal, valid);
+  if (!valid)
+      return nullptr;
   if (!Before)
     ++Instance;
   return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 3c6141d5724828c44ad8cae7c9eca5b6375c6220..90d71bdaa0cdd4741c35d36896dd5107bfd578a2 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -987,8 +987,11 @@ bool AsmParser::parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc)
         IDVal = Split.first;
       }
       if (IDVal == "f" || IDVal == "b") {
+        bool valid;
         MCSymbol *Sym =
-            Ctx.getDirectionalLocalSymbol(IntVal, IDVal == "b");
+            Ctx.getDirectionalLocalSymbol(IntVal, IDVal == "b", valid);
+        if (!valid)
+            return true;
         Res = MCSymbolRefExpr::create(Sym, Variant, getContext());
         if (IDVal == "b" && Sym->isUndefined()) {
           //return Error(Loc, "invalid reference to undefined symbol");
@@ -1602,8 +1605,14 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info,
           return true;
       }
       Sym = getContext().getOrCreateSymbol(IDVal);
-    } else
-      Sym = Ctx.createDirectionalLocalSymbol(LocalLabelVal);
+    } else {
+      bool valid;
+      Sym = Ctx.createDirectionalLocalSymbol(LocalLabelVal, valid);
+      if (!valid) {
+          Info.KsError = KS_ERR_ASM_LABEL_INVALID;
+          return true;
+      }
+    }
 
     Sym->redefineIfPossible();
 
diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index a1c46f75e3464b11ccf441d988dd0a0db3eeffc2..4c1e13c29165e60e3c53eea9834f86e2647ca992 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1468,8 +1468,11 @@ bool X86AsmParser::ParseIntelExpression(IntelExprStateMachine &SM, SMLoc &End)
       if (getLexer().getKind() == AsmToken::Identifier) {
         StringRef IDVal = getTok().getString();
         if (IDVal == "f" || IDVal == "b") {
+          bool valid;
           MCSymbol *Sym =
-              getContext().getDirectionalLocalSymbol(IntVal, IDVal == "b");
+              getContext().getDirectionalLocalSymbol(IntVal, IDVal == "b", valid);
+          if (!valid)
+              return true;
           MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
           const MCExpr *Val =
               MCSymbolRefExpr::create(Sym, Variant, getContext());