Index: llvm/include/llvm/Bitcode/LLVMBitCodes.h
===================================================================
--- llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -411,6 +411,7 @@
                               //                 sideeffect|alignstack|
                               //                 asmdialect|unwind,
                               //                 asmstr,conststr]
+  CST_CODE_UNKNOWN_PROVENANCE = 31, // UNKNOWN_PROVENANCE
 };
 
 /// CastOpcodes - These are values used in the bitcode files to encode which
Index: llvm/lib/Bitcode/Reader/BitcodeReader.cpp
===================================================================
--- llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -3004,6 +3004,11 @@
     case bitc::CST_CODE_UNDEF:     // UNDEF
       V = UndefValue::get(CurTy);
       break;
+    case bitc::CST_CODE_UNKNOWN_PROVENANCE: // UNKNOWN_PROVENANCE
+      if (!CurTy->isPointerTy())
+        return error("Invalid type for a unknown_provenance");
+      V = UnknownProvenance::get(cast<PointerType>(CurTy));
+      break;
     case bitc::CST_CODE_POISON:    // POISON
       V = PoisonValue::get(CurTy);
       break;
Index: llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -2563,6 +2563,8 @@
       Code = bitc::CST_CODE_POISON;
     } else if (isa<UndefValue>(C)) {
       Code = bitc::CST_CODE_UNDEF;
+    } else if (isa<UnknownProvenance>(C)) {
+      Code = bitc::CST_CODE_UNKNOWN_PROVENANCE;
     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
       if (IV->getBitWidth() <= 64) {
         uint64_t V = IV->getSExtValue();