diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 2a2dd085a9461..c1191d964a60c 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -141,8 +141,6 @@ enum {
 
   // FUNCTION_BLOCK abbrev id's.
   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
-  FUNCTION_INST_UNOP_ABBREV,
-  FUNCTION_INST_UNOP_FLAGS_ABBREV,
   FUNCTION_INST_BINOP_ABBREV,
   FUNCTION_INST_BINOP_FLAGS_ABBREV,
   FUNCTION_INST_CAST_ABBREV,
@@ -3127,13 +3125,10 @@ void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
     break;
   case Instruction::FNeg: {
     Code = bitc::FUNC_CODE_INST_UNOP;
-    if (!pushValueAndType(I.getOperand(0), InstID, Vals))
-      AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
+    pushValueAndType(I.getOperand(0), InstID, Vals);
     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
     uint64_t Flags = getOptimizationFlags(&I);
     if (Flags != 0) {
-      if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
-        AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
       Vals.push_back(Flags);
     }
     break;
@@ -3946,25 +3941,6 @@ void ModuleBitcodeWriter::writeBlockInfo() {
         FUNCTION_INST_LOAD_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
-  { // INST_UNOP abbrev for FUNCTION_BLOCK.
-    auto Abbv = std::make_shared<BitCodeAbbrev>();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
-        FUNCTION_INST_UNOP_ABBREV)
-      llvm_unreachable("Unexpected abbrev ordering!");
-  }
-  { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
-    auto Abbv = std::make_shared<BitCodeAbbrev>();
-    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
-    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
-        FUNCTION_INST_UNOP_FLAGS_ABBREV)
-      llvm_unreachable("Unexpected abbrev ordering!");
-  }
   { // INST_BINOP abbrev for FUNCTION_BLOCK.
     auto Abbv = std::make_shared<BitCodeAbbrev>();
     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));