diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -593,14 +593,17 @@
   llvm_unreachable("Invalid ordering");
 }
 
+// Abbrev6 is used if all characters fit in char6, else Abbrev8.
 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
-                              StringRef Str, unsigned AbbrevToUse) {
+                              StringRef Str, unsigned Abbrev6 = 0,
+                              unsigned Abbrev8 = 0) {
   SmallVector<unsigned, 64> Vals;
 
+  unsigned AbbrevToUse = Abbrev6 ? Abbrev6 : Abbrev8;
   // Code: [strchar x N]
   for (char C : Str) {
     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
-      AbbrevToUse = 0;
+      AbbrevToUse = Abbrev8;
     Vals.push_back(C);
   }
 
@@ -898,7 +901,12 @@
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
-  unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
+  unsigned StructNameAbbrev6 = Stream.EmitAbbrev(std::move(Abbv));
+  Abbv = std::make_shared<BitCodeAbbrev>();
+  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
+  unsigned StructNameAbbrev8 = Stream.EmitAbbrev(std::move(Abbv));
 
   // Abbrev for TYPE_CODE_STRUCT_NAMED.
   Abbv = std::make_shared<BitCodeAbbrev>();
@@ -996,7 +1004,7 @@
         // Emit the name if it is present.
         if (!ST->getName().empty())
           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
-                            StructNameAbbrev);
+                            StructNameAbbrev6, StructNameAbbrev8);
       }
       break;
     }