Index: tools/llvm-exegesis/lib/BenchmarkResult.cpp
===================================================================
--- tools/llvm-exegesis/lib/BenchmarkResult.cpp
+++ tools/llvm-exegesis/lib/BenchmarkResult.cpp
@@ -15,6 +15,72 @@
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 
+namespace exegesis {
+
+void serialize(const exegesis::BenchmarkResultContext &Context,
+               const llvm::MCOperand &MCOperand, llvm::raw_ostream &OS) {
+  if (MCOperand.isReg()) {
+    OS << Context.getRegName(MCOperand.getReg());
+  } else if (MCOperand.isImm()) {
+    OS << MCOperand.getImm();
+  } else if (MCOperand.isFPImm()) {
+    OS << MCOperand.getFPImm();
+  } else {
+    OS << "INVALID";
+  }
+}
+
+void serialize(const exegesis::BenchmarkResultContext &Context,
+               const llvm::MCInst &MCInst, llvm::raw_ostream &OS) {
+  OS << Context.getInstrName(MCInst.getOpcode());
+  for (const auto &Op : MCInst) {
+    OS << ' ';
+    serialize(Context, Op, OS);
+  }
+}
+
+llvm::MCOperand deserialize(const exegesis::BenchmarkResultContext &Context,
+                            llvm::StringRef String) {
+  assert(!String.empty());
+  // Starts with an uppercase, this is a Register.
+  if (std::isupper(String.front()))
+    return llvm::MCOperand::createReg(Context.getRegNo(String));
+  // There's a dot, this is a floating point.
+  if (String.count('.')) {
+    double Value = 0;
+    if (String.getAsDouble(Value))
+      return {};
+    return llvm::MCOperand::createFPImm(Value);
+  }
+  // Try as Integer.
+  int64_t Value = 0;
+  if (String.getAsInteger(10, Value))
+    return {};
+  return llvm::MCOperand::createImm(Value);
+}
+
+llvm::StringRef deserialize(const exegesis::BenchmarkResultContext &Context,
+                            llvm::StringRef String, llvm::MCInst &Value) {
+  llvm::SmallVector<llvm::StringRef, 8> Pieces;
+  String.split(Pieces, " ");
+  if (Pieces.empty())
+    return "Invalid Instruction";
+  bool ProcessOpcode = true;
+  for (llvm::StringRef Piece : Pieces) {
+    if (ProcessOpcode) {
+      ProcessOpcode = false;
+      Value.setOpcode(Context.getInstrOpcode(Piece));
+      if (Value.getOpcode() == 0)
+        return "Unknown Opcode Name";
+    } else {
+      Value.addOperand(deserialize(Context, Piece));
+    }
+  }
+  return {};
+}
+
+} // namespace exegesis
+
 // Defining YAML traits for IO.
 namespace llvm {
 namespace yaml {
@@ -25,25 +91,18 @@
 };
 
 template <> struct ScalarTraits<llvm::MCInst> {
+  static const exegesis::BenchmarkResultContext &getContext(void *Ctx) {
+    assert(Ctx);
+    return *static_cast<const exegesis::BenchmarkResultContext *>(Ctx);
+  }
 
   static void output(const llvm::MCInst &Value, void *Ctx,
                      llvm::raw_ostream &Out) {
-    assert(Ctx);
-    auto *Context = static_cast<const exegesis::BenchmarkResultContext *>(Ctx);
-    const StringRef Name = Context->getInstrName(Value.getOpcode());
-    assert(!Name.empty());
-    Out << Name;
+    serialize(getContext(Ctx), Value, Out);
   }
 
   static StringRef input(StringRef Scalar, void *Ctx, llvm::MCInst &Value) {
-    assert(Ctx);
-    auto *Context = static_cast<const exegesis::BenchmarkResultContext *>(Ctx);
-    const unsigned Opcode = Context->getInstrOpcode(Scalar);
-    if (Opcode == 0) {
-      return "Unable to parse instruction";
-    }
-    Value.setOpcode(Opcode);
-    return StringRef();
+    return deserialize(getContext(Ctx), Scalar, Value);
   }
 
   static QuotingType mustQuote(StringRef) { return QuotingType::Single; }
Index: unittests/tools/llvm-exegesis/BenchmarkResultTest.cpp
===================================================================
--- unittests/tools/llvm-exegesis/BenchmarkResultTest.cpp
+++ unittests/tools/llvm-exegesis/BenchmarkResultTest.cpp
@@ -28,23 +28,46 @@
   return std::tie(A.Key, A.Value) == std::tie(B.Key, B.Value);
 }
 
-MATCHER(EqMCInst, "") {
-  return get<0>(arg).getOpcode() == get<1>(arg).getOpcode();
+static std::string Dump(const llvm::MCInst &McInst) {
+  std::string Buffer;
+  llvm::raw_string_ostream OS(Buffer);
+  McInst.print(OS);
+  return Buffer;
+}
+
+MATCHER(EqMcinst, "") {
+  const std::string Lhs = Dump(get<0>(arg));
+  const std::string Rhs = Dump(get<1>(arg));
+  if (Lhs != Rhs) {
+    *result_listener << Lhs << " <=> " << Rhs;
+    return false;
+  }
+  return true;
 }
 
 namespace {
 
 static constexpr const unsigned kInstrId = 5;
 static constexpr const char kInstrName[] = "Instruction5";
+static constexpr const unsigned kReg1Id = 1;
+static constexpr const char kReg1Name[] = "Reg1";
+static constexpr const unsigned kReg2Id = 2;
+static constexpr const char kReg2Name[] = "Reg2";
 
 TEST(BenchmarkResultTest, WriteToAndReadFromDisk) {
   BenchmarkResultContext Ctx;
   Ctx.addInstrEntry(kInstrId, kInstrName);
+  Ctx.addRegEntry(kReg1Id, kReg1Name);
+  Ctx.addRegEntry(kReg2Id, kReg2Name);
 
   InstructionBenchmark ToDisk;
 
   ToDisk.Key.OpcodeName = "name";
-  ToDisk.Key.Instructions.push_back(llvm::MCInstBuilder(kInstrId));
+  ToDisk.Key.Instructions.push_back(llvm::MCInstBuilder(kInstrId)
+                                        .addReg(kReg1Id)
+                                        .addReg(kReg2Id)
+                                        .addImm(123)
+                                        .addFPImm(0.5));
   ToDisk.Key.Mode = InstructionBenchmarkKey::Latency;
   ToDisk.Key.Config = "config";
   ToDisk.CpuName = "cpu_name";
@@ -68,7 +91,7 @@
 
     EXPECT_EQ(FromDisk.Key.OpcodeName, ToDisk.Key.OpcodeName);
     EXPECT_THAT(FromDisk.Key.Instructions,
-                Pointwise(EqMCInst(), ToDisk.Key.Instructions));
+                Pointwise(EqMcinst(), ToDisk.Key.Instructions));
     EXPECT_EQ(FromDisk.Key.Mode, ToDisk.Key.Mode);
     EXPECT_EQ(FromDisk.Key.Config, ToDisk.Key.Config);
     EXPECT_EQ(FromDisk.CpuName, ToDisk.CpuName);
@@ -86,7 +109,7 @@
     const auto FromDisk = FromDiskVector[0];
     EXPECT_EQ(FromDisk.Key.OpcodeName, ToDisk.Key.OpcodeName);
     EXPECT_THAT(FromDisk.Key.Instructions,
-                Pointwise(EqMCInst(), ToDisk.Key.Instructions));
+                Pointwise(EqMcinst(), ToDisk.Key.Instructions));
     EXPECT_EQ(FromDisk.Key.Mode, ToDisk.Key.Mode);
     EXPECT_EQ(FromDisk.Key.Config, ToDisk.Key.Config);
     EXPECT_EQ(FromDisk.CpuName, ToDisk.CpuName);