Index: llvm/unittests/tools/llvm-exegesis/Mips/BenchmarkResultTest.cpp
===================================================================
--- /dev/null
+++ llvm/unittests/tools/llvm-exegesis/Mips/BenchmarkResultTest.cpp
@@ -0,0 +1,141 @@
+//===-- BenchmarkResultTest.cpp ---------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "BenchmarkResult.h"
+#include "MipsInstrInfo.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/YAMLTraits.h"
+#include "llvm/Support/raw_ostream.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+using ::testing::AllOf;
+using ::testing::Eq;
+using ::testing::get;
+using ::testing::Pointwise;
+using ::testing::Property;
+
+namespace llvm {
+namespace exegesis {
+
+void InitializeMipsExegesisTarget();
+
+bool operator==(const BenchmarkMeasure &A, const BenchmarkMeasure &B) {
+  return std::tie(A.Key, A.PerInstructionValue, A.PerSnippetValue) ==
+         std::tie(B.Key, B.PerInstructionValue, B.PerSnippetValue);
+}
+
+static std::string Dump(const MCInst &McInst) {
+  std::string Buffer;
+  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 {
+
+TEST(BenchmarkResultTest, WriteToAndReadFromDisk) {
+  LLVMInitializeMipsTargetInfo();
+  LLVMInitializeMipsTarget();
+  LLVMInitializeMipsTargetMC();
+  InitializeMipsExegesisTarget();
+
+  // Read benchmarks.
+  const LLVMState State("mips-unknown-linux", "mips32");
+
+  ExitOnError ExitOnErr;
+
+  InstructionBenchmark ToDisk;
+
+  ToDisk.Key.Instructions.push_back(MCInstBuilder(Mips::XOR)
+                                        .addReg(Mips::T0)
+                                        .addReg(Mips::T1)
+                                        .addReg(Mips::T2));
+  ToDisk.Key.Config = "config";
+  ToDisk.Key.RegisterInitialValues = {
+      RegisterValue{Mips::T1, APInt(8, "123", 10)},
+      RegisterValue{Mips::T2, APInt(8, "456", 10)}};
+  ToDisk.Mode = InstructionBenchmark::Latency;
+  ToDisk.CpuName = "cpu_name";
+  ToDisk.LLVMTriple = "llvm_triple";
+  ToDisk.NumRepetitions = 1;
+  ToDisk.Measurements.push_back(BenchmarkMeasure{"a", 1, 1});
+  ToDisk.Measurements.push_back(BenchmarkMeasure{"b", 2, 2});
+  ToDisk.Error = "error";
+  ToDisk.Info = "info";
+
+  SmallString<64> Filename;
+  std::error_code EC;
+  EC = sys::fs::createUniqueDirectory("BenchmarkResultTestDir", Filename);
+  ASSERT_FALSE(EC);
+  sys::path::append(Filename, "data.yaml");
+  errs() << Filename << "-------\n";
+  ExitOnErr(ToDisk.writeYaml(State, Filename));
+
+  {
+    // One-element version.
+    const auto FromDisk =
+        ExitOnErr(InstructionBenchmark::readYaml(State, Filename));
+
+    EXPECT_THAT(FromDisk.Key.Instructions,
+                Pointwise(EqMCInst(), ToDisk.Key.Instructions));
+    EXPECT_EQ(FromDisk.Key.Config, ToDisk.Key.Config);
+    EXPECT_EQ(FromDisk.Mode, ToDisk.Mode);
+    EXPECT_EQ(FromDisk.CpuName, ToDisk.CpuName);
+    EXPECT_EQ(FromDisk.LLVMTriple, ToDisk.LLVMTriple);
+    EXPECT_EQ(FromDisk.NumRepetitions, ToDisk.NumRepetitions);
+    EXPECT_THAT(FromDisk.Measurements, ToDisk.Measurements);
+    EXPECT_THAT(FromDisk.Error, ToDisk.Error);
+    EXPECT_EQ(FromDisk.Info, ToDisk.Info);
+  }
+  {
+    // Vector version.
+    const auto FromDiskVector =
+        ExitOnErr(InstructionBenchmark::readYamls(State, Filename));
+    ASSERT_EQ(FromDiskVector.size(), size_t{1});
+    const auto FromDisk = FromDiskVector[0];
+    EXPECT_THAT(FromDisk.Key.Instructions,
+                Pointwise(EqMCInst(), ToDisk.Key.Instructions));
+    EXPECT_EQ(FromDisk.Key.Config, ToDisk.Key.Config);
+    EXPECT_EQ(FromDisk.Mode, ToDisk.Mode);
+    EXPECT_EQ(FromDisk.CpuName, ToDisk.CpuName);
+    EXPECT_EQ(FromDisk.LLVMTriple, ToDisk.LLVMTriple);
+    EXPECT_EQ(FromDisk.NumRepetitions, ToDisk.NumRepetitions);
+    EXPECT_THAT(FromDisk.Measurements, ToDisk.Measurements);
+    EXPECT_THAT(FromDisk.Error, ToDisk.Error);
+    EXPECT_EQ(FromDisk.Info, ToDisk.Info);
+  }
+}
+
+TEST(BenchmarkResultTest, PerInstructionStats) {
+  PerInstructionStats Stats;
+  Stats.push(BenchmarkMeasure{"a", 0.5, 0.0});
+  Stats.push(BenchmarkMeasure{"a", 1.5, 0.0});
+  Stats.push(BenchmarkMeasure{"a", -1.0, 0.0});
+  Stats.push(BenchmarkMeasure{"a", 0.0, 0.0});
+  EXPECT_EQ(Stats.min(), -1.0);
+  EXPECT_EQ(Stats.max(), 1.5);
+  EXPECT_EQ(Stats.avg(), 0.25); // (0.5+1.5-1.0+0.0) / 4
+}
+} // namespace
+} // namespace exegesis
+} // namespace llvm
Index: llvm/unittests/tools/llvm-exegesis/Mips/CMakeLists.txt
===================================================================
--- llvm/unittests/tools/llvm-exegesis/Mips/CMakeLists.txt
+++ llvm/unittests/tools/llvm-exegesis/Mips/CMakeLists.txt
@@ -14,6 +14,7 @@
   )
 
 add_llvm_unittest(LLVMExegesisMipsTests
+  BenchmarkResultTest.cpp
   TargetTest.cpp
   )
 target_link_libraries(LLVMExegesisMipsTests PRIVATE