Index: include/llvm/Support/MathExtras.h
===================================================================
--- include/llvm/Support/MathExtras.h
+++ include/llvm/Support/MathExtras.h
@@ -839,6 +839,18 @@
   return SaturatingAdd(A, Product, &Overflowed);
 }
 
+/// Add two integers \p LHS and \p RHS, write into \p Res if non-null and the
+/// operation does not oveflow.
+/// Does not guarantee saturating arithmetic.
+/// \return Whether the result overflows.
+bool checkedAdd(int64_t LHS, int64_t RHS, int64_t *Res=nullptr);
+
+/// Multiply two integers \p LHS and \p RHS, write into \p Res if non-null and
+/// the operation does not oveflow.
+/// Does not guarantee saturating arithmetic.
+/// \return Whether the result overflows.
+bool checkedMul(int64_t LHS, int64_t RHS, int64_t *Res=nullptr);
+
 /// Use this rather than HUGE_VALF; the latter causes warnings on MSVC.
 extern const float huge_valf;
 } // End llvm namespace
Index: lib/Support/MathExtras.cpp
===================================================================
--- lib/Support/MathExtras.cpp
+++ lib/Support/MathExtras.cpp
@@ -18,9 +18,39 @@
 #else
 #include <math.h>
 #endif
+#include <llvm/ADT/APInt.h>
+#include <functional>
 
 namespace llvm {
 
+static bool checkedOp(
+    int64_t LHS,
+    int64_t RHS,
+    std::function<llvm::APInt(llvm::APInt *, const llvm::APInt &, bool &)> Op,
+    int64_t *Res = nullptr) {
+  llvm::APInt ALHS(/*BitSize=*/64, LHS, /*Signed=*/true);
+  llvm::APInt ARHS(/*BitSize=*/64, RHS, /*Signed=*/true);
+  bool Overflow;
+  llvm::APInt Out = Op(&ALHS, ARHS, Overflow);
+  if (!Overflow && Res)
+    *Res = Out.getSExtValue();
+  return Overflow;
+}
+
+bool checkedAdd(
+    int64_t LHS,
+    int64_t RHS,
+    int64_t *Res) {
+  return checkedOp(LHS, RHS, &llvm::APInt::sadd_ov, Res);
+}
+
+bool checkedMul(
+    int64_t LHS,
+    int64_t RHS,
+    int64_t *Res) {
+  return checkedOp(LHS, RHS, &llvm::APInt::smul_ov, Res);
+}
+
 #if defined(_MSC_VER)
   // Visual Studio defines the HUGE_VAL class of macros using purposeful
   // constant arithmetic overflow, which it then warns on when encountered.
Index: unittests/Support/MathExtrasTest.cpp
===================================================================
--- unittests/Support/MathExtrasTest.cpp
+++ unittests/Support/MathExtrasTest.cpp
@@ -469,4 +469,27 @@
   EXPECT_FALSE((isShiftedInt<6, 10>(int64_t(1) << 15)));
 }
 
+TEST(MathExtras, CheckedAdd) {
+  const int64_t Max = std::numeric_limits<int64_t>::max();
+  const int64_t Min = std::numeric_limits<int64_t>::min();
+  EXPECT_EQ(checkedAdd(Max, Max), true);
+  EXPECT_EQ(checkedAdd(Min, -1), true);
+  EXPECT_EQ(checkedAdd(Max, 1), true);
+  int64_t Out;
+  EXPECT_EQ(checkedAdd(10, 1, &Out), false);
+  EXPECT_EQ(Out, 11);
+
+}
+
+TEST(MathExtras, CheckedMul) {
+  const int64_t Max = std::numeric_limits<int64_t>::max();
+  const int64_t Min = std::numeric_limits<int64_t>::min();
+  EXPECT_EQ(checkedMul(Max, 2), true);
+  EXPECT_EQ(checkedMul(Max, Max), true);
+  EXPECT_EQ(checkedMul(Min, 2), true);
+  int64_t Out;
+  EXPECT_EQ(checkedMul(10, 2, &Out), false);
+  EXPECT_EQ(Out, 20);
+}
+
 } // namespace