diff --git a/llvm/include/llvm/Analysis/TargetTransformInfo.h b/llvm/include/llvm/Analysis/TargetTransformInfo.h
--- a/llvm/include/llvm/Analysis/TargetTransformInfo.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfo.h
@@ -27,6 +27,7 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/AtomicOrdering.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/InstructionCost.h"
 #include <functional>
 
 namespace llvm {
@@ -231,19 +232,26 @@
   ///
   /// Note, this method does not cache the cost calculation and it
   /// can be expensive in some cases.
-  int getInstructionCost(const Instruction *I, enum TargetCostKind kind) const {
+  InstructionCost getInstructionCost(const Instruction *I,
+                                     enum TargetCostKind kind) const {
+    InstructionCost Cost;
     switch (kind) {
     case TCK_RecipThroughput:
-      return getInstructionThroughput(I);
-
+      Cost = getInstructionThroughput(I);
+      break;
     case TCK_Latency:
-      return getInstructionLatency(I);
-
+      Cost = getInstructionLatency(I);
+      break;
     case TCK_CodeSize:
     case TCK_SizeAndLatency:
-      return getUserCost(I, kind);
+      Cost = getUserCost(I, kind);
+      break;
+    default:
+      llvm_unreachable("Unknown instruction cost kind");
     }
-    llvm_unreachable("Unknown instruction cost kind");
+    if (Cost == -1)
+      Cost.setInvalid();
+    return Cost;
   }
 
   /// Underlying constants for 'cost' values in this interface.
diff --git a/llvm/include/llvm/IR/DiagnosticInfo.h b/llvm/include/llvm/IR/DiagnosticInfo.h
--- a/llvm/include/llvm/IR/DiagnosticInfo.h
+++ b/llvm/include/llvm/IR/DiagnosticInfo.h
@@ -35,6 +35,7 @@
 class DiagnosticPrinter;
 class Function;
 class Instruction;
+class InstructionCost;
 class LLVMContext;
 class Module;
 class SMDiagnostic;
@@ -437,6 +438,7 @@
     Argument(StringRef Key, ElementCount EC);
     Argument(StringRef Key, bool B) : Key(Key), Val(B ? "true" : "false") {}
     Argument(StringRef Key, DebugLoc dl);
+    Argument(StringRef Key, InstructionCost C);
   };
 
   /// \p PassName is the name of the pass emitting this diagnostic. \p
diff --git a/llvm/include/llvm/Support/InstructionCost.h b/llvm/include/llvm/Support/InstructionCost.h
new file mode 100644
--- /dev/null
+++ b/llvm/include/llvm/Support/InstructionCost.h
@@ -0,0 +1,245 @@
+//===- InstructionCost.h ----------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file defines an InstructionCost class that is used when calculating
+/// the cost of an instruction, or a group of instructions. In addition to a
+/// numeric value representing the cost the class also contains a state that
+/// can be used to encode particular properties, i.e. a cost being invalid or
+/// unknown.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_INSTRUCTIONCOST_H
+#define LLVM_SUPPORT_INSTRUCTIONCOST_H
+
+#include "llvm/ADT/Optional.h"
+
+namespace llvm {
+
+class raw_ostream;
+
+class InstructionCost {
+public:
+  using CostType = int;
+
+  /// These states can currently be used to indicate whether a cost is valid or
+  /// invalid. Examples of an invalid cost might be where the cost is
+  /// prohibitively expensive and the user wants to prevent certain
+  /// optimizations being performed. Or perhaps the cost is simply unknown
+  /// because the operation makes no sense in certain circumstances. These
+  /// states can be expanded in future to support other cases if necessary.
+  enum CostState { Valid, Invalid };
+
+private:
+  CostType Value;
+  CostState State;
+
+  void propagateState(const InstructionCost &RHS) {
+    if (RHS.State == Invalid)
+      State = Invalid;
+  }
+
+public:
+  InstructionCost() = default;
+
+  InstructionCost(CostType Val) : Value(Val), State(Valid) {}
+
+  static InstructionCost getInvalid(CostType Val = 0) {
+    InstructionCost Tmp(Val);
+    Tmp.setInvalid();
+    return Tmp;
+  }
+
+  bool isValid() const { return State == Valid; }
+  void setValid() { State = Valid; }
+  void setInvalid() { State = Invalid; }
+  CostState getState() const { return State; }
+
+  /// This function is intended to be used as sparingly as possible, since the
+  /// class provides the full range of operator support required for arithmetic
+  /// and comparisons.
+  Optional<CostType> getValue() const {
+    if (isValid())
+      return Value;
+    return None;
+  }
+
+  /// For all of the arithmetic operators provided here any invalid state is
+  /// perpetuated and cannot be removed. Once a cost becomes invalid it stays
+  /// invalid, and it also inherits any invalid state from the RHS. Regardless
+  /// of the state, arithmetic and comparisons work on the actual values in the
+  /// same way as they would on a basic type, such as integer.
+
+  InstructionCost &operator+=(const InstructionCost &RHS) {
+    propagateState(RHS);
+    Value += RHS.Value;
+    return *this;
+  }
+
+  InstructionCost &operator+=(const CostType RHS) {
+    InstructionCost RHS2(RHS);
+    *this += RHS2;
+    return *this;
+  }
+
+  InstructionCost &operator-=(const InstructionCost &RHS) {
+    propagateState(RHS);
+    Value -= RHS.Value;
+    return *this;
+  }
+
+  InstructionCost &operator-=(const CostType RHS) {
+    InstructionCost RHS2(RHS);
+    *this -= RHS2;
+    return *this;
+  }
+
+  InstructionCost &operator*=(const InstructionCost &RHS) {
+    propagateState(RHS);
+    Value *= RHS.Value;
+    return *this;
+  }
+
+  InstructionCost &operator*=(const CostType RHS) {
+    InstructionCost RHS2(RHS);
+    *this *= RHS2;
+    return *this;
+  }
+
+  InstructionCost &operator/=(const InstructionCost &RHS) {
+    propagateState(RHS);
+    Value /= RHS.Value;
+    return *this;
+  }
+
+  InstructionCost &operator/=(const CostType RHS) {
+    InstructionCost RHS2(RHS);
+    *this /= RHS2;
+    return *this;
+  }
+
+  InstructionCost &operator++() {
+    *this += 1;
+    return *this;
+  }
+
+  InstructionCost operator++(int) {
+    InstructionCost Copy = *this;
+    ++*this;
+    return Copy;
+  }
+
+  InstructionCost &operator--() {
+    *this -= 1;
+    return *this;
+  }
+
+  InstructionCost operator--(int) {
+    InstructionCost Copy = *this;
+    --*this;
+    return Copy;
+  }
+
+  bool operator==(const InstructionCost &RHS) const {
+    return State == RHS.State && Value == RHS.Value;
+  }
+
+  bool operator!=(const InstructionCost &RHS) const { return !(*this == RHS); }
+
+  bool operator==(const CostType RHS) const {
+    return State == Valid && Value == RHS;
+  }
+
+  bool operator!=(const CostType RHS) const { return !(*this == RHS); }
+
+  /// For the comparison operators we have chosen to use total ordering with
+  /// the following rules:
+  ///  1. If either of the states != Valid then a lexicographical order is
+  ///     applied based upon the state.
+  ///  2. If both states are valid then order based upon value.
+  /// This avoids having to add asserts the comparison operators that the states
+  /// are valid and users can test for validity of the cost explicitly.
+  bool operator<(const InstructionCost &RHS) const {
+    if (State != Valid || RHS.State != Valid)
+      return State < RHS.State;
+    return Value < RHS.Value;
+  }
+
+  bool operator>(const InstructionCost &RHS) const { return RHS < *this; }
+
+  bool operator<=(const InstructionCost &RHS) const { return !(RHS < *this); }
+
+  bool operator>=(const InstructionCost &RHS) const { return !(*this < RHS); }
+
+  bool operator<(const CostType RHS) const {
+    InstructionCost RHS2(RHS);
+    return *this < RHS2;
+  }
+
+  bool operator>(const CostType RHS) const {
+    InstructionCost RHS2(RHS);
+    return *this > RHS2;
+  }
+
+  bool operator<=(const CostType RHS) const {
+    InstructionCost RHS2(RHS);
+    return *this <= RHS2;
+  }
+
+  bool operator>=(const CostType RHS) const {
+    InstructionCost RHS2(RHS);
+    return *this >= RHS2;
+  }
+
+  static InstructionCost min(InstructionCost LHS, InstructionCost RHS) {
+    return LHS < RHS ? LHS : RHS;
+  }
+
+  static InstructionCost max(InstructionCost LHS, InstructionCost RHS) {
+    return LHS > RHS ? LHS : RHS;
+  }
+
+  void print(raw_ostream &OS) const;
+};
+
+inline InstructionCost operator+(const InstructionCost &LHS,
+                                 const InstructionCost &RHS) {
+  InstructionCost LHS2(LHS);
+  LHS2 += RHS;
+  return LHS2;
+}
+
+inline InstructionCost operator-(const InstructionCost &LHS,
+                                 const InstructionCost &RHS) {
+  InstructionCost LHS2(LHS);
+  LHS2 -= RHS;
+  return LHS2;
+}
+
+inline InstructionCost operator*(const InstructionCost &LHS,
+                                 const InstructionCost &RHS) {
+  InstructionCost LHS2(LHS);
+  LHS2 *= RHS;
+  return LHS2;
+}
+
+inline InstructionCost operator/(const InstructionCost &LHS,
+                                 const InstructionCost &RHS) {
+  InstructionCost LHS2(LHS);
+  LHS2 /= RHS;
+  return LHS2;
+}
+
+inline raw_ostream &operator<<(raw_ostream &OS, const InstructionCost &V) {
+  V.print(OS);
+  return OS;
+}
+
+} // namespace llvm
+
+#endif
diff --git a/llvm/lib/Analysis/CostModel.cpp b/llvm/lib/Analysis/CostModel.cpp
--- a/llvm/lib/Analysis/CostModel.cpp
+++ b/llvm/lib/Analysis/CostModel.cpp
@@ -57,7 +57,7 @@
     /// Returns -1 if the cost is unknown.
     /// Note, this method does not cache the cost calculation and it
     /// can be expensive in some cases.
-    unsigned getInstructionCost(const Instruction *I) const {
+    InstructionCost getInstructionCost(const Instruction *I) const {
       return TTI->getInstructionCost(I, TargetTransformInfo::TCK_RecipThroughput);
     }
 
@@ -103,9 +103,9 @@
 
   for (BasicBlock &B : *F) {
     for (Instruction &Inst : B) {
-      unsigned Cost = TTI->getInstructionCost(&Inst, CostKind);
-      if (Cost != (unsigned)-1)
-        OS << "Cost Model: Found an estimated cost of " << Cost;
+      InstructionCost Cost = TTI->getInstructionCost(&Inst, CostKind);
+      if (auto CostVal = Cost.getValue())
+        OS << "Cost Model: Found an estimated cost of " << *CostVal;
       else
         OS << "Cost Model: Unknown cost";
 
diff --git a/llvm/lib/CodeGen/InterleavedLoadCombinePass.cpp b/llvm/lib/CodeGen/InterleavedLoadCombinePass.cpp
--- a/llvm/lib/CodeGen/InterleavedLoadCombinePass.cpp
+++ b/llvm/lib/CodeGen/InterleavedLoadCombinePass.cpp
@@ -1130,8 +1130,8 @@
   std::set<Instruction *> Is;
   std::set<Instruction *> SVIs;
 
-  unsigned InterleavedCost;
-  unsigned InstructionCost = 0;
+  InstructionCost InterleavedCost;
+  InstructionCost InstructionCost = 0;
 
   // Get the interleave factor
   unsigned Factor = InterleavedLoad.size();
@@ -1174,6 +1174,10 @@
     }
   }
 
+  // We need to have a valid cost in order to proceed.
+  if (!InstructionCost.isValid())
+    return false;
+
   // We know that all LoadInst are within the same BB. This guarantees that
   // either everything or nothing is loaded.
   LoadInst *First = findFirstLoad(LIs);
diff --git a/llvm/lib/IR/DiagnosticInfo.cpp b/llvm/lib/IR/DiagnosticInfo.cpp
--- a/llvm/lib/IR/DiagnosticInfo.cpp
+++ b/llvm/lib/IR/DiagnosticInfo.cpp
@@ -32,6 +32,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/InstructionCost.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/ScopedPrinter.h"
@@ -220,6 +221,13 @@
   EC.print(OS);
 }
 
+DiagnosticInfoOptimizationBase::Argument::Argument(StringRef Key,
+                                                   InstructionCost C)
+    : Key(std::string(Key)) {
+  raw_string_ostream OS(Val);
+  C.print(OS);
+}
+
 DiagnosticInfoOptimizationBase::Argument::Argument(StringRef Key, DebugLoc Loc)
     : Key(std::string(Key)), Loc(Loc) {
   if (Loc) {
diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -128,6 +128,7 @@
   GraphWriter.cpp
   Hashing.cpp
   InitLLVM.cpp
+  InstructionCost.cpp
   IntEqClasses.cpp
   IntervalMap.cpp
   ItaniumManglingCanonicalizer.cpp
diff --git a/llvm/lib/Support/InstructionCost.cpp b/llvm/lib/Support/InstructionCost.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/lib/Support/InstructionCost.cpp
@@ -0,0 +1,24 @@
+//===- InstructionCost.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
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file includes the function definitions for the InstructionCost class
+/// that is used when calculating the cost of an instruction, or a group of
+/// instructions.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/InstructionCost.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+void InstructionCost::print(raw_ostream &OS) const {
+  if (isValid())
+    OS << Value;
+  else
+    OS << "Invalid";
+}
diff --git a/llvm/lib/Transforms/IPO/HotColdSplitting.cpp b/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
--- a/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
+++ b/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
@@ -233,11 +233,11 @@
 }
 
 /// Get the benefit score of outlining \p Region.
-static int getOutliningBenefit(ArrayRef<BasicBlock *> Region,
-                               TargetTransformInfo &TTI) {
+static InstructionCost getOutliningBenefit(ArrayRef<BasicBlock *> Region,
+                                           TargetTransformInfo &TTI) {
   // Sum up the code size costs of non-terminator instructions. Tight coupling
   // with \ref getOutliningPenalty is needed to model the costs of terminators.
-  int Benefit = 0;
+  InstructionCost Benefit = 0;
   for (BasicBlock *BB : Region)
     for (Instruction &I : BB->instructionsWithoutDebug())
       if (&I != BB->getTerminator())
@@ -324,12 +324,12 @@
   // splitting.
   SetVector<Value *> Inputs, Outputs, Sinks;
   CE.findInputsOutputs(Inputs, Outputs, Sinks);
-  int OutliningBenefit = getOutliningBenefit(Region, TTI);
+  InstructionCost OutliningBenefit = getOutliningBenefit(Region, TTI);
   int OutliningPenalty =
       getOutliningPenalty(Region, Inputs.size(), Outputs.size());
   LLVM_DEBUG(dbgs() << "Split profitability: benefit = " << OutliningBenefit
                     << ", penalty = " << OutliningPenalty << "\n");
-  if (OutliningBenefit <= OutliningPenalty)
+  if (!OutliningBenefit.isValid() || OutliningBenefit <= OutliningPenalty)
     return nullptr;
 
   Function *OrigF = Region[0]->getParent();
diff --git a/llvm/lib/Transforms/Scalar/CallSiteSplitting.cpp b/llvm/lib/Transforms/Scalar/CallSiteSplitting.cpp
--- a/llvm/lib/Transforms/Scalar/CallSiteSplitting.cpp
+++ b/llvm/lib/Transforms/Scalar/CallSiteSplitting.cpp
@@ -208,7 +208,7 @@
   // instructions before the call is less then DuplicationThreshold. The
   // instructions before the call will be duplicated in the split blocks and
   // corresponding uses will be updated.
-  unsigned Cost = 0;
+  InstructionCost Cost = 0;
   for (auto &InstBeforeCall :
        llvm::make_range(CallSiteBB->begin(), CB.getIterator())) {
     Cost += TTI.getInstructionCost(&InstBeforeCall,
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -7192,8 +7192,12 @@
       return std::min(CallCost, getVectorIntrinsicCost(CI, VF));
     return CallCost;
   }
-  case Instruction::ExtractValue:
-    return TTI.getInstructionCost(I, TTI::TCK_RecipThroughput);
+  case Instruction::ExtractValue: {
+    InstructionCost ExtractCost =
+        TTI.getInstructionCost(I, TTI::TCK_RecipThroughput);
+    assert(ExtractCost.isValid() && "Invalid cost for ExtractValue");
+    return *(ExtractCost.getValue());
+  }
   default:
     // The cost of executing VF copies of the scalar instruction. This opcode
     // is unknown. Assume that it is the same as 'mul'.
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -3793,17 +3793,23 @@
       if (NeedToShuffleReuses) {
         for (unsigned Idx : E->ReuseShuffleIndices) {
           Instruction *I = cast<Instruction>(VL[Idx]);
-          ReuseShuffleCost -= TTI->getInstructionCost(I, CostKind);
+          InstructionCost Cost = TTI->getInstructionCost(I, CostKind);
+          assert(Cost.isValid() && "Invalid instruction cost");
+          ReuseShuffleCost -= *(Cost.getValue());
         }
         for (Value *V : VL) {
           Instruction *I = cast<Instruction>(V);
-          ReuseShuffleCost += TTI->getInstructionCost(I, CostKind);
+          InstructionCost Cost = TTI->getInstructionCost(I, CostKind);
+          assert(Cost.isValid() && "Invalid instruction cost");
+          ReuseShuffleCost += *(Cost.getValue());
         }
       }
       for (Value *V : VL) {
         Instruction *I = cast<Instruction>(V);
         assert(E->isOpcodeOrAlt(I) && "Unexpected main/alternate opcode");
-        ScalarCost += TTI->getInstructionCost(I, CostKind);
+        InstructionCost Cost = TTI->getInstructionCost(I, CostKind);
+        assert(Cost.isValid() && "Invalid instruction cost");
+        ScalarCost += *(Cost.getValue());
       }
       // VecCost is equal to sum of the cost of creating 2 vectors
       // and the cost of creating shuffle.
diff --git a/llvm/unittests/Support/CMakeLists.txt b/llvm/unittests/Support/CMakeLists.txt
--- a/llvm/unittests/Support/CMakeLists.txt
+++ b/llvm/unittests/Support/CMakeLists.txt
@@ -40,6 +40,7 @@
   GlobPatternTest.cpp
   Host.cpp
   IndexedAccessorTest.cpp
+  InstructionCostTest.cpp
   ItaniumManglingCanonicalizerTest.cpp
   JSONTest.cpp
   KnownBitsTest.cpp
diff --git a/llvm/unittests/Support/InstructionCostTest.cpp b/llvm/unittests/Support/InstructionCostTest.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/unittests/Support/InstructionCostTest.cpp
@@ -0,0 +1,64 @@
+//===- InstructionCostTest.cpp - InstructionCost tests --------------------===//
+//
+// 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 "llvm/Support/InstructionCost.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+struct CostTest : public testing::Test {
+  CostTest() {}
+};
+
+} // namespace
+
+TEST_F(CostTest, Operators) {
+  InstructionCost VThree = 3;
+  InstructionCost VNegTwo = -2;
+  InstructionCost VSix = 6;
+  InstructionCost IThreeA = InstructionCost::getInvalid(3);
+  InstructionCost IThreeB = InstructionCost::getInvalid(3);
+  InstructionCost TmpCost;
+
+  EXPECT_NE(VThree, VNegTwo);
+  EXPECT_GT(VThree, VNegTwo);
+  EXPECT_NE(VThree, IThreeA);
+  EXPECT_EQ(IThreeA, IThreeB);
+  EXPECT_GE(IThreeA, VNegTwo);
+  EXPECT_LT(VSix, IThreeA);
+  EXPECT_EQ(VSix - IThreeA, IThreeB);
+  EXPECT_EQ(VThree - VNegTwo, 5);
+  EXPECT_EQ(VThree * VNegTwo, -6);
+  EXPECT_EQ(VSix / VThree, 2);
+
+  EXPECT_FALSE(IThreeA.isValid());
+  EXPECT_EQ(IThreeA.getState(), InstructionCost::Invalid);
+
+  TmpCost = VThree + IThreeA;
+  EXPECT_FALSE(TmpCost.isValid());
+
+  // Test increments, decrements
+  EXPECT_EQ(++VThree, 4);
+  EXPECT_EQ(VThree++, 4);
+  EXPECT_EQ(VThree, 5);
+  EXPECT_EQ(--VThree, 4);
+  EXPECT_EQ(VThree--, 4);
+  EXPECT_EQ(VThree, 3);
+
+  TmpCost = VThree * IThreeA;
+  EXPECT_FALSE(TmpCost.isValid());
+
+  // Test value extraction
+  EXPECT_EQ(*(VThree.getValue()), 3);
+  EXPECT_EQ(IThreeA.getValue(), None);
+
+  EXPECT_EQ(InstructionCost::min(VThree, VNegTwo), -2);
+  EXPECT_EQ(InstructionCost::max(VThree, VSix), 6);
+}