Index: include/llvm/Analysis/TargetTransformInfo.h
===================================================================
--- include/llvm/Analysis/TargetTransformInfo.h
+++ include/llvm/Analysis/TargetTransformInfo.h
@@ -603,6 +603,22 @@
   /// \return The size of a cache line in bytes.
   unsigned getCacheLineSize() const;
 
+  /// The possible cache levels
+  enum class CacheLevel {
+    L1D,   // The L1 data cache
+    L2D,   // The L2 data cache
+
+    // We currently do not model L3 caches, as their sizes differ widely between
+    // microarchitectures. Also, we currently do not have a use for L3 cache
+    // size modeling yet.
+  };
+
+  /// \return The size of the cache level in bytes, if available.
+  llvm::Optional<unsigned> getCacheSize(CacheLevel Level) const;
+
+  /// \return The associativity of the cache level, if available.
+  llvm::Optional<unsigned> getCacheAssociativity(CacheLevel Level) const;
+
   /// \return How much before a load we should place the prefetch instruction.
   /// This is currently measured in number of instructions.
   unsigned getPrefetchDistance() const;
@@ -937,6 +953,8 @@
   virtual bool shouldConsiderAddressTypePromotion(
       const Instruction &I, bool &AllowPromotionWithoutCommonHeader) = 0;
   virtual unsigned getCacheLineSize() = 0;
+  virtual llvm::Optional<unsigned> getCacheSize(CacheLevel Level) = 0;
+  virtual llvm::Optional<unsigned> getCacheAssociativity(CacheLevel Level) = 0;
   virtual unsigned getPrefetchDistance() = 0;
   virtual unsigned getMinPrefetchStride() = 0;
   virtual unsigned getMaxPrefetchIterationsAhead() = 0;
@@ -1209,6 +1227,12 @@
   unsigned getCacheLineSize() override {
     return Impl.getCacheLineSize();
   }
+  llvm::Optional<unsigned> getCacheSize(CacheLevel Level) override {
+    return Impl.getCacheSize(Level);
+  }
+  llvm::Optional<unsigned> getCacheAssociativity(CacheLevel Level) override {
+    return Impl.getCacheAssociativity(Level);
+  }
   unsigned getPrefetchDistance() override { return Impl.getPrefetchDistance(); }
   unsigned getMinPrefetchStride() override {
     return Impl.getMinPrefetchStride();
Index: include/llvm/Analysis/TargetTransformInfoImpl.h
===================================================================
--- include/llvm/Analysis/TargetTransformInfoImpl.h
+++ include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -340,6 +340,29 @@
 
   unsigned getCacheLineSize() { return 0; }
 
+  llvm::Optional<unsigned> getCacheSize(TargetTransformInfo::CacheLevel Level) {
+    switch (Level) {
+    case TargetTransformInfo::CacheLevel::L1D:
+      LLVM_FALLTHROUGH;
+    case TargetTransformInfo::CacheLevel::L2D:
+      return llvm::Optional<unsigned>();
+    }
+
+    llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
+  }
+
+  llvm::Optional<unsigned> getCacheAssociativity(
+    TargetTransformInfo::CacheLevel Level) {
+    switch (Level) {
+    case TargetTransformInfo::CacheLevel::L1D:
+      LLVM_FALLTHROUGH;
+    case TargetTransformInfo::CacheLevel::L2D:
+      return llvm::Optional<unsigned>();
+    }
+
+    llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
+  }
+
   unsigned getPrefetchDistance() { return 0; }
 
   unsigned getMinPrefetchStride() { return 1; }
Index: lib/Analysis/TargetTransformInfo.cpp
===================================================================
--- lib/Analysis/TargetTransformInfo.cpp
+++ lib/Analysis/TargetTransformInfo.cpp
@@ -321,6 +321,16 @@
   return TTIImpl->getCacheLineSize();
 }
 
+llvm::Optional<unsigned> TargetTransformInfo::getCacheSize(CacheLevel Level)
+  const {
+  return TTIImpl->getCacheSize(Level);
+}
+
+llvm::Optional<unsigned> TargetTransformInfo::getCacheAssociativity(
+  CacheLevel Level) const {
+  return TTIImpl->getCacheAssociativity(Level);
+}
+
 unsigned TargetTransformInfo::getPrefetchDistance() const {
   return TTIImpl->getPrefetchDistance();
 }
Index: lib/Target/X86/X86TargetTransformInfo.h
===================================================================
--- lib/Target/X86/X86TargetTransformInfo.h
+++ lib/Target/X86/X86TargetTransformInfo.h
@@ -47,6 +47,14 @@
 
   /// @}
 
+  /// \name Cache TTI Implementation
+  /// @{
+  llvm::Optional<unsigned> getCacheSize(
+    TargetTransformInfo::CacheLevel Level) const;
+  llvm::Optional<unsigned> getCacheAssociativity(
+    TargetTransformInfo::CacheLevel Level) const;
+  /// @}
+
   /// \name Vector TTI Implementations
   /// @{
 
Index: lib/Target/X86/X86TargetTransformInfo.cpp
===================================================================
--- lib/Target/X86/X86TargetTransformInfo.cpp
+++ lib/Target/X86/X86TargetTransformInfo.cpp
@@ -66,6 +66,57 @@
   return ST->hasPOPCNT() ? TTI::PSK_FastHardware : TTI::PSK_Software;
 }
 
+llvm::Optional<unsigned> X86TTIImpl::getCacheSize(
+  TargetTransformInfo::CacheLevel Level) const {
+  switch (Level) {
+  case TargetTransformInfo::CacheLevel::L1D:
+    //   - Penry
+    //   - Nehalem
+    //   - Westmere
+    //   - Sandy Bridge
+    //   - Ivy Bridge
+    //   - Haswell
+    //   - Broadwell
+    //   - Skylake
+    //   - Kabylake
+    return 32 * 1024;  //  32 KByte
+  case TargetTransformInfo::CacheLevel::L2D:
+    //   - Penry
+    //   - Nehalem
+    //   - Westmere
+    //   - Sandy Bridge
+    //   - Ivy Bridge
+    //   - Haswell
+    //   - Broadwell
+    //   - Skylake
+    //   - Kabylake
+    return 256 * 1024; // 256 KByte
+  }
+
+  llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
+}
+
+llvm::Optional<unsigned> X86TTIImpl::getCacheAssociativity(
+  TargetTransformInfo::CacheLevel Level) const {
+  //   - Penry
+  //   - Nehalem
+  //   - Westmere
+  //   - Sandy Bridge
+  //   - Ivy Bridge
+  //   - Haswell
+  //   - Broadwell
+  //   - Skylake
+  //   - Kabylake
+  switch (Level) {
+  case TargetTransformInfo::CacheLevel::L1D:
+    LLVM_FALLTHROUGH;
+  case TargetTransformInfo::CacheLevel::L2D:
+    return 8;
+  }
+
+  llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
+}
+
 unsigned X86TTIImpl::getNumberOfRegisters(bool Vector) {
   if (Vector && !ST->hasSSE1())
     return 0;