diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
--- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -371,6 +371,34 @@
     return false;
   }
 
+  unsigned getCacheLineSize() const { return 0; }
+
+  llvm::Optional<unsigned> getCacheSize(TargetTransformInfo::CacheLevel Level) const {
+    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) const {
+    switch (Level) {
+    case TargetTransformInfo::CacheLevel::L1D:
+      LLVM_FALLTHROUGH;
+    case TargetTransformInfo::CacheLevel::L2D:
+      return llvm::Optional<unsigned>();
+    }
+
+    llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
+  }
+
+  unsigned getPrefetchDistance() const { return 0; }
+  unsigned getMinPrefetchStride() const { return 1; }
+  unsigned getMaxPrefetchIterationsAhead() const { return UINT_MAX; }
+
   unsigned getMaxInterleaveFactor(unsigned VF) { return 1; }
 
   unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty,
diff --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -523,8 +523,13 @@
 
   virtual Optional<unsigned>
   getCacheAssociativity(TargetTransformInfo::CacheLevel Level) const {
-    return Optional<unsigned>(
-      getST()->getCacheAssociativity(static_cast<unsigned>(Level)));
+    Optional<unsigned> TargetResult =
+        getST()->getCacheAssociativity(static_cast<unsigned>(Level));
+
+    if (TargetResult)
+      return TargetResult;
+
+    return BaseT::getCacheAssociativity(Level);
   }
 
   virtual unsigned getCacheLineSize() const {
diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -40,34 +40,6 @@
 struct NoTTIImpl : TargetTransformInfoImplCRTPBase<NoTTIImpl> {
   explicit NoTTIImpl(const DataLayout &DL)
       : TargetTransformInfoImplCRTPBase<NoTTIImpl>(DL) {}
-
-  unsigned getCacheLineSize() const { return 0; }
-
-  llvm::Optional<unsigned> getCacheSize(TargetTransformInfo::CacheLevel Level) const {
-    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) const {
-    switch (Level) {
-    case TargetTransformInfo::CacheLevel::L1D:
-      LLVM_FALLTHROUGH;
-    case TargetTransformInfo::CacheLevel::L2D:
-      return llvm::Optional<unsigned>();
-    }
-
-    llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
-  }
-
-  unsigned getPrefetchDistance() const { return 0; }
-  unsigned getMinPrefetchStride() const { return 1; }
-  unsigned getMaxPrefetchIterationsAhead() const { return UINT_MAX; }
 };
 }