Index: llvm/include/llvm/Analysis/ValueTracking.h
===================================================================
--- llvm/include/llvm/Analysis/ValueTracking.h
+++ llvm/include/llvm/Analysis/ValueTracking.h
@@ -334,12 +334,15 @@
   /// the specified value, returning the original object being addressed. Note
   /// that the returned value has pointer type if the specified value does. If
   /// the MaxLookup value is non-zero, it limits the number of instructions to
-  /// be stripped off.
+  /// be stripped off. If a NoAlias vector is provided, it is filled with any
+  /// llvm.noalias intrinsics looked through to find the underlying object.
   Value *GetUnderlyingObject(Value *V, const DataLayout &DL,
-                             unsigned MaxLookup = 6);
-  inline const Value *GetUnderlyingObject(const Value *V, const DataLayout &DL,
-                                          unsigned MaxLookup = 6) {
-    return GetUnderlyingObject(const_cast<Value *>(V), DL, MaxLookup);
+                             unsigned MaxLookup = 6,
+                             SmallVectorImpl<Instruction *> *NoAlias = nullptr);
+  inline const Value *GetUnderlyingObject(const Value *V,
+                 const DataLayout &DL, unsigned MaxLookup = 6,
+                 SmallVectorImpl<Instruction *> *NoAlias = nullptr) {
+    return GetUnderlyingObject(const_cast<Value *>(V), DL, MaxLookup, NoAlias);
   }
 
   /// This method is similar to GetUnderlyingObject except that it can
@@ -369,11 +372,14 @@
   ///
   /// Since A[i] and A[i-1] are independent pointers, getUnderlyingObjects
   /// should not assume that Curr and Prev share the same underlying object thus
-  /// it shouldn't look through the phi above.
+  /// it shouldn't look through the phi above. If a NoAlias vector is provided,
+  /// it is filled with any llvm.noalias intrinsics looked through to find the
+  /// underlying objects.
   void GetUnderlyingObjects(const Value *V,
                             SmallVectorImpl<const Value *> &Objects,
                             const DataLayout &DL, LoopInfo *LI = nullptr,
-                            unsigned MaxLookup = 6);
+                            unsigned MaxLookup = 6,
+                            SmallVectorImpl<Instruction *> *NoAlias = nullptr);
 
   /// This is a wrapper around GetUnderlyingObjects and adds support for basic
   /// ptrtoint+arithmetic+inttoptr sequences.
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -3713,7 +3713,8 @@
 }
 
 Value *llvm::GetUnderlyingObject(Value *V, const DataLayout &DL,
-                                 unsigned MaxLookup) {
+                                 unsigned MaxLookup,
+                                 SmallVectorImpl<Instruction *> *NoAlias) {
   if (!V->getType()->isPointerTy())
     return V;
   for (unsigned Count = 0; MaxLookup == 0 || Count < MaxLookup; ++Count) {
@@ -3731,6 +3732,9 @@
       return V;
     } else {
       if (auto *Call = dyn_cast<CallBase>(V)) {
+        if (NoAlias && Call->getIntrinsicID() == Intrinsic::noalias)
+          NoAlias->push_back(Call);
+
         // CaptureTracking can know about special capturing properties of some
         // intrinsics like launder.invariant.group, that can't be expressed with
         // the attributes, but have properties like returning aliasing pointer.
@@ -3764,13 +3768,14 @@
 void llvm::GetUnderlyingObjects(const Value *V,
                                 SmallVectorImpl<const Value *> &Objects,
                                 const DataLayout &DL, LoopInfo *LI,
-                                unsigned MaxLookup) {
+                                unsigned MaxLookup,
+                                SmallVectorImpl<Instruction *> *NoAlias) {
   SmallPtrSet<const Value *, 4> Visited;
   SmallVector<const Value *, 4> Worklist;
   Worklist.push_back(V);
   do {
     const Value *P = Worklist.pop_back_val();
-    P = GetUnderlyingObject(P, DL, MaxLookup);
+    P = GetUnderlyingObject(P, DL, MaxLookup, NoAlias);
 
     if (!Visited.insert(P).second)
       continue;