Index: llvm/trunk/include/llvm/Analysis/ValueTracking.h
===================================================================
--- llvm/trunk/include/llvm/Analysis/ValueTracking.h
+++ llvm/trunk/include/llvm/Analysis/ValueTracking.h
@@ -307,20 +307,26 @@
   uint64_t GetStringLength(const Value *V, unsigned CharSize = 8);
 
   /// This function returns call pointer argument that is considered the same by
-  /// aliasing rules. You CAN'T use it to replace one value with another.
-  const Value *getArgumentAliasingToReturnedPointer(const CallBase *Call);
-  inline Value *getArgumentAliasingToReturnedPointer(CallBase *Call) {
+  /// aliasing rules. You CAN'T use it to replace one value with another. If
+  /// \p MustPreserveNullness is true, the call must preserve the nullness of
+  /// the pointer.
+  const Value *getArgumentAliasingToReturnedPointer(const CallBase *Call,
+                                                    bool MustPreserveNullness);
+  inline Value *
+  getArgumentAliasingToReturnedPointer(CallBase *Call,
+                                       bool MustPreserveNullness) {
     return const_cast<Value *>(getArgumentAliasingToReturnedPointer(
-        const_cast<const CallBase *>(Call)));
+        const_cast<const CallBase *>(Call), MustPreserveNullness));
   }
 
-  // {launder,strip}.invariant.group returns pointer that aliases its argument,
-  // and it only captures pointer by returning it.
-  // These intrinsics are not marked as nocapture, because returning is
-  // considered as capture. The arguments are not marked as returned neither,
-  // because it would make it useless.
+  /// {launder,strip}.invariant.group returns pointer that aliases its argument,
+  /// and it only captures pointer by returning it.
+  /// These intrinsics are not marked as nocapture, because returning is
+  /// considered as capture. The arguments are not marked as returned neither,
+  /// because it would make it useless. If \p MustPreserveNullness is true,
+  /// the intrinsic must preserve the nullness of the pointer.
   bool isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
-      const CallBase *Call);
+      const CallBase *Call, bool MustPreserveNullness);
 
   /// This method strips off any GEP address adjustments and pointer casts from
   /// the specified value, returning the original object being addressed. Note
Index: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
===================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
@@ -481,7 +481,7 @@
         // because it should be in sync with CaptureTracking. Not using it may
         // cause weird miscompilations where 2 aliasing pointers are assumed to
         // noalias.
-        if (auto *RP = getArgumentAliasingToReturnedPointer(Call)) {
+        if (auto *RP = getArgumentAliasingToReturnedPointer(Call, true)) {
           V = RP;
           continue;
         }
Index: llvm/trunk/lib/Analysis/CaptureTracking.cpp
===================================================================
--- llvm/trunk/lib/Analysis/CaptureTracking.cpp
+++ llvm/trunk/lib/Analysis/CaptureTracking.cpp
@@ -251,7 +251,8 @@
       // marked with nocapture do not capture. This means that places like
       // GetUnderlyingObject in ValueTracking or DecomposeGEPExpression
       // in BasicAA also need to know about this property.
-      if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(Call)) {
+      if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(Call,
+                                                                      true)) {
         AddUses(Call);
         break;
       }
Index: llvm/trunk/lib/Analysis/Loads.cpp
===================================================================
--- llvm/trunk/lib/Analysis/Loads.cpp
+++ llvm/trunk/lib/Analysis/Loads.cpp
@@ -107,7 +107,7 @@
                                               DL, CtxI, DT, Visited);
 
   if (const auto *Call = dyn_cast<CallBase>(V))
-    if (auto *RP = getArgumentAliasingToReturnedPointer(Call))
+    if (auto *RP = getArgumentAliasingToReturnedPointer(Call, true))
       return isDereferenceableAndAlignedPointer(RP, Align, Size, DL, CtxI, DT,
                                                 Visited);
 
Index: llvm/trunk/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp
@@ -2073,7 +2073,7 @@
     if (const auto *Call = dyn_cast<CallBase>(V)) {
       if (Call->isReturnNonNull())
         return true;
-      if (const auto *RP = getArgumentAliasingToReturnedPointer(Call))
+      if (const auto *RP = getArgumentAliasingToReturnedPointer(Call, true))
         return isKnownNonZero(RP, Depth, Q);
     }
   }
@@ -3658,19 +3658,22 @@
   return Len == ~0ULL ? 1 : Len;
 }
 
-const Value *llvm::getArgumentAliasingToReturnedPointer(const CallBase *Call) {
+const Value *
+llvm::getArgumentAliasingToReturnedPointer(const CallBase *Call,
+                                           bool MustPreserveNullness) {
   assert(Call &&
          "getArgumentAliasingToReturnedPointer only works on nonnull calls");
   if (const Value *RV = Call->getReturnedArgOperand())
     return RV;
   // This can be used only as a aliasing property.
-  if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(Call))
+  if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
+          Call, MustPreserveNullness))
     return Call->getArgOperand(0);
   return nullptr;
 }
 
 bool llvm::isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
-    const CallBase *Call) {
+    const CallBase *Call, bool MustPreserveNullness) {
   return Call->getIntrinsicID() == Intrinsic::launder_invariant_group ||
          Call->getIntrinsicID() == Intrinsic::strip_invariant_group ||
          Call->getIntrinsicID() == Intrinsic::aarch64_irg ||
@@ -3732,7 +3735,7 @@
         // because it should be in sync with CaptureTracking. Not using it may
         // cause weird miscompilations where 2 aliasing pointers are assumed to
         // noalias.
-        if (auto *RP = getArgumentAliasingToReturnedPointer(Call)) {
+        if (auto *RP = getArgumentAliasingToReturnedPointer(Call, true)) {
           V = RP;
           continue;
         }