3 files changed, 22 insertions, 13 deletions
diff --git a/llvm/include/llvm/Analysis/ValueTracking.h b/llvm/include/llvm/Analysis/ValueTracking.h
index 603b3a210b8..0afe22da1c8 100644
--- a/llvm/include/llvm/Analysis/ValueTracking.h
+++ b/llvm/include/llvm/Analysis/ValueTracking.h
@@ -323,7 +323,7 @@ class Value;
 
   /// This is a wrapper around GetUnderlyingObjects and adds support for basic
   /// ptrtoint+arithmetic+inttoptr sequences.
-  void getUnderlyingObjectsForCodeGen(const Value *V,
+  bool getUnderlyingObjectsForCodeGen(const Value *V,
                             SmallVectorImpl<Value *> &Objects,
                             const DataLayout &DL);
 
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index e505b1cc5a1..d9e164500c3 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -3430,7 +3430,8 @@ static const Value *getUnderlyingObjectFromInt(const Value *V) {
 
 /// This is a wrapper around GetUnderlyingObjects and adds support for basic
 /// ptrtoint+arithmetic+inttoptr sequences.
-void llvm::getUnderlyingObjectsForCodeGen(const Value *V,
+/// It returns false if unidentified object is found in GetUnderlyingObjects.
+bool llvm::getUnderlyingObjectsForCodeGen(const Value *V,
                           SmallVectorImpl<Value *> &Objects,
                           const DataLayout &DL) {
   SmallPtrSet<const Value *, 16> Visited;
@@ -3456,11 +3457,12 @@ void llvm::getUnderlyingObjectsForCodeGen(const Value *V,
       // getUnderlyingObjectsForCodeGen also fails for safety.
       if (!isIdentifiedObject(V)) {
         Objects.clear();
-        return;
+        return false;
       }
       Objects.push_back(const_cast<Value *>(V));
     }
   } while (!Working.empty());
+  return true;
 }
 
 /// Return true if the only users of this pointer are lifetime markers.
diff --git a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
index 08b785d742a..be129b8766a 100644
--- a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -121,9 +121,11 @@ ScheduleDAGInstrs::ScheduleDAGInstrs(MachineFunction &mf,
   SchedModel.init(ST.getSchedModel(), &ST, TII);
 }
 
-/// If this machine instr has memory reference information and it can be tracked
-/// to a normal reference to a known object, return the Value for that object.
-static void getUnderlyingObjectsForInstr(const MachineInstr *MI,
+/// If this machine instr has memory reference information and it can be
+/// tracked to a normal reference to a known object, return the Value
+/// for that object. This function returns false the memory location is
+/// unknown or may alias anything.
+static bool getUnderlyingObjectsForInstr(const MachineInstr *MI,
                                          const MachineFrameInfo &MFI,
                                          UnderlyingObjectsVector &Objects,
                                          const DataLayout &DL) {
@@ -151,7 +153,8 @@ static void getUnderlyingObjectsForInstr(const MachineInstr *MI,
         Objects.push_back(UnderlyingObjectsVector::value_type(PSV, MayAlias));
       } else if (const Value *V = MMO->getValue()) {
         SmallVector<Value *, 4> Objs;
-        getUnderlyingObjectsForCodeGen(V, Objs, DL);
+        if (!getUnderlyingObjectsForCodeGen(V, Objs, DL))
+          return false;
 
         for (Value *V : Objs) {
           assert(isIdentifiedObject(V));
@@ -163,8 +166,12 @@ static void getUnderlyingObjectsForInstr(const MachineInstr *MI,
     return true;
   };
 
-  if (!allMMOsOkay())
+  if (!allMMOsOkay()) {
     Objects.clear();
+    return false;
+  }
+
+  return true;
 }
 
 void ScheduleDAGInstrs::startBlock(MachineBasicBlock *bb) {
@@ -860,13 +867,13 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA,
 
     // Find the underlying objects for MI. The Objs vector is either
     // empty, or filled with the Values of memory locations which this
-    // SU depends on. An empty vector means the memory location is
-    // unknown, and may alias anything.
+    // SU depends on.
     UnderlyingObjectsVector Objs;
-    getUnderlyingObjectsForInstr(&MI, MFI, Objs, MF.getDataLayout());
+    bool ObjsFound = getUnderlyingObjectsForInstr(&MI, MFI, Objs,
+                                                  MF.getDataLayout());
 
     if (MI.mayStore()) {
-      if (Objs.empty()) {
+      if (!ObjsFound) {
         // An unknown store depends on all stores and loads.
         addChainDependencies(SU, Stores);
         addChainDependencies(SU, NonAliasStores);
@@ -901,7 +908,7 @@ void ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA,
         addChainDependencies(SU, Stores, UnknownValue);
       }
     } else { // SU is a load.
-      if (Objs.empty()) {
+      if (!ObjsFound) {
         // An unknown load depends on all stores.
         addChainDependencies(SU, Stores);
         addChainDependencies(SU, NonAliasStores);