[llvm] Use pop_back_val (NFC)

lib/Transforms/Coroutines/CoroFrame.cpp

@@ -913,8 +913,7 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
       // StoreAliases contains aliases of the memory location stored into.
       SmallVector<Instruction *, 4> StoreAliases = {AI};
       while (!StoreAliases.empty()) {
-        Instruction *I = StoreAliases.back();
-        StoreAliases.pop_back();
+        Instruction *I = StoreAliases.pop_back_val();
         for (User *U : I->users()) {
           // If we are loading from the memory location, we are creating an
           // alias of the original pointer.
@@ -2005,8 +2004,7 @@ static void sinkSpillUsesAfterCoroBegin(Function &F,
   }
   // Recursively collect users before coro.begin.
   while (!Worklist.empty()) {
-    auto *Def = Worklist.back();
-    Worklist.pop_back();
+    auto *Def = Worklist.pop_back_val();
     for (User *U : Def->users()) {
       auto Inst = cast<Instruction>(U);
       if (Dom.dominates(CoroBegin, Inst))

lib/Transforms/IPO/ArgumentPromotion.cpp

@@ -824,8 +824,7 @@ static bool canPaddingBeAccessed(Argument *arg) {
   // sanely.
   SmallVector<Value *, 16> WorkList(arg->users());
   while (!WorkList.empty()) {
-    Value *V = WorkList.back();
-    WorkList.pop_back();
+    Value *V = WorkList.pop_back_val();
     if (isa<GetElementPtrInst>(V) || isa<PHINode>(V)) {
       if (PtrValues.insert(V).second)
         llvm::append_range(WorkList, V->users());

lib/Transforms/Scalar/LoopStrengthReduce.cpp

@@ -507,8 +507,7 @@ void Formula::canonicalize(const Loop &L) {
 
   // Keep the invariant sum in BaseRegs and one of the variant sum in ScaledReg.
   if (!ScaledReg) {
-    ScaledReg = BaseRegs.back();
-    BaseRegs.pop_back();
+    ScaledReg = BaseRegs.pop_back_val();
     Scale = 1;
   }
 

lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp

@@ -531,8 +531,7 @@ public:
     // list.
     LLVM_DEBUG(dbgs() << "Forward-propagate shapes:\n");
     while (!WorkList.empty()) {
-      Instruction *Inst = WorkList.back();
-      WorkList.pop_back();
+      Instruction *Inst = WorkList.pop_back_val();
 
       // New entry, set the value and insert operands
       bool Propagate = false;
@@ -602,8 +601,7 @@ public:
     // worklist.
     LLVM_DEBUG(dbgs() << "Backward-propagate shapes:\n");
     while (!WorkList.empty()) {
-      Value *V = WorkList.back();
-      WorkList.pop_back();
+      Value *V = WorkList.pop_back_val();
 
       size_t BeforeProcessingV = WorkList.size();
       if (!isa<Instruction>(V))

lib/Transforms/Scalar/NewGVN.cpp

@@ -2876,8 +2876,7 @@ void NewGVN::cleanupTables() {
   }
 
   while (!TempInst.empty()) {
-    auto *I = TempInst.back();
-    TempInst.pop_back();
+    auto *I = TempInst.pop_back_val();
     I->deleteValue();
   }
 

lib/Transforms/Scalar/Reassociate.cpp

@@ -1128,8 +1128,7 @@ static Value *EmitAddTreeOfValues(Instruction *I,
                                   SmallVectorImpl<WeakTrackingVH> &Ops) {
   if (Ops.size() == 1) return Ops.back();
 
-  Value *V1 = Ops.back();
-  Ops.pop_back();
+  Value *V1 = Ops.pop_back_val();
   Value *V2 = EmitAddTreeOfValues(I, Ops);
   return CreateAdd(V2, V1, "reass.add", I, I);
 }

lib/Transforms/Scalar/SCCP.cpp

@@ -1448,8 +1448,7 @@ void SCCPSolver::Solve() {
 
     // Process the basic block work list.
     while (!BBWorkList.empty()) {
-      BasicBlock *BB = BBWorkList.back();
-      BBWorkList.pop_back();
+      BasicBlock *BB = BBWorkList.pop_back_val();
 
       LLVM_DEBUG(dbgs() << "\nPopped off BBWL: " << *BB << '\n');
 

lib/Transforms/Utils/FixIrreducible.cpp

@@ -320,8 +320,7 @@ static bool FixIrreducibleImpl(Function &F, LoopInfo &LI, DominatorTree &DT) {
   append_range(WorkList, LI);
 
   while (!WorkList.empty()) {
-    auto L = WorkList.back();
-    WorkList.pop_back();
+    auto L = WorkList.pop_back_val();
     LLVM_DEBUG(dbgs() << "visiting loop with header "
                       << L->getHeader()->getName() << "\n");
     Changed |= makeReducible(LI, DT, *L);

lib/Transforms/Utils/LoopUnrollAndJam.cpp

@@ -148,8 +148,7 @@ static bool processHeaderPhiOperands(BasicBlock *Header, BasicBlock *Latch,
   }
 
   while (!Worklist.empty()) {
-    Instruction *I = Worklist.back();
-    Worklist.pop_back();
+    Instruction *I = Worklist.pop_back_val();
     if (!Visit(I))
       return false;
 

lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -5164,8 +5164,7 @@ BoUpSLP::BlockScheduling::tryScheduleBundle(ArrayRef<Value *> VL, BoUpSLP *SLP,
   // cancelScheduling).
   while (!Bundle->isReady() && !ReadyInsts.empty()) {
 
-    ScheduleData *pickedSD = ReadyInsts.back();
-    ReadyInsts.pop_back();
+    ScheduleData *pickedSD = ReadyInsts.pop_back_val();
 
     if (pickedSD->isSchedulingEntity() && pickedSD->isReady()) {
       schedule(pickedSD, ReadyInsts);
@@ -5338,8 +5337,7 @@ void BoUpSLP::BlockScheduling::calculateDependencies(ScheduleData *SD,
   WorkList.push_back(SD);
 
   while (!WorkList.empty()) {
-    ScheduleData *SD = WorkList.back();
-    WorkList.pop_back();
+    ScheduleData *SD = WorkList.pop_back_val();
 
     ScheduleData *BundleMember = SD;
     while (BundleMember) {