Convert a bunch of loops to foreach. NFC.

After r244074, we now have a successors() method to iterate over
all the successors of a TerminatorInst.  This commit changes a bunch
of eligible loops to use it.

llvm-svn: 244260

Author: cooperp

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -5034,8 +5034,7 @@ ScalarEvolution::ComputeExitLimit(const Loop *L, BasicBlock *ExitingBlock) {
       if (!Pred)
         return getCouldNotCompute();
       TerminatorInst *PredTerm = Pred->getTerminator();
-      for (unsigned i = 0, e = PredTerm->getNumSuccessors(); i != e; ++i) {
-        BasicBlock *PredSucc = PredTerm->getSuccessor(i);
+      for (const BasicBlock *PredSucc : PredTerm->successors()) {
         if (PredSucc == BB)
           continue;
         // If the predecessor has a successor that isn't BB and isn't

llvm/lib/IR/BasicBlock.cpp

@@ -404,8 +404,7 @@ void BasicBlock::replaceSuccessorsPhiUsesWith(BasicBlock *New) {
     // Cope with being called on a BasicBlock that doesn't have a terminator
     // yet. Clang's CodeGenFunction::EmitReturnBlock() likes to do this.
     return;
-  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
-    BasicBlock *Succ = TI->getSuccessor(i);
+  for (BasicBlock *Succ : TI->successors()) {
     // N.B. Succ might not be a complete BasicBlock, so don't assume
     // that it ends with a non-phi instruction.
     for (iterator II = Succ->begin(), IE = Succ->end(); II != IE; ++II) {

llvm/lib/Target/ARM/ARMFastISel.cpp

@@ -1355,8 +1355,8 @@ bool ARMFastISel::SelectIndirectBr(const Instruction *I) {
                           TII.get(Opc)).addReg(AddrReg));
 
   const IndirectBrInst *IB = cast<IndirectBrInst>(I);
-  for (unsigned i = 0, e = IB->getNumSuccessors(); i != e; ++i)
-    FuncInfo.MBB->addSuccessor(FuncInfo.MBBMap[IB->getSuccessor(i)]);
+  for (const BasicBlock *SuccBB : IB->successors())
+    FuncInfo.MBB->addSuccessor(FuncInfo.MBBMap[SuccBB]);
 
   return true;
 }

llvm/lib/Target/PowerPC/PPCFastISel.cpp

@@ -1759,8 +1759,8 @@ bool PPCFastISel::SelectIndirectBr(const Instruction *I) {
   BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(PPC::BCTR8));
 
   const IndirectBrInst *IB = cast<IndirectBrInst>(I);
-  for (unsigned i = 0, e = IB->getNumSuccessors(); i != e; ++i)
-    FuncInfo.MBB->addSuccessor(FuncInfo.MBBMap[IB->getSuccessor(i)]);
+  for (const BasicBlock *SuccBB : IB->successors())
+    FuncInfo.MBB->addSuccessor(FuncInfo.MBBMap[SuccBB]);
 
   return true;
 }

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -2927,8 +2927,8 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL,
       }
     }
 
-    for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-      Worklist.push_back(TI->getSuccessor(i));
+    for (BasicBlock *SuccBB : TI->successors())
+      Worklist.push_back(SuccBB);
   } while (!Worklist.empty());
 
   // Once we've found all of the instructions to add to instcombine's worklist,

llvm/lib/Transforms/Scalar/LoopRotation.cpp

@@ -467,8 +467,8 @@ bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
   // terminator into OrigPreHeader. Fix up the PHI nodes in each of OrigHeader's
   // successors by duplicating their incoming values for OrigHeader.
   TerminatorInst *TI = OrigHeader->getTerminator();
-  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-    for (BasicBlock::iterator BI = TI->getSuccessor(i)->begin();
+  for (BasicBlock *SuccBB : TI->successors())
+    for (BasicBlock::iterator BI = SuccBB->begin();
          PHINode *PN = dyn_cast<PHINode>(BI); ++BI)
       PN->addIncoming(PN->getIncomingValueForBlock(OrigHeader), OrigPreheader);
 

llvm/lib/Transforms/Scalar/SCCP.cpp

@@ -1796,10 +1796,9 @@ bool IPSCCP::runOnModule(Module &M) {
         MadeChanges = true;
 
         TerminatorInst *TI = BB->getTerminator();
-        for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
-          BasicBlock *Succ = TI->getSuccessor(i);
+        for (BasicBlock *Succ : TI->successors()) {
           if (!Succ->empty() && isa<PHINode>(Succ->begin()))
-            TI->getSuccessor(i)->removePredecessor(BB);
+            Succ->removePredecessor(BB);
         }
         if (!TI->use_empty())
           TI->replaceAllUsesWith(UndefValue::get(TI->getType()));

llvm/lib/Transforms/Scalar/StructurizeCFG.cpp

@@ -358,13 +358,9 @@ void StructurizeCFG::analyzeLoops(RegionNode *N) {
     BasicBlock *BB = N->getNodeAs<BasicBlock>();
     BranchInst *Term = cast<BranchInst>(BB->getTerminator());
 
-    for (unsigned i = 0, e = Term->getNumSuccessors(); i != e; ++i) {
-      BasicBlock *Succ = Term->getSuccessor(i);
-
-      if (Visited.count(Succ)) {
+    for (BasicBlock *Succ : Term->successors())
+      if (Visited.count(Succ))
         Loops[Succ] = BB;
-      }
-    }
   }
 }
 

llvm/lib/Transforms/Utils/BasicBlockUtils.cpp

@@ -41,8 +41,8 @@ void llvm::DeleteDeadBlock(BasicBlock *BB) {
 
   // Loop through all of our successors and make sure they know that one
   // of their predecessors is going away.
-  for (unsigned i = 0, e = BBTerm->getNumSuccessors(); i != e; ++i)
-    BBTerm->getSuccessor(i)->removePredecessor(BB);
+  for (BasicBlock *Succ : BBTerm->successors())
+    Succ->removePredecessor(BB);
 
   // Zap all the instructions in the block.
   while (!BB->empty()) {

llvm/lib/Transforms/Utils/CloneFunction.cpp

@@ -400,8 +400,8 @@ void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
       // If the director says to skip with a terminate instruction, we still
       // need to clone this block's successors.
       const TerminatorInst *TI = NewBB->getTerminator();
-      for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-        ToClone.push_back(TI->getSuccessor(i));
+      for (const BasicBlock *Succ : TI->successors())
+        ToClone.push_back(Succ);
       return;
     }
     assert(Action != CloningDirector::SkipInstruction && 
@@ -450,8 +450,8 @@ void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
 
     // Recursively clone any reachable successor blocks.
     const TerminatorInst *TI = BB->getTerminator();
-    for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-      ToClone.push_back(TI->getSuccessor(i));
+    for (const BasicBlock *Succ : TI->successors())
+      ToClone.push_back(Succ);
   }
 
   if (CodeInfo) {

llvm/lib/Transforms/Utils/Local.cpp

@@ -188,9 +188,8 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions,
       BasicBlock *BB = SI->getParent();
 
       // Remove entries from PHI nodes which we no longer branch to...
-      for (unsigned i = 0, e = SI->getNumSuccessors(); i != e; ++i) {
+      for (BasicBlock *Succ : SI->successors()) {
         // Found case matching a constant operand?
-        BasicBlock *Succ = SI->getSuccessor(i);
         if (Succ == TheOnlyDest)
           TheOnlyDest = nullptr; // Don't modify the first branch to TheOnlyDest
         else

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -2565,8 +2565,7 @@ static bool SimplifyTerminatorOnSelect(TerminatorInst *OldTerm, Value *Cond,
   BasicBlock *KeepEdge2 = TrueBB != FalseBB ? FalseBB : nullptr;
 
   // Then remove the rest.
-  for (unsigned I = 0, E = OldTerm->getNumSuccessors(); I != E; ++I) {
-    BasicBlock *Succ = OldTerm->getSuccessor(I);
+  for (BasicBlock *Succ : OldTerm->successors()) {
     // Make sure only to keep exactly one copy of each edge.
     if (Succ == KeepEdge1)
       KeepEdge1 = nullptr;