[Utils] Use range-based for loops (NFC) (#139426)

Author: kazutakahirata

llvm/lib/Transforms/Utils/BasicBlockUtils.cpp

@@ -168,8 +168,8 @@ bool llvm::DeleteDeadPHIs(BasicBlock *BB, const TargetLibraryInfo *TLI,
   SmallVector<WeakTrackingVH, 8> PHIs(llvm::make_pointer_range(BB->phis()));
 
   bool Changed = false;
-  for (unsigned i = 0, e = PHIs.size(); i != e; ++i)
-    if (PHINode *PN = dyn_cast_or_null<PHINode>(PHIs[i].operator Value*()))
+  for (const auto &PHI : PHIs)
+    if (PHINode *PN = dyn_cast_or_null<PHINode>(PHI.operator Value *()))
       Changed |= RecursivelyDeleteDeadPHINode(PN, TLI, MSSAU);
 
   return Changed;

llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp

@@ -931,13 +931,10 @@ void PromoteMem2Reg::run() {
   // hasn't traversed.  If this is the case, the PHI nodes may not
   // have incoming values for all predecessors.  Loop over all PHI nodes we have
   // created, inserting poison values if they are missing any incoming values.
-  for (DenseMap<std::pair<unsigned, unsigned>, PHINode *>::iterator
-           I = NewPhiNodes.begin(),
-           E = NewPhiNodes.end();
-       I != E; ++I) {
+  for (const auto &PhiNode : NewPhiNodes) {
     // We want to do this once per basic block.  As such, only process a block
     // when we find the PHI that is the first entry in the block.
-    PHINode *SomePHI = I->second;
+    PHINode *SomePHI = PhiNode.second;
     BasicBlock *BB = SomePHI->getParent();
     if (&BB->front() != SomePHI)
       continue;

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -7080,8 +7080,8 @@ static bool switchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder,
     APInt One(TableSizePowOf2, 1);
     // Build bitmask; fill in a 1 bit for every case.
     const ResultListTy &ResultList = ResultLists[PHIs[0]];
-    for (size_t I = 0, E = ResultList.size(); I != E; ++I) {
-      uint64_t Idx = (ResultList[I].first->getValue() - TableIndexOffset->getValue())
+    for (const auto &Result : ResultList) {
+      uint64_t Idx = (Result.first->getValue() - TableIndexOffset->getValue())
                          .getLimitedValue();
       MaskInt |= One << Idx;
     }