[NFC][SimplifyCFG] removeEmptyCleanup(): use BasicBlock::phis()

Author: LebedevRI

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -4468,12 +4468,8 @@ static bool removeEmptyCleanup(CleanupReturnInst *RI, DomTreeUpdater *DTU) {
   if (UnwindDest) {
     // First, go through the PHI nodes in UnwindDest and update any nodes that
     // reference the block we are removing
-    for (BasicBlock::iterator I = UnwindDest->begin(),
-                              IE = DestEHPad->getIterator();
-         I != IE; ++I) {
-      PHINode *DestPN = cast<PHINode>(I);
-
-      int Idx = DestPN->getBasicBlockIndex(BB);
+    for (PHINode &DestPN : UnwindDest->phis()) {
+      int Idx = DestPN.getBasicBlockIndex(BB);
       // Since BB unwinds to UnwindDest, it has to be in the PHI node.
       assert(Idx != -1);
       // This PHI node has an incoming value that corresponds to a control
@@ -4487,40 +4483,37 @@ static bool removeEmptyCleanup(CleanupReturnInst *RI, DomTreeUpdater *DTU) {
       // predecessors must unwind to these blocks, and since no instruction
       // can have multiple unwind destinations, there will be no overlap in
       // incoming blocks between SrcPN and DestPN.
-      Value *SrcVal = DestPN->getIncomingValue(Idx);
+      Value *SrcVal = DestPN.getIncomingValue(Idx);
       PHINode *SrcPN = dyn_cast<PHINode>(SrcVal);
 
       // Remove the entry for the block we are deleting.
-      DestPN->removeIncomingValue(Idx, false);
+      DestPN.removeIncomingValue(Idx, false);
 
       if (SrcPN && SrcPN->getParent() == BB) {
         // If the incoming value was a PHI node in the cleanup pad we are
         // removing, we need to merge that PHI node's incoming values into
         // DestPN.
         for (unsigned SrcIdx = 0, SrcE = SrcPN->getNumIncomingValues();
              SrcIdx != SrcE; ++SrcIdx) {
-          DestPN->addIncoming(SrcPN->getIncomingValue(SrcIdx),
-                              SrcPN->getIncomingBlock(SrcIdx));
+          DestPN.addIncoming(SrcPN->getIncomingValue(SrcIdx),
+                             SrcPN->getIncomingBlock(SrcIdx));
         }
       } else {
         // Otherwise, the incoming value came from above BB and
         // so we can just reuse it.  We must associate all of BB's
         // predecessors with this value.
         for (auto *pred : predecessors(BB)) {
-          DestPN->addIncoming(SrcVal, pred);
+          DestPN.addIncoming(SrcVal, pred);
         }
       }
     }
 
     // Sink any remaining PHI nodes directly into UnwindDest.
     Instruction *InsertPt = DestEHPad;
-    for (BasicBlock::iterator I = BB->begin(),
-                              IE = BB->getFirstNonPHI()->getIterator();
-         I != IE;) {
+    for (PHINode &PN : BB->phis()) {
       // The iterator must be incremented here because the instructions are
       // being moved to another block.
-      PHINode *PN = cast<PHINode>(I++);
-      if (PN->use_empty() || !PN->isUsedOutsideOfBlock(BB))
+      if (PN.use_empty() || !PN.isUsedOutsideOfBlock(BB))
         // If the PHI node has no uses or all of its uses are in this basic
         // block (meaning they are debug or lifetime intrinsics), just leave
         // it.  It will be erased when we erase BB below.
@@ -4532,8 +4525,8 @@ static bool removeEmptyCleanup(CleanupReturnInst *RI, DomTreeUpdater *DTU) {
       // BB.  In this case, the PHI value must reference itself.
       for (auto *pred : predecessors(UnwindDest))
         if (pred != BB)
-          PN->addIncoming(PN, pred);
-      PN->moveBefore(InsertPt);
+          PN.addIncoming(&PN, pred);
+      PN.moveBefore(InsertPt);
     }
   }