[NFC] Use predecessors to replace make_range.

[rriddle]

The mlir tag in the commit title looks off, this is a change in polly (which is based on LLVMIR)

[jacquesguan]

In D127085#3562118, @rriddle wrote:

The mlir tag in the commit title looks off, this is a change in polly (which is based on LLVMIR)

Done.

polly/lib/CodeGen/BlockGenerators.cpp

for (BasicBlock *BB : SeenBlocks) {
     Value *NullVal = Builder.getInt32(0);
     PHINode *LoopPHI =
         PHINode::Create(Builder.getInt32Ty(), 2, "polly.subregion.iv");
     Instruction *LoopPHIInc = BinaryOperator::CreateAdd(
         LoopPHI, Builder.getInt32(1), "polly.subregion.iv.inc");
     LoopPHI->insertBefore(&BBCopy->front());
     LoopPHIInc->insertBefore(BBCopy->getTerminator());
 
-    for (auto *PredBB : make_range(pred_begin(BB), pred_end(BB))) {
+    for (auto *PredBB : predecessors(BB)) {
       if (!R->contains(PredBB))
         continue;
       if (L->contains(PredBB))
         LoopPHI->addIncoming(LoopPHIInc, EndBlockMap[PredBB]);
       else
         LoopPHI->addIncoming(NullVal, EndBlockMap[PredBB]);
     }
 
-    for (auto *PredBBCopy : make_range(pred_begin(BBCopy), pred_end(BBCopy)))
+    for (auto *PredBBCopy : predecessors(BBCopy))
       if (LoopPHI->getBasicBlockIndex(PredBBCopy) < 0)
         LoopPHI->addIncoming(NullVal, PredBBCopy);
 
     LTS[L] = SE.getUnknown(LoopPHI);
   }
 
   // Continue generating code in the exit block.
   Builder.SetInsertPoint(&*ExitBBCopy->getFirstInsertionPt());