Revert "[InstCombine] Don't use getFirstNonPHI in FoldIntegerTypedPHI"

This reverts commit 5214dbb.

This does not fix the compile-time issue that we initially saw.
Reverting this commit in order to revert the initial commit.

rdar://58878122

Author: francisvm

llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp

@@ -180,14 +180,13 @@ Instruction *InstCombiner::FoldIntegerTypedPHI(PHINode &PN) {
          "Not enough available ptr typed incoming values");
   PHINode *MatchingPtrPHI = nullptr;
   unsigned NumPhis = 0;
-  for (auto II = BB->begin(); II != BB->end(); II++, NumPhis++) {
+  for (auto II = BB->begin(), EI = BasicBlock::iterator(BB->getFirstNonPHI());
+       II != EI; II++, NumPhis++) {
     // FIXME: consider handling this in AggressiveInstCombine
-    PHINode *PtrPHI = dyn_cast<PHINode>(II);
-    if (!PtrPHI)
-      break;
     if (NumPhis > MaxNumPhis)
       return nullptr;
-    if (PtrPHI == &PN || PtrPHI->getType() != IntToPtr->getType())
+    PHINode *PtrPHI = dyn_cast<PHINode>(II);
+    if (!PtrPHI || PtrPHI == &PN || PtrPHI->getType() != IntToPtr->getType())
       continue;
     MatchingPtrPHI = PtrPHI;
     for (unsigned i = 0; i != PtrPHI->getNumIncomingValues(); ++i) {