Convert PHI getIncomingValue() to foreach over incoming_values().  NFC.

We already had a method to iterate over all the incoming values of a PHI.  This just changes all eligible code to use it.

Ineligible code included anything which cared about the index, or was also trying to get the i'th incoming BB.

llvm-svn: 237169
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 4d75658..dca3f1b 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -105,8 +105,8 @@
     }
 
     if (const PHINode *PN = dyn_cast<const PHINode>(P)) {
-      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
-        Worklist.push_back(PN->getIncomingValue(i));
+      for (Value *IncValue : PN->incoming_values())
+        Worklist.push_back(IncValue);
       continue;
     }
   } while (!Worklist.empty());