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/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 13917f4..f37a287 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -3204,8 +3204,8 @@
 
     // For a PHI node, push all of its incoming values.
     if (PHINode *P = dyn_cast<PHINode>(V)) {
-      for (unsigned i = 0, e = P->getNumIncomingValues(); i != e; ++i)
-        worklist.push_back(P->getIncomingValue(i));
+      for (Value *IncValue : P->incoming_values())
+        worklist.push_back(IncValue);
       continue;
     }