ValueEnumerator: Use std::find_if, NFC

Mehdi's pattern recognition pulled this one out.  This is cleaner with
std::find_if than with the strange helper function that took an iterator
by reference and updated it.

llvm-svn: 267271
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
index 068bf62..4de0d26 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -575,11 +575,15 @@
 
   while (!Worklist.empty()) {
     const MDNode *N = Worklist.back().first;
-    MDNode::op_iterator &I = Worklist.back().second;
 
-    // Enumerate operands until the worklist changes.  We need to traverse new
-    // nodes before visiting the rest of N's operands.
-    if (const MDNode *Op = enumerateMetadataOperands(F, I, N->op_end())) {
+    // Enumerate operands until we hit a new node.  We need to traverse these
+    // nodes' operands before visiting the rest of N's operands.
+    MDNode::op_iterator I = std::find_if(
+        Worklist.back().second, N->op_end(),
+        [&](const Metadata *MD) { return enumerateMetadataImpl(F, MD); });
+    if (I != N->op_end()) {
+      auto *Op = cast<MDNode>(*I);
+      Worklist.back().second = ++I;
       Worklist.push_back(std::make_pair(Op, Op->op_begin()));
       continue;
     }
@@ -591,15 +595,6 @@
   }
 }
 
-const MDNode *
-ValueEnumerator::enumerateMetadataOperands(unsigned F, MDNode::op_iterator &I,
-                                           MDNode::op_iterator E) {
-  while (I != E)
-    if (const MDNode *N = enumerateMetadataImpl(F, *I++)) // Always increment I.
-      return N;
-  return nullptr;
-}
-
 const MDNode *ValueEnumerator::enumerateMetadataImpl(unsigned F, const Metadata *MD) {
   if (!MD)
     return nullptr;