[C++] Use trie to pickfind implicit rules

28.0 secs => 1.8 secs

1 files changed, 1 insertions, 1 deletions

diff --git a/eval.cc b/eval.cc
index 9d984da..62d799a 100644
--- a/eval.cc
+++ b/eval.cc
@@ -131,7 +131,7 @@ void Evaluator::EvalRule(const RuleAST* ast) {
   }
 
   for (StringPiece output : rule_var.outputs) {
-    auto p = rule_vars_.emplace(output, static_cast<Vars*>(NULL));
+    auto p = rule_vars_.emplace(output, nullptr);
     if (p.second) {
       p.first->second = new Vars;
     }