3 files changed, 13 insertions, 7 deletions
diff --git a/src/graph.cc b/src/graph.cc
index 9c2f784..bf9363d 100644
--- a/src/graph.cc
+++ b/src/graph.cc
@@ -75,12 +75,16 @@ bool DependencyScan::RecomputeDirty(Node* node, vector<Node*>* stack,
       return false;
   }
 
-  if (!dep_loader_.LoadDeps(edge, err)) {
-    if (!err->empty())
-      return false;
-    // Failed to load dependency info: rebuild to regenerate it.
-    // LoadDeps() did EXPLAIN() already, no need to do it here.
-    dirty = edge->deps_missing_ = true;
+  if (!edge->deps_loaded_) {
+    // This is our first encounter with this edge.  Load discovered deps.
+    edge->deps_loaded_ = true;
+    if (!dep_loader_.LoadDeps(edge, err)) {
+      if (!err->empty())
+        return false;
+      // Failed to load dependency info: rebuild to regenerate it.
+      // LoadDeps() did EXPLAIN() already, no need to do it here.
+      dirty = edge->deps_missing_ = true;
+    }
   }
 
   // Visit all inputs; we're dirty if any of the inputs are dirty.
diff --git a/src/graph.h b/src/graph.h
index d58fecd..20af578 100644
--- a/src/graph.h
+++ b/src/graph.h
@@ -136,7 +136,7 @@ struct Edge {
   };
 
   Edge() : rule_(NULL), pool_(NULL), env_(NULL), mark_(VisitNone),
-           outputs_ready_(false), deps_missing_(false),
+           outputs_ready_(false), deps_loaded_(false), deps_missing_(false),
            implicit_deps_(0), order_only_deps_(0), implicit_outs_(0) {}
 
   /// Return true if all inputs' in-edges are ready.
@@ -165,6 +165,7 @@ struct Edge {
   BindingEnv* env_;
   VisitMark mark_;
   bool outputs_ready_;
+  bool deps_loaded_;
   bool deps_missing_;
 
   const Rule& rule() const { return *rule_; }
diff --git a/src/state.cc b/src/state.cc
index 9b3c7e1..74cf4c1 100644
--- a/src/state.cc
+++ b/src/state.cc
@@ -186,6 +186,7 @@ void State::Reset() {
     i->second->ResetState();
   for (vector<Edge*>::iterator e = edges_.begin(); e != edges_.end(); ++e) {
     (*e)->outputs_ready_ = false;
+    (*e)->deps_loaded_ = false;
     (*e)->mark_ = Edge::VisitNone;
   }
 }