Fix scheduler to correctly schedule nested diamonds.

src/compiler/verifier.cc

Index: src/compiler/verifier.cc
diff --git a/src/compiler/verifier.cc b/src/compiler/verifier.cc
index 23cec7a809794623625823e99d8f0b2688508d6b..26d5373b65491ee557cbd81220966f135aca842a 100644
--- a/src/compiler/verifier.cc
+++ b/src/compiler/verifier.cc
@@ -271,6 +271,12 @@ static bool HasDominatingDef(Schedule* schedule, Node* node,
 }
 
 
+static bool Dominates(Schedule* schedule, Node* dominator, Node* dominee) {

[titzer, 2014/09/25 12:19:24]

You should walk up the dominator tree and very the dominator is in that chain.
It's not enough to just have an RPO number that is lower.

[titzer, 2014/09/26 10:44:38]

BTW can you split this check out into a separate CL and land it? It'd be nice to
have right away.

[sigurds, 2014/09/26 11:35:24]

Done.

+  return schedule->block(dominator)->rpo_number_ <=
+         schedule->block(dominee)->rpo_number_;
+}
+
+
 static void CheckInputsDominate(Schedule* schedule, BasicBlock* block,
                                 Node* node, int use_pos) {
   for (int j = OperatorProperties::GetValueInputCount(node->op()) - 1; j >= 0;
@@ -289,6 +295,15 @@ static void CheckInputsDominate(Schedule* schedule, BasicBlock* block,
                input->op()->mnemonic());
     }
   }
+  if (OperatorProperties::GetControlInputCount(node->op()) == 1) {
+    Node* ctl = NodeProperties::GetControlInput(node);
+    if (!Dominates(schedule, ctl, node)) {
+      V8_Fatal(__FILE__, __LINE__,
+               "Node #%d:%s in B%d is not dominated by control input #%d:%s",
+               node->id(), node->op()->mnemonic(), block->id(), ctl->id(),
+               ctl->op()->mnemonic());
+    }
+  }
 }