Make special RPO computation iterative during scheduling.

src/compiler/schedule.cc

Index: src/compiler/schedule.cc
diff --git a/src/compiler/schedule.cc b/src/compiler/schedule.cc
index 51400cf04c2d12b71a1b6d1a3126e2da5f69458d..50ece951d689210dae8768931ecb05ab2f84c09a 100644
--- a/src/compiler/schedule.cc
+++ b/src/compiler/schedule.cc
@@ -16,10 +16,11 @@ BasicBlock::BasicBlock(Zone* zone, Id id)
     : ao_number_(-1),
       rpo_number_(-1),
       deferred_(false),
+      dominator_depth_(-1),
       dominator_(NULL),
       loop_header_(NULL),
+      loop_end_(NULL),
       loop_depth_(0),
-      loop_end_(-1),
       control_(kNone),
       control_input_(NULL),
       nodes_(zone),
@@ -32,8 +33,9 @@ bool BasicBlock::LoopContains(BasicBlock* block) const {
   // RPO numbers must be initialized.
   DCHECK(rpo_number_ >= 0);
   DCHECK(block->rpo_number_ >= 0);
-  if (loop_end_ < 0) return false;  // This is not a loop.
-  return block->rpo_number_ >= rpo_number_ && block->rpo_number_ < loop_end_;
+  if (loop_end_ == NULL) return false;  // This is not a loop.
+  return block->rpo_number_ >= rpo_number_ &&
+         block->rpo_number_ < loop_end_->rpo_number_;
 }
 
 
@@ -60,6 +62,11 @@ void BasicBlock::set_control_input(Node* control_input) {
 }
 
 
+void BasicBlock::set_dominator_depth(int32_t dominator_depth) {
+  dominator_depth_ = dominator_depth;
+}
+
+
 void BasicBlock::set_dominator(BasicBlock* dominator) {
   dominator_ = dominator;
 }
@@ -75,7 +82,7 @@ void BasicBlock::set_rpo_number(int32_t rpo_number) {
 }
 
 
-void BasicBlock::set_loop_end(int32_t loop_end) { loop_end_ = loop_end; }
+void BasicBlock::set_loop_end(BasicBlock* loop_end) { loop_end_ = loop_end; }
 
 
 void BasicBlock::set_loop_header(BasicBlock* loop_header) {