[turbofan] Deferred blocks splintering.

src/compiler/instruction.h

Index: src/compiler/instruction.h
diff --git a/src/compiler/instruction.h b/src/compiler/instruction.h
index 4f6a515f1151fe20f4933b70dd4442c9cd634281..a0718f3c215a023a1c204b9d6b0ae746ee37c596 100644
--- a/src/compiler/instruction.h
+++ b/src/compiler/instruction.h
@@ -778,9 +778,13 @@ class RpoNumber final {
     return other.index_ == this->index_ + 1;
   }
 
-  bool operator==(RpoNumber other) const {
-    return this->index_ == other.index_;
-  }
+  // Comparison operators.
+  bool operator==(RpoNumber other) const { return index_ == other.index_; }
+  bool operator!=(RpoNumber other) const { return index_ != other.index_; }
+  bool operator>(RpoNumber other) const { return index_ > other.index_; }
+  bool operator<(RpoNumber other) const { return index_ < other.index_; }
+  bool operator<=(RpoNumber other) const { return index_ <= other.index_; }
+  bool operator>=(RpoNumber other) const { return index_ >= other.index_; }
 
  private:
   explicit RpoNumber(int32_t index) : index_(index) {}
@@ -992,6 +996,9 @@ class InstructionBlock final : public ZoneObject {
   bool must_deconstruct_frame() const { return must_deconstruct_frame_; }
   void mark_must_deconstruct_frame() { must_deconstruct_frame_ = true; }
 
+  void set_last_deferred(RpoNumber last) { last_deferred_ = last; }
+  RpoNumber last_deferred() const { return last_deferred_; }
+
  private:
   Successors successors_;
   Predecessors predecessors_;
@@ -1007,6 +1014,7 @@ class InstructionBlock final : public ZoneObject {
   bool needs_frame_;
   bool must_construct_frame_;
   bool must_deconstruct_frame_;
+  RpoNumber last_deferred_;
 };
 
 typedef ZoneDeque<Constant> ConstantDeque;