[turbofan] Alternative splintering mechanism.

src/compiler/register-allocator.h

Index: src/compiler/register-allocator.h
diff --git a/src/compiler/register-allocator.h b/src/compiler/register-allocator.h
index ba10743765a5da7eb3eba843ab00e80343437c7f..773e49f2e2ccc9e7bc8a13a8e688c1762df4ed23 100644
--- a/src/compiler/register-allocator.h
+++ b/src/compiler/register-allocator.h
@@ -58,6 +58,8 @@ class LifetimePosition final {
 
   // Returns true if this lifetime position corresponds to a START value
   bool IsStart() const { return (value_ & (kHalfStep - 1)) == 0; }
+  // Returns true if this lifetime position corresponds to an END value
+  bool IsEnd() const { return (value_ & (kHalfStep - 1)) == 1; }
   // Returns true if this lifetime position corresponds to a gap START value
   bool IsFullStart() const { return (value_ & (kStep - 1)) == 0; }