[turbofan] Greedy: live range grouping.

src/compiler/register-allocator.cc

Index: src/compiler/register-allocator.cc
diff --git a/src/compiler/register-allocator.cc b/src/compiler/register-allocator.cc
index 482448eb2e6b9dda25c4ab67ee632da0198f426a..840c13b1a779aacef537cdd85e94949feaed8a9f 100644
--- a/src/compiler/register-allocator.cc
+++ b/src/compiler/register-allocator.cc
@@ -247,7 +247,8 @@ LiveRange::LiveRange(int relative_id, MachineType machine_type,
       last_processed_use_(nullptr),
       current_hint_position_(nullptr),
       size_(kInvalidSize),
-      weight_(kInvalidWeight) {
+      weight_(kInvalidWeight),
+      group_(nullptr) {
   DCHECK(AllocatedOperand::IsSupportedMachineType(machine_type));
   bits_ = AssignedRegisterField::encode(kUnassignedRegister) |
           MachineTypeField::encode(machine_type);