[Turbofan] Merge SpillRanges by byte_width rather than kind.

src/compiler/register-allocator.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/adapters.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/register-allocator.h"
 #include "src/string-stream.h"
 
 namespace v8 {
@@ skipping 1173 matching lines @@
 
   while (interval != nullptr) {
     os << '[' << interval->start() << ", " << interval->end() << ')'
        << std::endl;
     interval = interval->next();
   }
   os << "}";
   return os;
 }
 
-
 SpillRange::SpillRange(TopLevelLiveRange* parent, Zone* zone)
     : live_ranges_(zone),
       assigned_slot_(kUnassignedSlot),
-      byte_width_(GetByteWidth(parent->representation())),
-      kind_(parent->kind()) {
+      byte_width_(GetByteWidth(parent->representation())) {
   // Spill ranges are created for top level, non-splintered ranges. This is so
   // that, when merging decisions are made, we consider the full extent of the
   // virtual register, and avoid clobbering it.
   DCHECK(!parent->IsSplinter());
   UseInterval* result = nullptr;
   UseInterval* node = nullptr;
   // Copy the intervals for all ranges.
   for (LiveRange* range = parent; range != nullptr; range = range->next()) {
     UseInterval* src = range->first_interval();
     while (src != nullptr) {
@@ skipping 18 matching lines @@
       this->End() <= other->use_interval_->start() ||
       other->End() <= this->use_interval_->start()) {
     return false;
   }
   return AreUseIntervalsIntersecting(use_interval_, other->use_interval_);
 }
 
 
 bool SpillRange::TryMerge(SpillRange* other) {
   if (HasSlot() || other->HasSlot()) return false;
-  // TODO(dcarney): byte widths should be compared here not kinds.
-  if (live_ranges_[0]->kind() != other->live_ranges_[0]->kind() ||
-      IsIntersectingWith(other)) {
+  if (byte_width() != other->byte_width() || IsIntersectingWith(other))

[Mircea Trofin, 2016/06/30 23:58:29]

since the return is on the next line, please put {}

     return false;
-  }
 
   LifetimePosition max = LifetimePosition::MaxPosition();
   if (End() < other->End() && other->End() != max) {
     end_position_ = other->End();
   }
   other->end_position_ = max;
 
   MergeDisjointIntervals(other->use_interval_);
   other->use_interval_ = nullptr;
 
@@ skipping 2532 matching lines @@
         }
       }
     }
   }
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8