[turbofan]: More optimizations to add and subtract operations on x64

src/compiler/instruction-selector.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/compiler/instruction-selector.h"
 
 #include "src/compiler/graph.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties-inl.h"
@@ skipping 136 matching lines @@
   instructions_.push_back(instr);
   return instr;
 }
 
 
 bool InstructionSelector::IsNextInAssemblyOrder(const BasicBlock* block) const {
   return current_block_->GetAoNumber().IsNext(block->GetAoNumber());
 }
 
 
+bool InstructionSelector::ValueOwnedBy(Node* owner, Node* value) const {

[titzer, 2014/11/20 12:39:24]

Maybe we can move this to a more generic location like NodeProperties?
Also, a test.

[danno, 2014/11/20 13:43:07]

As discussed, the new patch set uses IsLive rather than this, so I removed it
completely.

+  Node::Uses uses = value->uses();
+  bool found_use = false;
+  for (Node::Uses::iterator current = uses.begin(); current != uses.end();

[titzer, 2014/11/20 12:39:24]

You can use a C++ foreach here now!

+       ++current) {
+    Node* use = *current;
+    if (use == owner) {
+      found_use = true;
+    } else if (!NodeProperties::IsEffectEdge(current.edge())) {
+      return false;
+    }
+  }
+  return found_use;
+}
+
+
 bool InstructionSelector::CanCover(Node* user, Node* node) const {
   return node->OwnedBy(user) &&
          schedule()->block(node) == schedule()->block(user);
 }
 
 
 int InstructionSelector::GetVirtualRegister(const Node* node) {
   if (node_map_[node->id()] == kNodeUnmapped) {
     node_map_[node->id()] = sequence()->NextVirtualRegister();
   }
@@ skipping 947 matching lines @@
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   return MachineOperatorBuilder::Flag::kNoFlags;
 }
 
 #endif  // !V8_TURBOFAN_BACKEND
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8