[x64] Recognize MOVSXWL.

src/compiler/x64/instruction-selector-x64.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/generic-node-inl.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 328 matching lines @@
   VisitWord32Shift(this, node, kX64Shr32);
 }
 
 
 void InstructionSelector::VisitWord64Shr(Node* node) {
   VisitWord64Shift(this, node, kX64Shr);
 }
 
 
 void InstructionSelector::VisitWord32Sar(Node* node) {
+  X64OperandGenerator g(this);
+  Int32BinopMatcher m(node);
+  if (CanCover(m.node(), m.left().node()) && m.left().IsWord32Shl()) {
+    Int32BinopMatcher mleft(m.left().node());
+    if (mleft.right().Is(16) && m.right().Is(16)) {
+      Emit(kX64Movsxwl, g.DefineAsRegister(node), g.Use(mleft.left().node()));
+      return;
+    }
+  }
   VisitWord32Shift(this, node, kX64Sar32);
 }
 
 
 void InstructionSelector::VisitWord64Sar(Node* node) {
   VisitWord64Shift(this, node, kX64Sar);
 }
 
 
 void InstructionSelector::VisitWord32Ror(Node* node) {
   VisitWord32Shift(this, node, kX64Ror32);
 }
 
 
 void InstructionSelector::VisitWord64Ror(Node* node) {
   VisitWord64Shift(this, node, kX64Ror);
 }
 
+
 namespace {
 
 AddressingMode GenerateMemoryOperandInputs(X64OperandGenerator* g, Node* scaled,
                                            int scale_exponent, Node* offset,
                                            Node* constant,
                                            InstructionOperand* inputs[],
                                            size_t* input_count) {
   AddressingMode mode = kMode_MRI;
   if (offset != NULL) {
     inputs[(*input_count)++] = g->UseRegister(offset);
@@ skipping 777 matching lines @@
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
   if (CpuFeatures::IsSupported(SSE4_1)) {
     return MachineOperatorBuilder::kFloat64Floor |
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8