[x64] Recognize MOVSXBL.

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 335 matching lines @@
 
 
 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;
+    } else if (mleft.right().Is(24) && m.right().Is(24)) {
+      Emit(kX64Movsxbl, g.DefineAsRegister(node), g.Use(mleft.left().node()));
+      return;
     }
   }
   VisitWord32Shift(this, node, kX64Sar32);
 }
 
 
 void InstructionSelector::VisitWord64Sar(Node* node) {
   VisitWord64Shift(this, node, kX64Sar);
 }
 
@@ skipping 802 matching lines @@
     return MachineOperatorBuilder::kFloat64Floor |
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8