[x64] Recognize MOVSXBL.

src/x64/assembler-x64.cc

 // Copyright 2012 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/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/macro-assembler.h"
@@ skipping 1365 matching lines @@
     src->link_to(pc_offset() - sizeof(int32_t));
   } else {
     DCHECK(src->is_unused());
     int32_t current = pc_offset();
     emitl(current);
     src->link_to(current);
   }
 }
 
 
+void Assembler::movsxbl(Register dst, Register src) {
+  EnsureSpace ensure_space(this);
+  if (!src.is_byte_register()) {
+    // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
+    emit_rex_32(dst, src);
+  } else {
+    emit_optional_rex_32(dst, src);
+  }
+  emit(0x0F);
+  emit(0xBE);
+  emit_modrm(dst, src);
+}
+
+
 void Assembler::movsxbl(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xBE);
   emit_operand(dst, src);
 }
 
 
 void Assembler::movsxbq(Register dst, const Operand& src) {
@@ skipping 1774 matching lines @@
 
 
 bool RelocInfo::IsInConstantPool() {
   return false;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64