Ensure using byte registers for byte instructions on ia32 and x64.

src/x64/lithium-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1775 matching lines @@
     STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
     __ CmpObjectType(input, FIRST_SPEC_OBJECT_TYPE, temp);
     __ j(below, is_false);
     __ j(equal, is_true);
     __ CmpInstanceType(temp, LAST_SPEC_OBJECT_TYPE);
     __ j(equal, is_true);
   } else {
     // Faster code path to avoid two compares: subtract lower bound from the
     // actual type and do a signed compare with the width of the type range.
     __ movq(temp, FieldOperand(input, HeapObject::kMapOffset));
-    __ movq(temp2, FieldOperand(temp, Map::kInstanceTypeOffset));
-    __ subb(temp2, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
-    __ cmpb(temp2,
-            Immediate(static_cast<int8_t>(LAST_NONCALLABLE_SPEC_OBJECT_TYPE -
-                                          FIRST_NONCALLABLE_SPEC_OBJECT_TYPE)));
+    __ movzxbl(temp2, FieldOperand(temp, Map::kInstanceTypeOffset));
+    __ subq(temp2, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
+    __ cmpq(temp2, Immediate(LAST_NONCALLABLE_SPEC_OBJECT_TYPE -
+                             FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
     __ j(above, is_false);
   }
 
   // Now we are in the FIRST-LAST_NONCALLABLE_SPEC_OBJECT_TYPE range.
   // Check if the constructor in the map is a function.
   __ movq(temp, FieldOperand(temp, Map::kConstructorOffset));
 
   // Objects with a non-function constructor have class 'Object'.
   __ CmpObjectType(temp, JS_FUNCTION_TYPE, kScratchRegister);
   if (class_name->IsEqualTo(CStrVector("Object"))) {
@@ skipping 2601 matching lines @@
   RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64