Simple elimination of redundant array-hole checks.

src/x64/lithium-codegen-x64.cc

 // Copyright 2011 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 2376 matching lines @@
   Register result = ToRegister(instr->result());
   ASSERT(result.is(elements));
 
   // Load the result.
   __ movq(result, FieldOperand(elements,
                                key,
                                times_pointer_size,
                                FixedArray::kHeaderSize));
 
   // Check for the hole value.
-  __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
-  DeoptimizeIf(equal, instr->environment());
+  if (instr->check_hole_value()) {
+    __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
+    DeoptimizeIf(equal, instr->environment());
+  }
 }
 
 
 void LCodeGen::DoLoadKeyedSpecializedArrayElement(
     LLoadKeyedSpecializedArrayElement* instr) {
   Register external_pointer = ToRegister(instr->external_pointer());
   Register key = ToRegister(instr->key());
   ExternalArrayType array_type = instr->array_type();
   if (array_type == kExternalFloatArray) {
     XMMRegister result(ToDoubleRegister(instr->result()));
@@ skipping 1693 matching lines @@
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64