Use signaling NaN for holes in fixed double arrays.

src/arm64/lithium-codegen-arm64.cc

 // Copyright 2013 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"
 
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/arm64/lithium-gap-resolver-arm64.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 3587 matching lines @@
     mem_op = PrepareKeyedArrayOperand(load_base, elements, key, key_is_tagged,
                                       instr->hydrogen()->elements_kind(),
                                       instr->hydrogen()->representation(),
                                       instr->base_offset());
   }
 
   __ Ldr(result, mem_op);
 
   if (instr->hydrogen()->RequiresHoleCheck()) {
     Register scratch = ToRegister(instr->temp());
-    // Detect the hole NaN by adding one to the integer representation of the
-    // result, and checking for overflow.
-    STATIC_ASSERT(kHoleNanInt64 == 0x7fffffffffffffff);
-    __ Ldr(scratch, mem_op);
-    __ Cmn(scratch, 1);
-    DeoptimizeIf(vs, instr, "hole");
+    __ Fmov(scratch, result);
+    __ Eor(scratch, scratch, kHoleNanInt64);
+    DeoptimizeIfZero(scratch, instr, "hole");
   }
 }
 
 
 void LCodeGen::DoLoadKeyedFixed(LLoadKeyedFixed* instr) {
   Register elements = ToRegister(instr->elements());
   Register result = ToRegister(instr->result());
   MemOperand mem_op;
 
   Representation representation = instr->hydrogen()->representation();
@@ skipping 2442 matching lines @@
   Handle<ScopeInfo> scope_info = instr->scope_info();
   __ Push(scope_info);
   __ Push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 
 } }  // namespace v8::internal