Prevent deopt when assigning double values to typed arrays

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 1531 matching lines @@
     __ bind(&done);
   }
 }
 
 
 void LCodeGen::DoIsNullAndBranch(LIsNullAndBranch* instr) {
   Register reg = ToRegister(instr->InputAt(0));
 
   int false_block = chunk_->LookupDestination(instr->false_block_id());
 
-  if (instr->hydrogen()->representation().IsSpecialization() ||
+  if (instr->hydrogen()->representation().IsUntagged() ||
       instr->hydrogen()->type().IsSmi()) {
     // If the expression is known to untagged or smi, then it's definitely
     // not null, and it can't be a an undetectable object.
     // Jump directly to the false block.
     EmitGoto(false_block);
     return;
   }
 
   int true_block = chunk_->LookupDestination(instr->true_block_id());
 
@@ skipping 2453 matching lines @@
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64