ARM64: Optimize AllocateHeapNumber to use STP.

src/arm64/stub-cache-arm64.cc

 // Copyright 2013 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 380 matching lines @@
     __ B(ne, miss_label);
   } else if (representation.IsSmi()) {
     __ JumpIfNotSmi(value_reg, miss_label);
   } else if (representation.IsHeapObject()) {
     __ JumpIfSmi(value_reg, miss_label);
   } else if (representation.IsDouble()) {
     UseScratchRegisterScope temps(masm);
     DoubleRegister temp_double = temps.AcquireD();
     __ SmiUntagToDouble(temp_double, value_reg, kSpeculativeUntag);
 
-    Label do_store, heap_number;
-    __ AllocateHeapNumber(storage_reg, slow, scratch1, scratch2);
-
+    Label do_store;
     __ JumpIfSmi(value_reg, &do_store);
 
     __ CheckMap(value_reg, scratch1, Heap::kHeapNumberMapRootIndex,
                 miss_label, DONT_DO_SMI_CHECK);
     __ Ldr(temp_double, FieldMemOperand(value_reg, HeapNumber::kValueOffset));
 
     __ Bind(&do_store);
-    __ Str(temp_double, FieldMemOperand(storage_reg, HeapNumber::kValueOffset));
+    __ AllocateHeapNumber(storage_reg, slow, scratch1, scratch2, temp_double);
   }
 
   // Stub never generated for non-global objects that require access checks.
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
   if ((details.type() == FIELD) &&
       (object->map()->unused_property_fields() == 0)) {
     // The properties must be extended before we can store the value.
     // We jump to a runtime call that extends the properties array.
@@ skipping 1065 matching lines @@
 
   // Miss case, call the runtime.
   __ Bind(&miss);
   TailCallBuiltin(masm, Builtins::kKeyedLoadIC_Miss);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64