ARM64: Optimize AllocateHeapNumber to use STP.

src/arm64/macro-assembler-arm64.h

Index: src/arm64/macro-assembler-arm64.h
diff --git a/src/arm64/macro-assembler-arm64.h b/src/arm64/macro-assembler-arm64.h
index 1777c38e35b01e152bc718243985bf0b23d27797..3061c1f0c14947a8e3685896d48daea3df2ebd32 100644
--- a/src/arm64/macro-assembler-arm64.h
+++ b/src/arm64/macro-assembler-arm64.h
@@ -802,7 +802,7 @@ class MacroAssembler : public Assembler {
   inline void InitializeRootRegister();
 
   // Load an object from the root table.
-  void LoadRoot(Register destination,
+  void LoadRoot(CPURegister destination,
                 Heap::RootListIndex index);
   // Store an object to the root table.
   void StoreRoot(Register source,
@@ -883,6 +883,9 @@ class MacroAssembler : public Assembler {
   void AssertNotSmi(Register object, BailoutReason reason = kOperandIsASmi);
   void AssertSmi(Register object, BailoutReason reason = kOperandIsNotASmi);
 
+  inline void ObjectTag(Register tagged_obj, Register obj);
+  inline void ObjectUntag(Register untagged_obj, Register obj);
+
   // Abort execution if argument is not a name, enabled via --debug-code.
   void AssertName(Register object);
 
@@ -1354,13 +1357,8 @@ class MacroAssembler : public Assembler {
                           Label* gc_required,
                           Register scratch1,
                           Register scratch2,
-                          Register heap_number_map = NoReg);
-  void AllocateHeapNumberWithValue(Register result,
-                                   DoubleRegister value,
-                                   Label* gc_required,
-                                   Register scratch1,
-                                   Register scratch2,
-                                   Register heap_number_map = NoReg);
+                          CPURegister value = NoFPReg,
+                          CPURegister heap_number_map = NoReg);
 
   // ---------------------------------------------------------------------------
   // Support functions.