ARM: Make use of d16-d31 when available.

build/common.gypi

 # Copyright 2012 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 33 matching lines @@
     'v8_can_use_unaligned_accesses%': 'default',
 
     # Setting 'v8_can_use_vfp2_instructions' to 'true' will enable use of ARM VFP
     # instructions in the V8 generated code. VFP instructions will be enabled
     # both for the snapshot and for the ARM target. Leaving the default value
     # of 'false' will avoid VFP instructions in the snapshot and use CPU feature
     # probing when running on the target.
     'v8_can_use_vfp2_instructions%': 'false',
     'v8_can_use_vfp3_instructions%': 'false',
 
+    # Setting 'v8_can_use_vfp32dregs' to 'true' will cause V8 to use the VFP
+    # registers d16-d31 in the generated code, both in the snapshot and for the
+    # ARM target. Leaving the default value of 'false' will avoid the use of
+    # these registers in the snapshot and use CPU feature probing when running
+    # on the target.
+    'v8_can_use_vfp32dregs%': 'false',
+
     # Similar to vfp but on MIPS.
     'v8_can_use_fpu_instructions%': 'true',
 
     # Setting v8_use_arm_eabi_hardfloat to true will turn on V8 support for ARM
     # EABI calling convention where double arguments are passed in VFP
     # registers. Note that the GCC flag '-mfloat-abi=hard' should be used as
     # well when compiling for the ARM target.
     'v8_use_arm_eabi_hardfloat%': 'false',
 
     # Similar to the ARM hard float ABI but on MIPS.
@@ skipping 107 matching lines @@
             'target_conditions': [
               ['_toolset=="target"', {
                 'cflags': ['-mfloat-abi=hard',],
               }],
             ],
           }, {
             'defines': [
               'USE_EABI_HARDFLOAT=0',
             ],
           }],
+          [ 'v8_can_use_vfp32dregs=="true"', {
+            'defines': [
+              'CAN_USE_VFP32DREGS',
+            ],
+          }],
         ],
       }],  # v8_target_arch=="arm"
       ['v8_target_arch=="ia32"', {
         'defines': [
           'V8_TARGET_ARCH_IA32',
         ],
       }],  # v8_target_arch=="ia32"
       ['v8_target_arch=="mipsel"', {
         'defines': [
           'V8_TARGET_ARCH_MIPS',
@@ skipping 264 matching lines @@
                 'OptimizeReferences': '2',
                 'EnableCOMDATFolding': '2',
               },
             },
           }],  # OS=="win"
         ],  # conditions
       },  # Release
     },  # configurations
   },  # target_defaults
 }