ARM: Make use of d16-d31 when available.

src/ia32/assembler-ia32.cc

Index: src/ia32/assembler-ia32.cc
diff --git a/src/ia32/assembler-ia32.cc b/src/ia32/assembler-ia32.cc
index fd53bbf2de07c1a89128e2d3cb3ce516b4205edc..a975431c050e1894137f03353d96228f32ebe816 100644
--- a/src/ia32/assembler-ia32.cc
+++ b/src/ia32/assembler-ia32.cc
@@ -55,6 +55,12 @@ uint64_t CpuFeatures::supported_ = 0;
 uint64_t CpuFeatures::found_by_runtime_probing_ = 0;
 
 
+ExternalReference ExternalReference::cpu_features() {
+  ASSERT(CpuFeatures::initialized_);
+  return ExternalReference(&CpuFeatures::supported_);
+}
+
+
 int IntelDoubleRegister::NumAllocatableRegisters() {
   if (CpuFeatures::IsSupported(SSE2)) {
     return XMMRegister::kNumAllocatableRegisters;