ARM: Make use of d16-d31 when available.

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 9484f85f97e38ff87de543ec4c25dee3b9d6984e..b5f01b3f7f62a3de39e349238d869e877b5dff3b 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -2036,8 +2036,11 @@ void StoreBufferOverflowStub::Generate(MacroAssembler* masm) {
   __ stm(db_w, sp, kCallerSaved | lr.bit());
   if (save_doubles_ == kSaveFPRegs) {
     CpuFeatures::Scope scope(VFP2);
-    __ sub(sp, sp, Operand(kDoubleSize * DwVfpRegister::kNumRegisters));
-    for (int i = 0; i < DwVfpRegister::kNumRegisters; i++) {
+    // Number of d-regs not known at snapshot time.
+    ASSERT(!Serializer::enabled());
+    __ sub(sp, sp, Operand(kDoubleSize *
+                           DwVfpRegister::NumAvailableRegisters()));
+    for (int i = 0; i < DwVfpRegister::NumAvailableRegisters(); i++) {
       DwVfpRegister reg = DwVfpRegister::from_code(i);
       __ vstr(reg, MemOperand(sp, i * kDoubleSize));
     }
@@ -2054,11 +2057,12 @@ void StoreBufferOverflowStub::Generate(MacroAssembler* masm) {
       argument_count);
   if (save_doubles_ == kSaveFPRegs) {
     CpuFeatures::Scope scope(VFP2);
-    for (int i = 0; i < DwVfpRegister::kNumRegisters; i++) {
+    for (int i = 0; i < DwVfpRegister::NumAvailableRegisters(); i++) {
       DwVfpRegister reg = DwVfpRegister::from_code(i);
       __ vldr(reg, MemOperand(sp, i * kDoubleSize));
     }
-    __ add(sp, sp, Operand(kDoubleSize * DwVfpRegister::kNumRegisters));
+    __ add(sp, sp, Operand(kDoubleSize *
+                           DwVfpRegister::NumAvailableRegisters()));
   }
   __ ldm(ia_w, sp, kCallerSaved | pc.bit());  // Also pop pc to get Ret(0).
 }