DBC: Enables unboxed doubles

runtime/vm/deopt_instructions.cc

Index: runtime/vm/deopt_instructions.cc
diff --git a/runtime/vm/deopt_instructions.cc b/runtime/vm/deopt_instructions.cc
index f31a8976590d103ef9e61168423dd7086b855128..75c8ed55f0fd6566e0f7c0c2dc0e0b68bdb12400 100644
--- a/runtime/vm/deopt_instructions.cc
+++ b/runtime/vm/deopt_instructions.cc
@@ -1045,6 +1045,10 @@ FpuRegisterSource DeoptInfoBuilder::ToFpuRegisterSource(
   Location::Kind stack_slot_kind) {
   if (loc.IsFpuRegister()) {
     return FpuRegisterSource(FpuRegisterSource::kRegister, loc.fpu_reg());
+#if defined(TARGET_ARCH_DBC)
+  } else if (loc.IsRegister()) {
+    return FpuRegisterSource(FpuRegisterSource::kRegister, loc.reg());
+#endif
   } else {
     ASSERT((stack_slot_kind == Location::kQuadStackSlot) ||
            (stack_slot_kind == Location::kDoubleStackSlot));