MIPS: Use mutable heapnumbers to store doubles in fields.

src/mips/ic-mips.cc

Index: src/mips/ic-mips.cc
diff --git a/src/mips/ic-mips.cc b/src/mips/ic-mips.cc
index e434fdb77417a2147dcecb1a15d42f5857fb204b..02055a4483a7d75e1088a30a37dde0092530a1eb 100644
--- a/src/mips/ic-mips.cc
+++ b/src/mips/ic-mips.cc
@@ -1440,6 +1440,25 @@ void KeyedStoreIC::GenerateMiss(MacroAssembler* masm, ICMissMode miss_mode) {
 }
 
 
+void StoreIC::GenerateSlow(MacroAssembler* masm) {
+  // ---------- S t a t e --------------
+  //  -- a0     : value
+  //  -- a2     : key
+  //  -- a1     : receiver
+  //  -- ra     : return address
+  // -----------------------------------
+
+  // Push receiver, key and value for runtime call.
+  __ Push(a1, a2, a0);
+
+  // The slow case calls into the runtime to complete the store without causing
+  // an IC miss that would otherwise cause a transition to the generic stub.
+  ExternalReference ref =
+      ExternalReference(IC_Utility(kKeyedStoreIC_Slow), masm->isolate());
+  __ TailCallExternalReference(ref, 3, 1);
+}
+
+
 void KeyedStoreIC::GenerateSlow(MacroAssembler* masm) {
   // ---------- S t a t e --------------
   //  -- a0     : value