Make map check in NamedStoreHandlerCompiler::GenerateFieldTypeChecks weak.

src/ic/arm64/handler-compiler-arm64.cc

Index: src/ic/arm64/handler-compiler-arm64.cc
diff --git a/src/ic/arm64/handler-compiler-arm64.cc b/src/ic/arm64/handler-compiler-arm64.cc
index 1c28bf51a215ac265a891e37b6cae695efe9d147..7c198d40a626e6f35e08146ac6098f427cb4f9bb 100644
--- a/src/ic/arm64/handler-compiler-arm64.cc
+++ b/src/ic/arm64/handler-compiler-arm64.cc
@@ -427,13 +427,17 @@ void NamedStoreHandlerCompiler::GenerateConstantCheck(Register map_reg,
 void NamedStoreHandlerCompiler::GenerateFieldTypeChecks(HeapType* field_type,
                                                         Register value_reg,
                                                         Label* miss_label) {
+  Register map_reg = scratch1();
+  Register scratch = scratch2();
+  DCHECK(!value_reg.is(map_reg));
+  DCHECK(!value_reg.is(scratch));
   __ JumpIfSmi(value_reg, miss_label);
   HeapType::Iterator<Map> it = field_type->Classes();
   if (!it.Done()) {
-    __ Ldr(scratch1(), FieldMemOperand(value_reg, HeapObject::kMapOffset));
+    __ Ldr(map_reg, FieldMemOperand(value_reg, HeapObject::kMapOffset));
     Label do_store;
     while (true) {
-      __ CompareMap(scratch1(), it.Current());
+      __ CmpWeakValue(map_reg, Map::WeakCellForMap(it.Current()), scratch);
       it.Advance();
       if (it.Done()) {
         __ B(ne, miss_label);