MIPS: Add negative lookups to polymorphic loads in Crankshaft.

src/mips/macro-assembler-mips.h

Index: src/mips/macro-assembler-mips.h
diff --git a/src/mips/macro-assembler-mips.h b/src/mips/macro-assembler-mips.h
index 1766866ee8b90f6410b3999efc9309b5868a6517..bb3dc01e393f621326f1ee02a8db3d6311748d0a 100644
--- a/src/mips/macro-assembler-mips.h
+++ b/src/mips/macro-assembler-mips.h
@@ -992,6 +992,15 @@ class MacroAssembler: public Assembler {
                            Label* branch_to,
                            CompareMapMode mode = REQUIRE_EXACT_MAP);
 
+  // As above, but the map of the object is already loaded into the register
+  // which is preserved by the code generated.
+  void CompareMapAndBranch(Register obj_map,
+                           Handle<Map> map,
+                           Label* early_success,
+                           Condition cond,
+                           Label* branch_to,
+                           CompareMapMode mode = REQUIRE_EXACT_MAP);
+
   // Check if the map of an object is equal to a specified map and branch to
   // label if not. Skip the smi check if not required (object is known to be a
   // heap object). If mode is ALLOW_ELEMENT_TRANSITION_MAPS, then also match