MIPS: Add monomorphic CompareNilICs and Crankshaft support

src/mips/full-codegen-mips.cc

Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index 884b62ae5113ffaa2ce53633a9b06d3289bfed38..bf0d93170a2998ef0176b3ed6fadb22bb0149393 100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -4452,26 +4452,21 @@ void FullCodeGenerator::EmitLiteralCompareNil(CompareOperation* expr,
 
   VisitForAccumulatorValue(sub_expr);
   PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  Heap::RootListIndex nil_value = nil == kNullValue ?
-      Heap::kNullValueRootIndex :
-      Heap::kUndefinedValueRootIndex;
+  EqualityKind kind = expr->op() == Token::EQ_STRICT
+      ? kStrictEquality : kNonStrictEquality;
   __ mov(a0, result_register());
-  __ LoadRoot(a1, nil_value);
-  if (expr->op() == Token::EQ_STRICT) {
+  if (kind == kStrictEquality) {
+    Heap::RootListIndex nil_value = nil == kNullValue ?
+        Heap::kNullValueRootIndex :
+        Heap::kUndefinedValueRootIndex;
+    __ LoadRoot(a1, nil_value);
     Split(eq, a0, Operand(a1), if_true, if_false, fall_through);
   } else {
-    Heap::RootListIndex other_nil_value = nil == kNullValue ?
-        Heap::kUndefinedValueRootIndex :
-        Heap::kNullValueRootIndex;
-    __ Branch(if_true, eq, a0, Operand(a1));
-    __ LoadRoot(a1, other_nil_value);
-    __ Branch(if_true, eq, a0, Operand(a1));
-    __ JumpIfSmi(a0, if_false);
-    // It can be an undetectable object.
-    __ lw(a1, FieldMemOperand(a0, HeapObject::kMapOffset));
-    __ lbu(a1, FieldMemOperand(a1, Map::kBitFieldOffset));
-    __ And(a1, a1, Operand(1 << Map::kIsUndetectable));
-    Split(ne, a1, Operand(zero_reg), if_true, if_false, fall_through);
+    Handle<Code> ic = CompareNilICStub::GetUninitialized(isolate(),
+                                                         kNonStrictEquality,
+                                                         nil);
+    CallIC(ic, RelocInfo::CODE_TARGET, expr->CompareOperationFeedbackId());
+    Split(ne, v0, Operand(zero_reg), if_true, if_false, fall_through);
   }
   context()->Plug(if_true, if_false);
 }