MIPS: Reland 10216 - Optimize the equality check case of ICCompare stubs.

Port r10219 (56686b).

Original commit message:

Now with arm and x64 support. Additionally, added default unreachable case to switch statement in CompareIC::TargetState to make win and mac compilers happy.

Reviewer guide:
This is an exact copy of 10216 except:
src/arm/*
src/x64/*
src/ic.cc (added default case to swith in CompareIC::TargetState)

BUG=
TEST=
Review URL: http://codereview.chromium.org/8896022

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10232 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/code-stubs-mips.cc

@@ -6869,26 +6869,39 @@ void ICCompareStub::GenerateObjects(MacroAssembler* masm) {
 }
 
 
-void ICCompareStub::GenerateMiss(MacroAssembler* masm) {
-  __ Push(a1, a0);
-  __ push(ra);
+void ICCompareStub::GenerateKnownObjects(MacroAssembler* masm) {
+  Label miss;
+  __ And(a2, a1, a0);
+  __ JumpIfSmi(a2, &miss);
+  __ lw(a2, FieldMemOperand(a0, HeapObject::kMapOffset));
+  __ lw(a3, FieldMemOperand(a1, HeapObject::kMapOffset));
+  __ Branch(&miss, ne, a2, Operand(known_map_));
+  __ Branch(&miss, ne, a3, Operand(known_map_));
+
+  __ Ret(USE_DELAY_SLOT);
+  __ subu(v0, a0, a1);
 
-  // Call the runtime system in a fresh internal frame.
-  ExternalReference miss = ExternalReference(IC_Utility(IC::kCompareIC_Miss),
-                                             masm->isolate());
+  __ bind(&miss);
+  GenerateMiss(masm);
+}
+
+void ICCompareStub::GenerateMiss(MacroAssembler* masm) {
   {
+    // Call the runtime system in a fresh internal frame.
+    ExternalReference miss =
+        ExternalReference(IC_Utility(IC::kCompareIC_Miss), masm->isolate());
     FrameScope scope(masm, StackFrame::INTERNAL);
     __ Push(a1, a0);
+    __ push(ra);
+    __ Push(a1, a0);
     __ li(t0, Operand(Smi::FromInt(op_)));
     __ push(t0);
     __ CallExternalReference(miss, 3);
+    // Compute the entry point of the rewritten stub.
+    __ Addu(a2, v0, Operand(Code::kHeaderSize - kHeapObjectTag));
+    // Restore registers.
+    __ Pop(a1, a0, ra);
   }
-  // Compute the entry point of the rewritten stub.
-  __ Addu(a2, v0, Operand(Code::kHeaderSize - kHeapObjectTag));
-  // Restore registers.
-  __ pop(ra);
-  __ pop(a0);
-  __ pop(a1);
   __ Jump(a2);
 }
 

src/mips/ic-mips.cc

@@ -1587,6 +1587,9 @@ void CompareIC::UpdateCaches(Handle<Object> x, Handle<Object> y) {
     rewritten = stub.GetCode();
   } else {
     ICCompareStub stub(op_, state);
+    if (state == KNOWN_OBJECTS) {
+      stub.set_known_map(Handle<Map>(Handle<JSObject>::cast(x)->map()));
+    }
     rewritten = stub.GetCode();
   }
   set_target(*rewritten);