Revert 10216 Optimize the equality check case of ICCompare stubs.

src/ia32/code-stubs-ia32.cc

Index: src/ia32/code-stubs-ia32.cc
===================================================================
--- src/ia32/code-stubs-ia32.cc	(revision 10216)
+++ src/ia32/code-stubs-ia32.cc	(working copy)
@@ -6670,45 +6670,33 @@
 }
 
 
-void ICCompareStub::GenerateKnownObjects(MacroAssembler* masm) {
-  Label miss;
-  __ mov(ecx, edx);
-  __ and_(ecx, eax);
-  __ JumpIfSmi(ecx, &miss, Label::kNear);
-
-  __ mov(ecx, FieldOperand(eax, HeapObject::kMapOffset));
-  __ mov(ebx, FieldOperand(edx, HeapObject::kMapOffset));
-  __ cmp(ecx, known_map_);
-  __ j(not_equal, &miss, Label::kNear);
-  __ cmp(ebx, known_map_);
-  __ j(not_equal, &miss, Label::kNear);
-
-  __ sub(eax, edx);
-  __ ret(0);
-
-  __ bind(&miss);
-  GenerateMiss(masm);
-}
-
-
 void ICCompareStub::GenerateMiss(MacroAssembler* masm) {
+  // Save the registers.
+  __ pop(ecx);
+  __ push(edx);
+  __ push(eax);
+  __ push(ecx);
+
   {
     // 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(edx);  // Preserve edx and eax.
+    __ push(edx);
     __ push(eax);
-    __ push(edx);  // And also use them as the arguments.
-    __ push(eax);
     __ push(Immediate(Smi::FromInt(op_)));
     __ CallExternalReference(miss, 3);
-    // Compute the entry point of the rewritten stub.
-    __ lea(edi, FieldOperand(eax, Code::kHeaderSize));
-    __ pop(eax);
-    __ pop(edx);
   }
 
+  // Compute the entry point of the rewritten stub.
+  __ lea(edi, FieldOperand(eax, Code::kHeaderSize));
+
+  // Restore registers.
+  __ pop(ecx);
+  __ pop(eax);
+  __ pop(edx);
+  __ push(ecx);
+
   // Do a tail call to the rewritten stub.
   __ jmp(edi);
 }