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

src/arm/code-stubs-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
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 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6698 matching lines @@
 
   ASSERT(GetCondition() == eq);
   __ sub(r0, r0, Operand(r1));
   __ Ret();
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
+void ICCompareStub::GenerateKnownObjects(MacroAssembler* masm) {
+  Label miss;
+  __ and_(r2, r1, Operand(r0));
+  __ JumpIfSmi(r2, &miss);
+  __ ldr(r2, FieldMemOperand(r0, HeapObject::kMapOffset));
+  __ ldr(r3, FieldMemOperand(r1, HeapObject::kMapOffset));
+  __ cmp(r2, Operand(known_map_));
+  __ b(ne, &miss);
+  __ cmp(r3, Operand(known_map_));
+  __ b(ne, &miss);
+
+  __ sub(r0, r0, Operand(r1));
+  __ Ret();
+
+  __ bind(&miss);
+  GenerateMiss(masm);
+}
+
+
+
 void ICCompareStub::GenerateMiss(MacroAssembler* masm) {
   __ Push(r1, r0);

[Kevin Millikin (Chromium), 2011/12/09 09:10:31]

You could move this (and the corresponding pops) to use the internal frame
instead of using the caller's frame.

[Rico, 2011/12/09 09:28:31]

Done.

   __ push(lr);
 
   // 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(r1, r0);
     __ mov(ip, Operand(Smi::FromInt(op_)));
     __ push(ip);
@@ skipping 605 matching lines @@
   __ StoreNumberToDoubleElements(r0, r3, r1, r5, r6, r7, r9, r10,
                                  &slow_elements);
   __ Ret();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM