Inline ordered relative compares of mixed double/undefined values.

src/x64/code-stubs-x64.cc

 // Copyright 2012 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5504 matching lines @@
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
 void ICCompareStub::GenerateHeapNumbers(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::HEAP_NUMBERS);
 
   Label generic_stub;
-  Label unordered;
+  Label unordered, maybe_undefined1, maybe_undefined2;
   Label miss;
   Condition either_smi = masm->CheckEitherSmi(rax, rdx);
   __ j(either_smi, &generic_stub, Label::kNear);
 
   __ CmpObjectType(rax, HEAP_NUMBER_TYPE, rcx);
-  __ j(not_equal, &miss, Label::kNear);
+  __ j(not_equal, &maybe_undefined1, Label::kNear);
   __ CmpObjectType(rdx, HEAP_NUMBER_TYPE, rcx);
-  __ j(not_equal, &miss, Label::kNear);
+  __ j(not_equal, &maybe_undefined2, Label::kNear);
 
   // Load left and right operand
   __ movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
   __ movsd(xmm1, FieldOperand(rax, HeapNumber::kValueOffset));
 
   // Compare operands
   __ ucomisd(xmm0, xmm1);
 
   // Don't base result on EFLAGS when a NaN is involved.
   __ j(parity_even, &unordered, Label::kNear);
 
   // Return a result of -1, 0, or 1, based on EFLAGS.
   // Performing mov, because xor would destroy the flag register.
   __ movl(rax, Immediate(0));
   __ movl(rcx, Immediate(0));
   __ setcc(above, rax);  // Add one to zero if carry clear and not equal.
   __ sbbq(rax, rcx);  // Subtract one if below (aka. carry set).
   __ ret(0);
 
   __ bind(&unordered);
-
   CompareStub stub(GetCondition(), strict(), NO_COMPARE_FLAGS);
   __ bind(&generic_stub);
   __ jmp(stub.GetCode(), RelocInfo::CODE_TARGET);
 
+  __ bind(&maybe_undefined1);
+  if (Token::IsOrderedRelationalCompareOp(op_)) {
+    __ Cmp(rax, masm->isolate()->factory()->undefined_value());
+    __ j(not_equal, &miss);
+    __ CmpObjectType(rdx, HEAP_NUMBER_TYPE, rcx);
+    __ j(not_equal, &maybe_undefined2, Label::kNear);
+    __ jmp(&unordered);
+  }
+
+  __ bind(&maybe_undefined2);
+  if (Token::IsOrderedRelationalCompareOp(op_)) {
+    __ Cmp(rdx, masm->isolate()->factory()->undefined_value());
+    __ j(equal, &unordered);
+  }
+
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
 void ICCompareStub::GenerateSymbols(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::SYMBOLS);
   ASSERT(GetCondition() == equal);
 
   // Registers containing left and right operands respectively.
@@ skipping 743 matching lines @@
                                  xmm0,
                                  &slow_elements);
   __ ret(0);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64