Inline inequality compares of strings into CompareICStub.

src/ia32/code-stubs-ia32.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 6444 matching lines @@
          FieldOperand(right, length, times_1, SeqAsciiString::kHeaderSize));
   __ neg(length);
   Register index = length;  // index = -length;
 
   // Compare loop.
   Label loop;
   __ bind(&loop);
   __ mov_b(scratch, Operand(left, index, times_1, 0));
   __ cmpb(scratch, Operand(right, index, times_1, 0));
   __ j(not_equal, chars_not_equal, chars_not_equal_near);
-  __ add(index, Immediate(1));
+  __ inc(index);
   __ j(not_zero, &loop);
 }
 
 
 void StringCompareStub::Generate(MacroAssembler* masm) {
   Label runtime;
 
   // Stack frame on entry.
   //  esp[0]: return address
   //  esp[4]: right string
@@ skipping 162 matching lines @@
   __ bind(&done);
   __ ret(0);
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
 void ICCompareStub::GenerateStrings(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::STRINGS);
-  ASSERT(GetCondition() == equal);
   Label miss;
 
+  bool equality = Token::IsEqualityOp(op_);
+
   // Registers containing left and right operands respectively.
   Register left = edx;
   Register right = eax;
   Register tmp1 = ecx;
   Register tmp2 = ebx;
   Register tmp3 = edi;
 
   // Check that both operands are heap objects.
   __ mov(tmp1, left);
   STATIC_ASSERT(kSmiTag == 0);
@@ skipping 18 matching lines @@
   __ j(not_equal, &not_same, Label::kNear);
   STATIC_ASSERT(EQUAL == 0);
   STATIC_ASSERT(kSmiTag == 0);
   __ Set(eax, Immediate(Smi::FromInt(EQUAL)));
   __ ret(0);
 
   // Handle not identical strings.
   __ bind(&not_same);
 
   // Check that both strings are symbols. If they are, we're done
-  // because we already know they are not identical.
-  Label do_compare;
-  STATIC_ASSERT(kSymbolTag != 0);
-  __ and_(tmp1, tmp2);
-  __ test(tmp1, Immediate(kIsSymbolMask));
-  __ j(zero, &do_compare, Label::kNear);
-  // Make sure eax is non-zero. At this point input operands are
-  // guaranteed to be non-zero.
-  ASSERT(right.is(eax));
-  __ ret(0);
+  // because we already know they are not identical.  But in the case of
+  // non-equality compare, we still need to determine the order.
+  if (equality) {
+    Label do_compare;
+    STATIC_ASSERT(kSymbolTag != 0);
+    __ and_(tmp1, tmp2);
+    __ test(tmp1, Immediate(kIsSymbolMask));
+    __ j(zero, &do_compare, Label::kNear);
+    // Make sure eax is non-zero. At this point input operands are
+    // guaranteed to be non-zero.
+    ASSERT(right.is(eax));
+    __ ret(0);
+    __ bind(&do_compare);
+  }
 
   // Check that both strings are sequential ASCII.
   Label runtime;
-  __ bind(&do_compare);
   __ JumpIfNotBothSequentialAsciiStrings(left, right, tmp1, tmp2, &runtime);
 
   // Compare flat ASCII strings. Returns when done.
-  StringCompareStub::GenerateFlatAsciiStringEquals(
-      masm, left, right, tmp1, tmp2);
+  if (equality) {
+    StringCompareStub::GenerateFlatAsciiStringEquals(
+        masm, left, right, tmp1, tmp2);
+  } else {
+    StringCompareStub::GenerateCompareFlatAsciiStrings(
+        masm, left, right, tmp1, tmp2, tmp3);
+  }
 
   // Handle more complex cases in runtime.
   __ bind(&runtime);
   __ pop(tmp1);  // Return address.
   __ push(left);
   __ push(right);
   __ push(tmp1);
-  __ TailCallRuntime(Runtime::kStringEquals, 2, 1);
+  if (equality) {
+    __ TailCallRuntime(Runtime::kStringEquals, 2, 1);
+  } else {
+    __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
+  }
 
   __ bind(&miss);
   GenerateMiss(masm);
 }
 
 
 void ICCompareStub::GenerateObjects(MacroAssembler* masm) {
   ASSERT(state_ == CompareIC::OBJECTS);
   Label miss;
   __ mov(ecx, edx);
@@ skipping 637 matching lines @@
                                  false);
   __ pop(edx);
   __ ret(0);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32