[compiler] Introduce code stubs for string relational comparisons.

src/mips64/code-stubs-mips64.cc

Index: src/mips64/code-stubs-mips64.cc
diff --git a/src/mips64/code-stubs-mips64.cc b/src/mips64/code-stubs-mips64.cc
index c2b6429636ed446aca87adcd4b82dbfe2d89dc30..e08ed69a7d2a4bf706a34041b0ecd5ac70fd9d7b 100644
--- a/src/mips64/code-stubs-mips64.cc
+++ b/src/mips64/code-stubs-mips64.cc
@@ -3007,39 +3007,6 @@ void StringHelper::GenerateOneByteCharsCompareLoop(
 }
 
 
-void StringCompareStub::Generate(MacroAssembler* masm) {
-  // ----------- S t a t e -------------
-  //  -- a1    : left
-  //  -- a0    : right
-  //  -- ra    : return address
-  // -----------------------------------
-  __ AssertString(a1);
-  __ AssertString(a0);
-
-  Label not_same;
-  __ Branch(&not_same, ne, a0, Operand(a1));
-  __ li(v0, Operand(Smi::FromInt(EQUAL)));
-  __ IncrementCounter(isolate()->counters()->string_compare_native(), 1, a1,
-                      a2);
-  __ Ret();
-
-  __ bind(&not_same);
-
-  // Check that both objects are sequential one-byte strings.
-  Label runtime;
-  __ JumpIfNotBothSequentialOneByteStrings(a1, a0, a2, a3, &runtime);
-
-  // Compare flat ASCII strings natively.
-  __ IncrementCounter(isolate()->counters()->string_compare_native(), 1, a2,
-                      a3);
-  StringHelper::GenerateCompareFlatOneByteStrings(masm, a1, a0, a2, a3, t0, t1);
-
-  __ bind(&runtime);
-  __ Push(a1, a0);
-  __ TailCallRuntime(Runtime::kStringCompare);
-}
-
-
 void BinaryOpICWithAllocationSiteStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- a1    : left