s390x: cleanup unused labels for s390x

R=joransiu@ca.ibm.com

Change-Id: I20d53b99ac65817b24b1b1f87bfec1910e21d37b
Reviewed-on: https://chromium-review.googlesource.com/c/1454264Reviewed-by: Milad Farazmand <miladfar@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#59380}

src/builtins/s390/builtins-s390.cc

@@ -45,7 +45,6 @@ void Builtins::Generate_InternalArrayConstructor(MacroAssembler* masm) {
   //  -- lr     : return address
   //  -- sp[...]: constructor arguments
   // -----------------------------------
-  Label generic_array_code, one_or_more_arguments, two_or_more_arguments;
 
   if (FLAG_debug_code) {
     // Initial map for the builtin InternalArray functions should be maps.
@@ -92,7 +91,6 @@ static void GenerateTailCallToReturnedCode(MacroAssembler* masm,
 namespace {
 
 void Generate_JSBuiltinsConstructStubHelper(MacroAssembler* masm) {
-  Label post_instantiation_deopt_entry;
   // ----------- S t a t e -------------
   //  -- r2     : number of arguments
   //  -- r3     : constructor function
@@ -2879,7 +2877,7 @@ void Builtins::Generate_MathPowInternal(MacroAssembler* masm) {
   const Register scratch = r1;
   const Register scratch2 = r9;
 
-  Label call_runtime, done, int_exponent;
+  Label done, int_exponent;
 
   // Detect integer exponents stored as double.
   __ TryDoubleToInt32Exact(scratch, double_exponent, scratch2, double_scratch);

src/compiler/backend/s390/code-generator-s390.cc

@@ -2639,7 +2639,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       Register index = i.InputRegister(1);
       Register value = i.InputRegister(2);
       Register output = i.OutputRegister();
-      Label two, unaligned, done;
+      Label two, done;
       __ la(r1, MemOperand(base, index));
       __ tmll(r1, Operand(3));
       __ b(Condition(2), &two);

src/regexp/s390/regexp-macro-assembler-s390.cc

@@ -356,7 +356,6 @@ void RegExpMacroAssemblerS390::CheckNotBackReference(int start_reg,
                                                      bool read_backward,
                                                      Label* on_no_match) {
   Label fallthrough;
-  Label success;
 
   // Find length of back-referenced capture.
   __ LoadP(r2, register_location(start_reg));