Remove unused last_pc_ in AssemblerX64.

src/x64/code-stubs-x64.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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2943 matching lines @@
     GenerateConvertHashCodeToIndex(masm, scratch, mask);
 
     Register index = scratch;
     Register probe = mask;
     __ movq(probe,
             FieldOperand(number_string_cache,
                          index,
                          times_1,
                          FixedArray::kHeaderSize));
     __ JumpIfSmi(probe, not_found);
-    ASSERT(CpuFeatures::IsSupported(SSE2));
-    CpuFeatures::Scope fscope(SSE2);
     __ movsd(xmm0, FieldOperand(object, HeapNumber::kValueOffset));
     __ movsd(xmm1, FieldOperand(probe, HeapNumber::kValueOffset));
     __ ucomisd(xmm0, xmm1);
     __ j(parity_even, not_found);  // Bail out if NaN is involved.
     __ j(not_equal, not_found);  // The cache did not contain this value.
     __ jmp(&load_result_from_cache);
   }
 
   __ bind(&is_smi);
   __ SmiToInteger32(scratch, object);
@@ skipping 2149 matching lines @@
   // Do a tail call to the rewritten stub.
   __ jmp(rdi);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64