Call IncDecHelper only for Ints

hphp/runtime/vm/translator/hopt/codegen.cpp

@@ -966,6 +966,7 @@ bool CodeGenerator::emitIncDecHelper(SSATmp* dst, SSATmp* src1, SSATmp* src2,
                                      void(Asm::*emitFunc)(Reg64)) {
   if (src1->getReg() != InvalidReg &&
       dst ->getReg() != InvalidReg &&
+      src1->isA(Type::Int) &&
       // src2 == 1:
       src2->isConst() && src2->isA(Type::Int) && src2->getValInt() == 1) {
     emitMovRegReg(m_as, src1->getReg(), dst->getReg());