enable integer reduction on windows

Author: haojin2

src/operator/tensor/broadcast_reduce-inl.h

@@ -241,8 +241,6 @@ void Reduce(Stream<cpu>* s, const TBlob& small, const OpReqType req,
       N, M, req == kAddTo, big.dptr<DType>(), small.dptr<DType>(),
       big.shape_.get<ndim>(), small.shape_.get<ndim>(), rshape, rstride);
   } else {
-    // TODO(haojin2): Use real-only type swtich for windows temporarily due to CI issues.
-#ifndef _WIN32
     MXNET_ACC_TYPE_SWITCH(mshadow::DataType<DType>::kFlag, DataType, AType, {
       typedef typename std::conditional<safe_acc, AType, DataType>::type AccType;
       MSHADOW_TYPE_SWITCH_WITH_BOOL(small.type_flag_, OType, {
@@ -252,17 +250,6 @@ void Reduce(Stream<cpu>* s, const TBlob& small, const OpReqType req,
           big.shape_.get<ndim>(), small.shape_.get<ndim>(), rshape, rstride);
       });
     });
-#else
-    MXNET_REAL_ACC_TYPE_SWITCH(mshadow::DataType<DType>::kFlag, DataType, AType, {
-      typedef typename std::conditional<safe_acc, AType, DataType>::type AccType;
-      MSHADOW_TYPE_SWITCH_WITH_BOOL(small.type_flag_, OType, {
-        typedef typename std::conditional<safe_acc, OType, DataType>::type OutType;
-        seq_reduce_compute<Reducer, ndim, AccType, DataType, OutType, OP>(
-          N, M, req == kAddTo, big.dptr<DataType>(), small.dptr<OutType>(),
-          big.shape_.get<ndim>(), small.shape_.get<ndim>(), rshape, rstride);
-      });
-    });
-#endif
   }
 }