Is bit selection of variables possible in C++ source code for the HLS compiler?

Bit selection is possible by using the ac_int type.

Please refer to the following document. 
^<Quartus® Prime installation>/hls/include/ref/ac_datatypes_ref.pdf 
2.3.9. Bit Select Operator: [] 
2.3.10. Slice Read Method: slc 
2.3.11. Slice Write Method: set_slc

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Category: HLS 
Tools: HLS Compiler 
Device: -