SSR FFT creates ap_memory instead of ap_fifo about vitis_libraries HOT 2 CLOSED

Hi Arash,

There are some changes on the pragma in Vitis HLS, and it should be the cause of your issue.

In FFT source code, we can find some of the FIFOs are described like:

T_scaledFFTOutputType fftOutData_local2[t_R][t_L / t_R];
#pragma HLS data_pack variable = fftOutData_local2
#pragma HLS RESOURCE variable = fftOutData_local2 core = FIFO_LUTRAM
#pragma HLS STREAM variable = fftOutData_local2 depth = 8 dim = 2 

In the code above, the third pragma is no longer supported in vitis_hls, so it is ignored and consequently leads to an ap_memory interface because vitis_hls now sees fftOutData_local2 as a buffer instead of a FIFO.

It is no longer the preferred way to use pragma to specify an array as FIFO, and the code will be refactored to use hls::stream when a FIFO is expected. We will fix Vitis HLS compatibility issues in DSP sub library in 2020.2 release.

The current release should work with vivado_hls, although the tool has entered end of its life cycle.

from vitis_libraries.

I want to confirm that using the exact same code in vivado_hls and activating c++11 flag for gcc, produces the correct ap_fifo interfaces with correct bit count.

from vitis_libraries.