Free Running Pipeline - Free Running Pipeline - 2026.1 English - UG1448

Vitis HLS Messaging (UG1448)

Document ID
UG1448
Release Date
2026-06-23
Version
2026.1 English

Description

Warning: [HLS 200-1966] Disabling free running pipeline (frp) architecture on pipeline 'VITIS_LOOP_51_1' in module 'reader', because it has a control structure that is incompatible.

Explanation

Complex constructs such as stream_of_blocks and the associated locking of blocks are not supported inside a free-running pipeline.

Example

void reader(hls::stream_of_blocks<ppbuf> &in, int out[N]) {
  hls::read_lock<ppbuf> arr(in);
  for(unsigned i = 0; i < N; ++i) {
#pragma HLS pipeline II=1 style=frp
     out[i] =arr[N-1-i];
  }
}