Loop Unroll - Multiple Constraints - 2023.2 English

Vitis HLS Messaging (UG1448)

Document ID
UG1448
Release Date
2023-10-18
Version
2023.2 English

Description

Warning: [200-937] Multiple loop unroll directives in one loop, use the first one and ignore the rest.
This message reports that the code is violating loop unrolling optimization rules.

Explanation

The tool is ignoring multiple unrolling optimization constraints. This happens when the constraints defined are in the same scope, as shown below.

for(int i=0;i<var;i++)
{
#pragma HLS unroll
...
...
#pragma HLS unroll factor =8
...
...
}

Solution

Review the multiple conflicting pragmas in the same scope and remove one of them.