Error: loop with non-constant loop condition must terminate within 250 iterations

You may try the following solution:

Description

This error may appear in the Quartus® II software when synthesis iterates through a loop in Verilog HDL for more than the synthesis loop limit. This limit prevents synthesis from potentially running into an infinite loop. By default, this loop limit is set to 250 iterations.

Resolution

To work around this error, the loop limit can be set using the VERILOG_NON_CONSTANT_LOOP_LIMIT option in the Quartus II Settings File (.qsf). For example:

set_global_assignment -name VERILOG_NON_CONSTANT_LOOP_LIMIT 300