Intel Software: Quartus II, Quartus Prime

Type: Answers

Area: Tools

How do I get identical results from compilations in the Quartus Prime software?


To get identical results from compilations in the Quartus® Prime software the following items must be identical for each compilation:

  • All design source files including Synopsys Design Constraints (.sdc) files
    • Note that changes to comments or naming may cause different compilation results.
  • All Quartus Prime project settings
  • The version of the Quartus Prime software including patches
  • The portion of the design that is preserved with the Rapid recompile option or with incremental compilation partitions
    • Note that the db and incremental_db directories must be identical from compilation to compilation to ensure identical results.
    • For example, the first compilation after turning on a preservation option may have different results than the previous compilation for portions of the design that are not preserved. Subsequent compilations with no changes will be identical.
  • Operating system and CPU  
    • For example, compiling on Windows OS may give different results than compiling on Linux OS
    • Compiling using the 32-bit version of the Quartus II software may give different results than compiling using the 64-bit version.
    • Different CPU architectures can have different floating-point implementations. 
  • Additionally, if you are using the SignalTap™ II Logic Analyzer, you must select nodes using the SignalTap II: pre-synthesis filter to ensure identical results.

If any of these items are changed, the Fitter starts with a different initial placement for its fitting algorithms that can give different compilation results, programming files and project checksum.  

Note:  If only Operating System and/or CPUs changes,  seed noise will be seen but results will be of similar QOR.