Warnings from Quartus-generated files

[Altera_Forum]

I'm working on my first NIOS II project, and when compiling the Cyclone II FPGA, get several warnings from the SOPC-generated file "motorctl.vhd" (motorctl is the name of the NIOS II). The messages are: 

 Warning (10335): Unrecognized synthesis attribute "auto_dissolve" at motorctl.vhd(52)  There is also a warning:  Warning: Can't analyze file -- file C:/altera/72/qdesigns/0982motorctl/altera_europa_support.vhd is missing  Are either of these warnings significant? If so, how do I fix them?

[Altera_Forum]

Neither warning is significant. The first warning identifies a third-party synthesis attribute that QIS doesn't recognize. In this case, "auto_dissolve" is a LeonardoSpectrum attribute that prevents cross-hierarchy optimizations. The attribute was probably added years ago to improve QoR with LeonardoSpectrum and has hung around unnoticed until Quartus II started to issue warnings for unrecognized synthesis attributes in 7.2 (or maybe it was 7.1).  

 The second warning says that Quartus II couldn't find a VHDL Design file that was explicitly listed in your project. The warning would be followed by an error if your design actually dependend on the design units defined by the file. :)   That particular file is a standard package used by SOPC Builder, and it was probably added to your project by SOPC Builder itself. Quartus II now includes this package among the standard VHDL packages in /quartus/libraries/vhdl/altera, which are all automatically analyzed. I suspect that's why you don't see an error. Go to your project file's list and delete the listing for the missing file. With old projects, you sometimes need to clean house occassionally! :)