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Design doesn't fit using 5.1, but used to fit with 5.0
A design that used to fit using the 5.0.0 XEPLD software no longer
fits using the 5.1.0 software (with no design changes).
The 5.1.0 software uses a different logic optimization routine than
the 5.0.0, and in some cases may not optimize the design as efficiently
as the older version.
One way to allow the 5.1.0 software to behave more like the 5.0.0
software is to add the following global attribute to a schematic:
To add this option in a top-level PLD file, insert the following
statement before the EQUATIONS keyword:
OPTIONS OFF DENSITY_OPT