Preserve Registers logic option

A logic option that prevents a register from minimizing during synthesis and prevents sequential netlist optimizations. Sequential netlist optimizations can eliminate redundant registers and registers with constant drivers.

This option is useful for preserving a register so that you can observe it during Simulation. It is also useful for creating a preliminary version of the design in which secondary signals are not specified. This option is ignored if the register does not drive anything, in which case, the register is removed by the netlist optimization.

This option must be assigned to either a register or design entity or it is ignored.

Scripting Information

Keyword: preserve_register

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