synplify mapper

[Jason Zheng]

Does anyone know a synthesis directive that can prevent synplify's
mapper from pruning redundant instances that I intended to put in the
design? I have a design where I have two copies of identify state
machine to perform lockstep checking. Though the synthesizer did not
prune out the redundant state machine, the mapper always remove it
because it thinks they are identical:

@W: BN132: MREU_MACLK.v(291): Removing user instance primary_fsm,
because it is equivalent to instance secondary_fsm

I have tried synthesis directives such as syn_keep, syn_preserve, and
they have no effect on the mapper. Does anyone have a clue how to
prevent this from happening?

thanks,

jz

 

[Jason Zheng]

Jason Zheng wrote:

Does anyone know a synthesis directive that can prevent synplify's
mapper from pruning redundant instances that I intended to put in the
design? I have a design where I have two copies of identify state
machine to perform lockstep checking. Though the synthesizer did not
prune out the redundant state machine, the mapper always remove it
because it thinks they are identical:

@W: BN132: MREU_MACLK.v(291): Removing user instance primary_fsm,
because it is equivalent to instance secondary_fsm

I have tried synthesis directives such as syn_keep, syn_preserve, and
they have no effect on the mapper. Does anyone have a clue how to
prevent this from happening?

thanks,

jz

Nevermind folks,

syn_nonprune does the trick.

-jz