After speaking with the author of ABC he let me know that ifraig is a very old command, and that &get; &fraig -x; &put is over 100x faster than ifraig with improved PPA results.
After making the change I confirmed that this is in fact a major speed up. On our internal designs in O(millions) of standard cells we saw multi hour reductions in runtime.
Also included is an improvement to the dress command. Using AIG based transformations removes the spec it SATs against. Proving the input blif will make sure that no matter what commands are run the dress command can still do its job. I noticed a regression against some LUT mapping jobs that prompted me to fix this.
Verific generates a lot of FFs with an unused async load and we cannot
always optimize that away before running clk2fflogic, so check for that
special case here.
Find FFs with undefined initialization values for which changing the
initialization does not change the observable behavior and initialize
them. For -ff2anyinit, this reduces the number of generated $anyinit
cells that drive wires with private names.
This attribute can be used by formal backends to indicate which clocks
were mapped to the global clock. Update the btor and smt2 backend which
already handle clock inputs to understand this attribute.
These can be used to protect undefined flip-flop initialization values
from optimizations that are not sound for formal verification and can
help mapping all solver-provided values in witness traces for flows that
use different backends simultaneously.
The formal backends do not support multiple clocks. This includes
constant clocks. Constant clocks do appear in what isn't a proper
multiclock design, for example when mapping not fully initialized ROMs.
As converting FFs with constant clocks to FFs using the global is doable
even in a single clock flow, make async2sync do this.
POSIX defines $TMPDIR as containing the pathname of the directory where
programs can create temporary files. On most systems, this variable points to
"/tmp". However, on some systems it can point to a different location.
Without respecting this variable, yosys fails to run on such systems.
Signed-off-by: Mohamed A. Bamakhrama <mohamed@alumni.tum.de>
Both of these options consider a selection containing only empty modules
as non-empty. This wasn't mentioned in the documentation nor did the
error message when using `select -assert-none` list those empty modules,
which produced a very confusing error message complaining about a
non-empty selection followed by an empty listing of the selection.
This fixes the documentation and changes the `-assert-none` and
`-assert-any` assertion error messages to also output fully selected
modules (this includes selected empty modules).
It doesn't change the messages for `-assert-count` etc. as they don't
count modules.
Jacob Lifshay
