From: Marcelina Kościelnicka <mwk@0x04.net>
Date: Sun, 5 Jul 2020 02:57:24 +0000 (+0200)
Subject: dfflegalize: Prefer mapping dff to sdff before adff
X-Git-Tag: working-ls180~412
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f3f55ae7c28628892a9c4d40711251c5784ca997;p=yosys.git

dfflegalize: Prefer mapping dff to sdff before adff

This ensures that, when both sync and async FFs are available and abc9
is involved, the sync FFs will be used, and will thus remain available
for sequential synthesis.
---

diff --git a/passes/techmap/dfflegalize.cc b/passes/techmap/dfflegalize.cc
index 7f2cdc6ac..b2fe90702 100644
--- a/passes/techmap/dfflegalize.cc
+++ b/passes/techmap/dfflegalize.cc
@@ -364,7 +364,7 @@ flip_dqi:
 				// Some DFF is supported with this init val.  Just pick a type.
 				if (ff_type == FF_DFF) {
 					// Try adding a set or reset pin.
-					for (auto new_type: {FF_ADFF0, FF_ADFF1, FF_SDFF0, FF_SDFF1})
+					for (auto new_type: {FF_SDFF0, FF_SDFF1, FF_ADFF0, FF_ADFF1})
 						if (supported_cells[new_type] & initmask) {
 							ff_type = new_type;
 							sig_r = State::S0;