From: Marcelina Kościelnicka <mwk@0x04.net>
Date: Thu, 27 Aug 2020 09:58:56 +0000 (+0200)
Subject: dfflegalize: Fix decision tree for adffe.
X-Git-Tag: working-ls180~298
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=880df4c89763464b471b1e2044f3f296bb3332b4;p=yosys.git

dfflegalize: Fix decision tree for adffe.

When an adffe is being legalized, and is not natively supported,
prioritize unmapping to adff over converting to dffsre if dffsre is not
natively supported itself.

Fixes #2361.
---

diff --git a/passes/techmap/dfflegalize.cc b/passes/techmap/dfflegalize.cc
index 8ad65493f..c1e7e557d 100644
--- a/passes/techmap/dfflegalize.cc
+++ b/passes/techmap/dfflegalize.cc
@@ -418,7 +418,8 @@ unmap_enable:
 					ff_type = has_set ? FF_ADFFE1 : FF_ADFFE0;
 					break;
 				}
-				if (supported_dffsr & initmask) {
+				if (supported_cells[has_en ? FF_DFFSRE : FF_DFFSR] & initmask) {
+adff_to_dffsr:
 					// Throw in a set/reset, retry in DFFSR/DFFSRE branch.
 					if (has_set) {
 						sig_s = sig_r;
@@ -441,6 +442,9 @@ unmap_enable:
 					ff_type = has_set ? FF_ADFF1 : FF_ADFF0;
 					goto unmap_enable;
 				}
+				if (supported_dffsr & initmask) {
+					goto adff_to_dffsr;
+				}
 				log_assert(!((has_set ? supported_adff1 : supported_adff0) & initmask));
 				// Alright, so this particular combination of initval and
 				// resetval is not natively supported.  First, try flipping