From: Pepijn de Vos <pepijndevos@gmail.com>
Date: Sat, 6 Nov 2021 15:09:30 +0000 (+0100)
Subject: gowin: widelut support (#3042)
X-Git-Tag: yosys-0.12~50
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0c7461fe5e7ff8deacf4a16fa0e67e6666a17441;p=yosys.git

gowin: widelut support (#3042)
---

diff --git a/passes/opt/opt_lut_ins.cc b/passes/opt/opt_lut_ins.cc
index 99043ef7e..2f7c392b2 100644
--- a/passes/opt/opt_lut_ins.cc
+++ b/passes/opt/opt_lut_ins.cc
@@ -193,6 +193,12 @@ struct OptLutInsPass : public Pass {
 								swz += extra;
 					}
 				}
+				if (techname == "gowin") {
+					// Pad the LUT to 1 input, adding consts from the front.
+					if (new_inputs.empty()) {
+						new_inputs.insert(new_inputs.begin(), State::S0);
+					}
+				}
 				Const new_lut(0, 1 << GetSize(new_inputs));
 				for (int i = 0; i < GetSize(new_lut); i++) {
 					int lidx = 0;
@@ -209,9 +215,9 @@ struct OptLutInsPass : public Pass {
 					}
 					new_lut[i] = lut[lidx];
 				}
-				// For ecp5, do not replace with a const driver — the nextpnr
+				// For ecp5, and gowin do not replace with a const driver — the nextpnr
 				// packer requires a complete set of LUTs for wide LUT muxes.
-				if (new_inputs.empty() && techname != "ecp5") {
+				if (new_inputs.empty() && techname != "ecp5" && techname != "gowin") {
 					// const driver.
 					remove_cells.push_back(cell);
 					module->connect(output, new_lut[0]);
diff --git a/techlibs/gowin/synth_gowin.cc b/techlibs/gowin/synth_gowin.cc
index 087f6b8cf..f35a7af4d 100644
--- a/techlibs/gowin/synth_gowin.cc
+++ b/techlibs/gowin/synth_gowin.cc
@@ -126,7 +126,6 @@ struct SynthGowinPass : public ScriptPass
 				json_file = args[++argidx];
 				nobram = true;
 				nolutram = true;
-				nowidelut = true;
 				noalu = true;
 				continue;
 			}