diff --git a/ice40/arch.cc b/ice40/arch.cc
index a5c920bb..1825c142 100644
--- a/ice40/arch.cc
+++ b/ice40/arch.cc
@@ -707,23 +707,28 @@ void Arch::assignArchArgs()
     }
     for (auto &cell : getCtx()->cells) {
         CellInfo *ci = cell.second.get();
-        ci->belType = belTypeFromId(ci->type);
-        if (ci->type == id_icestorm_lc) {
-            ci->lcInfo.dffEnable = bool_or_default(ci->params, id_dff_en);
-            ci->lcInfo.negClk = bool_or_default(ci->params, id_neg_clk);
-            ci->lcInfo.clk = get_net_or_empty(ci, id_clk);
-            ci->lcInfo.cen = get_net_or_empty(ci, id_cen);
-            ci->lcInfo.sr = get_net_or_empty(ci, id_sr);
-            ci->lcInfo.inputCount = 0;
-            if (get_net_or_empty(ci, id_i0))
-                ci->lcInfo.inputCount++;
-            if (get_net_or_empty(ci, id_i1))
-                ci->lcInfo.inputCount++;
-            if (get_net_or_empty(ci, id_i2))
-                ci->lcInfo.inputCount++;
-            if (get_net_or_empty(ci, id_i3))
-                ci->lcInfo.inputCount++;
-        }
+        assignCellArgs(ci);
+    }
+}
+
+void Arch::assignCellArgs(CellInfo *cell)
+{
+    cell->belType = belTypeFromId(cell->type);
+    if (cell->type == id_icestorm_lc) {
+        cell->lcInfo.dffEnable = bool_or_default(cell->params, id_dff_en);
+        cell->lcInfo.negClk = bool_or_default(cell->params, id_neg_clk);
+        cell->lcInfo.clk = get_net_or_empty(cell, id_clk);
+        cell->lcInfo.cen = get_net_or_empty(cell, id_cen);
+        cell->lcInfo.sr = get_net_or_empty(cell, id_sr);
+        cell->lcInfo.inputCount = 0;
+        if (get_net_or_empty(cell, id_i0))
+            cell->lcInfo.inputCount++;
+        if (get_net_or_empty(cell, id_i1))
+            cell->lcInfo.inputCount++;
+        if (get_net_or_empty(cell, id_i2))
+            cell->lcInfo.inputCount++;
+        if (get_net_or_empty(cell, id_i3))
+            cell->lcInfo.inputCount++;
     }
 }
 
diff --git a/ice40/arch.h b/ice40/arch.h
index 8821ded2..8c1a3d41 100644
--- a/ice40/arch.h
+++ b/ice40/arch.h
@@ -709,6 +709,7 @@ struct Arch : BaseCtx
     // Assign architecure-specific arguments to nets and cells, which must be called between packing or further
     // netlist modifications, and validity checks
     void assignArchArgs();
+    void assignCellArgs(CellInfo *cell);
 
     IdString id_glb_buf_out;
     IdString id_icestorm_lc, id_sb_io, id_sb_gb;
diff --git a/ice40/arch_place.cc b/ice40/arch_place.cc
index dc1bc3eb..1f2943a0 100644
--- a/ice40/arch_place.cc
+++ b/ice40/arch_place.cc
@@ -31,45 +31,37 @@ bool Arch::logicCellsCompatible(const std::vector<const CellInfo *> &cells) cons
     int locals_count = 0;
 
     for (auto cell : cells) {
-        if (bool_or_default(cell->params, id_dff_en)) {
+        NPNR_ASSERT(cell->belType == TYPE_ICESTORM_LC);
+        if (cell->lcInfo.dffEnable) {
             if (!dffs_exist) {
                 dffs_exist = true;
-                cen = get_net_or_empty(cell, id_cen);
-                clk = get_net_or_empty(cell, id_clk);
-                sr = get_net_or_empty(cell, id_sr);
+                cen = cell->lcInfo.cen;
+                clk = cell->lcInfo.clk;
+                sr = cell->lcInfo.sr;
 
-                if (!isGlobalNet(cen) && cen != nullptr)
+                if (cen != nullptr && !cen->is_global)
                     locals_count++;
-                if (!isGlobalNet(clk) && clk != nullptr)
+                if (clk != nullptr && !clk->is_global)
                     locals_count++;
-                if (!isGlobalNet(sr) && sr != nullptr)
+                if (sr != nullptr && !sr->is_global)
                     locals_count++;
 
-                if (bool_or_default(cell->params, id_neg_clk)) {
+                if (cell->lcInfo.negClk) {
                     dffs_neg = true;
                 }
             } else {
-                if (cen != get_net_or_empty(cell, id_cen))
+                if (cen != cell->lcInfo.cen)
                     return false;
-                if (clk != get_net_or_empty(cell, id_clk))
+                if (clk != cell->lcInfo.clk)
                     return false;
-                if (sr != get_net_or_empty(cell, id_sr))
+                if (sr != cell->lcInfo.sr)
                     return false;
-                if (dffs_neg != bool_or_default(cell->params, id_neg_clk))
+                if (dffs_neg != cell->lcInfo.negClk)
                     return false;
             }
         }
 
-        const NetInfo *i0 = get_net_or_empty(cell, id_i0), *i1 = get_net_or_empty(cell, id_i1),
-                      *i2 = get_net_or_empty(cell, id_i2), *i3 = get_net_or_empty(cell, id_i3);
-        if (i0 != nullptr)
-            locals_count++;
-        if (i1 != nullptr)
-            locals_count++;
-        if (i2 != nullptr)
-            locals_count++;
-        if (i3 != nullptr)
-            locals_count++;
+        locals_count += cell->lcInfo.inputCount;
     }
 
     return locals_count <= 32;
diff --git a/ice40/place_legaliser.cc b/ice40/place_legaliser.cc
index ebcc0da7..3c82a1bd 100644
--- a/ice40/place_legaliser.cc
+++ b/ice40/place_legaliser.cc
@@ -372,6 +372,7 @@ class PlacementLegaliser
         NPNR_ASSERT(ctx->nets.find(co_i3_name) == ctx->nets.end());
         ctx->nets[co_i3_name] = std::move(co_i3_net);
         IdString name = lc->name;
+        ctx->assignCellArgs(lc.get());
         ctx->cells[lc->name] = std::move(lc);
         createdCells.insert(name);
         return ctx->cells[name].get();
@@ -416,6 +417,7 @@ class PlacementLegaliser
         ctx->nets[out_net_name] = std::move(out_net);
 
         IdString name = lc->name;
+        ctx->assignCellArgs(lc.get());
         ctx->cells[lc->name] = std::move(lc);
         createdCells.insert(name);
         return ctx->cells[name].get();