From 3bad9c26cff1ba2da7f1810e5915246874780744 Mon Sep 17 00:00:00 2001
From: David Shah <davey1576@gmail.com>
Date: Fri, 20 Jul 2018 11:36:32 +0200
Subject: [PATCH] ice40: Optimise reset/enable net checking

Signed-off-by: David Shah <davey1576@gmail.com>
---
 ice40/arch.cc       | 10 +++++++++-
 ice40/arch_place.cc | 14 ++++----------
 ice40/archdefs.h    |  1 +
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/ice40/arch.cc b/ice40/arch.cc
index 1aa02294..786d8ba1 100644
--- a/ice40/arch.cc
+++ b/ice40/arch.cc
@@ -25,7 +25,7 @@
 #include "placer1.h"
 #include "router1.h"
 #include "util.h"
-
+#include "cells.h"
 NEXTPNR_NAMESPACE_BEGIN
 
 // -----------------------------------------------------------------------
@@ -704,6 +704,14 @@ void Arch::assignArchInfo()
         NetInfo *ni = net.second.get();
         if (isGlobalNet(ni))
             ni->is_global = true;
+        ni->is_enable = false;
+        ni->is_reset = false;
+        for (auto usr : ni->users) {
+            if (is_enable_port(this, usr))
+                ni->is_enable = true;
+            if (is_reset_port(this, usr))
+                ni->is_reset = true;
+        }
     }
     for (auto &cell : getCtx()->cells) {
         CellInfo *ci = cell.second.get();
diff --git a/ice40/arch_place.cc b/ice40/arch_place.cc
index 1f2943a0..116ab7d3 100644
--- a/ice40/arch_place.cc
+++ b/ice40/arch_place.cc
@@ -108,21 +108,15 @@ bool Arch::isValidBelForCell(CellInfo *cell, BelId bel) const
     } else if (cell->type == id_sb_io) {
         return getBelPackagePin(bel) != "";
     } else if (cell->type == id_sb_gb) {
-        bool is_reset = false, is_cen = false;
         NPNR_ASSERT(cell->ports.at(id_glb_buf_out).net != nullptr);
-        for (auto user : cell->ports.at(id_glb_buf_out).net->users) {
-            if (is_reset_port(this, user))
-                is_reset = true;
-            if (is_enable_port(this, user))
-                is_cen = true;
-        }
+        const NetInfo *net = cell->ports.at(id_glb_buf_out).net;
         IdString glb_net = getWireName(getWireBelPin(bel, PIN_GLOBAL_BUFFER_OUTPUT));
         int glb_id = std::stoi(std::string("") + glb_net.str(this).back());
-        if (is_reset && is_cen)
+        if (net->is_reset && net->is_enable)
             return false;
-        else if (is_reset)
+        else if (net->is_reset)
             return (glb_id % 2) == 0;
-        else if (is_cen)
+        else if (net->is_enable)
             return (glb_id % 2) == 1;
         else
             return true;
diff --git a/ice40/archdefs.h b/ice40/archdefs.h
index 55e2c2fb..14b0d2be 100644
--- a/ice40/archdefs.h
+++ b/ice40/archdefs.h
@@ -153,6 +153,7 @@ struct DecalId
 struct ArchNetInfo
 {
     bool is_global = false;
+    bool is_reset = false, is_enable = false;
 };
 
 struct NetInfo;