diff --git a/.cirrus.yml b/.cirrus.yml
deleted file mode 100644
index 86edee59..00000000
--- a/.cirrus.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-task:
-  name: build-test-ubuntu2004
-  container:
-    cpu: 5
-    memory: 20
-    dockerfile: .cirrus/Dockerfile.ubuntu20.04
-
-  submodule_script: git submodule sync --recursive && git submodule update --init --recursive
-  build_script: mkdir build && cd build && cmake .. -DARCH='ecp5;generic;gowin;ice40;machxo2;nexus' -DOXIDE_INSTALL_PREFIX=$HOME/.cargo -DBUILD_TESTS=on -DBUILD_GUI=on -DWERROR=on && make -j3
-  test_generic_script: cd build && ./nextpnr-generic-test
-  flow_test_generic_script: export NPNR=$(pwd)/build/nextpnr-generic && cd tests/generic/flow && ./run.sh
-  test_ice40_script: cd build && ./nextpnr-ice40-test
-  smoketest_ice40_script: export NEXTPNR=$(pwd)/build/nextpnr-ice40 && cd ice40/smoketest/attosoc && ./smoketest.sh
-  test_ecp5_script: cd build && ./nextpnr-ecp5-test
-  smoketest_generic_script: export NEXTPNR=$(pwd)/build/nextpnr-generic && cd generic/examples && ./simple.sh && ./simtest.sh
-  regressiontest_ice40_script: make -j $(nproc) -C tests/ice40/regressions NPNR=$(pwd)/build/nextpnr-ice40
-  regressiontest_ecp5_script: make -j $(nproc) -C tests/ecp5/regressions NPNR=$(pwd)/build/nextpnr-ecp5
-  archcheck_script: BUILD_DIR=$(pwd)/build ./.cirrus/archcheck.sh
diff --git a/.cirrus/Dockerfile.ubuntu20.04 b/.cirrus/Dockerfile.ubuntu20.04
deleted file mode 100644
index 35ea18bd..00000000
--- a/.cirrus/Dockerfile.ubuntu20.04
+++ /dev/null
@@ -1,68 +0,0 @@
-FROM ubuntu:focal-20201106
-
-ENV DEBIAN_FRONTEND=noninteractive
-
-RUN set -e -x ;\
-    apt-get -y update ;\
-    apt-get -y upgrade ;\
-    apt-get -y install \
-        build-essential autoconf cmake clang bison wget flex gperf \
-        libreadline-dev gawk tcl-dev libffi-dev graphviz xdot python3-dev \
-        libboost-all-dev qt5-default git libftdi-dev pkg-config libeigen3-dev \
-        zlib1g-dev curl python3-pip libcapnp-dev capnproto
-
-
-RUN set -e -x ;\
-    mkdir -p /usr/local/src ;\
-    cd /usr/local/src ;\
-    git clone --recursive https://github.com/steveicarus/iverilog.git ;\
-    cd iverilog ;\
-    git reset --hard 84b4ebee0cfcda28a242d89a07020cd70b1d3e7f ;\
-    sh autoconf.sh ;\
-    ./configure ;\
-    make -j $(nproc) ;\
-    make install ;\
-    rm -rf /usr/local/src/iverilog
-
-RUN set -e -x ;\
-    mkdir -p /usr/local/src ;\
-    cd /usr/local/src ;\
-    git clone --recursive https://github.com/YosysHQ/icestorm.git ;\
-    cd icestorm ;\
-    git reset --hard 9f66f9ce16941c6417813cb87653c735a78b53ae ;\
-    make -j $(nproc) ;\
-    make install
-
-RUN set -e -x ;\
-    mkdir -p /usr/local/src ;\
-    cd /usr/local/src ;\
-    git clone --recursive https://github.com/YosysHQ/yosys.git ;\
-    cd yosys ;\
-    git reset --hard cd8b2ed4e6f9447c94d801de7db7ae6ce0976d57 ;\
-    make -j $(nproc) ;\
-    make install ;\
-    rm -rf /usr/local/src/yosys
-
-RUN set -e -x ;\
-    mkdir -p /usr/local/src ;\
-    cd /usr/local/src ;\
-    git clone --recursive https://github.com/YosysHQ/prjtrellis.git ;\
-    cd prjtrellis ;\
-    git reset --hard 26f917d6052e084df30211ae3a78c8a165121e09 ;\
-    cd libtrellis ;\
-    cmake . ;\
-    make -j $(nproc) ;\
-    make install
-
-RUN set -e -x ;\
-    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y ;\
-    mkdir -p /usr/local/src ;\
-    cd /usr/local/src ;\
-    git clone --recursive https://github.com/gatecat/prjoxide.git ;\
-    cd prjoxide ;\
-    git reset --hard 318331f8b30c2e2a31cc41d51f104b671e180a8a ;\
-    cd libprjoxide ;\
-    PATH=$PATH:$HOME/.cargo/bin cargo install --path prjoxide
-
-RUN set -e -x ;\
-    pip3 install apycula==0.2a4
diff --git a/.cirrus/archcheck.sh b/.cirrus/archcheck.sh
deleted file mode 100755
index 6ff6c043..00000000
--- a/.cirrus/archcheck.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/usr/bin/env bash
-set -ex
-echo "Running archcheck!"
-${BUILD_DIR}/nextpnr-ice40 --hx8k --package ct256 --test
-${BUILD_DIR}/nextpnr-ice40 --up5k --package sg48 --test
-${BUILD_DIR}/nextpnr-ecp5 --um5g-25k --package CABGA381 --test
-${BUILD_DIR}/nextpnr-nexus --device LIFCL-40-9BG400CES --test
-${BUILD_DIR}/nextpnr-gowin --device GW1N-UV4LQ144C6/I5 --test
diff --git a/.github/ci/build_common.sh b/.github/ci/build_common.sh
new file mode 100644
index 00000000..2a2d8447
--- /dev/null
+++ b/.github/ci/build_common.sh
@@ -0,0 +1,55 @@
+#!/bin/bash
+
+# Install latest Yosys
+function build_yosys {
+    PREFIX=`pwd`/.yosys
+    YOSYS_PATH=${DEPS_PATH}/yosys
+    mkdir -p ${YOSYS_PATH}
+    git clone --recursive https://github.com/YosysHQ/yosys ${YOSYS_PATH}
+    pushd ${YOSYS_PATH}
+    git reset --hard ${YOSYS_REVISION}
+    make -j`nproc` PREFIX=$PREFIX
+    make install PREFIX=$PREFIX
+    popd
+}
+
+function build_icestorm {
+    PREFIX=`pwd`/.icestorm
+    ICESTORM_PATH=${DEPS_PATH}/icestorm
+    mkdir -p ${ICESTORM_PATH}
+    git clone --recursive https://github.com/YosysHQ/icestorm ${ICESTORM_PATH}
+    pushd ${ICESTORM_PATH}
+    git reset --hard ${ICESTORM_REVISION}
+    make -j`nproc` PREFIX=${PREFIX}
+    make install PREFIX=${PREFIX}
+    popd
+}
+
+function build_trellis {
+    PREFIX=`pwd`/.trellis
+    TRELLIS_PATH=${DEPS_PATH}/prjtrellis
+    mkdir -p ${TRELLIS_PATH}
+    git clone --recursive https://github.com/YosysHQ/prjtrellis ${TRELLIS_PATH}
+    pushd ${TRELLIS_PATH}
+    git reset --hard ${TRELLIS_REVISION}
+    mkdir -p libtrellis/build
+    pushd libtrellis/build
+    cmake -DCMAKE_INSTALL_PREFIX=${PREFIX} ..
+    make -j`nproc`
+    make install
+    popd
+    popd
+}
+
+function build_prjoxide {
+    PREFIX=`pwd`/.prjoxide
+    PRJOXIDE_PATH=${DEPS_PATH}/prjoxide
+    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y ;\
+    mkdir -p ${PRJOXIDE_PATH}
+    git clone --recursive https://github.com/gatecat/prjoxide ${PRJOXIDE_PATH}
+    pushd ${PRJOXIDE_PATH}
+    git reset --hard ${PRJOXIDE_REVISION}
+    cd libprjoxide
+    PATH=$PATH:$HOME/.cargo/bin cargo install --root $PREFIX --path prjoxide
+    popd
+}
diff --git a/.github/ci/build_ecp5.sh b/.github/ci/build_ecp5.sh
new file mode 100644
index 00000000..2d09a6f6
--- /dev/null
+++ b/.github/ci/build_ecp5.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+function get_dependencies {
+    :
+}
+
+function build_nextpnr {
+    mkdir build
+    pushd build
+    cmake .. -DARCH=ecp5 -DTRELLIS_INSTALL_PREFIX=${GITHUB_WORKSPACE}/.trellis -DWERROR=on -DBUILD_GUI=on -DUSE_IPO=off
+    make nextpnr-ecp5 -j`nproc`
+    popd
+}
+
+function run_tests {
+    export PATH=${GITHUB_WORKSPACE}/.trellis/bin:${GITHUB_WORKSPACE}/.yosys/bin:$PATH
+    make -j $(nproc) -C tests/ecp5/regressions NPNR=$(pwd)/build/nextpnr-ecp5
+}
+
+function run_archcheck {
+    pushd build
+    ./nextpnr-ecp5 --um5g-25k --package CABGA381 --test
+    popd
+}
diff --git a/.github/ci/build_generic.sh b/.github/ci/build_generic.sh
new file mode 100644
index 00000000..49a73d3a
--- /dev/null
+++ b/.github/ci/build_generic.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+
+function get_dependencies {
+    :
+}
+
+function build_nextpnr {
+    mkdir build
+    pushd build
+    cmake .. -DARCH=generic -DWERROR=on
+    make nextpnr-generic -j`nproc`
+    popd
+}
+
+function run_tests {
+    export PATH=${GITHUB_WORKSPACE}/.yosys/bin:$PATH
+    ( export NPNR=$(pwd)/build/nextpnr-generic && cd tests/generic/flow && ./run.sh )
+}
+
+function run_archcheck {
+    pushd build
+    # TODO
+    # ./nextpnr-generic --uarch example --test
+    popd
+}
diff --git a/.github/ci/build_gowin.sh b/.github/ci/build_gowin.sh
new file mode 100644
index 00000000..430cd2b0
--- /dev/null
+++ b/.github/ci/build_gowin.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+
+function get_dependencies {
+    pip3 install apycula==${APYCULA_REVISION}
+}
+
+function build_nextpnr {
+    mkdir build
+    pushd build
+    cmake .. -DARCH=gowin -DWERROR=on -DBUILD_GUI=on -DUSE_IPO=off
+    make nextpnr-gowin -j`nproc`
+    popd
+}
+
+function run_tests {
+    :
+}
+
+function run_archcheck {
+    pushd build
+    ./nextpnr-gowin --device GW1N-UV4LQ144C6/I5 --test
+    popd
+}
diff --git a/.github/ci/build_ice40.sh b/.github/ci/build_ice40.sh
new file mode 100644
index 00000000..ea9234cc
--- /dev/null
+++ b/.github/ci/build_ice40.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+function get_dependencies {
+    :
+}
+
+function build_nextpnr {
+    mkdir build
+    pushd build
+    cmake .. -DARCH=ice40 -DICESTORM_INSTALL_PREFIX=${GITHUB_WORKSPACE}/.icestorm -DWERROR=on -DBUILD_TESTS=on -DBUILD_GUI=on
+    make nextpnr-ice40 nextpnr-ice40-test -j`nproc`
+    popd
+}
+
+function run_tests {
+    export PATH=${GITHUB_WORKSPACE}/.yosys/bin:${GITHUB_WORKSPACE}/.icestorm/bin:$PATH
+    (cd build && ./nextpnr-ice40-test)
+    (export NEXTPNR=$(pwd)/build/nextpnr-ice40 && cd ice40/smoketest/attosoc && ./smoketest.sh)
+    make -j $(nproc) -C tests/ice40/regressions NPNR=$(pwd)/build/nextpnr-ice40
+}
+
+function run_archcheck {
+    pushd build
+    ./nextpnr-ice40 --hx8k --package ct256 --test
+    ./nextpnr-ice40 --up5k --package sg48 --test
+    popd
+}
diff --git a/.github/ci/build_machxo2.sh b/.github/ci/build_machxo2.sh
new file mode 100644
index 00000000..c81a538b
--- /dev/null
+++ b/.github/ci/build_machxo2.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+
+function get_dependencies {
+    :
+}
+
+function build_nextpnr {
+    mkdir build
+    pushd build
+    cmake .. -DARCH=machxo2 -DTRELLIS_INSTALL_PREFIX=${GITHUB_WORKSPACE}/.trellis -DWERROR=on -DUSE_IPO=off
+    make nextpnr-machxo2 -j`nproc`
+    popd
+}
+
+function run_tests {
+    :
+}
+
+function run_archcheck {
+    :
+}
diff --git a/.github/ci/build_mistral.sh b/.github/ci/build_mistral.sh
index 3c809b0e..807c6206 100644
--- a/.github/ci/build_mistral.sh
+++ b/.github/ci/build_mistral.sh
@@ -1,5 +1,7 @@
 #!/bin/bash
 
+export MISTRAL_PATH=${DEPS_PATH}/mistral
+
 function get_dependencies {
     # Fetch mistral
     mkdir -p ${MISTRAL_PATH}
@@ -17,6 +19,10 @@ function build_nextpnr {
     popd
 }
 
+function run_tests {
+    :
+}
+
 function run_archcheck {
     pushd build
     ./nextpnr-mistral --device 5CEBA2F17A7 --test
diff --git a/.github/ci/build_nexus.sh b/.github/ci/build_nexus.sh
new file mode 100644
index 00000000..e8acd9b6
--- /dev/null
+++ b/.github/ci/build_nexus.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+
+function get_dependencies {
+    :
+}
+
+function build_nextpnr {
+    mkdir build
+    pushd build
+    cmake .. -DARCH=nexus -DOXIDE_INSTALL_PREFIX=${GITHUB_WORKSPACE}/.prjoxide
+    make nextpnr-nexus -j`nproc`
+    popd
+}
+
+function run_tests {
+    :
+}
+
+function run_archcheck {
+    pushd build
+    ./nextpnr-nexus --device LIFCL-40-9BG400CES --test
+    popd
+}
diff --git a/.github/workflows/arch_ci.yml b/.github/workflows/arch_ci.yml
new file mode 100644
index 00000000..5bf83630
--- /dev/null
+++ b/.github/workflows/arch_ci.yml
@@ -0,0 +1,95 @@
+# CI for everything other than the sui generis FPGA interchange arrangements
+
+name: Arch CI tests
+
+on: [push, pull_request]
+
+jobs:
+  Build-nextpnr:
+    strategy:
+      fail-fast: false
+      matrix:
+        arch: [mistral, ice40, ecp5, generic, nexus, machxo2, gowin]
+    runs-on: ubuntu-latest
+    env:
+      DEPS_PATH: ${{ github.workspace }}/deps
+      YOSYS_REVISION: bd7ee79486d4e8788f36de8c25a3fb2df451d682
+      ICESTORM_REVISION: 9f66f9ce16941c6417813cb87653c735a78b53ae
+      TRELLIS_REVISION: 48486ebd1e03e4ac42c96299e881adf9d43bc241
+      PRJOXIDE_REVISION: c3fb1526cf4a2165e15b74f4a994d153c7695fe4
+      MISTRAL_REVISION: ebfc0dd2cc7d6d2159b641a397c88554840e93c9
+      APYCULA_REVISION: 0.2a4
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: recursive
+
+    - uses: actions/setup-python@v2
+
+    - name: Install
+      run: |
+        sudo apt-get update
+        sudo apt-get install git make cmake libboost-all-dev python3-dev libeigen3-dev tcl-dev lzma-dev libftdi-dev clang bison flex swig qt5-default iverilog
+
+    - name: Cache yosys installation
+      uses: actions/cache@v2
+      id: cache-yosys
+      with:
+        path: .yosys
+        key: cache-yosys-${{ env.YOSYS_REVISION }}-r2
+
+    - name: Build yosys
+      run: |
+        source ./.github/ci/build_common.sh
+        build_yosys
+      if: steps.cache-yosys.outputs.cache-hit != 'true'
+
+    - name: Cache icestorm installation
+      uses: actions/cache@v2
+      id: cache-icestorm
+      with:
+        path: .icestorm
+        key: cache-icestorm-${{ env.ICESTORM_REVISION }}
+      if: matrix.arch == 'ice40'
+
+    - name: Build icestorm
+      run: |
+        source ./.github/ci/build_common.sh
+        build_icestorm
+      if: matrix.arch == 'ice40' && steps.cache-icestorm.outputs.cache-hit != 'true'
+
+    - name: Cache trellis installation
+      uses: actions/cache@v2
+      id: cache-trellis
+      with:
+        path: .trellis
+        key: cache-trellis-${{ env.TRELLIS_REVISION }}
+      if: matrix.arch == 'ecp5' || matrix.arch == 'machxo2'
+
+    - name: Build trellis
+      run: |
+        source ./.github/ci/build_common.sh
+        build_trellis
+      if: (matrix.arch == 'ecp5' || matrix.arch == 'machxo2') && steps.cache-trellis.outputs.cache-hit != 'true'
+
+    - name: Cache prjoxide installation
+      uses: actions/cache@v2
+      id: cache-prjoxide
+      with:
+        path: .prjoxide
+        key: cache-prjoxide-${{ env.PRJOXIDE_REVISION }}
+      if: matrix.arch == 'nexus'
+
+    - name: Build prjoxide
+      run: |
+        source ./.github/ci/build_common.sh
+        build_prjoxide
+      if: matrix.arch == 'nexus' && steps.cache-prjoxide.outputs.cache-hit != 'true'
+
+    - name: Execute build nextpnr
+      run: |
+        source ./.github/ci/build_${{ matrix.arch }}.sh
+        get_dependencies
+        build_nextpnr
+        run_tests
+        run_archcheck
diff --git a/.github/workflows/mistral_ci.yml b/.github/workflows/mistral_ci.yml
deleted file mode 100644
index b0bbfb52..00000000
--- a/.github/workflows/mistral_ci.yml
+++ /dev/null
@@ -1,29 +0,0 @@
-name: Mistral CI tests
-
-on: [push, pull_request]
-
-jobs:
-  Build-nextpnr:
-    runs-on: ubuntu-latest
-    steps:
-
-    - uses: actions/checkout@v2
-      with:
-        submodules: recursive
-
-    - uses: actions/setup-python@v2
-
-    - name: Install
-      run: |
-        sudo apt-get update
-        sudo apt-get install git make cmake libboost-all-dev python3-dev libeigen3-dev tcl-dev lzma-dev clang bison flex swig
-
-    - name: Execute build nextpnr
-      env:
-        MISTRAL_PATH: ${{ github.workspace }}/deps/mistral
-        MISTRAL_REVISION: ebfc0dd2cc7d6d2159b641a397c88554840e93c9 
-      run: |
-        source ./.github/ci/build_mistral.sh
-        get_dependencies
-        build_nextpnr
-        run_archcheck
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 89bdb360..3120cf40 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -134,7 +134,7 @@ if (MSVC)
     set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /W4 /wd4100 /wd4244 /wd4125 /wd4800 /wd4456 /wd4458 /wd4305 /wd4459 /wd4121 /wd4996 /wd4127")
 else()
     # N.B. the -Wno-array-bounds is to work around a false positive in GCC 9
-    set(WARN_FLAGS "-Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wno-array-bounds")
+    set(WARN_FLAGS "-Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wno-array-bounds -Wno-format-truncation")
     if (WERROR)
         set(WARN_FLAGS "${WARN_FLAGS} -Werror")
     endif()
diff --git a/ice40/smoketest/attosoc/smoketest.sh b/ice40/smoketest/attosoc/smoketest.sh
index 05408ab1..65823461 100755
--- a/ice40/smoketest/attosoc/smoketest.sh
+++ b/ice40/smoketest/attosoc/smoketest.sh
@@ -4,6 +4,6 @@ yosys -q -p 'synth_ice40 -json attosoc.json -top attosoc' attosoc.v picorv32.v
 $NEXTPNR --hx8k --json attosoc.json --pcf attosoc.pcf --asc attosoc.asc --freq 50
 icetime -tmd hx8k -c 50 attosoc.asc
 icebox_vlog -L -l -p attosoc.pcf -c -n attosoc attosoc.asc > attosoc_pnr.v
-iverilog -o attosoc_pnr_tb attosoc_pnr.v attosoc_tb.v `yosys-config --datdir/ice40/cells_sim.v`
+iverilog -DNO_ICE40_DEFAULT_ASSIGNMENTS -o attosoc_pnr_tb attosoc_pnr.v attosoc_tb.v `yosys-config --datdir/ice40/cells_sim.v`
 vvp attosoc_pnr_tb
 diff output.txt golden.txt
diff --git a/tests b/tests
index ccc61e5e..00c55a9e 160000
--- a/tests
+++ b/tests
@@ -1 +1 @@
-Subproject commit ccc61e5ec7cc04410462ec3196ad467354787afb
+Subproject commit 00c55a9eb9ea2e062b51fe0d64741412b185d95d