diff --git a/.travis.yml b/.travis.yml
index 4513e08cec..c9886151ab 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,14 +13,14 @@ matrix:
       env: TARGET=x86_64-unknown-linux-gnu
       install: true
     - name: "x86_64-unknown-linux-gnu-emulated (runs all assert_instr tests)"
-      env: TARGET=x86_64-unknown-linux-gnu-emulated STDSIMD_TEST_EVERYTHING=1 RUSTFLAGS="--cfg stdsimd_intel_sde"
+      env: TARGET=x86_64-unknown-linux-gnu-emulated STDSIMD_TEST_EVERYTHING=1 RUSTFLAGS="--cfg stdsimd_intel_sde" NOLIBSTDBUILD=1
       install: true
     - name: "x86_64-linux-android - no assert_instr"
-      env: TARGET=x86_64-linux-android STDSIMD_DISABLE_ASSERT_INSTR=1
+      env: TARGET=x86_64-linux-android STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
     - name: "arm-unknown-linux-gnueabihf"
       env: TARGET=arm-unknown-linux-gnueabihf
     - name: "arm-linux-androideabi - no assert_instr"
-      env: TARGET=arm-linux-androideabi STDSIMD_DISABLE_ASSERT_INSTR=1
+      env: TARGET=arm-linux-androideabi STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
     - name: "armv7-unknown-linux-gnueabihf - NEON"
       env: TARGET=armv7-unknown-linux-gnueabihf RUSTFLAGS="-C target-feature=+neon"
     - name: "aarch64-unknown-linux-gnu"
@@ -28,13 +28,13 @@ matrix:
     - name: "mips-unknown-linux-gnu - build-only"
       env: TARGET=mips-unknown-linux-gnu NORUN=1
     - name: "mipsel-unknown-linux-musl - build-only"
-      env: TARGET=mipsel-unknown-linux-musl NORUN=1
+      env: TARGET=mipsel-unknown-linux-musl NORUN=1 NOLIBSTDBUILD=1
     - name: "mips64-unknown-linux-gnuabi64 - build-only"
       env: TARGET=mips64-unknown-linux-gnuabi64 NORUN=1
     - name: "mips64el-unknown-linux-gnuabi64 - build-only"
       env: TARGET=mips64el-unknown-linux-gnuabi64 NORUN=1
     - name: "aarch64-linux-android - no assert_instr"
-      env: TARGET=aarch64-linux-android STDSIMD_DISABLE_ASSERT_INSTR=1
+      env: TARGET=aarch64-linux-android STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
     - name: "powerpc-unknown-linux-gnu - no assert_instr"
       env: TARGET=powerpc-unknown-linux-gnu STDSIMD_DISABLE_ASSERT_INSTR=1
     - name: "powerpc64-unknown-linux-gnu - no assert_instr, no simd_test"
@@ -57,16 +57,16 @@ matrix:
     - name: "wasm32-unknown-unknown"
       env: TARGET=wasm32-unknown-unknown
     - name: "thumbv6m-none-eabi - build libcore only"
-      env: TARGET=thumbv6m-none-eabi NORUN=1 NOSTD=1
+      env: TARGET=thumbv6m-none-eabi NORUN=1 NOSTD=1 NOLIBSTDBUILD=1
       script: ci/run.sh
     - name: "thumbv7m-none-eabi - build libcore only"
-      env: TARGET=thumbv7m-none-eabi NORUN=1 NOSTD=1
+      env: TARGET=thumbv7m-none-eabi NORUN=1 NOSTD=1 NOLIBSTDBUILD=1
       script: ci/run.sh
     - name: "thumbv7em-none-eabi - build libcore only"
-      env: TARGET=thumbv7em-none-eabi NORUN=1 NOSTD=1
+      env: TARGET=thumbv7em-none-eabi NORUN=1 NOSTD=1 NOLIBSTDBUILD=1
       script: ci/run.sh
     - name: "thumbv7em-none-eabihf - build libcore only"
-      env: TARGET=thumbv7em-none-eabihf NORUN=1 NOSTD=1
+      env: TARGET=thumbv7em-none-eabihf NORUN=1 NOSTD=1 NOLIBSTDBUILD=1
       script: ci/run.sh
     - name: "x86_64-pc-windows-msvc"
       env: TARGET=x86_64-pc-windows-msvc
@@ -75,16 +75,16 @@ matrix:
       install: true
     - name: "x86_64-pc-windows-gnu - no assert_instr"
       # FIXME: https://github.com/rust-lang-nursery/stdsimd/issues/595
-      env: TARGET=x86_64-pc-windows-gnu STDSIMD_DISABLE_ASSERT_INSTR=1
+      env: TARGET=x86_64-pc-windows-gnu STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
       os: windows
       script: ci/run.sh
     - name: "i686-pc-windows-msvc - no assert_instr"
       # FIXME: https://github.com/rust-lang-nursery/stdsimd/issues/595
-      env: TARGET=i686-pc-windows-msvc STDSIMD_DISABLE_ASSERT_INSTR=1
+      env: TARGET=i686-pc-windows-msvc STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
       os: windows
       script: ci/run.sh
     - name: "i686-pc-windows-gnu"
-      env: TARGET=i686-pc-windows-gnu
+      env: TARGET=i686-pc-windows-gnu STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
       os: windows
       script: ci/run.sh
     - name: "Documentation"
@@ -109,8 +109,8 @@ matrix:
         - shellcheck ci/*.sh
   allow_failures:
     # FIXME: https://github.com/rust-lang/rust/issues/56153
-    - env: TARGET=x86_64-pc-windows-gnu STDSIMD_DISABLE_ASSERT_INSTR=1
-    - env: TARGET=i686-pc-windows-gnu
+    - env: TARGET=x86_64-pc-windows-gnu STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
+    - env: TARGET=i686-pc-windows-gnu STDSIMD_DISABLE_ASSERT_INSTR=1 NOLIBSTDBUILD=1
 
 install: rustup target add $TARGET
 script: 
diff --git a/ci/docker/aarch64-unknown-linux-gnu/Dockerfile b/ci/docker/aarch64-unknown-linux-gnu/Dockerfile
index 68261a2f03..f3fda53b92 100644
--- a/ci/docker/aarch64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/aarch64-unknown-linux-gnu/Dockerfile
@@ -7,7 +7,18 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libc6-dev-arm64-cross \
   qemu-user \
   make \
-  file
+  file \
+  g++ \
+  g++-aarch64-linux-gnu \
+  git \
+  python \
+  curl \
+  bzip2 \
+  perl \
+  wget \
+  autoconf \
+  gettext
+
 
 ENV CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER=aarch64-linux-gnu-gcc \
     CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUNNER="qemu-aarch64 -L /usr/aarch64-linux-gnu" \
diff --git a/ci/docker/arm-unknown-linux-gnueabihf/Dockerfile b/ci/docker/arm-unknown-linux-gnueabihf/Dockerfile
index c7bd61f0a7..cd2b86ed9e 100644
--- a/ci/docker/arm-unknown-linux-gnueabihf/Dockerfile
+++ b/ci/docker/arm-unknown-linux-gnueabihf/Dockerfile
@@ -7,7 +7,18 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libc6-dev-armhf-cross \
   qemu-user \
   make \
-  file
+  file \
+  g++ \
+  g++-arm-linux-gnueabihf \
+  git \
+  python \
+  curl \
+  bzip2 \
+  perl \
+  wget \
+  autoconf \
+  gettext
+
 ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_GNUEABIHF_LINKER=arm-linux-gnueabihf-gcc \
     CARGO_TARGET_ARM_UNKNOWN_LINUX_GNUEABIHF_RUNNER="qemu-arm -L /usr/arm-linux-gnueabihf" \
     OBJDUMP=arm-linux-gnueabihf-objdump
diff --git a/ci/docker/armv7-unknown-linux-gnueabihf/Dockerfile b/ci/docker/armv7-unknown-linux-gnueabihf/Dockerfile
index e01b87afdf..42c0a2e81e 100644
--- a/ci/docker/armv7-unknown-linux-gnueabihf/Dockerfile
+++ b/ci/docker/armv7-unknown-linux-gnueabihf/Dockerfile
@@ -7,7 +7,18 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libc6-dev-armhf-cross \
   qemu-user \
   make \
-  file
+  file \
+  g++ \
+  g++-arm-linux-gnueabihf \
+  git \
+  python \
+  curl \
+  bzip2 \
+  perl \
+  wget \
+  autoconf \
+  gettext
+
 ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_GNUEABIHF_LINKER=arm-linux-gnueabihf-gcc \
     CARGO_TARGET_ARMV7_UNKNOWN_LINUX_GNUEABIHF_RUNNER="qemu-arm -L /usr/arm-linux-gnueabihf" \
     OBJDUMP=arm-linux-gnueabihf-objdump
diff --git a/ci/docker/i586-unknown-linux-gnu/Dockerfile b/ci/docker/i586-unknown-linux-gnu/Dockerfile
index 857974a858..9f83e06c04 100644
--- a/ci/docker/i586-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/i586-unknown-linux-gnu/Dockerfile
@@ -4,4 +4,14 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libc6-dev \
   file \
   make \
-  ca-certificates
+  ca-certificates \
+  g++-multilib \
+  git \
+  python \
+  curl \
+  bzip2 \
+  perl \
+  wget \
+  autoconf \
+  gettext
+
diff --git a/ci/docker/i686-unknown-linux-gnu/Dockerfile b/ci/docker/i686-unknown-linux-gnu/Dockerfile
index 857974a858..9f83e06c04 100644
--- a/ci/docker/i686-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/i686-unknown-linux-gnu/Dockerfile
@@ -4,4 +4,14 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libc6-dev \
   file \
   make \
-  ca-certificates
+  ca-certificates \
+  g++-multilib \
+  git \
+  python \
+  curl \
+  bzip2 \
+  perl \
+  wget \
+  autoconf \
+  gettext
+
diff --git a/ci/docker/mips-unknown-linux-gnu/Dockerfile b/ci/docker/mips-unknown-linux-gnu/Dockerfile
index 4711cead37..49b4297d90 100644
--- a/ci/docker/mips-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/mips-unknown-linux-gnu/Dockerfile
@@ -6,7 +6,18 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         qemu-system-mips \
         qemu-user \
         make \
-        file
+        file \
+        g++ \
+        g++-mips-linux-gnu \
+        git \     
+        python \  
+        curl \
+        bzip2 \
+        perl \
+        wget \
+        autoconf \
+        gettext
+
 
 ENV CARGO_TARGET_MIPS_UNKNOWN_LINUX_GNU_LINKER=mips-linux-gnu-gcc \
     CARGO_TARGET_MIPS_UNKNOWN_LINUX_GNU_RUNNER="qemu-mips -L /usr/mips-linux-gnu" \
diff --git a/ci/docker/mips64-unknown-linux-gnuabi64/Dockerfile b/ci/docker/mips64-unknown-linux-gnuabi64/Dockerfile
index 1422e8c809..d5b58829fc 100644
--- a/ci/docker/mips64-unknown-linux-gnuabi64/Dockerfile
+++ b/ci/docker/mips64-unknown-linux-gnuabi64/Dockerfile
@@ -3,7 +3,17 @@ FROM ubuntu:17.10
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates \
         gcc-mips64-linux-gnuabi64 libc6-dev-mips64-cross \
-        qemu-system-mips64 qemu-user
+        qemu-system-mips64 qemu-user \
+        g++ \
+        g++-mips64-linux-gnuabi64 \
+        git \
+        python \
+        curl \
+        bzip2 \
+        perl \
+        wget \
+        autoconf \
+        gettext
 
 ENV CARGO_TARGET_MIPS64_UNKNOWN_LINUX_GNUABI64_LINKER=mips64-linux-gnuabi64-gcc \
     CARGO_TARGET_MIPS64_UNKNOWN_LINUX_GNUABI64_RUNNER="qemu-mips64 -L /usr/mips64-linux-gnuabi64" \
diff --git a/ci/docker/mips64el-unknown-linux-gnuabi64/Dockerfile b/ci/docker/mips64el-unknown-linux-gnuabi64/Dockerfile
index d94deb5b20..b0568da272 100644
--- a/ci/docker/mips64el-unknown-linux-gnuabi64/Dockerfile
+++ b/ci/docker/mips64el-unknown-linux-gnuabi64/Dockerfile
@@ -3,7 +3,18 @@ FROM ubuntu:17.10
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates \
         gcc-mips64el-linux-gnuabi64 libc6-dev-mips64el-cross \
-        qemu-system-mips64el
+        qemu-system-mips64el \
+        g++ \
+        g++-mips64el-linux-gnuabi64 \
+        git \
+        python \
+        curl \
+        bzip2 \
+        perl \
+        wget \
+        autoconf \
+        gettext
+
 
 ENV CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_GNUABI64_LINKER=mips64el-linux-gnuabi64-gcc \
     CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_GNUABI64_RUNNER="qemu-mips64el -L /usr/mips64el-linux-gnuabi64" \
diff --git a/ci/docker/mipsel-unknown-linux-musl/Dockerfile b/ci/docker/mipsel-unknown-linux-musl/Dockerfile
index 40ac50675b..d1c8f17eae 100644
--- a/ci/docker/mipsel-unknown-linux-musl/Dockerfile
+++ b/ci/docker/mipsel-unknown-linux-musl/Dockerfile
@@ -12,6 +12,7 @@ RUN apt-get update && \
     curl \
     file
 
+
 RUN mkdir /toolchain
 
 # Note that this originally came from:
diff --git a/ci/docker/powerpc-unknown-linux-gnu/Dockerfile b/ci/docker/powerpc-unknown-linux-gnu/Dockerfile
index 43b174ed87..19cf1f4943 100644
--- a/ci/docker/powerpc-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/powerpc-unknown-linux-gnu/Dockerfile
@@ -5,7 +5,17 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc-powerpc-linux-gnu libc6-dev-powerpc-cross \
         qemu-system-ppc \
         make \
-        file
+        file \
+        g++ \
+        g++-powerpc-linux-gnu \
+        git \
+        python \
+        curl \
+        bzip2 \
+        perl \
+        wget \
+        autoconf \
+        gettext
 
 ENV CARGO_TARGET_POWERPC_UNKNOWN_LINUX_GNU_LINKER=powerpc-linux-gnu-gcc \
     CARGO_TARGET_POWERPC_UNKNOWN_LINUX_GNU_RUNNER="qemu-ppc -cpu Vger -L /usr/powerpc-linux-gnu" \
diff --git a/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile b/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile
index 7757ad28a4..dbd5fbe8fd 100644
--- a/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/powerpc64-unknown-linux-gnu/Dockerfile
@@ -9,7 +9,17 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     qemu-user  \
     qemu-system-ppc \
     make \
-    file 
+    file \
+    g++ \
+    g++-powerpc64-linux-gnu \
+    git \
+    python \
+    curl \
+    bzip2 \
+    perl \
+    wget \
+    autoconf \
+    gettext
 
 ENV CARGO_TARGET_POWERPC64_UNKNOWN_LINUX_GNU_LINKER=powerpc64-linux-gnu-gcc \
     CARGO_TARGET_POWERPC64_UNKNOWN_LINUX_GNU_RUNNER="qemu-ppc64 -L /usr/powerpc64-linux-gnu" \
diff --git a/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile b/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile
index 0b0c214fdf..713bf5e3f2 100644
--- a/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile
@@ -3,7 +3,18 @@ FROM ubuntu:17.10
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates \
         gcc-powerpc64le-linux-gnu libc6-dev-ppc64el-cross \
-        qemu-system-ppc file make
+        qemu-system-ppc file make \
+        g++ \
+        g++-powerpc64le-linux-gnu \
+        git \
+        python \
+        curl \
+        bzip2 \
+        perl \
+        wget \
+        autoconf \
+        gettext
+
 
 ENV CARGO_TARGET_POWERPC64LE_UNKNOWN_LINUX_GNU_LINKER=powerpc64le-linux-gnu-gcc \
     CARGO_TARGET_POWERPC64LE_UNKNOWN_LINUX_GNU_RUNNER="qemu-ppc64le -L /usr/powerpc64le-linux-gnu" \
diff --git a/ci/docker/s390x-unknown-linux-gnu/Dockerfile b/ci/docker/s390x-unknown-linux-gnu/Dockerfile
index 89d9d87a15..702d1a5231 100644
--- a/ci/docker/s390x-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/s390x-unknown-linux-gnu/Dockerfile
@@ -6,7 +6,17 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc-s390x-linux-gnu libc6-dev-s390x-cross \
         qemu-user \
         make \
-        file
+        file \
+        g++ \
+        g++-s390x-linux-gnu \
+        git \
+        python \
+        curl \
+        bzip2 \
+        perl \
+        wget \
+        autoconf \
+        gettext
 
 ENV CARGO_TARGET_S390X_UNKNOWN_LINUX_GNU_LINKER=s390x-linux-gnu-gcc \
     CARGO_TARGET_S390X_UNKNOWN_LINUX_GNU_RUNNER="qemu-s390x -L /usr/s390x-linux-gnu" \
diff --git a/ci/docker/wasm32-unknown-unknown/Dockerfile b/ci/docker/wasm32-unknown-unknown/Dockerfile
index e385541f9c..bf638f4b3c 100644
--- a/ci/docker/wasm32-unknown-unknown/Dockerfile
+++ b/ci/docker/wasm32-unknown-unknown/Dockerfile
@@ -9,7 +9,16 @@ RUN apt-get update -y && apt-get install -y --no-install-recommends \
   libc6-dev \
   make \
   python \
-  xz-utils
+  xz-utils \
+  g++ \
+  git \
+  python \
+  curl \
+  bzip2 \
+  perl \
+  wget \
+  autoconf \
+  gettext
 
 # Install `wasm2wat`
 RUN git clone --recursive https://github.com/WebAssembly/wabt
diff --git a/ci/docker/x86_64-unknown-linux-gnu/Dockerfile b/ci/docker/x86_64-unknown-linux-gnu/Dockerfile
index 44206fe872..ad7bbc0c19 100644
--- a/ci/docker/x86_64-unknown-linux-gnu/Dockerfile
+++ b/ci/docker/x86_64-unknown-linux-gnu/Dockerfile
@@ -4,4 +4,13 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libc6-dev \
   file \
   make \
-  ca-certificates
+  ca-certificates \
+  g++ \
+  git \
+  python \
+  curl \
+  bzip2 \
+  perl \
+  wget \
+  autoconf \
+  gettext
diff --git a/ci/run-docker.sh b/ci/run-docker.sh
index bd02dcd9bc..e403429492 100755
--- a/ci/run-docker.sh
+++ b/ci/run-docker.sh
@@ -9,6 +9,7 @@ run() {
     echo "Building docker container for TARGET=${1}"
     docker build -t stdsimd -f "ci/docker/${1}/Dockerfile" ci/
     mkdir -p target
+    mkdir -p ../rustc
     target=$(echo "${1}" | sed 's/-emulated//')
     echo "Running docker"
     # shellcheck disable=SC2016
@@ -25,10 +26,12 @@ run() {
       --env STDSIMD_DISABLE_ASSERT_INSTR \
       --env NOSTD \
       --env NORUN \
+      --env NOLIBSTDBUILD \
       --env RUSTFLAGS \
       --env STDSIMD_TEST_NORUN \
       --volume "$(pwd)":/checkout:ro \
       --volume "$(pwd)"/target:/checkout/target \
+      --volume "$(pwd)"/../rustc:/rustc \
       --workdir /checkout \
       --privileged \
       stdsimd \
diff --git a/ci/run.sh b/ci/run.sh
index dd4e518038..feb867ed13 100755
--- a/ci/run.sh
+++ b/ci/run.sh
@@ -10,7 +10,7 @@ export RUST_TEST_THREADS=1
 #export RUST_BACKTRACE=full
 #export RUST_TEST_NOCAPTURE=1
 
-RUSTFLAGS="$RUSTFLAGS --cfg stdsimd_strict"
+RUSTFLAGS="${RUSTFLAGS} --cfg stdsimd_strict"
 
 case ${TARGET} in
     # On 32-bit use a static relocation model which avoids some extra
@@ -34,13 +34,11 @@ echo "STDSIMD_TEST_EVERYTHING=${STDSIMD_TEST_EVERYTHING}"
 
 cargo_test() {
     subcmd="test"
-    if [ "$NORUN" = "1" ]
-    then
+    if [ "${NORUN}" = "1" ]; then
         export subcmd="build"
     fi
-    cmd="cargo ${subcmd} --target=$TARGET $1"
-    if [ "$NOSTD" = "1" ]
-    then
+    cmd="cargo ${subcmd} --target=${TARGET} ${1}"
+    if [ "${NOSTD}" = "1" ]; then
         cmd="$cmd -p coresimd"
     else
         cmd="$cmd -p coresimd -p stdsimd"
@@ -49,20 +47,62 @@ cargo_test() {
     $cmd
 }
 
-cargo_test
-cargo_test "--release"
+#cargo_test
+#cargo_test "--release"
 
 # Test targets compiled with extra features.
 case ${TARGET} in
     x86*)
         export STDSIMD_DISABLE_ASSERT_INSTR=1
         export RUSTFLAGS="${RUSTFLAGS} -C target-feature=+avx"
-        cargo_test "--release"
+        #cargo_test "--release"
         ;;
     wasm32-unknown-unknown*)
         # export RUSTFLAGS="${RUSTFLAGS} -C target-feature=+simd128"
-        cargo_test "--release --features=wasm_simd128"
+        #cargo_test "--release --features=wasm_simd128"
         ;;
     *)
         ;;
 esac
+
+if [ "${NOLIBSTDBUILD}" = "1" ]; then
+    echo "Whether libstd builds with this stdsimd is not tested!"
+else
+    echo "Testing that libcore and libstd build with this stdsimd..."
+    stdsimd="$(pwd)"
+    stdsimd_hash="$(git rev-parse HEAD)"
+
+    case ${TARGET} in
+        *apple*)
+            export RUSTC_DIR=~/rustc
+            ;;
+        *windows*)
+            export RUSTC_DIR=~/rustc
+            ;;
+        *)
+            export RUSTC_DIR=/rustc
+            ;;
+    esac
+
+    git clone --depth 1 https://github.com/rust-lang/rust.git "${RUSTC_DIR}"
+    cd "${RUSTC_DIR}"
+
+    git submodule init
+    git config -f .gitmodules submodule.stdsimd.url "${stdsimd}"
+    git add -u
+    git -c user.name='Travis CI' -c user.email='travis@ci.org' commit -m 'Update stdsimd submodule'
+
+    git submodule sync
+    ./x.py clean
+
+    (
+        cd src/stdsimd
+        git checkout "${stdsimd_hash}"
+    )
+
+    git add src/stdsimd
+    git -c user.name='Travis CI' -c user.email='travis@ci.org' commit -m 'Update stdsimd'
+
+    ./x.py check src/libcore --stage 1 --target "${TARGET}"
+    ./x.py check src/libstd --stage 1 --target "${TARGET}"
+fi
diff --git a/coresimd/mod.rs b/coresimd/mod.rs
index 470d76f906..192d8219a9 100644
--- a/coresimd/mod.rs
+++ b/coresimd/mod.rs
@@ -5,6 +5,8 @@ mod macros;
 
 mod simd;
 
+mod fooooooo;
+
 /// Platform dependent vendor intrinsics.
 ///
 /// This documentation is for the version of this module in the `coresimd`