diff --git a/configure b/configure
index 2b493ee91b50..e08bcc028272 100755
--- a/configure
+++ b/configure
@@ -490,6 +490,7 @@ valopt musl-root-armhf "" "arm-unknown-linux-musleabihf install directory"
 valopt musl-root-armv7 "" "armv7-unknown-linux-musleabihf install directory"
 valopt extra-filename "" "Additional data that is hashed and passed to the -C extra-filename flag"
 valopt qemu-armhf-rootfs "" "rootfs in qemu testing, you probably don't want to use this"
+valopt experimental-targets "" "experimental LLVM targets to build"
 
 if [ -e ${CFG_SRC_DIR}.git ]
 then
diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index 902cd0997a8e..3ada846e3823 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -497,6 +497,9 @@ macro_rules! check {
                 "CFG_TARGET" if value.len() > 0 => {
                     self.target.extend(value.split(" ").map(|s| s.to_string()));
                 }
+                "CFG_EXPERIMENTAL_TARGETS" if value.len() > 0 => {
+                    self.llvm_experimental_targets = Some(value.to_string());
+                }
                 "CFG_MUSL_ROOT" if value.len() > 0 => {
                     self.musl_root = Some(parse_configure_path(value));
                 }
diff --git a/src/ci/docker/disabled/wasm32/Dockerfile b/src/ci/docker/disabled/wasm32/Dockerfile
index daf398ac0962..f3dd48ae411d 100644
--- a/src/ci/docker/disabled/wasm32/Dockerfile
+++ b/src/ci/docker/disabled/wasm32/Dockerfile
@@ -20,7 +20,7 @@ RUN sh /scripts/dumb-init.sh
 # emscripten
 COPY scripts/emscripten.sh /scripts/
 RUN bash /scripts/emscripten.sh
-COPY wasm32/node.sh /usr/local/bin/node
+COPY disabled/wasm32/node.sh /usr/local/bin/node
 
 # env
 ENV PATH=$PATH:/emsdk-portable
@@ -30,9 +30,9 @@ ENV EMSCRIPTEN=/emsdk-portable/emscripten/1.37.13/
 ENV BINARYEN_ROOT=/emsdk-portable/clang/e1.37.13_64bit/binaryen/
 ENV EM_CONFIG=/emsdk-portable/.emscripten
 
-ENV TARGETS=wasm32-unknown-emscripten
+ENV TARGETS=wasm32-unknown-emscripten,wasm32-experimental-emscripten
 
-ENV RUST_CONFIGURE_ARGS --target=$TARGETS
+ENV RUST_CONFIGURE_ARGS --target=$TARGETS --experimental-targets=WebAssembly
 
 ENV SCRIPT python2.7 ../x.py test --target $TARGETS
 
diff --git a/src/ci/docker/scripts/emscripten.sh b/src/ci/docker/scripts/emscripten.sh
index 8aa5a98d7fc5..516ef0ae0d27 100644
--- a/src/ci/docker/scripts/emscripten.sh
+++ b/src/ci/docker/scripts/emscripten.sh
@@ -40,9 +40,12 @@ hide_output ./emsdk install sdk-1.37.13-64bit
 source ./emsdk_env.sh
 echo "main(){}" > a.c
 HOME=/emsdk-portable/ emcc a.c
-HOME=/emsdk-portable/ emcc -s BINARYEN=1 a.c
+HOME=/emsdk-portable/ emcc -s WASM=1 a.c
 rm -f a.*
 
+# Make emscripten use Rust's LLVM
+echo "LLVM_ROOT='/checkout/obj/build/x86_64-unknown-linux-gnu/llvm/bin'" >> /root/.emscripten
+
 # Make emsdk usable by any user
 cp /root/.emscripten /emsdk-portable
 chmod a+rxw -R /emsdk-portable
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 01419c425707..3b3a94c6c582 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1280,6 +1280,12 @@ fn compose_and_run_compiler(&self, args: ProcArgs, input: Option<String>) -> Pro
         let extra_link_args = vec!["-L".to_owned(),
                                    aux_dir.to_str().unwrap().to_owned()];
 
+        let mut env = self.props.rustc_env.clone();
+        // Tell emscripten to link using libc produced with LLVM backend
+        if self.config.target.contains("wasm32") && self.config.target.contains("experimental") {
+            env.push(("EMCC_WASM_BACKEND".to_string(), "1".to_string()));
+        }
+
         for rel_ab in &self.props.aux_builds {
             let aux_testpaths = self.compute_aux_test_paths(rel_ab);
             let aux_props = self.props.from_aux_file(&aux_testpaths.file,
@@ -1319,7 +1325,7 @@ fn compose_and_run_compiler(&self, args: ProcArgs, input: Option<String>) -> Pro
             };
             let aux_args = aux_cx.make_compile_args(crate_type, &aux_testpaths.file, aux_output);
             let auxres = aux_cx.compose_and_run(aux_args,
-                                                Vec::new(),
+                                                env.clone(),
                                                 aux_cx.config.compile_lib_path.to_str().unwrap(),
                                                 Some(aux_dir.to_str().unwrap()),
                                                 None);
@@ -1332,13 +1338,12 @@ fn compose_and_run_compiler(&self, args: ProcArgs, input: Option<String>) -> Pro
         }
 
         self.compose_and_run(args,
-                             self.props.rustc_env.clone(),
+                             env,
                              self.config.compile_lib_path.to_str().unwrap(),
                              Some(aux_dir.to_str().unwrap()),
                              input)
     }
 
-
     fn compose_and_run(&self,
                        ProcArgs{ args, prog }: ProcArgs,
                        procenv: Vec<(String, String)> ,