diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 000000000000..26b26e3f8410
--- /dev/null
+++ b/.github/workflows/release.yml
@@ -0,0 +1,112 @@
+name: CI with sysroot compiled in release mode
+
+on:
+  - push
+  - pull_request
+
+permissions:
+  contents: read
+
+env:
+  # Enable backtraces for easier debugging
+  RUST_BACKTRACE: 1
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        libgccjit_version:
+          - { gcc: "libgccjit.so", artifacts_branch: "master" }
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - uses: actions/checkout@v2
+      with:
+        repository: llvm/llvm-project
+        path: llvm
+
+    - name: Install packages
+      run: sudo apt-get install ninja-build ripgrep
+
+    - name: Download artifact
+      uses: dawidd6/action-download-artifact@v2
+      with:
+          workflow: main.yml
+          name: ${{ matrix.libgccjit_version.gcc }}
+          path: gcc-build
+          repo: antoyo/gcc
+          branch: ${{ matrix.libgccjit_version.artifacts_branch }}
+          event: push
+          search_artifacts: true # Because, instead, the action only check the last job ran and that won't work since we want multiple artifacts.
+
+    - name: Setup path to libgccjit
+      run: |
+          echo $(readlink -f gcc-build) > gcc_path
+          # NOTE: the filename is still libgccjit.so even when the artifact name is different.
+          ln gcc-build/libgccjit.so gcc-build/libgccjit.so.0
+
+    - name: Set env
+      run: |
+        echo "LIBRARY_PATH=$(cat gcc_path)" >> $GITHUB_ENV
+        echo "LD_LIBRARY_PATH=$(cat gcc_path)" >> $GITHUB_ENV
+        echo "workspace="$GITHUB_WORKSPACE >> $GITHUB_ENV
+
+    - name: Set RUST_COMPILER_RT_ROOT
+      run: echo "RUST_COMPILER_RT_ROOT="${{ env.workspace }}/llvm/compiler-rt >> $GITHUB_ENV
+
+    # https://github.com/actions/cache/issues/133
+    - name: Fixup owner of ~/.cargo/
+      # Don't remove the trailing /. It is necessary to follow the symlink.
+      run: sudo chown -R $(whoami):$(id -ng) ~/.cargo/
+
+    - name: Cache cargo installed crates
+      uses: actions/cache@v1.1.2
+      with:
+        path: ~/.cargo/bin
+        key: cargo-installed-crates2-ubuntu-latest
+
+    - name: Cache cargo registry
+      uses: actions/cache@v1
+      with:
+        path: ~/.cargo/registry
+        key: ${{ runner.os }}-cargo-registry2-${{ hashFiles('**/Cargo.lock') }}
+
+    - name: Cache cargo index
+      uses: actions/cache@v1
+      with:
+        path: ~/.cargo/git
+        key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
+
+    - name: Cache cargo target dir
+      uses: actions/cache@v1.1.2
+      with:
+        path: target
+        key: ${{ runner.os }}-cargo-build-target-${{ hashFiles('rust-toolchain') }}
+
+    - name: Build
+      run: |
+        ./prepare_build.sh
+        ./build.sh --release --release-sysroot
+        cargo test
+        ./clean_all.sh
+
+    - name: Prepare dependencies
+      run: |
+        git config --global user.email "user@example.com"
+        git config --global user.name "User"
+        ./prepare.sh
+
+    # Compile is a separate step, as the actions-rs/cargo action supports error annotations
+    - name: Compile
+      uses: actions-rs/cargo@v1.0.3
+      with:
+        command: build
+        args: --release
+
+    - name: Run tests
+      run: |
+        ./test.sh --release --clean --release-sysroot --build-sysroot --mini-tests --std-tests # --test-libcore # FIXME(antoyo): libcore tests fail.
diff --git a/src/back/write.rs b/src/back/write.rs
index efcf18d31eb0..5f54ac4ebc69 100644
--- a/src/back/write.rs
+++ b/src/back/write.rs
@@ -57,6 +57,7 @@ pub(crate) unsafe fn codegen(cgcx: &CodegenContext<GccCodegenBackend>, _diag_han
                 if env::var("CG_GCCJIT_DUMP_TO_FILE").as_deref() == Ok("1") {
                     let _ = fs::create_dir("/tmp/gccjit_dumps");
                     let path = &format!("/tmp/gccjit_dumps/{}.c", module.name);
+                    context.set_debug_info(true);
                     context.dump_to_file(path, true);
                 }
                 context.compile_to_file(OutputKind::ObjectFile, obj_out.to_str().expect("path to str"));
diff --git a/src/base.rs b/src/base.rs
index 8cc9581e842c..b60382496c2a 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -126,6 +126,9 @@ pub fn compile_codegen_unit<'tcx>(tcx: TyCtxt<'tcx>, cgu_name: Symbol, supports_
             context.add_command_line_option("-fdata-sections");
         }
 
+        if env::var("CG_GCCJIT_DUMP_TREE_ALL").as_deref() == Ok("1") {
+            context.add_command_line_option("-fdump-tree-all");
+        }
         if env::var("CG_GCCJIT_DUMP_CODE").as_deref() == Ok("1") {
             context.set_dump_code_on_compile(true);
         }
diff --git a/src/builder.rs b/src/builder.rs
index 95080e024fc9..f0582fdcef2d 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -858,26 +858,31 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
     }
 
     fn gep(&mut self, _typ: Type<'gcc>, ptr: RValue<'gcc>, indices: &[RValue<'gcc>]) -> RValue<'gcc> {
-        let mut result = ptr;
+        let ptr_type = ptr.get_type();
+        let mut pointee_type = ptr.get_type();
+        // NOTE: we cannot use array indexing here like in inbounds_gep because array indexing is
+        // always considered in bounds in GCC (TODO(antoyo): to be verified).
+        // So, we have to cast to a number.
+        let mut result = self.context.new_bitcast(None, ptr, self.sizet_type);
+        // FIXME(antoyo): if there were more than 1 index, this code is probably wrong and would
+        // require dereferencing the pointer.
         for index in indices {
-            result = self.context.new_array_access(None, result, *index).get_address(None).to_rvalue();
+            pointee_type = pointee_type.get_pointee().expect("pointee type");
+            let pointee_size = self.context.new_rvalue_from_int(index.get_type(), pointee_type.get_size() as i32);
+            result = result + self.gcc_int_cast(*index * pointee_size, self.sizet_type);
         }
-        result
+        self.context.new_bitcast(None, result, ptr_type)
     }
 
     fn inbounds_gep(&mut self, _typ: Type<'gcc>, ptr: RValue<'gcc>, indices: &[RValue<'gcc>]) -> RValue<'gcc> {
-        // FIXME(antoyo): would be safer if doing the same thing (loop) as gep.
-        // TODO(antoyo): specify inbounds somehow.
-        match indices.len() {
-            1 => {
-                self.context.new_array_access(None, ptr, indices[0]).get_address(None)
-            },
-            2 => {
-                let array = ptr.dereference(None); // TODO(antoyo): assert that first index is 0?
-                self.context.new_array_access(None, array, indices[1]).get_address(None)
-            },
-            _ => unimplemented!(),
+        // NOTE: array indexing is always considered in bounds in GCC (TODO(antoyo): to be verified).
+        let mut indices = indices.into_iter();
+        let index = indices.next().expect("first index in inbounds_gep");
+        let mut result = self.context.new_array_access(None, ptr, *index);
+        for index in indices {
+            result = self.context.new_array_access(None, result, *index);
         }
+        result.get_address(None)
     }
 
     fn struct_gep(&mut self, value_type: Type<'gcc>, ptr: RValue<'gcc>, idx: u64) -> RValue<'gcc> {
diff --git a/src/int.rs b/src/int.rs
index 0c5dab004668..0cf1204791d3 100644
--- a/src/int.rs
+++ b/src/int.rs
@@ -389,18 +389,22 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
                 };
             self.context.new_comparison(None, op, cmp, self.context.new_rvalue_from_int(self.int_type, limit))
         }
+        else if a_type.get_pointee().is_some() && b_type.get_pointee().is_some() {
+            // NOTE: gcc cannot compare pointers to different objects, but rustc does that, so cast them to usize.
+            lhs = self.context.new_bitcast(None, lhs, self.usize_type);
+            rhs = self.context.new_bitcast(None, rhs, self.usize_type);
+            self.context.new_comparison(None, op.to_gcc_comparison(), lhs, rhs)
+        }
         else {
-            let left_type = lhs.get_type();
-            let right_type = rhs.get_type();
-            if left_type != right_type {
+            if a_type != b_type {
                 // NOTE: because libgccjit cannot compare function pointers.
-                if left_type.dyncast_function_ptr_type().is_some() && right_type.dyncast_function_ptr_type().is_some() {
+                if a_type.dyncast_function_ptr_type().is_some() && b_type.dyncast_function_ptr_type().is_some() {
                     lhs = self.context.new_cast(None, lhs, self.usize_type.make_pointer());
                     rhs = self.context.new_cast(None, rhs, self.usize_type.make_pointer());
                 }
                 // NOTE: hack because we try to cast a vector type to the same vector type.
-                else if format!("{:?}", left_type) != format!("{:?}", right_type) {
-                    rhs = self.context.new_cast(None, rhs, left_type);
+                else if format!("{:?}", a_type) != format!("{:?}", b_type) {
+                    rhs = self.context.new_cast(None, rhs, a_type);
                 }
             }
             self.context.new_comparison(None, op.to_gcc_comparison(), lhs, rhs)
diff --git a/test.sh b/test.sh
index 2bdf362ab40d..4841922416c7 100755
--- a/test.sh
+++ b/test.sh
@@ -44,7 +44,7 @@ while [[ $# -gt 0 ]]; do
             shift
             ;;
         "--test-rustc")
-            funcs=(test_rustc)
+            funcs+=(test_rustc)
             shift
             ;;
         "--test-successful-rustc")