diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d2b7724a221..1b690e9bf75 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,9 +19,8 @@ jobs:
       fail-fast: false
       matrix:
         libgccjit_version:
-          - { gcc: "libgccjit.so", extra: "", env_extra: "", artifacts_branch: "master" }
-          - { gcc: "libgccjit_without_int128.so", extra: "", env_extra: "", artifacts_branch: "master-without-128bit-integers" }
-          - { gcc: "libgccjit12.so", extra: "--no-default-features", env_extra: "TEST_FLAGS='-Cpanic=abort -Zpanic-abort-tests'", artifacts_branch: "gcc12" }
+          - { gcc: "libgccjit.so", artifacts_branch: "master" }
+          - { gcc: "libgccjit_without_int128.so", artifacts_branch: "master-without-128bit-integers" }
         commands: [
           "--mini-tests",
           "--std-tests",
@@ -48,12 +47,7 @@ jobs:
       # `llvm-14-tools` is needed to install the `FileCheck` binary which is used for asm tests.
       run: sudo apt-get install ninja-build ripgrep llvm-14-tools
 
-    - name: Install libgccjit12
-      if: matrix.libgccjit_version.gcc == 'libgccjit12.so'
-      run: sudo apt-get install libgccjit-12-dev
-
     - name: Download artifact
-      if: matrix.libgccjit_version.gcc != 'libgccjit12.so'
       uses: dawidd6/action-download-artifact@v2
       with:
           workflow: main.yml
@@ -65,11 +59,6 @@ jobs:
           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
-      if: matrix.libgccjit_version.gcc == 'libgccjit12.so'
-      run: echo /usr/lib/gcc/x86_64-linux-gnu/12 > gcc_path
-
-    - name: Setup path to libgccjit
-      if: matrix.libgccjit_version.gcc != 'libgccjit12.so'
       run: |
           echo $(readlink -f gcc-build) > gcc_path
           # NOTE: the filename is still libgccjit.so even when the artifact name is different.
@@ -120,8 +109,8 @@ jobs:
     - name: Build
       run: |
         ./prepare_build.sh
-        ${{ matrix.libgccjit_version.env_extra }} ./build.sh ${{ matrix.libgccjit_version.extra }}
-        ${{ matrix.libgccjit_version.env_extra }} cargo test ${{ matrix.libgccjit_version.extra }}
+        ./build.sh
+        cargo test
         ./clean_all.sh
 
     - name: Prepare dependencies
@@ -137,13 +126,9 @@ jobs:
         command: build
         args: --release
 
-    - name: Add more failing tests for GCC 12
-      if: ${{ matrix.libgccjit_version.gcc == 'libgccjit12.so' }}
-      run: cat failing-ui-tests12.txt >> failing-ui-tests.txt
-
     - name: Run tests
       run: |
-        ${{ matrix.libgccjit_version.env_extra }} ./test.sh --release --clean --build-sysroot ${{ matrix.commands }} ${{ matrix.libgccjit_version.extra }}
+        ./test.sh --release --clean --build-sysroot ${{ matrix.commands }}
 
   duplicates:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/gcc12.yml b/.github/workflows/gcc12.yml
new file mode 100644
index 00000000000..9181785ce7d
--- /dev/null
+++ b/.github/workflows/gcc12.yml
@@ -0,0 +1,127 @@
+name: CI libgccjit 12
+
+on:
+  - push
+  - pull_request
+
+permissions:
+  contents: read
+
+env:
+  # Enable backtraces for easier debugging
+  RUST_BACKTRACE: 1
+  TEST_FLAGS: "-Cpanic=abort -Zpanic-abort-tests"
+
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+
+    strategy:
+      fail-fast: false
+      matrix:
+        commands: [
+          "--mini-tests",
+          "--std-tests",
+          # FIXME: re-enable asm tests when GCC can emit in the right syntax.
+          # "--asm-tests",
+          "--test-libcore",
+          "--extended-rand-tests",
+          "--extended-regex-example-tests",
+          "--extended-regex-tests",
+          "--test-successful-rustc --nb-parts 2 --current-part 0",
+          "--test-successful-rustc --nb-parts 2 --current-part 1",
+          "--test-failing-rustc",
+        ]
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - uses: actions/checkout@v3
+      with:
+        repository: llvm/llvm-project
+        path: llvm
+
+    - name: Install packages
+      # `llvm-14-tools` is needed to install the `FileCheck` binary which is used for asm tests.
+      run: sudo apt-get install ninja-build ripgrep llvm-14-tools
+
+    - name: Install libgccjit12
+      run: sudo apt-get install libgccjit-12-dev
+
+    - name: Setup path to libgccjit
+      run: echo /usr/lib/gcc/x86_64-linux-gnu/12 > gcc_path
+
+    - 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
+
+    - name: Cache cargo installed crates
+      uses: actions/cache@v3
+      with:
+        path: ~/.cargo/bin
+        key: cargo-installed-crates2-ubuntu-latest
+
+    - name: Cache cargo registry
+      uses: actions/cache@v3
+      with:
+        path: ~/.cargo/registry
+        key: ${{ runner.os }}-cargo-registry2-${{ hashFiles('**/Cargo.lock') }}
+
+    - name: Cache cargo index
+      uses: actions/cache@v3
+      with:
+        path: ~/.cargo/git
+        key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
+
+    - name: Cache cargo target dir
+      uses: actions/cache@v3
+      with:
+        path: target
+        key: ${{ runner.os }}-cargo-build-target-${{ hashFiles('rust-toolchain') }}
+
+    #- name: Cache rust repository
+      ## We only clone the rust repository for rustc tests
+      #if: ${{ contains(matrix.commands, 'rustc') }}
+      #uses: actions/cache@v3
+      #id: cache-rust-repository
+      #with:
+        #path: rust
+        #key: ${{ runner.os }}-packages-${{ hashFiles('rust/.git/HEAD') }}
+
+    - name: Build
+      run: |
+        ./prepare_build.sh
+        ./build.sh --no-default-features
+        cargo test --no-default-features
+        ./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: Add more failing tests for GCC 12
+      run: cat failing-ui-tests12.txt >> failing-ui-tests.txt
+
+    - name: Run tests
+      run: |
+        ./test.sh --release --clean --build-sysroot ${{ matrix.commands }} --no-default-features
+
+  duplicates:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - run: python tools/check_intrinsics_duplicates.py
diff --git a/.ignore b/.ignore
new file mode 100644
index 00000000000..96b327623e4
--- /dev/null
+++ b/.ignore
@@ -0,0 +1,7 @@
+!/build_sysroot/sysroot_src
+!/simple-raytracer
+!/regex
+!/rand
+!/test-backend
+!/gcc_path
+!/benchmarks
diff --git a/patches/0022-core-Disable-not-compiling-tests.patch b/patches/0022-core-Disable-not-compiling-tests.patch
index 4db56fa3bd2..4e19e15672f 100644
--- a/patches/0022-core-Disable-not-compiling-tests.patch
+++ b/patches/0022-core-Disable-not-compiling-tests.patch
@@ -20,7 +20,7 @@ index 0000000..46fd999
 +++ b/library/core/tests/Cargo.toml
 @@ -0,0 +1,12 @@
 +[package]
-+name = "core"
++name = "coretests"
 +version = "0.0.0"
 +edition = "2021"
 +
diff --git a/src/type_.rs b/src/type_.rs
index daa661f35c4..6d8e50c3a25 100644
--- a/src/type_.rs
+++ b/src/type_.rs
@@ -200,7 +200,8 @@ impl<'gcc, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         value.get_type()
     }
 
-    fn type_array(&self, ty: Type<'gcc>, len: u64) -> Type<'gcc> {
+    #[cfg_attr(feature="master", allow(unused_mut))]
+    fn type_array(&self, ty: Type<'gcc>, mut len: u64) -> Type<'gcc> {
         // TODO: remove this as well?
         /*if let Some(struct_type) = ty.is_struct() {
             if struct_type.get_field_count() == 0 {
@@ -212,6 +213,12 @@ impl<'gcc, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
             }
         }*/
 
+        // NOTE: see note above. Some other test uses usize::MAX.
+        #[cfg(not(feature="master"))]
+        if len >= i32::MAX as u64 {
+            len = 0;
+        }
+
         self.context.new_array_type(None, ty, len)
     }
 }