diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index 05af54d9a3..8b13789179 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -1,79 +1 @@
-steps:
-  - label: "CUDA Julia v{{matrix.version}}"
-    matrix:
-      setup:
-        version:
-          - "1.10"
-          - "1.11"
-          - "1.12"
-    plugins:
-      - JuliaCI/julia#v1:
-          version: "{{matrix.version}}"
-    agents:
-      queue: "cuda"
-    if: build.message !~ /\[skip tests\]/
-    timeout_in_minutes: 60
-    commands: |
-      echo "--- Setup Julia packages"
-      JULIA_PKG_PRECOMPILE_AUTO="false" julia --color=yes -e '
-          using Pkg
-          pkgs = [PackageSpec(; path) for path in (".", "lib/EnzymeCore", "lib/EnzymeTestUtils")]
-          Pkg.develop(pkgs)
-          Pkg.add(PackageSpec(; name="CUDA", version="6"))' || exit 3
 
-      echo "+++ Run tests"
-      julia --color=yes test/cuda.jl
-    env:
-      JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
-
-#   - label: "AMDGPU Julia v{{matrix.version}}"
-#     matrix:
-#       setup:
-#         version:
-#           - "1.10"
-#     plugins:
-#       - JuliaCI/julia#v1:
-#           version: "{{matrix.version}}"
-#     agents:
-#       queue: "rocm"
-#     if: build.message !~ /\[skip tests\]/
-#     timeout_in_minutes: 60
-#     commands: |
-#       echo "--- Setup Julia packages"
-#       julia --color=yes -e '
-#           using Pkg
-#           pkgs = [PackageSpec(; path) for path in (".", "lib/EnzymeCore", "lib/EnzymeTestUtils")]
-#           push!(pkgs, PackageSpec(; name="AMDGPU"))
-#           Pkg.develop(pkgs)' || exit 3
-# 
-#       echo "+++ Run tests"
-#       julia --color=yes test/amdgpu.jl
-#     env:
-#       JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
-# 
-#   - label: "Metal Julia v{{matrix.version}}"
-#     matrix:
-#       setup:
-#         version:
-#           - "1.10"
-#     plugins:
-#       - JuliaCI/julia#v1:
-#           version: "{{matrix.version}}"
-#     agents:
-#       queue: "juliaecosystem"
-#       os: "macos"
-#       arch: "aarch64"
-#     if: build.message !~ /\[skip tests\]/
-#     timeout_in_minutes: 60
-#     commands: |
-#       echo "--- Setup Julia packages"
-#       julia --color=yes -e '
-#           using Pkg
-#           pkgs = [PackageSpec(; path) for path in (".", "lib/EnzymeCore", "lib/EnzymeTestUtils")]
-#           push!(pkgs, PackageSpec(; name="Metal"))
-#           Pkg.develop(pkgs)' || exit 3
-# 
-#       echo "+++ Run tests"
-#       julia --color=yes test/metal.jl
-#     env:
-#       JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index b3e095e483..ccd594f8cf 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -45,8 +45,6 @@ jobs:
           - '1.12'
           - 'nightly'
         os:
-          - ubuntu-24.04
-          - macOS-latest
           - windows-latest
         llvm_args:
           - ''
@@ -59,44 +57,6 @@ jobs:
           - os: windows-latest
             arch: default
             libEnzyme: local
-        include:
-          - os: ubuntu-24.04
-            arch: x86
-            libEnzyme: packaged
-            version: '1.10'
-            assertions: false
-          - os: ubuntu-24.04
-            arch: default
-            libEnzyme: packaged
-            version: '1.10'
-            assertions: true
-          - os: ubuntu-24.04
-            arch: default
-            libEnzyme: packaged
-            version: '1.11'
-            assertions: true
-          - os: ubuntu-24.04
-            arch: default
-            libEnzyme: packaged
-            version: '1.12'
-            assertions: true
-          - os: ubuntu-24.04
-            arch: default
-            libEnzyme: packaged
-            version: '1.13'
-            assertions: true
-          - os: ubuntu-24.04
-            arch: default
-            libEnzyme: packaged
-            version: '1.10'
-            assertions: true
-            llvm_args: '--opaque-pointers'
-          - os: ubuntu-24.04
-            arch: default
-            libEnzyme: packaged
-            version: '1.11'
-            assertions: false
-            llvm_args: '--opaque-pointers'
     steps:
       - uses: actions/checkout@v7
       - uses: julia-actions/setup-julia@v3
@@ -177,115 +137,3 @@ jobs:
           files: lcov.info
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: false  # or true if you want CI to fail when Codecov fails
-
-  enzymetestutils:
-    timeout-minutes: 60
-    name: EnzymeTestUtils - Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ matrix.libEnzyme }} libEnzyme - ${{ github.event_name }}
-    runs-on: ${{ matrix.os }}
-    continue-on-error: ${{ matrix.version == 'nightly' }}
-    env:
-      JULIA_PROJECT: "lib/EnzymeTestUtils"
-    strategy:
-      fail-fast: false
-      matrix:
-        version:
-          - '1.10'
-          - '1.11'
-          - '1.12'
-          - 'nightly'
-        os:
-          - ubuntu-latest
-        arch:
-          - default
-        libEnzyme: [packaged]
-    steps:
-      - uses: actions/checkout@v7
-      - uses: julia-actions/setup-julia@v3
-        with:
-          version: ${{ matrix.version }}
-          arch: ${{ matrix.arch }}
-      - uses: julia-actions/cache@v3
-      - name: setup EnzymeTestUtils
-        shell: julia --color=yes {0}
-        id: setup_testutils
-        continue-on-error: ${{ matrix.version == 'nightly' }}
-        run: |
-          using Pkg
-          Pkg.develop([PackageSpec(; path) for path in (".", "lib/EnzymeCore")])
-          Pkg.instantiate()
-        env:
-          JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
-      - name: Run the tests
-        if: matrix.version != 'nightly' || steps.setup_testutils.outcome == 'success'
-        continue-on-error: ${{ matrix.version == 'nightly' }}
-        id: run_tests
-        shell: julia --color=yes {0}
-        run: |
-          using Pkg
-          Pkg.test("EnzymeTestUtils"; coverage=true)
-      - uses: julia-actions/julia-processcoverage@v1
-        if: matrix.version != 'nightly' || steps.run_tests.outcome == 'success'
-        with:
-          directories: lib/EnzymeTestUtils/src
-      - uses: codecov/codecov-action@v7
-        if: matrix.version != 'nightly' || steps.run_tests.outcome == 'success'
-        with:
-          files: lcov.info
-          token: ${{ secrets.CODECOV_TOKEN }}
-          fail_ci_if_error: false  # or true if you want CI to fail when Codecov fails
-
-  enzymecore:
-    timeout-minutes: 20
-    name: EnzymeCore - Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ matrix.libEnzyme }} libEnzyme - ${{ github.event_name }}
-    runs-on: ${{ matrix.os }}
-    continue-on-error: ${{ matrix.version == 'nightly' }}
-    env:
-      JULIA_PROJECT: "lib/EnzymeCore"
-    strategy:
-      fail-fast: false
-      matrix:
-        version:
-          - '1.10'
-          - '1.11'
-          - '1.12'
-          - 'nightly'
-        os:
-          - ubuntu-latest
-        arch:
-          - default
-        libEnzyme: [packaged]
-    steps:
-      - uses: actions/checkout@v7
-      - uses: julia-actions/setup-julia@v3
-        with:
-          version: ${{ matrix.version }}
-          arch: ${{ matrix.arch }}
-      - uses: julia-actions/cache@v3
-      - name: setup EnzymeCore
-        shell: julia --color=yes {0}
-        id: setup_testutils
-        continue-on-error: ${{ matrix.version == 'nightly' }}
-        run: |
-          using Pkg
-          Pkg.develop([PackageSpec(; path) for path in (".",)])
-          Pkg.instantiate()
-        env:
-          JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
-      - name: Run the tests
-        if: matrix.version != 'nightly' || steps.setup_testutils.outcome == 'success'
-        continue-on-error: ${{ matrix.version == 'nightly' }}
-        id: run_tests
-        shell: julia --color=yes {0}
-        run: |
-          using Pkg
-          Pkg.test("EnzymeCore"; coverage=true)
-      - uses: julia-actions/julia-processcoverage@v1
-        if: matrix.version != 'nightly' || steps.run_tests.outcome == 'success'
-        with:
-          directories: lib/EnzymeCore/src
-      - uses: codecov/codecov-action@v7
-        if: matrix.version != 'nightly' || steps.run_tests.outcome == 'success'
-        with:
-          files: lcov.info
-          token: ${{ secrets.CODECOV_TOKEN }}
-          fail_ci_if_error: false  # or true if you want CI to fail when Codecov fails
diff --git a/src/utils.jl b/src/utils.jl
index bb12d3dc5d..933d6ce3d2 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -8,8 +8,11 @@
 function unsafe_to_pointer end
 export unsafe_to_pointer
 
+const compiler_roots = Dict{Ptr{Cvoid}, Any}()
+const compiler_roots_lock = ReentrantLock()
+
 if VERSION >= v"1.12-"
-    @inline function unsafe_to_pointer(@nospecialize(val::Type))
+    @inline function _unsafe_to_pointer(@nospecialize(val::Type))
         return Core.Intrinsics.llvmcall((
             """
             declare nonnull ptr @julia.pointer_from_objref(ptr addrspace(11))
@@ -22,7 +25,7 @@ if VERSION >= v"1.12-"
             """, "f"), Ptr{Cvoid}, Tuple{Any}, val)
     end
 elseif Int == Int64
-    @inline function unsafe_to_pointer(@nospecialize(val::Type))
+    @inline function _unsafe_to_pointer(@nospecialize(val::Type))
         return Base.llvmcall((
             """
             declare nonnull {}* @julia.pointer_from_objref({} addrspace(11)*)
@@ -36,7 +39,7 @@ elseif Int == Int64
             """, "f"), Ptr{Cvoid}, Tuple{Any}, val)
     end
 else
-    @inline function unsafe_to_pointer(@nospecialize(val::Type))
+    @inline function _unsafe_to_pointer(@nospecialize(val::Type))
         return Base.llvmcall((
             """
             declare nonnull {}* @julia.pointer_from_objref({} addrspace(11)*)
@@ -51,6 +54,14 @@ else
     end
 end
 
+function unsafe_to_pointer(@nospecialize(val::Type))
+    ptr = _unsafe_to_pointer(val)
+    lock(compiler_roots_lock) do
+        compiler_roots[ptr] = val
+    end
+    return ptr
+end
+
 
 @inline is_concrete_tuple(x::Type{T2}) where {T2} =
     (T2 <: Tuple) && !(T2 === Tuple) && !(T2 isa UnionAll)
diff --git a/test/runtests.jl b/test/runtests.jl
index 31dcf8b65b..10920de6b7 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,42 +1,18 @@
-import Enzyme
-import Enzyme_jll
-using ParallelTestRunner: addworker, filter_tests!, find_tests, parse_args, runtests
+using Enzyme
+using Test
 
-# Start with autodiscovered tests
-testsuite = find_tests(@__DIR__)
-# Add threads tests to be run with multiple Julia threads (will be configured in
-# `test_worker`).
-testsuite["threads/2"] = :(include($(joinpath(@__DIR__, "threads.jl"))))
-# Exclude integration tests, they're handled differently (they each run in their
-# own environment)
-for (k, _) in testsuite
-    startswith(k, "integration/") && delete!(testsuite, k)
-end
-
-# Parse arguments
-args = parse_args(ARGS)
-
-if filter_tests!(testsuite, args)
-    # Skip GPU-specific tests by default.
-    delete!(testsuite, "metal")
-    delete!(testsuite, "cuda")
-    delete!(testsuite, "amdgpu")
-    delete!(testsuite, "common")
+Enzyme.API.printall!(true)
+Enzyme.Compiler.DumpPostOpt[] = true
 
-    # Skipped until https://github.com/EnzymeAD/Enzyme.jl/issues/2620 is fixed.
-    if Sys.iswindows()
-        delete!(testsuite, "ext/specialfunctions")
-    end
-end
+@testset "BigFloat arithmetic" begin
+    a = BigFloat(1.234)
+    da = BigFloat(-0.23)
+    b = BigFloat(0.56)
+    db = BigFloat(0.27)
+    af64 = 1.234 # for testing mixed methods
+    daf64 = -0.23 # for testing mixed methods
+    bf64 = 0.56 # for testing mixed methods
+    dbf64 = 0.27 # for testing mixed methods
 
-function test_worker(name)
-    if name == "threads/2"
-        # Run the `threads/2` testset, with multiple threads.
-        return addworker(; exeflags = ["--threads=2"])
-    end
+    @test autodiff(Enzyme.Forward, +, Duplicated, Duplicated(a, da), Duplicated(b, db))[:1] ≈ da+db 
 end
-
-const init_code = quote end
-
-@info "Testing against" Enzyme_jll.libEnzyme
-runtests(Enzyme, args; testsuite, init_code, test_worker)
diff --git a/test/test_isolated.jl b/test/test_isolated.jl
new file mode 100644
index 0000000000..571c02b927
--- /dev/null
+++ b/test/test_isolated.jl
@@ -0,0 +1,47 @@
+using Enzyme, LinearAlgebra, Test
+
+function run_test()
+    T = UpperTriangular
+    TE = ComplexF64
+    sizeB = (3,)
+    n = sizeB[1]
+    M = rand(TE, n, n)
+    B = rand(TE, sizeB...)
+    Y = zeros(TE, sizeB...)
+    A = T(M)
+    _A = T(A)
+    f!(Y, A, B, ::T) where {T} = ldiv!(Y, T(A), B)
+    
+    dY = (zeros(TE, sizeB...), zeros(TE, sizeB...))
+    dM = (zeros(TE, n, n), zeros(TE, n, n))
+    
+    activities = (
+        Const(f!),
+        BatchDuplicated(Y, dY),
+        BatchDuplicated(M, dM),
+        Const(B),
+        Const(_A)
+    )
+    
+    forward, reverse = autodiff_thunk(
+        ReverseSplitWithPrimal,
+        Const{typeof(f!)},
+        BatchDuplicated, # return activity
+        map(typeof, Base.tail(activities))... # argument activities
+    )
+    
+    println("Running targeted thunk forward...")
+    tape, y_ad, shadow_result = forward(Const(f!), Base.tail(activities)...)
+    
+    ȳ = (ones(TE, sizeB...), ones(TE, sizeB...))
+    for (sr, dy) in zip(shadow_result, ȳ)
+        copyto!(sr, dy)
+    end
+    
+    println("Running targeted thunk reverse...")
+    reverse(Const(f!), Base.tail(activities)..., tape)
+end
+
+@testset "Isolated custom test" begin
+    run_test()
+end