diff --git a/.github/workflows/fortran.yml b/.github/workflows/fortran.yml
index 01aa62ae1ea..0e7762eb398 100644
--- a/.github/workflows/fortran.yml
+++ b/.github/workflows/fortran.yml
@@ -36,68 +36,78 @@ concurrency:
   cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 
 jobs:
-  build-and-test-fortran:
-    name: Fortran ${{matrix.build}} ${{matrix.os}} ${{matrix.compiler}} ${{matrix.version}} llvm ${{matrix.llvm}}
+  build-and-test-fortran-flang:
+    name: Fortran ${{matrix.build}} ${{matrix.os}} ${{matrix.compiler}} ${{matrix.llvm}}
     runs-on: ${{matrix.os}}
     strategy:
       fail-fast: false
       matrix:
         build: [Release, Debug]
         os: [ubuntu-22.04]
-        compiler: [flang, ifx]
-        llvm: [15, 16, 17]
+        compiler: [flang]
+        llvm: [21]
         mpi: [2021.7.1]
-        include:
-          - compiler: flang
-            FC: flang-21
-            llvm: 21
-            version: 21
-          - compiler: ifx
-            FC: ifx
-            llvm: 15
-            version: 2023.0.0
-          - compiler: ifx
-            FC: ifx
-            llvm: 16
-            version: 2023.1.0
-          - compiler: ifx
-            FC: ifx
-            llvm: 17
-            version: 2023.2.4
     timeout-minutes: 60
     steps:
-    - name: add llvm without clang and flang
-      if: ${{ matrix.compiler == 'ifx' }}
+    - name: add llvm with clang and flang
       run: |
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key|sudo apt-key add -
         sudo apt-add-repository "deb http://apt.llvm.org/`lsb_release -c | cut -f2`/ llvm-toolchain-`lsb_release -c | cut -f2`-${{ matrix.llvm }} main"
-        sudo apt-get update && sudo apt-get install -y cmake gcc g++ llvm-${{ matrix.llvm }}-dev ninja-build pip
+        sudo apt-get update && sudo apt-get install -y cmake gcc g++ llvm-${{ matrix.llvm }}-dev ninja-build pip clang-${{ matrix.llvm }} flang-${{ matrix.llvm }}
         sudo python3 -m pip install --upgrade pip lit
-    - name: add llvm with clang and flang
-      if: ${{ matrix.compiler != 'ifx' }}
+    - uses: actions/checkout@v4
+    - name: generate build system
+      run: |
+        rm -rf build && mkdir build && cd build
+        cmake ../enzyme -GNinja -DCMAKE_BUILD_TYPE=${{ matrix.build }} -DLLVM_DIR=/usr/lib/llvm-${{ matrix.llvm }}/lib/cmake/llvm -DLLVM_EXTERNAL_LIT=`which lit` -DENZYME_FORTRAN=ON -DCMAKE_Fortran_COMPILER=${{ matrix.compiler }}-${{ matrix.llvm }}
+    - name: build enzyme
+      working-directory: 'build'
+      run: ninja LLVMEnzyme-${{ matrix.llvm }}
+    - name: run Fortran tests
+      working-directory: 'build'
+      run: ninja check-enzyme-fortran
+  build-and-test-fortran-ifx:
+    name: Fortran ${{matrix.build}} ${{matrix.os}} ${{matrix.compiler}} ${{matrix.versions.ifx}} llvm ${{matrix.versions.llvm}}
+    runs-on: ${{matrix.os}}
+    strategy:
+      fail-fast: false
+      matrix:
+        build: [Release, Debug]
+        os: [ubuntu-22.04]
+        compiler: [ifx]
+        mpi: [2021.7.1]
+        versions:
+          - llvm: 15
+            ifx: 2023.0.0
+          - llvm: 16
+            ifx: 2023.1.0
+          - llvm: 17
+            ifx: 2023.2.4
+    timeout-minutes: 60
+    steps:
+    - name: add llvm without clang and flang
       run: |
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key|sudo apt-key add -
-        sudo apt-add-repository "deb http://apt.llvm.org/`lsb_release -c | cut -f2`/ llvm-toolchain-`lsb_release -c | cut -f2`-${{ matrix.llvm }} main"
-        sudo apt-get update && sudo apt-get install -y cmake gcc g++ llvm-${{ matrix.llvm }}-dev ninja-build pip clang-${{ matrix.version }} flang-${{ matrix.version }}
+        sudo apt-add-repository "deb http://apt.llvm.org/`lsb_release -c | cut -f2`/ llvm-toolchain-`lsb_release -c | cut -f2`-${{ matrix.versions.llvm }} main"
+        sudo apt-get update && sudo apt-get install -y cmake gcc g++ llvm-${{ matrix.versions.llvm }}-dev ninja-build pip
         sudo python3 -m pip install --upgrade pip lit
     - name: add intel tools
-      if: ${{ matrix.compiler == 'ifx' }}
       run: |
         wget https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
         sudo apt-key add GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
         rm GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
         sudo echo "deb https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
-        sudo apt-get update && sudo apt-get install -y intel-oneapi-compiler-fortran-${{ matrix.version }} intel-oneapi-mpi-${{ matrix.mpi }} intel-oneapi-mpi-devel-${{ matrix.mpi }}
+        sudo apt-get update && sudo apt-get install -y intel-oneapi-compiler-fortran-${{ matrix.versions.ifx }} intel-oneapi-mpi-${{ matrix.mpi }} intel-oneapi-mpi-devel-${{ matrix.mpi }}
         source /opt/intel/oneapi/setvars.sh
         printenv >> $GITHUB_ENV
     - uses: actions/checkout@v4
     - name: generate build system
       run: |
         rm -rf build && mkdir build && cd build
-        cmake ../enzyme -GNinja -DCMAKE_BUILD_TYPE=${{ matrix.build }} -DLLVM_DIR=/usr/lib/llvm-${{ matrix.llvm }}/lib/cmake/llvm -DLLVM_EXTERNAL_LIT=`which lit` -DENZYME_FORTRAN=ON -DCMAKE_Fortran_COMPILER=${{ matrix.FC }}
+        cmake ../enzyme -GNinja -DCMAKE_BUILD_TYPE=${{ matrix.build }} -DLLVM_DIR=/usr/lib/llvm-${{ matrix.versions.llvm }}/lib/cmake/llvm -DLLVM_EXTERNAL_LIT=`which lit` -DENZYME_FORTRAN=ON -DCMAKE_Fortran_COMPILER=${{ matrix.compiler }}
     - name: build enzyme
       working-directory: 'build'
-      run: ninja LLVMEnzyme-${{ matrix.llvm }}
+      run: ninja LLVMEnzyme-${{ matrix.versions.llvm }}
     - name: run Fortran tests
       working-directory: 'build'
       run: ninja check-enzyme-fortran
diff --git a/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_bindings.f90 b/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_bindings.f90
index d929bc58c90..8d538764188 100644
--- a/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_bindings.f90
+++ b/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_bindings.f90
@@ -1,7 +1,7 @@
-! RUN: if [[ %fc != ifx ]]; then %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s; fi
-! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: if [[ %fc != ifx ]]; then %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s; fi
+! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
 
 ! NOTE: This test is only configured to run with the flang compiler at -O0
 !       For it to work with the ifx compiler we will need to figure out how to
diff --git a/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_explicit_interface.f90 b/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_explicit_interface.f90
index 493af6b0e7b..9547ad1e286 100644
--- a/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_explicit_interface.f90
+++ b/enzyme/test/Fortran/ForwardMode/allocatableArraySimple_with_explicit_interface.f90
@@ -1,8 +1,8 @@
 ! REQUIRES: ifx
-! RUN: %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
 
 ! NOTE: This test is only configured to run with the ifx compiler
 !       For it to work with the flang compiler we will need to address
diff --git a/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_bindings.f90 b/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_bindings.f90
index 3c6a61bb0e4..5c7da53c21c 100644
--- a/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_bindings.f90
+++ b/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_bindings.f90
@@ -1,8 +1,8 @@
 ! REQUIRES: fortran
-! RUN: if [[ %fc != ifx ]]; then %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s; fi
-! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: if [[ %fc != ifx ]]; then %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s; fi
+! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
 
 ! NOTE: This test is only configured to run with the flang compiler at -O0
 !       For it to work with the ifx compiler we will need to figure out how to
diff --git a/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_explicit_interface.f90 b/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_explicit_interface.f90
index 60459700e68..d64a898df5f 100644
--- a/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_explicit_interface.f90
+++ b/enzyme/test/Fortran/ReverseMode/allocatableArraySimple_with_explicit_interface.f90
@@ -1,8 +1,8 @@
 ! REQUIRES: ifx
-! RUN: %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
 
 ! NOTE: This test is only configured to run with the ifx compiler
 !       For it to work with the flang compiler we will need to address
diff --git a/enzyme/test/Fortran/ReverseMode/square_with_bindings.f90 b/enzyme/test/Fortran/ReverseMode/square_with_bindings.f90
index 535238cd493..945c6234555 100644
--- a/enzyme/test/Fortran/ReverseMode/square_with_bindings.f90
+++ b/enzyme/test/Fortran/ReverseMode/square_with_bindings.f90
@@ -1,7 +1,7 @@
-! RUN: if [[ %fc != ifx ]]; then %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s; fi
-! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: if [[ %fc != ifx ]]; then %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s; fi
+! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
 
 ! NOTE: This test is only configured to run with the flang compiler at -O0
 !       For it to work with the ifx compiler we will need to figure out how to
diff --git a/enzyme/test/Fortran/ReverseMode/square_with_explicit_interface.f90 b/enzyme/test/Fortran/ReverseMode/square_with_explicit_interface.f90
index 366826d7609..73c08aa8d0e 100644
--- a/enzyme/test/Fortran/ReverseMode/square_with_explicit_interface.f90
+++ b/enzyme/test/Fortran/ReverseMode/square_with_explicit_interface.f90
@@ -1,7 +1,7 @@
-! RUN: %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
-! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O0 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O0 -S -o %t.ll && %fc -flto -O0 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O1 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O1 -S -o %t.ll && %fc -flto -O1 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O2 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O2 -S -o %t.ll && %fc -flto -O2 %t.ll -o %t1 && %t1 | FileCheck %s
+! RUN: %fc -flto -O3 -c %loadFortran %s -o /dev/stdout | %opt %loadEnzyme %enzyme -o /dev/stdout | %opt %oflags -O3 -S -o %t.ll && %fc -flto -O3 %t.ll -o %t1 && %t1 | FileCheck %s
 
 module math
     interface
diff --git a/enzyme/test/lit.site.cfg.py.in b/enzyme/test/lit.site.cfg.py.in
index bb7d494764f..7451af860b5 100644
--- a/enzyme/test/lit.site.cfg.py.in
+++ b/enzyme/test/lit.site.cfg.py.in
@@ -126,6 +126,10 @@ config.substitutions.append(('%fc', config.fc))
 if config.fc == "ifx":
     config.available_features.add('ifx')
 config.substitutions.append(('%loadFortran', '-I@ENZYME_BINARY_DIR@/modules'))
+# LLVM 16 defaults to opaque pointer mode; IFX versions paired with LLVM 16
+# (e.g. ifx 2023.1.0) use an older LLVM backend that cannot parse `ptr`-typed IR.
+# Pass -opaque-pointers=0 to keep typed-pointer IR when optimising after Enzyme.
+config.substitutions.append(('%oflags', ('-opaque-pointers=0' if int(config.llvm_ver) == 16 else '')))
 
 # Let the main config do the real work.
 cfgfile = "@ENZYME_SOURCE_DIR@/test/lit.cfg.py"