diff --git a/openmp/CMakeLists.txt b/openmp/CMakeLists.txt
index c206386fa6b61..671602c1f8732 100644
--- a/openmp/CMakeLists.txt
+++ b/openmp/CMakeLists.txt
@@ -68,11 +68,9 @@ else()
   endif()
 
   # Check for flang
-  if (NOT MSVC)
-    set(OPENMP_TEST_Fortran_COMPILER ${LLVM_RUNTIME_OUTPUT_INTDIR}/flang)
-  else()
-    set(OPENMP_TEST_Fortran_COMPILER ${LLVM_RUNTIME_OUTPUT_INTDIR}/flang.exe)
-  endif()
+  set(OPENMP_TEST_Fortran_COMPILER ${CMAKE_Fortran_COMPILER} CACHE STRING
+    "FORTRAN compiler to use for testing OpenMP runtime libraries.")
+
 
   # Set fortran test compiler if flang is found
   if (EXISTS "${OPENMP_TEST_Fortran_COMPILER}")
diff --git a/openmp/README.rst b/openmp/README.rst
index 2dfc8630858b8..553dce5647cd7 100644
--- a/openmp/README.rst
+++ b/openmp/README.rst
@@ -119,6 +119,10 @@ Options for all Libraries
   Compiler to use for testing. Defaults to the compiler that was also used for
   building.
 
+**OPENMP_TEST_Fortran_COMPILER** = ``${CMAKE_Fortran_COMPILER}``
+  Compiler to use for testing. Defaults to the compiler that was also used for
+  building.
+
 **OPENMP_TEST_Fortran_COMPILER** = ``${CMAKE_Fortran_COMPILER}``
   Compiler to use for testing. Defaults to the compiler that was also used for
   building. Will default to flang if build is in-tree.
diff --git a/openmp/runtime/test/lit.cfg b/openmp/runtime/test/lit.cfg
index ca32985fe6c48..2f2593622630d 100644
--- a/openmp/runtime/test/lit.cfg
+++ b/openmp/runtime/test/lit.cfg
@@ -39,6 +39,12 @@ config.name = 'libomp'
 # suffixes: A list of file extensions to treat as test files.
 config.suffixes = ['.c', '.cpp']
 
+if config.test_fortran_compiler:
+    lit_config.note("OpenMP Fortran tests enabled")
+    config.suffixes += ['.f90']
+else:
+    lit_config.note("OpenMP Fortran tests disabled")
+
 # test_source_root: The root path where tests are located.
 config.test_source_root = os.path.dirname(__file__)
 
@@ -225,3 +231,13 @@ if config.has_ompt:
         config.substitutions.append(("%no-as-needed-flag", "-Wl,--no-as-needed"))
 else:
     config.substitutions.append(("FileCheck", config.test_filecheck))
+
+tools = [
+    ToolSubst(
+        "%flang",
+        command=config.test_fortran_compiler,
+        unresolved="fatal",
+    ),
+]
+
+llvm_config.add_tool_substitutions(tools, [config.llvm_tools_dir])
diff --git a/openmp/runtime/test/lit.site.cfg.in b/openmp/runtime/test/lit.site.cfg.in
index fc65289e4ce64..cc8b3b252d7d1 100644
--- a/openmp/runtime/test/lit.site.cfg.in
+++ b/openmp/runtime/test/lit.site.cfg.in
@@ -2,6 +2,7 @@
 
 config.test_c_compiler = "@OPENMP_TEST_C_COMPILER@"
 config.test_cxx_compiler = "@OPENMP_TEST_CXX_COMPILER@"
+config.test_fortran_compiler = "@OPENMP_TEST_Fortran_COMPILER@"
 config.test_compiler_features = @OPENMP_TEST_COMPILER_FEATURES@
 config.test_compiler_has_omp_h = @OPENMP_TEST_COMPILER_HAS_OMP_H@
 config.test_filecheck = "@OPENMP_FILECHECK_EXECUTABLE@"
@@ -24,6 +25,7 @@ config.has_omit_frame_pointer_flag = @OPENMP_TEST_COMPILER_HAS_OMIT_FRAME_POINTE
 config.target_arch = "@LIBOMP_ARCH@"
 config.compiler_frontend_variant = "@CMAKE_C_COMPILER_FRONTEND_VARIANT@"
 config.compiler_simulate_id = "@CMAKE_C_SIMULATE_ID@"
+config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
diff --git a/openmp/runtime/test/transform/unroll/heuristic_intdo.f90 b/openmp/runtime/test/transform/unroll/heuristic_intdo.f90
new file mode 100644
index 0000000000000..d0ef938dd3a8f
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/heuristic_intdo.f90
@@ -0,0 +1,26 @@
+! This test checks lowering of OpenMP unroll directive
+
+! RUN: %flang %flags %openmp_flags -fopenmp-version=51 %s -o %t.exe
+! RUN: %t.exe | FileCheck %s --match-full-lines
+
+
+program unroll_heuristic
+  integer :: i
+  print *, 'do'
+
+  !$OMP UNROLL
+  do i=7, 18, 3
+    print '("i=", I0)', i
+  end do
+  !$OMP END UNROLL
+
+  print *, 'done'
+end program
+
+
+! CHECK:      do
+! CHECK-NEXT: i=7
+! CHECK-NEXT: i=10
+! CHECK-NEXT: i=13
+! CHECK-NEXT: i=16
+! CHECK-NEXT: done