diff --git a/deps/CMakeLists.txt b/deps/CMakeLists.txt
index b6b63393..76e3a204 100644
--- a/deps/CMakeLists.txt
+++ b/deps/CMakeLists.txt
@@ -35,6 +35,12 @@ elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "Intel")
 -diag-disable 10121 \
 -assume norealloc_lhs \
 ${CMAKE_Fortran_FLAGS}"
+#-Wp,-P \
+  )
+elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "Flang")
+  set(OPS_DEFAULT_Fortran_FLAGS "\
+-fdefault-integer-8 -fdefault-real-8 \
+${CMAKE_Fortran_FLAGS}"
 #-Wp,-P \
   )
   set(CMAKE_Fortran_DEBUG_FLAGS "\
diff --git a/src/opsinputs/CMakeLists.txt b/src/opsinputs/CMakeLists.txt
index 7f14733e..3da86fe5 100644
--- a/src/opsinputs/CMakeLists.txt
+++ b/src/opsinputs/CMakeLists.txt
@@ -45,6 +45,8 @@ elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "Intel")
   set(FORTRAN_FLAGS_64_BIT_TYPES "-integer-size 64 -real-size 64")
 elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
   set(FORTRAN_FLAGS_64_BIT_TYPES "-double")
+elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "Flang")
+  set(FORTRAN_FLAGS_64_BIT_TYPES "-fdefault-integer-8 -fdefault-real-8")
 endif()
 set_source_files_properties(opsinputs_cxgenerate_mod.F90 PROPERTIES
                             COMPILE_FLAGS "${FORTRAN_FLAGS_64_BIT_TYPES}")