diff --git a/tests/d2/CMakeLists.txt b/tests/d2/CMakeLists.txt
index e275a632..733571ff 100644
--- a/tests/d2/CMakeLists.txt
+++ b/tests/d2/CMakeLists.txt
@@ -11,5 +11,17 @@ set(DMD_TEST_MODEL "${model}" CACHE STRING
 
 get_property(ldmd_path TARGET ldmd2 PROPERTY LOCATION)
 
-add_test(NAME dmd-testsuite WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/tests/d2/dmd-testsuite
-    COMMAND make RESULTS_DIR=${CMAKE_BINARY_DIR}/dmd_test_results DMD=${ldmd_path} MODEL=${DMD_TEST_MODEL} quick)
+# Build test suite in both debug and release modes. The DFLAGS environment
+# variable read by LDMD is used because the DMD testsuite build system
+# provides no way to run the test cases with a given set of flags without
+# trying all combinations of them.
+
+add_test(NAME dmd-testsuite-debug
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/tests/d2/dmd-testsuite
+    COMMAND make RESULTS_DIR=${CMAKE_BINARY_DIR}/dmd-testsuite-debug DMD=${ldmd_path} DFLAGS="-gc" MODEL=${DMD_TEST_MODEL} quick
+)
+
+add_test(NAME dmd-testsuite-release
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/tests/d2/dmd-testsuite
+    COMMAND make RESULTS_DIR=${CMAKE_BINARY_DIR}/dmd-testsuite-release DMD=${ldmd_path} DFLAGS=-O3\ -release MODEL=${DMD_TEST_MODEL} quick
+)