Index: flang/test/CMakeLists.txt
===================================================================
--- flang/test/CMakeLists.txt
+++ flang/test/CMakeLists.txt
@@ -100,3 +100,10 @@
     PARAMS ${FLANG_TEST_PARAMS}
     DEPENDS ${FLANG_TEST_DEPENDS})
 endif()
+
+# To modify the default target triple for flang tests.
+if (DEFINED FLANG_TEST_TARGET_TRIPLE)
+  if (NOT DEFINED LLVM_TARGET_TRIPLE_ENV OR LLVM_TARGET_TRIPLE_ENV STREQUAL "")
+    set(LLVM_TARGET_TRIPLE_ENV "FLANG_TEST_TARGET_TRIPLE")
+  endif()
+endif()
Index: flang/test/lit.cfg.py
===================================================================
--- flang/test/lit.cfg.py
+++ flang/test/lit.cfg.py
@@ -45,6 +45,11 @@
 for arch in config.targets_to_build.split():
     config.available_features.add(arch.lower() + '-registered-target')
 
+# To modify the default target triple for flang tests.
+if config.flang_test_triple:
+    config.target_triple = config.flang_test_triple
+    config.environment[config.llvm_target_triple_env] = config.flang_test_triple
+
 # excludes: A list of directories to exclude from the testsuite. The 'Inputs'
 # subdirectories contain auxiliary inputs for various tests in their parent
 # directories.
Index: flang/test/lit.site.cfg.py.in
===================================================================
--- flang/test/lit.site.cfg.py.in
+++ flang/test/lit.site.cfg.py.in
@@ -5,6 +5,7 @@
 config.llvm_tools_dir = lit_config.substitute("@LLVM_TOOLS_DIR@")
 config.llvm_shlib_dir = lit_config.substitute(path(r"@SHLIBDIR@"))
 config.llvm_plugin_ext = "@LLVM_PLUGIN_EXT@"
+config.llvm_target_triple_env = "@LLVM_TARGET_TRIPLE_ENV@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.errc_messages = "@LLVM_LIT_ERRC_MESSAGES@"
 config.flang_obj_root = "@FLANG_BINARY_DIR@"
@@ -13,6 +14,7 @@
 config.flang_intrinsic_modules_dir = "@FLANG_INTRINSIC_MODULES_DIR@"
 config.flang_llvm_tools_dir = "@CMAKE_BINARY_DIR@/bin"
 config.flang_lib_dir = "@CMAKE_BINARY_DIR@/lib"
+config.flang_test_triple = "@FLANG_TEST_TARGET_TRIPLE@"
 config.flang_examples = @FLANG_BUILD_EXAMPLES@
 config.python_executable = "@PYTHON_EXECUTABLE@"
 config.flang_standalone_build = @FLANG_STANDALONE_BUILD@