Reland "[test-suite] Disable Fortran FM509 test when -std=legacy is not supported""

This reverts commit aa1e969.

We are now using the standard method to do this, which should not
change how any other tests behave. I mistakenly believed that this
feature was broken when the change from macro to function was made.

Author: DavidSpickett

Fortran/UnitTests/fcvs21_f95/CMakeLists.txt

@@ -33,11 +33,17 @@
 # clean-up fort.* files otherwise one of the tests will fail
 llvm_test_prepare(rm -f %S/fort.*)
 
-# Test 509 requires this flag in more recent versions of GCC
+file(GLOB Source CONFIGURE_DEPENDS *.f)
+
+# Test 509 requires this flag in more recent versions of GCC.
+# If this flag is not supported, the test should be excluded.
 check_fortran_compiler_flag("-std=legacy" SUPPORTS_LEGACY)
 if (SUPPORTS_LEGACY)
   add_compile_options(-std=legacy)
-endif ()
+else()
+  # Regex because the GLOB returns the full path to each file
+  list(FILTER Source EXCLUDE REGEX "FM509\.f$")
+endif()
 
 set(FP_TOLERANCE 1.0e-11) # set by the most sensitive numerical test
 llvm_singlesource()

cmake/modules/SingleMultiSource.cmake

@@ -14,9 +14,9 @@
 #
 # llvm_singlesource([PREFIX p])
 #
-#   Invokes llvm_test_executable() for each c/c++ source file.  If
-#   'sources is emptyno sources are specified, creates test executables
-#   for all C/C++ files in current directory.
+#   Invokes llvm_test_executable() for each C/C++/Fortran source file. If
+#   'sources is empty no sources are specified, creates test executables
+#   for all source files in the current directory.
 #   Passes optional PREFIX parameter to llvm_test_executable().
 #
 # llvm_multisource(target)
@@ -27,7 +27,7 @@
 include(TestSuite)
 
 # Configure the current directory as a SingleSource subdirectory - i.e. every
-# file in *.{c,cpp,cc} is treated as its own test.
+# C/C++/Fortran file is treated as its own test.
 function(llvm_singlesource)
   cmake_parse_arguments(_LSARG "" "PREFIX" "" ${ARGN})
   if(DEFINED Source)