[Fortran/UnitTests][NFC] Remove reference to flang-experimental-exec

[tarunprabhu]

Summary

The -flang-experimental-exec flang is no longer needed when configuring the test suite.

[kiranchandramohan]

What about the other occurences of this flag?

gfortran/CMakeLists.txt:# If the test suite was configured by adding -flang-experimental-exec, remove
gfortran/CMakeLists.txt:# NOTE: This should be removed once the -flang-experimental-exec flag is no
gfortran/CMakeLists.txt:string(REPLACE "-flang-experimental-exec" "" TMP_FFLAGS "${CMAKE_Fortran_FLAGS}")
gfortran/CMakeLists.txt:  # NOTE: This should be removed when the -flang-experimental-exec flag is no
gfortran/CMakeLists.txt:  target_link_options(${test_target} PRIVATE -flang-experimental-exec)
gfortran/README.md:As of 18-Apr-2023, the `-flang-experimental-exec` flag may need to be used when
gfortran/README.md:      -DCMAKE_Fortran_FLAGS=-flang-experimental-exec \
gfortran/torture/compile/CMakeLists.txt:  # At some point, the -flang-experimental-exec flag will be removed.
gfortran/torture/compile/CMakeLists.txt:  target_link_options(${Dummy} PUBLIC "-flang-experimental-exec")

[tarunprabhu]

I had incorporated those changes into the other patch which enables the gfortran OpenMP "compile" tests but it just occurred to me that the buildbots will likely have broken so those would need to go in separately anyway. I'll update this patch to get rid of all the references.

[tarunprabhu]

Remove all references to -flang-experimental-exec. The first draft of this patch removed only those references that were not removed by this, but it is probably better to remove everything here because the buildbots are likely to be broken as a result of this change, so fixing this quicker is better.

[luporl]

LGTM. I agree that it's better to commit this quicker, as there are several broken build bots.
E.g.:
https://lab.llvm.org/buildbot/#/builders/176
https://lab.llvm.org/buildbot/#/builders/179
https://lab.llvm.org/buildbot/#/builders/198

Fortran/UnitTests/finalization/README.md

 The test-suite-build directory is created by the user
 and is initially empty until running CMake for the teset-suite.
 To configure, build and run the tests once llvm/flang has been built,
 a command similar to the following can be used from within test-suite-build:
 
 ``` shell
 cmake -DCMAKE_BUILD_TYPE=Release \
   -DCMAKE_Fortran_COMPILER:FILEPATH=/home/users/<you>/llvm-project/build/bin/flang-new \
-  -DCMAKE_Fortran_FLAGS=-flang-experimental-exec \
   -DTEST_SUITE_FORTRAN:BOOL=On \
   -DTEST_SUITE_SUBDIRS=Fortran/UnitTests/finalization \
   ../test-suite
 make -j 4
 ../build/bin/llvm-lit Fortran/UnitTests/finalization
 ```
 
 Summary of Tests

Fortran/gfortran/CMakeLists.txt

 cmake_minimum_required(VERSION 3.24.0)
 
 include(CheckFortranCompilerFlag)
 
 # NOTE: flang does not currently (as of 2023/03/20) support the -w flag. If
 # support for the flag is added, this should be removed.
 remove_definitions(-w)
 
-# If the test suite was configured by adding -flang-experimental-exec, remove
-# that flag from the default compilation flags. It is only needed at link-time
-# anyway, and for that it is explicitly added to those targets that need it.
-#
-# NOTE: This should be removed once the -flang-experimental-exec flag is no
-# longer needed.
-string(REPLACE "-flang-experimental-exec" "" TMP_FFLAGS "${CMAKE_Fortran_FLAGS}")
-set(CMAKE_Fortran_FLAGS "${TMP_FFLAGS}")
-
 # This option is added because as of 2023/03/20, several tests in this
 # directory have been disabled. Some of them exercise unsupported non-standard
 # extensions, others trigger a "not yet implemented" assertion while some cause
 # flang to crash. This option forces all the tests to build and can be used to
 # determine if any of the disabled tests can be enabled.
 option(TEST_SUITE_FORTRAN_FORCE_ALL_TESTS
   "Build and run all gfortran tests, including those in the 'unsupported', 'unimplemented', 'skipped', and 'failing' categories."
   OFF)
foreach(Source ${SOURCES})
     if("${Ext}" STREQUAL ".f03" OR
         "${Ext}" STREQUAL ".F03" OR
         "${Ext}" STREQUAL ".f08" OR
         "${Ext}" STREQUAL ".F08")
       set_source_files_properties(${Source} PROPERTIES LANGUAGE Fortran)
     endif()
   endforeach()
 
-  # NOTE: This should be removed when the -flang-experimental-exec flag is no
-  # longer needed.
-  target_link_options(${test_target} PRIVATE -flang-experimental-exec)
   set_target_properties(${test_target} PROPERTIES LINKER_LANGUAGE Fortran)
 endfunction()
 
 add_subdirectory(regression)
 add_subdirectory(torture)

Fortran/gfortran/README.md

 
 The _execute_ tests are built when the whole test suite is built and executed
 when the tests are run. The *unsupported*, *unimplemented*, and *skipped* tests
 fail to build for the reasons described above. The *failing* tests do build.
 
 
 ### Usage ###
 
-As of 18-Apr-2023, the `-flang-experimental-exec` flag may need to be used when
-configuring and compiling these tests. This can be passed to `cmake` via
-`CMAKE_Fortran_FLAGS`.
-
 By default, the *unsupported*, *unimplemented*, *skipped*, and *failing* tests
 are not run. The intention is that all tests in the test suite should pass by
 default.
 
 In order to enable the disabled tests, one or more of the following options can
 be passed to `cmake`:
 
     - `TEST_SUITE_FORTRAN_FORCE_ALL_TESTS`: Enable all disabled tests.

 A `cmake` command that would only run the Fortran tests in the test-suite is
 shown below
 
 ```
 cmake -DCMAKE_BUILD_TYPE=Release \
       -DCMAKE_C_COMPILER=/path/to/clang \
       -DCMAKE_CXX_COMPILER=/path/to/clang++ \
       -DCMAKE_Fortran_COMPILER=/path/to/flang-new \
-      -DCMAKE_Fortran_FLAGS=-flang-experimental-exec \
       -DTEST_SUITE_FORTRAN=On \
       -DTEST_SUITE_SUBDIRS=Fortran \
       -DTEST_SUITE_FORTRAN_ISO_C_HEADER_DIR=/path/to/dir/containing/header \
       /path/to/source/of/llvm-test-suite/
 ```
 
 The tests can be run as shown from the `llvm-test-suite` build directory:
 

Fortran/gfortran/torture/compile/CMakeLists.txt

function(add_tests UnsupportedTests UnimplementedTests SkippedTests FailingTests)
   # compile tests, there is nothing to be run. While a better solution will be
   # to modify the test suite to allow for cases like this, as a temporary
   # measure, just create an empty executable that will be run for each test.
   set(DummySrc ${CMAKE_CURRENT_BINARY_DIR}/dummy.f90)
   set(Dummy "dummy")
 
   file(WRITE ${DummySrc} "program test\nend program test")
   add_executable(${Dummy} ${DummySrc})
-  # At some point, the -flang-experimental-exec flag will be removed.
-  target_link_options(${Dummy} PUBLIC "-flang-experimental-exec")
 
   # All the "compile" tests in the gfortran torture tests are expected to
   # pass. Since diagnostics are only saved on failure, the diagnostics
   # file produced when compiling the test should be empty. An empty file can,
   # therefore, be used as reference output.
   set(Reference "${FilePrefix}-empty.reference.out")
   add_custom_command(
     OUTPUT ${Reference}