[CMake] Add -fno-experimental-isel for testing

[Hahnfeld]

Summary

GlobalISel doesn't yet implement blockaddress and falls back to
SelectionDAG. This results in additional branch instruction to
the next basic block which breaks the OMPT tests.
Disable GlobalISel for now when compiling the tests because fixing
them is not easily possible. See http://llvm.org/PR36313 for full
discussion history.

[rovka]

I'm not familiar enough with the CMake infrastructure to know if this does the trick for the openmp tests, but as I said on the bug report, I'm ok with this general direction.

[Hahnfeld]

In D43195#1006194, @rovka wrote:

I'm not familiar enough with the CMake infrastructure to know if this does the trick for the openmp tests, but as I said on the bug report, I'm ok with this general direction.

As I wrote most of this last year, I think that's what we need to do. Does it fix the tests for you?

[rovka]

Seems to pass now.

openmp/trunk/cmake/DetectTestCompiler/CMakeLists.txt

 cmake_minimum_required(VERSION 2.8)
 project(DetectTestCompiler C CXX)
 
+include(CheckCCompilerFlag)
+include(CheckCXXCompilerFlag)
+
 function(write_compiler_information lang)
   set(information "${CMAKE_${lang}_COMPILER}")
   set(information "${information}\\;${CMAKE_${lang}_COMPILER_ID}")
   set(information "${information}\\;${CMAKE_${lang}_COMPILER_VERSION}")
-  set(information "${information}\\;${OpenMP_${lang}_FLAGS}")
+  set(information "${information}\\;${${lang}_FLAGS}")
   file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/${lang}CompilerInformation.txt ${information})
 endfunction(write_compiler_information)
 
 find_package(OpenMP)
 if (NOT OpenMP_Found)
   set(OpenMP_C_FLAGS "-fopenmp")
   set(OpenMP_CXX_FLAGS "-fopenmp")
 endif()
 
+set(C_FLAGS ${flags} ${OpenMP_C_FLAGS})
+set(CXX_FLAGS ${flags} ${OpenMP_CXX_FLAGS})
+
+# TODO: Implement blockaddress in GlobalISel and remove this flag!
+if (CMAKE_C_COMPILER_ID STREQUAL "Clang")
+  check_c_compiler_flag("-fno-experimental-isel" C_HAS_EXPERIMENTAL_ISEL_FLAG)
+  check_cxx_compiler_flag("-fno-experimental-isel" CXX_HAS_EXPERIMENTAL_ISEL_FLAG)
+  macro(add_experimental_isel_flag lang)
+    if (${lang}_HAS_EXPERIMENTAL_ISEL_FLAG)
+      set(${lang}_FLAGS "-fno-experimental-isel ${${lang}_FLAGS}")
+    endif()
+  endmacro(add_experimental_isel_flag)
+
+  add_experimental_isel_flag(C)
+  add_experimental_isel_flag(CXX)
+endif()
+
 write_compiler_information(C)
 write_compiler_information(CXX)

openmp/trunk/cmake/OpenMPTesting.cmake

else()
     set_test_compiler_information(${CMAKE_CURRENT_BINARY_DIR}/DetectTestCompiler)
   endif()
 else()
   # Set the information that we know.
   set(OPENMP_TEST_COMPILER_ID "Clang")
   # Cannot use CLANG_VERSION because we are not guaranteed that this is already set.
   set(OPENMP_TEST_COMPILER_VERSION "${LLVM_VERSION}")
   set(OPENMP_TEST_COMPILER_VERSION_MAJOR "${LLVM_MAJOR_VERSION}")
-  set(OPENMP_TEST_COMPILER_OPENMP_FLAGS "-fopenmp")
+  # TODO: Implement blockaddress in GlobalISel and remove this flag!
+  set(OPENMP_TEST_COMPILER_OPENMP_FLAGS "-fopenmp -fno-experimental-isel")
 endif()
 
 # Function to set compiler features for use in lit.
 function(set_test_compiler_features)
   if ("${OPENMP_TEST_COMPILER_ID}" STREQUAL "GNU")
     set(comp "gcc")
   elseif ("${OPENMP_TEST_COMPILER_ID}" STREQUAL "Intel")
     set(comp "icc")