[llvm-branch-commits] [openmp] release/22.x: [openmp] Allow testing OpenMP in runtimes builds without a full clang build tree (PR #183054)

[Martin Storsjö via llvm-branch-commits]

https://github.com/mstorsjo updated https://github.com/llvm/llvm-project/pull/183054

>From 73391f9855f86f644f803a530eedf351ded8a4e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin at martin.st>
Date: Tue, 24 Feb 2026 14:51:06 +0200
Subject: [PATCH] [openmp] Allow testing OpenMP in runtimes builds without a
 full clang build tree

Having a build tree with "not" and "FileCheck" is still required, but if
Clang/Flang isn't configured in that build, run the tests with the same
compiler CMake uses. This is how testing worked in the standalone build
configurations that now have been removed.

This is a manually adapted backport of
48a5119d8e7d7236a28c14d06ec215ef3366ef90 / #182470 to the 22.x
release branch.

This allows testing OpenMP in the same way on both git main
and the 22.x release branch.
---
 openmp/CMakeLists.txt            | 33 ++++++++++++++++++--------------
 openmp/cmake/OpenMPTesting.cmake |  8 ++++++--
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/openmp/CMakeLists.txt b/openmp/CMakeLists.txt
index df568419824a6..cfe01daaa80d5 100644
--- a/openmp/CMakeLists.txt
+++ b/openmp/CMakeLists.txt
@@ -71,13 +71,26 @@ else()
         "Path where built OpenMP libraries should be installed.")
   endif()
 
-  if (NOT MSVC)
-    set(OPENMP_TEST_C_COMPILER ${LLVM_TOOLS_BINARY_DIR}/clang)
-    set(OPENMP_TEST_CXX_COMPILER ${LLVM_TOOLS_BINARY_DIR}/clang++)
-  else()
-    set(OPENMP_TEST_C_COMPILER ${LLVM_TOOLS_BINARY_DIR}/clang.exe)
-    set(OPENMP_TEST_CXX_COMPILER ${LLVM_TOOLS_BINARY_DIR}/clang++.exe)
+  set(OPENMP_TEST_C_COMPILER_default "${LLVM_TOOLS_BINARY_DIR}/clang${CMAKE_EXECUTABLE_SUFFIX}")
+  set(OPENMP_TEST_CXX_COMPILER_default "${LLVM_TOOLS_BINARY_DIR}/clang++${CMAKE_EXECUTABLE_SUFFIX}")
+  set(OPENMP_TEST_Fortran_COMPILER_default "${LLVM_TOOLS_BINARY_DIR}/flang${CMAKE_EXECUTABLE_SUFFIX}")
+  if (NOT TARGET "clang")
+    set(OPENMP_TEST_C_COMPILER_default "${CMAKE_C_COMPILER}")
+    set(OPENMP_TEST_CXX_COMPILER_default "${CMAKE_CXX_COMPILER}")
+  endif()
+  if (NOT TARGET "flang")
+    if (CMAKE_Fortran_COMPILER)
+      set(OPENMP_TEST_Fortran_COMPILER_default "${CMAKE_Fortran_COMPILER}")
+    else()
+      unset(OPENMP_TEST_Fortran_COMPILER_default)
+    endif()
   endif()
+  set(OPENMP_TEST_C_COMPILER "${OPENMP_TEST_C_COMPILER_default}" CACHE STRING
+    "C compiler to use for testing OpenMP runtime libraries.")
+  set(OPENMP_TEST_CXX_COMPILER "${OPENMP_TEST_CXX_COMPILER_default}" CACHE STRING
+    "C++ compiler to use for testing OpenMP runtime libraries.")
+  set(OPENMP_TEST_Fortran_COMPILER "${OPENMP_TEST_Fortran_COMPILER_default}" CACHE STRING
+    "Fortran compiler to use for testing OpenMP runtime libraries.")
 
   # Set fortran test compiler if flang is found
   if (EXISTS "${OPENMP_TEST_Fortran_COMPILER}")
@@ -116,14 +129,6 @@ math(EXPR LIBOMP_VERSION_BUILD_MONTH_DAY "${LIBOMP_VERSION_BUILD}%10000")
 set(LIBOMP_BUILD_DATE "No_Timestamp")
 
 
-# Check for flang
-set(OPENMP_TEST_Fortran_COMPILER_default "")
-if (CMAKE_Fortran_COMPILER)
-  set(OPENMP_TEST_Fortran_COMPILER_default "${CMAKE_Fortran_COMPILER}")
-endif ()
-set(OPENMP_TEST_Fortran_COMPILER "${OPENMP_TEST_Fortran_COMPILER_default}" CACHE STRING
-  "Fortran compiler to use for testing OpenMP runtime libraries.")
-
 set(LIBOMP_FORTRAN_MODULES FALSE CACHE BOOL
   "Create Fortran module files? (requires fortran compiler)")
 
diff --git a/openmp/cmake/OpenMPTesting.cmake b/openmp/cmake/OpenMPTesting.cmake
index 262ea968c8351..f46ff4268b731 100644
--- a/openmp/cmake/OpenMPTesting.cmake
+++ b/openmp/cmake/OpenMPTesting.cmake
@@ -221,19 +221,23 @@ function(add_openmp_testsuite target comment)
       USES_TERMINAL
     )
   else()
+    set(EXTRA_CHECK_DEPENDS "")
+    if (TARGET "clang")
+      list(APPEND EXTRA_CHECK_DEPENDS clang)
+    endif()
     if (ARG_EXCLUDE_FROM_CHECK_ALL)
       add_lit_testsuite(${target}
         ${comment}
         ${ARG_UNPARSED_ARGUMENTS}
         EXCLUDE_FROM_CHECK_ALL
-        DEPENDS clang FileCheck not ${ARG_DEPENDS}
+        DEPENDS ${EXTRA_CHECK_DEPENDS} FileCheck not ${ARG_DEPENDS}
         ARGS ${ARG_ARGS}
       )
     else()
       add_lit_testsuite(${target}
         ${comment}
         ${ARG_UNPARSED_ARGUMENTS}
-        DEPENDS clang FileCheck not ${ARG_DEPENDS}
+        DEPENDS ${EXTRA_CHECK_DEPENDS} FileCheck not ${ARG_DEPENDS}
         ARGS ${ARG_ARGS}
       )
     endif()