From fb08a8eca5aa057dec6ec3617c9dbc09d729658d Mon Sep 17 00:00:00 2001
From: Giulio Eulisse <10544+ktf@users.noreply.github.com>
Date: Tue, 23 Sep 2025 10:49:49 +0200
Subject: [PATCH] Avoid recompiling fpu.cxx a gazillion of times

This will simply link the object file from fpu.cxx,
which will be compiled only once.
---
 Common/Utils/CMakeLists.txt | 3 +++
 cmake/O2AddExecutable.cmake | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/Common/Utils/CMakeLists.txt b/Common/Utils/CMakeLists.txt
index def743d11791c..d9954e23ab435 100644
--- a/Common/Utils/CMakeLists.txt
+++ b/Common/Utils/CMakeLists.txt
@@ -91,3 +91,6 @@ o2_add_executable(treemergertool
             COMPONENT_NAME CommonUtils
           SOURCES src/TreeMergerTool.cxx
             PUBLIC_LINK_LIBRARIES O2::CommonUtils Boost::program_options ROOT::Core)
+
+add_library(fpu_support OBJECT src/fpu.cxx)
+add_library(O2::fpu_support ALIAS fpu_support)
diff --git a/cmake/O2AddExecutable.cmake b/cmake/O2AddExecutable.cmake
index d5fea084e2c23..752678c44baf0 100644
--- a/cmake/O2AddExecutable.cmake
+++ b/cmake/O2AddExecutable.cmake
@@ -92,7 +92,7 @@ function(o2_add_executable baseTargetName)
   endif()
 
   # add the executable with its sources
-  add_executable(${target} ${A_SOURCES} ${CMAKE_SOURCE_DIR}/Common/Utils/src/fpu.cxx)
+  add_executable(${target} ${A_SOURCES})
 
   # set the executable output name
   set_property(TARGET ${target} PROPERTY OUTPUT_NAME ${exeName})
@@ -118,6 +118,7 @@ function(o2_add_executable baseTargetName)
 
   # needed for fpu.c
   target_link_libraries(${target} PUBLIC ROOT::XMLIO)
+  target_link_libraries(${target} PUBLIC O2::fpu_support)
 
   if(NOT A_NO_INSTALL)
     # install the executable