diff --git a/Calorimeter/CaloLumiConditions/CMakeLists.txt b/Calorimeter/CaloLumiConditions/CMakeLists.txt
index 55ba96083f619f8534c7b27edeb04b0e5a152457..cac77b76f2230fead732e1ab7451fefe5911dd42 100644
--- a/Calorimeter/CaloLumiConditions/CMakeLists.txt
+++ b/Calorimeter/CaloLumiConditions/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
 
 # Declare the package name:
 atlas_subdir( CaloLumiConditions )
@@ -12,6 +12,12 @@ atlas_add_library( CaloLumiConditions
                    PUBLIC_HEADERS CaloLumiConditions
                    LINK_LIBRARIES CxxUtils Identifier AthenaKernel LArElecCalib
                    PRIVATE_LINK_LIBRARIES LArIdentifier LumiBlockData )
+if( CMAKE_COMPILER_IS_GNUCXX )
+  # When we compile with -flto, we get bogus warnings about ODR violations
+  # from the multiversioned function CaloBCIDCoeffs::calc().
+  # Just suppress the warnings for now.
+  set_target_properties( CaloLumiConditions PROPERTIES COMPILE_FLAGS "-Wno-odr -Wno-lto-type-mismatch" LINK_FLAGS "-Wno-odr -Wno-lto-type-mismatch" )
+endif()
 
 atlas_add_test( CaloBCIDCoeffs_test
                 SOURCES