diff --git a/CTestCustom.cmake.in b/CTestCustom.cmake.in
index 710681cce..48dd3debc 100644
--- a/CTestCustom.cmake.in
+++ b/CTestCustom.cmake.in
@@ -67,6 +67,7 @@ list(APPEND CTEST_CUSTOM_WARNING_EXCEPTION
   "cm(StringCommand|CTestTestHandler)\\.cxx.*warning.*rand.*may return deterministic values"
   "cm(StringCommand|CTestTestHandler)\\.cxx.*warning.*rand.*isn.*t random" # we do not do crypto
   "cm(StringCommand|CTestTestHandler)\\.cxx.*warning.*srand.*seed choices are.*poor" # we do not do crypto
+  "IPA warning: function.*multiply defined in"
 
   # Ignore clang's summary warning, assuming prior text has matched some
   # other warning expression: