diff --git a/include/boost/math/special_functions/trunc.hpp b/include/boost/math/special_functions/trunc.hpp
index 7ac33a92d3..8b4f64eb65 100644
--- a/include/boost/math/special_functions/trunc.hpp
+++ b/include/boost/math/special_functions/trunc.hpp
@@ -16,10 +16,11 @@
 #include <boost/math/tools/config.hpp>
 #include <boost/math/policies/error_handling.hpp>
 #include <boost/math/special_functions/fpclassify.hpp>
+#include <boost/math/tools/is_constant_evaluated.hpp>
 
 #ifndef BOOST_NO_CXX17_IF_CONSTEXPR
-#include <boost/math/ccmath/ldexp.hpp>
 #  if !defined(BOOST_MATH_NO_CONSTEXPR_DETECTION)
+#    include <boost/math/ccmath/ldexp.hpp>
 #    define BOOST_MATH_HAS_CONSTEXPR_LDEXP
 #  endif
 #endif
diff --git a/test/cohen_acceleration_test.cpp b/test/cohen_acceleration_test.cpp
index ad70c3f825..4269083050 100644
--- a/test/cohen_acceleration_test.cpp
+++ b/test/cohen_acceleration_test.cpp
@@ -71,7 +71,7 @@ void test_divergent()
 {
     auto g = Divergent<Real>();
     Real x = -cohen_acceleration(g);
-    CHECK_ULP_CLOSE(log(pi<Real>()/2)/2, x, (std::numeric_limits<Real>::digits > 100 ? 350 : 135));
+    CHECK_ULP_CLOSE(log(pi<Real>()/2)/2, x, (std::numeric_limits<Real>::digits > 100 ? 350 : 150));
 }
 
 int main()