diff --git a/include/fmt/format.h b/include/fmt/format.h
index 83b2a222..fcddeea4 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -391,11 +391,11 @@ class uint128_fallback {
       hi_ += (lo_ < n ? 1 : 0);
       return *this;
     }
-#if FMT_HAS_BUILTIN(__builtin_addcll)
+#if FMT_HAS_BUILTIN(__builtin_addcll) && !defined(__ibmxl__)
     unsigned long long carry;
     lo_ = __builtin_addcll(lo_, n, 0, &carry);
     hi_ += carry;
-#elif FMT_HAS_BUILTIN(__builtin_ia32_addcarryx_u64)
+#elif FMT_HAS_BUILTIN(__builtin_ia32_addcarryx_u64) && !defined(__ibmxl__)
     unsigned long long result;
     auto carry = __builtin_ia32_addcarryx_u64(0, lo_, n, &result);
     lo_ = result;