diff --git a/library/sha256.c b/library/sha256.c
index f0eb6ad58c..00a01ea3d6 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -102,7 +102,8 @@
 #  endif
 #  if defined(MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT)
 #    if defined(MBEDTLS_COMPILER_IS_GCC) && !defined(MBEDTLS_ARCH_IS_ARM64)
-#           warning "GCC only supports aarch64 for MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT, using C code only"
+#           warning \
+    "GCC only supports aarch64 for MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT, using C code only"
 #           undef MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT
 #    endif
 #    if defined(__unix__)