1 files changed, 27 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/builtin-bswap-12.c b/gcc/testsuite/gcc.dg/builtin-bswap-12.c
new file mode 100644
index 00000000000..8ff65d85300
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtin-bswap-12.c
@@ -0,0 +1,27 @@
+/* { dg-do run } */
+/* { dg-require-effective-target int128 } */
+/* { dg-require-effective-target stdint_types } */
+/* { dg-options "-O" } */
+
+#include <stdint.h>
+
+typedef union
+{
+  struct { uint64_t lo; uint64_t hi; } s;
+  __uint128_t n;
+} u;
+
+int
+main (void)
+{
+  /* Test constant folding.  */
+  extern void link_error (void);
+
+  const u U1 = { .s = { 0x1122334455667788ULL, 0xffffffffffffffffULL } };
+  const u U2 = { .s = { 0xffffffffffffffffULL, 0x8877665544332211ULL } };
+
+  if (__builtin_bswap128 (U1.n) != U2.n)
+    link_error ();
+
+  return 0;
+}