--- /dev/null
+/* PR middle-end/36106 */
+/* { dg-options "-O2" } */
+/* { dg-options "-O2 -mcx16" { target { { i?86-*-* x86_64-*-* } && lp64 } } } */
+
+#ifdef __x86_64__
+# include "cpuid.h"
+#endif
+
+extern void abort (void);
+
+int __attribute__((noinline))
+do_test (void)
+{
+ long double d = .0L;
+ int i;
+ #pragma omp parallel for shared (d)
+ for (i = 0; i < 10; i++)
+ #pragma omp atomic
+ d += 1.0L;
+ if (d != 10.0L)
+ abort ();
+ return 0;
+}
+
+int
+main (void)
+{
+#ifdef __x86_64__
+ unsigned int eax, ebx, ecx, edx;
+
+ if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+ return 0;
+
+ if (!(ecx & bit_CMPXCHG16B))
+ return 0;
+#endif
+
+ do_test ();
+
+ return 0;
+}