+/* align to next higher power-of-2 (except for: 0 => 0, overflow => 0) */
+static inline unsigned long ALIGN_POWER2(unsigned long u) {
+ /* clz(0) is undefined */
+ if (u == 1)
+ return 1;
+
+ /* left-shift overflow is undefined */
+ if (__builtin_clzl(u - 1UL) < 1)
+ return 0;
+
+ return 1UL << (sizeof(u) * 8 - __builtin_clzl(u - 1UL));
+}
+