macro: avoid subtraction overflow in ALIGN_POWER2()

2019-12-09 18:34:05 +01:00
parent fb4b0465ab
commit 85c267afa7
1 changed files with 5 additions and 0 deletions
@@ -163,6 +163,11 @@ static inline size_t ALIGN_TO(size_t l, size_t ali) {

 /* align to next higher power-of-2 (except for: 0 => 0, overflow => 0) */
 static inline unsigned long ALIGN_POWER2(unsigned long u) {
+
+        /* Avoid subtraction overflow */
+        if (u == 0)
+                return 0;
+
        /* clz(0) is undefined */
        if (u == 1)
                return 1;