Re: [PATCH v3 26/31] arm64: Miscellaneous library functions

+/*
+ * Use compiler builtins for simple inline operations.
+ */
+static inline unsigned long __ffs(unsigned long word)
+{
+	return __builtin_ffsl(word) - 1;
+}
+
+static inline int ffs(int x)
+{
+	return __builtin_ffs(x);
+}
+
+static inline unsigned long __fls(unsigned long word)
+{
+	return BITS_PER_LONG - 1 - __builtin_clzl(word);
+}
+
+static inline int fls(int x)
+{
+	return x ? sizeof(x) * BITS_PER_BYTE - __builtin_clz(x) : 0;
+}