[AArch64] Use GCC builtins to count leading/tailing zeros.

diff --git a/ChangeLog b/ChangeLog
index 8c0f2a2..c3fa6e5 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2014-04-22  Yufeng Zhang  <yufeng.zhang@arm.com>
+
+       * stdlib/longlong.h (count_leading_zeros, count_trailing_zeros)
+       (COUNT_LEADING_ZEROS_0): Define for AArch64.
+
 2014-04-22  Siddhesh Poyarekar  <siddhesh@redhat.com>
 
        * nptl/sysdeps/unix/sysv/linux/sem_trywait.c: Include atomic.h.

diff --git a/stdlib/longlong.h b/stdlib/longlong.h
index 10d76cf..d45dbe2 100644 (file)
--- a/stdlib/longlong.h
+++ b/stdlib/longlong.h
@@ -122,6 +122,22 @@ extern const UQItype __clz_tab[256] attribute_hidden;
 #define __AND_CLOBBER_CC , "cc"
 #endif /* __GNUC__ < 2 */
 
+#if defined (__aarch64__)
+
+#if W_TYPE_SIZE == 32
+#define count_leading_zeros(COUNT, X)  ((COUNT) = __builtin_clz (X))
+#define count_trailing_zeros(COUNT, X)   ((COUNT) = __builtin_ctz (X))
+#define COUNT_LEADING_ZEROS_0 32
+#endif /* W_TYPE_SIZE == 32 */
+
+#if W_TYPE_SIZE == 64
+#define count_leading_zeros(COUNT, X)  ((COUNT) = __builtin_clzll (X))
+#define count_trailing_zeros(COUNT, X)   ((COUNT) = __builtin_ctzll (X))
+#define COUNT_LEADING_ZEROS_0 64
+#endif /* W_TYPE_SIZE == 64 */
+
+#endif /* __aarch64__ */
+
 #if defined (__alpha) && W_TYPE_SIZE == 64
 #define umul_ppmm(ph, pl, m0, m1) \
   do {                                                                 \