[FFmpeg-devel] [PATCH 1/3] common: add ff_parity()

[Clément Bœsch]

---
 configure               | 2 ++
 libavutil/x86/intmath.h | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/configure b/configure
index 6710f85..610be92 100755
--- a/configure
+++ b/configure
@@ -1738,6 +1738,7 @@ BUILTIN_LIST="
     machine_rw_barrier
     MemoryBarrier
     mm_empty
+    parity
     rdtsc
     sarestart
     sync_val_compare_and_swap
@@ -5242,6 +5243,7 @@ check_builtin sarestart signal.h "SA_RESTART"
 check_builtin sync_val_compare_and_swap "" "int *ptr; int oldval, newval; __sync_val_compare_and_swap(ptr, oldval, newval)"
 check_builtin gmtime_r time.h "time_t *time; struct tm *tm; gmtime_r(time, tm)"
 check_builtin localtime_r time.h "time_t *time; struct tm *tm; localtime_r(time, tm)"
+check_builtin parity "" "__builtin_parity(123)"
 
 case "$custom_allocator" in
     jemalloc)
diff --git a/libavutil/x86/intmath.h b/libavutil/x86/intmath.h
index 611ef88..9c36bf2 100644
--- a/libavutil/x86/intmath.h
+++ b/libavutil/x86/intmath.h
@@ -75,6 +75,15 @@ static av_always_inline av_const int ff_ctzll_x86(long long v)
 
 #endif /* __POPCNT__ */
 
+static av_always_inline av_const int ff_parity(uint32_t v)
+{
+#if HAVE_PARITY
+    return __builtin_parity(v);
+#else
+    return av_popcount(v) & 1;
+#endif
+}
+
 #if defined(__BMI2__)
 
 #if AV_GCC_VERSION_AT_LEAST(5,1)
-- 
2.6.4