[FFmpeg-cvslog] avutil/mem: Optimize fill32() by unrolling and using 64bit

[Michael Niedermayer]

ffmpeg | branch: release/3.4 | Michael Niedermayer <michael at niedermayer.cc> | Thu Jan 17 22:35:10 2019 +0100| [9e5cb0df494b8ca352187fbb44f76d75499ddafb] | committer: Michael Niedermayer

avutil/mem: Optimize fill32() by unrolling and using 64bit

Reviewed-by: Marton Balint <cus at passwd.hu>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 12b1338be376a3e5fb606d9fe41b58dc4a9e62c7)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9e5cb0df494b8ca352187fbb44f76d75499ddafb
---

 libavutil/mem.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/libavutil/mem.c b/libavutil/mem.c
index 36740f1154..4f7ac75df1 100644
--- a/libavutil/mem.c
+++ b/libavutil/mem.c
@@ -385,6 +385,18 @@ static void fill32(uint8_t *dst, int len)
 {
     uint32_t v = AV_RN32(dst - 4);
 
+#if HAVE_FAST_64BIT
+    uint64_t v2= v + ((uint64_t)v<<32);
+    while (len >= 32) {
+        AV_WN64(dst   , v2);
+        AV_WN64(dst+ 8, v2);
+        AV_WN64(dst+16, v2);
+        AV_WN64(dst+24, v2);
+        dst += 32;
+        len -= 32;
+    }
+#endif
+
     while (len >= 4) {
         AV_WN32(dst, v);
         dst += 4;