[FFmpeg-devel] [PATCH 3/7] avutil/common: Implement av_sat_add64_c() with fewer branches
Michael Niedermayer
michael at niedermayer.cc
Mon Oct 19 17:24:57 EEST 2020
No benchmark because this is not used in any speed relevant pathes nor is it
used where __builtin_add_overflow is available.
So I do not know how to realistically benchmark it.
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
libavutil/common.h | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/libavutil/common.h b/libavutil/common.h
index 92b721a59c..a48c0648f8 100644
--- a/libavutil/common.h
+++ b/libavutil/common.h
@@ -303,11 +303,10 @@ static av_always_inline int64_t av_sat_add64_c(int64_t a, int64_t b) {
int64_t tmp;
return !__builtin_add_overflow(a, b, &tmp) ? tmp : (tmp < 0 ? INT64_MAX : INT64_MIN);
#else
- if (b >= 0 && a >= INT64_MAX - b)
- return INT64_MAX;
- if (b <= 0 && a <= INT64_MIN - b)
- return INT64_MIN;
- return a + b;
+ int64_t s = a+(uint64_t)b;
+ if ((int64_t)(a^b | ~s^b) >= 0)
+ return b < 0 ? INT64_MIN : INT64_MAX;
+ return s;
#endif
}
--
2.17.1
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