[FFmpeg-cvslog] avutil/softfloat: Fix multiple runtime error: left shift of negative value -8

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat May  6 00:13:05 2017 +0200| [35f3df0d76e28969fa77f2b865e2e40b3ba69722] | committer: Michael Niedermayer

avutil/softfloat: Fix multiple runtime error: left shift of negative value -8

Fixes: 1352/clusterfuzz-testcase-minimized-5757565017260032

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=35f3df0d76e28969fa77f2b865e2e40b3ba69722
---

 libavutil/softfloat.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavutil/softfloat.h b/libavutil/softfloat.h
index e6d30ad333..5d376e438a 100644
--- a/libavutil/softfloat.h
+++ b/libavutil/softfloat.h
@@ -234,12 +234,12 @@ static av_unused void av_sincos_sf(int a, int *s, int *c)
     int st, ct;
 
     idx = a >> 26;
-    sign = (idx << 27) >> 31;
+    sign = (int32_t)((unsigned)idx << 27) >> 31;
     cv = av_costbl_1_sf[idx & 0xf];
     cv = (cv ^ sign) - sign;
 
     idx -= 8;
-    sign = (idx << 27) >> 31;
+    sign = (int32_t)((unsigned)idx << 27) >> 31;
     sv = av_costbl_1_sf[idx & 0xf];
     sv = (sv ^ sign) - sign;