diff --git a/libavcodec/wavpack.c b/libavcodec/wavpack.c
index 98102f5661..e2450aac9d 100644
--- a/libavcodec/wavpack.c
+++ b/libavcodec/wavpack.c
@@ -307,8 +307,8 @@ static float wv_get_value_float(WavpackFrameContext *s, uint32_t *crc, int S)
         S  <<= s->float_shift;
         sign = S < 0;
         if (sign)
-            S = -S;
-        if (S >= 0x1000000) {
+            S = -(unsigned)S;
+        if (S >= 0x1000000U) {
             if (s->got_extra_bits && get_bits1(&s->gb_extra_bits))
                 S = get_bits(&s->gb_extra_bits, 23);
             else