Fix compiler warnings

- celt/modes.c:430:14: warning: cast from 'const unsigned char *' to
  'opus_int16 *' increases required alignment from 1 to 2 [-Wcast-align]
- 'C[0][1]' may be used uninitialized [-Wmaybe-uninitialized]
- Unused variable/parameter
- Value stored is never read
- MSVC warnings about "possible loss of data" due to type conversions
- MSVC warning C4146: unary minus operator applied to unsigned type
- silk/NLSF_del_dec_quant.c:137:20: warning: array subscript is above
  array bounds [-Warray-bounds] (gcc -O3 false positive)
- src/mlp_train.h:39:20: warning: function declaration isn't a prototype
  [-Wstrict-prototypes]
- Remove SMALL_FOOTPRINT code from SSE 4.1 FIR implementation, matching
  the C implementation.

The clang -Wcast-align warnings with SSE intrinsics are a known
clang issue: https://llvm.org/bugs/show_bug.cgi?id=20670

2 files changed, 5 insertions, 2 deletions

diff --git a/tests/opus_encode_regressions.c b/tests/opus_encode_regressions.c
index 2373884c..29234730 100644
--- a/tests/opus_encode_regressions.c
+++ b/tests/opus_encode_regressions.c
@@ -935,6 +935,7 @@ static int ec_enc_shrink_assert(void)
     opus_encoder_ctl(enc, OPUS_SET_PACKET_LOSS_PERC(6));
     opus_encoder_ctl(enc, OPUS_SET_BITRATE(6000));
     data_len = opus_encode(enc, pcm1, 960, data, 2000);
+    assert(data_len > 0);
 
     opus_encoder_ctl(enc, OPUS_SET_SIGNAL(OPUS_SIGNAL_VOICE));
     opus_encoder_ctl(enc, OPUS_SET_PREDICTION_DISABLED(1));
@@ -942,11 +943,13 @@ static int ec_enc_shrink_assert(void)
     opus_encoder_ctl(enc, OPUS_SET_INBAND_FEC(1));
     opus_encoder_ctl(enc, OPUS_SET_BITRATE(15600));
     data_len = opus_encode(enc, pcm2, 2880, data, 122);
+    assert(data_len > 0);
 
     opus_encoder_ctl(enc, OPUS_SET_SIGNAL(OPUS_SIGNAL_MUSIC));
     opus_encoder_ctl(enc, OPUS_SET_BITRATE(27000));
     data_len = opus_encode(enc, pcm3, 2880, data, 122); /* assertion failure */
-    (void)data_len;
+    assert(data_len > 0);
+
     opus_encoder_destroy(enc);
     return 0;
 }
diff --git a/tests/test_opus_encode.c b/tests/test_opus_encode.c
index b8427138..dae49c3d 100644
--- a/tests/test_opus_encode.c
+++ b/tests/test_opus_encode.c
@@ -582,7 +582,7 @@ int run_test1(int no_fuzz)
          the decoders in order to compare them. */
       if(opus_packet_parse(packet,len,&toc,frames,size,&payload_offset)<=0)test_failed();
       if((fast_rand()&1023)==0)len=0;
-      for(j=(frames[0]-packet);j<len;j++)for(jj=0;jj<8;jj++)packet[j]^=((!no_fuzz)&&((fast_rand()&1023)==0))<<jj;
+      for(j=(opus_int32)(frames[0]-packet);j<len;j++)for(jj=0;jj<8;jj++)packet[j]^=((!no_fuzz)&&((fast_rand()&1023)==0))<<jj;
       out_samples = opus_decode(dec_err[0], len>0?packet:NULL, len, out2buf, MAX_FRAME_SAMP, 0);
       if(out_samples<0||out_samples>MAX_FRAME_SAMP)test_failed();
       if((len>0&&out_samples!=frame_size))test_failed(); /*FIXME use lastframe*/