[Opus] Update to v1.2.1

third_party/opus/src/silk/LPC_analysis_filter.c

Index: third_party/opus/src/silk/LPC_analysis_filter.c
diff --git a/third_party/opus/src/silk/LPC_analysis_filter.c b/third_party/opus/src/silk/LPC_analysis_filter.c
index 20906673ff124610df2071cb765cbf9b09b33f08..7715f70f8d6763757b0ef194be4cd014ffd0c223 100644
--- a/third_party/opus/src/silk/LPC_analysis_filter.c
+++ b/third_party/opus/src/silk/LPC_analysis_filter.c
@@ -39,6 +39,13 @@ POSSIBILITY OF SUCH DAMAGE.
 /* first d output samples are set to zero  */
 /*******************************************/
 
+/* OPT: Using celt_fir() for this function should be faster, but it may cause
+   integer overflows in intermediate values (not final results), which the
+   current implementation silences by casting to unsigned. Enabling
+   this should be safe in pretty much all cases, even though it is not technically
+   C89-compliant. */
+#define USE_CELT_FIR 0
+
 void silk_LPC_analysis_filter(
     opus_int16                  *out,               /* O    Output signal                                               */
     const opus_int16            *in,                /* I    Input signal                                                */
@@ -49,8 +56,7 @@ void silk_LPC_analysis_filter(
 )
 {
     opus_int   j;
-#ifdef FIXED_POINT
-    opus_int16 mem[SILK_MAX_ORDER_LPC];
+#if defined(FIXED_POINT) && USE_CELT_FIR
     opus_int16 num[SILK_MAX_ORDER_LPC];
 #else
     int ix;
@@ -62,15 +68,12 @@ void silk_LPC_analysis_filter(
     silk_assert( (d & 1) == 0 );
     silk_assert( d <= len );
 
-#ifdef FIXED_POINT
+#if defined(FIXED_POINT) && USE_CELT_FIR
     silk_assert( d <= SILK_MAX_ORDER_LPC );
     for ( j = 0; j < d; j++ ) {
         num[ j ] = -B[ j ];
     }
-    for (j=0;j<d;j++) {
-        mem[ j ] = in[ d - j - 1 ];
-    }
-    celt_fir( in + d, num, out + d, len - d, d, mem, arch );
+    celt_fir( in + d, num, out + d, len - d, d, arch );
     for ( j = 0; j < d; j++ ) {
         out[ j ] = 0;
     }