slight clean up

9 files changed, 135 insertions, 94 deletions

diff --git a/silk/A2NLSF.c b/silk/A2NLSF.c
index a1edde1e..165049aa 100644
--- a/silk/A2NLSF.c
+++ b/silk/A2NLSF.c
@@ -40,7 +40,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 /* Number of binary divisions, when not in low complexity mode */
 #define BIN_DIV_STEPS_A2NLSF_FIX      3 /* must be no higher than 16 - log2( LSF_COS_TAB_SZ_FIX ) */
-#define MAX_ITERATIONS_A2NLSF_FIX    30
+#define MAX_ITERATIONS_A2NLSF_FIX    16
 
 /* Helper function for A2NLSF(..)                    */
 /* Transforms polynomials from cos(n*f) to cos(f)^n  */
@@ -239,13 +239,13 @@ void silk_A2NLSF(
                     /* Set NLSFs to white spectrum and exit */
                     NLSF[ 0 ] = (opus_int16)silk_DIV32_16( 1 << 15, d + 1 );
                     for( k = 1; k < d; k++ ) {
-                        NLSF[ k ] = (opus_int16)silk_SMULBB( k + 1, NLSF[ 0 ] );
+                        NLSF[ k ] = (opus_int16)silk_ADD16( NLSF[ k-1 ], NLSF[ 0 ] );
                     }
                     return;
                 }
 
                 /* Error: Apply progressively more bandwidth expansion and run again */
-                silk_bwexpander_32( a_Q16, d, 65536 - silk_SMULBB( 10 + i, i ) ); /* 10_Q16 = 0.00015*/
+				silk_bwexpander_32( a_Q16, d, 65536 - silk_LSHIFT( 1, i ) );
 
                 silk_A2NLSF_init( a_Q16, P, Q, dd );
                 p = P;                            /* Pointer to polynomial */
diff --git a/silk/LPC_fit.c b/silk/LPC_fit.c
new file mode 100644
index 00000000..69ff3958
--- /dev/null
+++ b/silk/LPC_fit.c
@@ -0,0 +1,81 @@
+/***********************************************************************
+Copyright (c) 2013, Koen Vos. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+- Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+- Neither the name of Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+***********************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "SigProc_FIX.h"
+
+/* Convert int32 coefficients to int16 coefs and make sure there's no wrap-around */
+void silk_LPC_fit(
+    opus_int16                  *a_QOUT,            /* O    Output signal                                               */
+    opus_int32			        *a_QIN,             /* I/O  Input signal                                                */
+    const opus_int              QOUT,               /* I    Input Q domain                                              */
+    const opus_int              QIN,                /* I    Input Q domain                                              */
+    const opus_int              d                   /* I    Filter order                                                */
+)
+{
+	opus_int	i, k, idx = 0;
+	opus_int32	maxabs, absval, chirp_Q16;
+
+    /* Limit the maximum absolute value of the prediction coefficients, so that they'll fit in int16 */
+    for( i = 0; i < 10; i++ ) {
+        /* Find maximum absolute value and its index */
+        maxabs = 0;
+        for( k = 0; k < d; k++ ) {
+            absval = silk_abs( a_QIN[k] );
+            if( absval > maxabs ) {
+                maxabs = absval;
+                idx    = k;
+            }
+        }
+        maxabs = silk_RSHIFT_ROUND( maxabs, QIN - QOUT );
+
+        if( maxabs > silk_int16_MAX ) {
+            /* Reduce magnitude of prediction coefficients */
+            maxabs = silk_min( maxabs, 163838 );  /* ( silk_int32_MAX >> 14 ) + silk_int16_MAX = 163838 */
+            chirp_Q16 = SILK_FIX_CONST( 0.999, 16 ) - silk_DIV32( silk_LSHIFT( maxabs - silk_int16_MAX, 14 ),
+                                        silk_RSHIFT32( silk_MUL( maxabs, idx + 1), 2 ) );
+            silk_bwexpander_32( a_QIN, d, chirp_Q16 );
+        } else {
+            break;
+        }
+    }
+
+    if( i == 10 ) {
+        /* Reached the last iteration, clip the coefficients */
+        for( k = 0; k < d; k++ ) {
+            a_QOUT[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( a_QIN[ k ], QIN - QOUT ) );
+            a_QIN[ k ] = silk_LSHIFT( (opus_int32)a_QOUT[ k ], QIN - QOUT );
+        }
+    } else {
+        for( k = 0; k < d; k++ ) {
+            a_QOUT[ k ] = (opus_int16)silk_RSHIFT_ROUND( a_QIN[ k ], QIN - QOUT );
+        }
+    }
+}
diff --git a/silk/LPC_inv_pred_gain.c b/silk/LPC_inv_pred_gain.c
index 4af89aa5..cb9983f5 100644
--- a/silk/LPC_inv_pred_gain.c
+++ b/silk/LPC_inv_pred_gain.c
@@ -30,6 +30,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 #include "SigProc_FIX.h"
+#include "define.h"
 
 #define QA                          24
 #define A_LIMIT                     SILK_FIX_CONST( 0.99975, QA )
@@ -39,68 +40,69 @@ POSSIBILITY OF SUCH DAMAGE.
 /* Compute inverse of LPC prediction gain, and                          */
 /* test if LPC coefficients are stable (all poles within unit circle)   */
 static opus_int32 LPC_inverse_pred_gain_QA(                 /* O   Returns inverse prediction gain in energy domain, Q30    */
-    opus_int32           A_QA[ 2 ][ SILK_MAX_ORDER_LPC ],   /* I   Prediction coefficients                                  */
+    opus_int32           A_QA[ SILK_MAX_ORDER_LPC ],        /* I   Prediction coefficients                                  */
     const opus_int       order                              /* I   Prediction order                                         */
 )
 {
     opus_int   k, n, mult2Q;
-    opus_int32 invGain_Q30, rc_Q31, rc_mult1_Q30, rc_mult2, tmp_QA;
-    opus_int32 *Aold_QA, *Anew_QA;
+    opus_int32 invGain_Q30, rc_Q31, rc_mult1_Q30, rc_mult2, tmp1, tmp2;
 
-    Anew_QA = A_QA[ order & 1 ];
-
-    invGain_Q30 = (opus_int32)1 << 30;
+    invGain_Q30 = SILK_FIX_CONST( 1, 30 );
     for( k = order - 1; k > 0; k-- ) {
         /* Check for stability */
-        if( ( Anew_QA[ k ] > A_LIMIT ) || ( Anew_QA[ k ] < -A_LIMIT ) ) {
+        if( ( A_QA[ k ] > A_LIMIT ) || ( A_QA[ k ] < -A_LIMIT ) ) {
             return 0;
         }
 
         /* Set RC equal to negated AR coef */
-        rc_Q31 = -silk_LSHIFT( Anew_QA[ k ], 31 - QA );
+        rc_Q31 = -silk_LSHIFT( A_QA[ k ], 31 - QA );
 
         /* rc_mult1_Q30 range: [ 1 : 2^30 ] */
-        rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 );
+        rc_mult1_Q30 = silk_SUB32( SILK_FIX_CONST( 1, 30 ), silk_SMMUL( rc_Q31, rc_Q31 ) );
         silk_assert( rc_mult1_Q30 > ( 1 << 15 ) );                   /* reduce A_LIMIT if fails */
         silk_assert( rc_mult1_Q30 <= ( 1 << 30 ) );
 
-        /* rc_mult2 range: [ 2^30 : silk_int32_MAX ] */
-        mult2Q = 32 - silk_CLZ32( silk_abs( rc_mult1_Q30 ) );
-        rc_mult2 = silk_INVERSE32_varQ( rc_mult1_Q30, mult2Q + 30 );
-
         /* Update inverse gain */
         /* invGain_Q30 range: [ 0 : 2^30 ] */
         invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 );
         silk_assert( invGain_Q30 >= 0           );
         silk_assert( invGain_Q30 <= ( 1 << 30 ) );
+        if( invGain_Q30 < SILK_FIX_CONST( 1.0f / MAX_PREDICTION_POWER_GAIN, 30 ) ) {
+            return 0;
+        }
 
-        /* Swap pointers */
-        Aold_QA = Anew_QA;
-        Anew_QA = A_QA[ k & 1 ];
+        /* rc_mult2 range: [ 2^30 : silk_int32_MAX ] */
+        mult2Q = 32 - silk_CLZ32( silk_abs( rc_mult1_Q30 ) );
+        rc_mult2 = silk_INVERSE32_varQ( rc_mult1_Q30, mult2Q + 30 );
 
         /* Update AR coefficient */
-        for( n = 0; n < k; n++ ) {
-            tmp_QA = Aold_QA[ n ] - MUL32_FRAC_Q( Aold_QA[ k - n - 1 ], rc_Q31, 31 );
-            Anew_QA[ n ] = MUL32_FRAC_Q( tmp_QA, rc_mult2 , mult2Q );
+        for( n = 0; n < (k + 1) >> 1; n++ ) {
+            tmp1 = A_QA[ n ];
+            tmp2 = A_QA[ k - n - 1 ];
+            A_QA[ n ] =			MUL32_FRAC_Q( tmp1 - MUL32_FRAC_Q( tmp2, rc_Q31, 31 ), rc_mult2, mult2Q );
+            A_QA[ k - n - 1 ] = MUL32_FRAC_Q( tmp2 - MUL32_FRAC_Q( tmp1, rc_Q31, 31 ), rc_mult2, mult2Q );
         }
     }
 
     /* Check for stability */
-    if( ( Anew_QA[ 0 ] > A_LIMIT ) || ( Anew_QA[ 0 ] < -A_LIMIT ) ) {
+    if( ( A_QA[ k ] > A_LIMIT ) || ( A_QA[ k ] < -A_LIMIT ) ) {
         return 0;
     }
 
     /* Set RC equal to negated AR coef */
-    rc_Q31 = -silk_LSHIFT( Anew_QA[ 0 ], 31 - QA );
+    rc_Q31 = -silk_LSHIFT( A_QA[ 0 ], 31 - QA );
 
     /* Range: [ 1 : 2^30 ] */
-    rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 );
+    rc_mult1_Q30 = silk_SUB32( SILK_FIX_CONST( 1, 30 ), silk_SMMUL( rc_Q31, rc_Q31 ) );
 
     /* Update inverse gain */
     /* Range: [ 0 : 2^30 ] */
     invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 );
-    silk_assert( invGain_Q30 >= 0     );
-    silk_assert( invGain_Q30 <= 1<<30 );
+    silk_assert( invGain_Q30 >= 0           );
+    silk_assert( invGain_Q30 <= ( 1 << 30 ) );
+    if( invGain_Q30 < SILK_FIX_CONST( 1.0f / MAX_PREDICTION_POWER_GAIN, 30 ) ) {
+        return 0;
+    }
 
     return invGain_Q30;
 }
@@ -112,16 +114,13 @@ opus_int32 silk_LPC_inverse_pred_gain(              /* O   Returns inverse predi
 )
 {
     opus_int   k;
-    opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ];
-    opus_int32 *Anew_QA;
+    opus_int32 Atmp_QA[ SILK_MAX_ORDER_LPC ];
     opus_int32 DC_resp = 0;
 
-    Anew_QA = Atmp_QA[ order & 1 ];
-
     /* Increase Q domain of the AR coefficients */
     for( k = 0; k < order; k++ ) {
         DC_resp += (opus_int32)A_Q12[ k ];
-        Anew_QA[ k ] = silk_LSHIFT32( (opus_int32)A_Q12[ k ], QA - 12 );
+        Atmp_QA[ k ] = silk_LSHIFT32( (opus_int32)A_Q12[ k ], QA - 12 );
     }
     /* If the DC is unstable, we don't even need to do the full calculations */
     if( DC_resp >= 4096 ) {
@@ -139,14 +138,11 @@ opus_int32 silk_LPC_inverse_pred_gain_Q24(          /* O    Returns inverse pred
 )
 {
     opus_int   k;
-    opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ];
-    opus_int32 *Anew_QA;
-
-    Anew_QA = Atmp_QA[ order & 1 ];
+    opus_int32 Atmp_QA[ SILK_MAX_ORDER_LPC ];
 
     /* Increase Q domain of the AR coefficients */
     for( k = 0; k < order; k++ ) {
-        Anew_QA[ k ] = silk_RSHIFT32( A_Q24[ k ], 24 - QA );
+        Atmp_QA[ k ] = silk_RSHIFT32( A_Q24[ k ], 24 - QA );
     }
 
     return LPC_inverse_pred_gain_QA( Atmp_QA, order );
diff --git a/silk/NLSF2A.c b/silk/NLSF2A.c
index b1c559ea..0ea5c17e 100644
--- a/silk/NLSF2A.c
+++ b/silk/NLSF2A.c
@@ -83,15 +83,14 @@ void silk_NLSF2A(
     opus_int32 P[ SILK_MAX_ORDER_LPC / 2 + 1 ], Q[ SILK_MAX_ORDER_LPC / 2 + 1 ];
     opus_int32 Ptmp, Qtmp, f_int, f_frac, cos_val, delta;
     opus_int32 a32_QA1[ SILK_MAX_ORDER_LPC ];
-    opus_int32 maxabs, absval, idx=0, sc_Q16;
 
     silk_assert( LSF_COS_TAB_SZ_FIX == 128 );
-    silk_assert( d==10||d==16 );
+    silk_assert( d==10 || d==16 );
 
     /* convert LSFs to 2*cos(LSF), using piecewise linear curve from table */
     ordering = d == 16 ? ordering16 : ordering10;
     for( k = 0; k < d; k++ ) {
-        silk_assert(NLSF[k] >= 0 );
+        silk_assert( NLSF[k] >= 0 );
 
         /* f_int on a scale 0-127 (rounded down) */
         f_int = silk_RSHIFT( NLSF[k], 15 - 7 );
@@ -126,52 +125,15 @@ void silk_NLSF2A(
         a32_QA1[ d-k-1 ] =  Qtmp - Ptmp;        /* QA+1 */
     }
 
-    /* Limit the maximum absolute value of the prediction coefficients, so that they'll fit in int16 */
-    for( i = 0; i < 10; i++ ) {
-        /* Find maximum absolute value and its index */
-        maxabs = 0;
-        for( k = 0; k < d; k++ ) {
-            absval = silk_abs( a32_QA1[k] );
-            if( absval > maxabs ) {
-                maxabs = absval;
-                idx    = k;
-            }
-        }
-        maxabs = silk_RSHIFT_ROUND( maxabs, QA + 1 - 12 );                                          /* QA+1 -> Q12 */
-
-        if( maxabs > silk_int16_MAX ) {
-            /* Reduce magnitude of prediction coefficients */
-            maxabs = silk_min( maxabs, 163838 );  /* ( silk_int32_MAX >> 14 ) + silk_int16_MAX = 163838 */
-            sc_Q16 = SILK_FIX_CONST( 0.999, 16 ) - silk_DIV32( silk_LSHIFT( maxabs - silk_int16_MAX, 14 ),
-                                        silk_RSHIFT32( silk_MUL( maxabs, idx + 1), 2 ) );
-            silk_bwexpander_32( a32_QA1, d, sc_Q16 );
-        } else {
-            break;
-        }
-    }
+    /* Convert int32 coefficients to Q12 int16 coefs */
+    silk_LPC_fit( a_Q12, a32_QA1, 12, QA + 1, d );
 
-    if( i == 10 ) {
-        /* Reached the last iteration, clip the coefficients */
+    for( i = 0; silk_LPC_inverse_pred_gain( a_Q12, d ) == 0 && i < MAX_LPC_STABILIZE_ITERATIONS; i++ ) {
+        /* Prediction coefficients are (too close to) unstable; apply bandwidth expansion   */
+        /* on the unscaled coefficients, convert to Q12 and measure again                   */
+        silk_bwexpander_32( a32_QA1, d, 65536 - silk_LSHIFT( 2, i ) );
         for( k = 0; k < d; k++ ) {
-            a_Q12[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 ) );  /* QA+1 -> Q12 */
-            a32_QA1[ k ] = silk_LSHIFT( (opus_int32)a_Q12[ k ], QA + 1 - 12 );
-        }
-    } else {
-        for( k = 0; k < d; k++ ) {
-            a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 );                /* QA+1 -> Q12 */
-        }
-    }
-
-    for( i = 0; i < MAX_LPC_STABILIZE_ITERATIONS; i++ ) {
-        if( silk_LPC_inverse_pred_gain( a_Q12, d ) < SILK_FIX_CONST( 1.0 / MAX_PREDICTION_POWER_GAIN, 30 ) ) {
-            /* Prediction coefficients are (too close to) unstable; apply bandwidth expansion   */
-            /* on the unscaled coefficients, convert to Q12 and measure again                   */
-            silk_bwexpander_32( a32_QA1, d, 65536 - silk_LSHIFT( 2, i ) );
-            for( k = 0; k < d; k++ ) {
-                a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 );            /* QA+1 -> Q12 */
-            }
-        } else {
-            break;
+            a_Q12[ k ] = (opus_int16)silk_RSHIFT_ROUND( a32_QA1[ k ], QA + 1 - 12 );            /* QA+1 -> Q12 */
         }
     }
 }
diff --git a/silk/SigProc_FIX.h b/silk/SigProc_FIX.h
index 3d3161c9..4d0e7df8 100644
--- a/silk/SigProc_FIX.h
+++ b/silk/SigProc_FIX.h
@@ -274,6 +274,15 @@ void silk_NLSF2A(
     const opus_int              d                   /* I    filter order (should be even)                               */
 );
 
+/* Convert int32 coefficients to int16 coefs and make sure there's no wrap-around */
+void silk_LPC_fit(
+    opus_int16                  *a_QOUT,            /* O    Output signal                                               */
+    opus_int32			        *a_QIN,             /* I/O  Input signal                                                */
+    const opus_int              QOUT,               /* I    Input Q domain                                              */
+    const opus_int              QIN,                /* I    Input Q domain                                              */
+    const opus_int              d                   /* I    Filter order                                                */
+);
+
 void silk_insertion_sort_increasing(
     opus_int32                  *a,                 /* I/O   Unsorted / Sorted vector                                   */
     opus_int                    *idx,               /* O     Index vector for the sorted elements                       */
diff --git a/silk/bwexpander.c b/silk/bwexpander.c
index 2eb44566..afa97907 100644
--- a/silk/bwexpander.c
+++ b/silk/bwexpander.c
@@ -45,7 +45,7 @@ void silk_bwexpander(
     /* Bias in silk_SMULWB can lead to unstable filters                                */
     for( i = 0; i < d - 1; i++ ) {
         ar[ i ]    = (opus_int16)silk_RSHIFT_ROUND( silk_MUL( chirp_Q16, ar[ i ]             ), 16 );
-        chirp_Q16 +=            silk_RSHIFT_ROUND( silk_MUL( chirp_Q16, chirp_minus_one_Q16 ), 16 );
+        chirp_Q16 +=             silk_RSHIFT_ROUND( silk_MUL( chirp_Q16, chirp_minus_one_Q16 ), 16 );
     }
     ar[ d - 1 ] = (opus_int16)silk_RSHIFT_ROUND( silk_MUL( chirp_Q16, ar[ d - 1 ] ), 16 );
 }
diff --git a/silk/control_codec.c b/silk/control_codec.c
index 1c2c857e..1911919f 100644
--- a/silk/control_codec.c
+++ b/silk/control_codec.c
@@ -324,7 +324,6 @@ static opus_int silk_setup_complexity(
         psEncC->la_shape                        = 3 * psEncC->fs_kHz;
         psEncC->nStatesDelayedDecision          = 1;
         psEncC->useInterpolatedNLSFs            = 0;
-        psEncC->LTPQuantLowComplexity           = 1;
         psEncC->NLSF_MSVQ_Survivors             = 2;
         psEncC->warping_Q16                     = 0;
     } else if( Complexity < 2 ) {
@@ -335,7 +334,6 @@ static opus_int silk_setup_complexity(
         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
         psEncC->nStatesDelayedDecision          = 1;
         psEncC->useInterpolatedNLSFs            = 0;
-        psEncC->LTPQuantLowComplexity           = 0;
         psEncC->NLSF_MSVQ_Survivors             = 3;
         psEncC->warping_Q16                     = 0;
     } else if( Complexity < 3 ) {
@@ -346,7 +344,6 @@ static opus_int silk_setup_complexity(
         psEncC->la_shape                        = 3 * psEncC->fs_kHz;
         psEncC->nStatesDelayedDecision          = 2;
         psEncC->useInterpolatedNLSFs            = 0;
-        psEncC->LTPQuantLowComplexity           = 1;
         psEncC->NLSF_MSVQ_Survivors             = 2;
         psEncC->warping_Q16                     = 0;
     } else if( Complexity < 4 ) {
@@ -357,7 +354,6 @@ static opus_int silk_setup_complexity(
         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
         psEncC->nStatesDelayedDecision          = 2;
         psEncC->useInterpolatedNLSFs            = 0;
-        psEncC->LTPQuantLowComplexity           = 0;
         psEncC->NLSF_MSVQ_Survivors             = 4;
         psEncC->warping_Q16                     = 0;
     } else if( Complexity < 6 ) {
@@ -368,7 +364,6 @@ static opus_int silk_setup_complexity(
         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
         psEncC->nStatesDelayedDecision          = 2;
         psEncC->useInterpolatedNLSFs            = 1;
-        psEncC->LTPQuantLowComplexity           = 0;
         psEncC->NLSF_MSVQ_Survivors             = 6;
         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
     } else if( Complexity < 8 ) {
@@ -379,7 +374,6 @@ static opus_int silk_setup_complexity(
         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
         psEncC->nStatesDelayedDecision          = 3;
         psEncC->useInterpolatedNLSFs            = 1;
-        psEncC->LTPQuantLowComplexity           = 0;
         psEncC->NLSF_MSVQ_Survivors             = 8;
         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
     } else {
@@ -390,7 +384,6 @@ static opus_int silk_setup_complexity(
         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
         psEncC->nStatesDelayedDecision          = MAX_DEL_DEC_STATES;
         psEncC->useInterpolatedNLSFs            = 1;
-        psEncC->LTPQuantLowComplexity           = 0;
         psEncC->NLSF_MSVQ_Survivors             = 16;
         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
     }
diff --git a/silk/structs.h b/silk/structs.h
index 3e8fa8ec..0e17ec28 100644
--- a/silk/structs.h
+++ b/silk/structs.h
@@ -170,7 +170,6 @@ typedef struct {
     opus_int                     pitchEstimationComplexity;         /* Complexity level for pitch estimator                             */
     opus_int                     pitchEstimationLPCOrder;           /* Whitening filter order for pitch estimator                       */
     opus_int32                   pitchEstimationThreshold_Q16;      /* Threshold for pitch estimator                                    */
-    opus_int                     LTPQuantLowComplexity;             /* Flag for low complexity LTP quantization                         */
     opus_int32                   sum_log_gain_Q7;                   /* Cumulative max prediction gain                                   */
     opus_int                     NLSF_MSVQ_Survivors;               /* Number of survivors in NLSF MSVQ                                 */
     opus_int                     first_frame_after_reset;           /* Flag for deactivating NLSF interpolation, pitch prediction       */
diff --git a/silk_sources.mk b/silk_sources.mk
index 72cdbfee..6869bf5d 100644
--- a/silk_sources.mk
+++ b/silk_sources.mk
@@ -74,7 +74,8 @@ silk/sum_sqr_shift.c \
 silk/stereo_decode_pred.c \
 silk/stereo_encode_pred.c \
 silk/stereo_find_predictor.c \
-silk/stereo_quant_pred.c
+silk/stereo_quant_pred.c \
+silk/LPC_fit.c
 
 SILK_SOURCES_SSE4_1 = silk/x86/NSQ_sse.c \
 silk/x86/NSQ_del_dec_sse.c \