Bug Summary

File:libs/opus-1.1-p2/silk/LPC_inv_pred_gain.c
Location:line 84, column 28
Description:The result of the '>>' expression is undefined

Annotated Source Code

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26***********************************************************************/
27
28#ifdef HAVE_CONFIG_H1
29#include "config.h"
30#endif
31
32#include "SigProc_FIX.h"
33
34#define QA24 24
35#define A_LIMIT((opus_int32)((0.99975) * ((long long)1 << (24)) + 0.5)
) SILK_FIX_CONST( 0.99975, QA )((opus_int32)((0.99975) * ((long long)1 << (24)) + 0.5)
)
36
37#define MUL32_FRAC_Q(a32, b32, Q)((opus_int32)(((Q) == 1 ? ((((long long)(a32) * (b32))) >>
1) + ((((long long)(a32) * (b32))) & 1) : (((((long long
)(a32) * (b32))) >> ((Q) - 1)) + 1) >> 1))) ((opus_int32)(silk_RSHIFT_ROUND64(silk_SMULL(a32, b32), Q)((Q) == 1 ? ((((long long)(a32) * (b32))) >> 1) + ((((long
long)(a32) * (b32))) & 1) : (((((long long)(a32) * (b32)
)) >> ((Q) - 1)) + 1) >> 1)))
38
39/* Compute inverse of LPC prediction gain, and */
40/* test if LPC coefficients are stable (all poles within unit circle) */
41static opus_int32 LPC_inverse_pred_gain_QA( /* O Returns inverse prediction gain in energy domain, Q30 */
42 opus_int32 A_QA[ 2 ][ SILK_MAX_ORDER_LPC16 ], /* I Prediction coefficients */
43 const opus_intint order /* I Prediction order */
44)
45{
46 opus_intint k, n, mult2Q;
47 opus_int32 invGain_Q30, rc_Q31, rc_mult1_Q30, rc_mult2, tmp_QA;
48 opus_int32 *Aold_QA, *Anew_QA;
49
50 Anew_QA = A_QA[ order & 1 ];
51
52 invGain_Q30 = (opus_int32)1 << 30;
53 for( k = order - 1; k > 0; k-- ) {
5
←
Assuming 'k' is > 0
→
6
←
Loop condition is true. Entering loop body
→
54 /* Check for stability */
55 if( ( Anew_QA[ k ] > A_LIMIT((opus_int32)((0.99975) * ((long long)1 << (24)) + 0.5)
) ) || ( Anew_QA[ k ] < -A_LIMIT((opus_int32)((0.99975) * ((long long)1 << (24)) + 0.5)
) ) ) {
7
←
Taking false branch
→
56 return 0;
57 }
58
59 /* Set RC equal to negated AR coef */
60 rc_Q31 = -silk_LSHIFT( Anew_QA[ k ], 31 - QA )((opus_int32)((opus_uint32)(Anew_QA[ k ])<<(31 - 24)));
61
62 /* rc_mult1_Q30 range: [ 1 : 2^30 ] */
63 rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 )(opus_int32)((((long long)((rc_Q31)) * ((rc_Q31))))>>(32
));
64 silk_assert( rc_mult1_Q30 > ( 1 << 15 ) ); /* reduce A_LIMIT if fails */
65 silk_assert( rc_mult1_Q30 <= ( 1 << 30 ) );
66
67 /* rc_mult2 range: [ 2^30 : silk_int32_MAX ] */
68 mult2Q = 32 - silk_CLZ32( silk_abs( rc_mult1_Q30 )(((rc_mult1_Q30) > 0) ? (rc_mult1_Q30) : -(rc_mult1_Q30)) );
69 rc_mult2 = silk_INVERSE32_varQ( rc_mult1_Q30, mult2Q + 30 );
70
71 /* Update inverse gain */
72 /* invGain_Q30 range: [ 0 : 2^30 ] */
73 invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 )((opus_int32)((opus_uint32)((opus_int32)((((long long)((invGain_Q30
)) * ((rc_mult1_Q30))))>>(32)))<<(2)));
74 silk_assert( invGain_Q30 >= 0 );
75 silk_assert( invGain_Q30 <= ( 1 << 30 ) );
76
77 /* Swap pointers */
78 Aold_QA = Anew_QA;
79 Anew_QA = A_QA[ k & 1 ];
80
81 /* Update AR coefficient */
82 for( n = 0; n < k; n++ ) {
8
←
Loop condition is true. Entering loop body
→
83 tmp_QA = Aold_QA[ n ] - MUL32_FRAC_Q( Aold_QA[ k - n - 1 ], rc_Q31, 31 )((opus_int32)(((31) == 1 ? ((((long long)(Aold_QA[ k - n - 1 ]
) * (rc_Q31))) >> 1) + ((((long long)(Aold_QA[ k - n - 1
]) * (rc_Q31))) & 1) : (((((long long)(Aold_QA[ k - n - 1
]) * (rc_Q31))) >> ((31) - 1)) + 1) >> 1)));
84 Anew_QA[ n ] = MUL32_FRAC_Q( tmp_QA, rc_mult2 , mult2Q )((opus_int32)(((mult2Q) == 1 ? ((((long long)(tmp_QA) * (rc_mult2
))) >> 1) + ((((long long)(tmp_QA) * (rc_mult2))) &
1) : (((((long long)(tmp_QA) * (rc_mult2))) >> ((mult2Q
) - 1)) + 1) >> 1)));
9
←
Within the expansion of the macro 'MUL32_FRAC_Q':
a
The result of the '>>' expression is undefined
85 }
86 }
87
88 /* Check for stability */
89 if( ( Anew_QA[ 0 ] > A_LIMIT((opus_int32)((0.99975) * ((long long)1 << (24)) + 0.5)
) ) || ( Anew_QA[ 0 ] < -A_LIMIT((opus_int32)((0.99975) * ((long long)1 << (24)) + 0.5)
) ) ) {
90 return 0;
91 }
92
93 /* Set RC equal to negated AR coef */
94 rc_Q31 = -silk_LSHIFT( Anew_QA[ 0 ], 31 - QA )((opus_int32)((opus_uint32)(Anew_QA[ 0 ])<<(31 - 24)));
95
96 /* Range: [ 1 : 2^30 ] */
97 rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 )(opus_int32)((((long long)((rc_Q31)) * ((rc_Q31))))>>(32
));
98
99 /* Update inverse gain */
100 /* Range: [ 0 : 2^30 ] */
101 invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 )((opus_int32)((opus_uint32)((opus_int32)((((long long)((invGain_Q30
)) * ((rc_mult1_Q30))))>>(32)))<<(2)));
102 silk_assert( invGain_Q30 >= 0 );
103 silk_assert( invGain_Q30 <= 1<<30 );
104
105 return invGain_Q30;
106}
107
108/* For input in Q12 domain */
109opus_int32 silk_LPC_inverse_pred_gain( /* O Returns inverse prediction gain in energy domain, Q30 */
110 const opus_int16 *A_Q12, /* I Prediction coefficients, Q12 [order] */
111 const opus_intint order /* I Prediction order */
112)
113{
114 opus_intint k;
115 opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC16 ];
116 opus_int32 *Anew_QA;
117 opus_int32 DC_resp = 0;
118
119 Anew_QA = Atmp_QA[ order & 1 ];
120
121 /* Increase Q domain of the AR coefficients */
122 for( k = 0; k < order; k++ ) {
1
Assuming 'k' is >= 'order'
→
2
←
Loop condition is false. Execution continues on line 127
→
123 DC_resp += (opus_int32)A_Q12[ k ];
124 Anew_QA[ k ] = silk_LSHIFT32( (opus_int32)A_Q12[ k ], QA - 12 )((opus_int32)((opus_uint32)((opus_int32)A_Q12[ k ])<<(24
- 12)));
125 }
126 /* If the DC is unstable, we don't even need to do the full calculations */
127 if( DC_resp >= 4096 ) {
3
←
Taking false branch
→
128 return 0;
129 }
130 return LPC_inverse_pred_gain_QA( Atmp_QA, order );
4
←
Calling 'LPC_inverse_pred_gain_QA'
→
131}
132
133#ifdef FIXED_POINT
134
135/* For input in Q24 domain */
136opus_int32 silk_LPC_inverse_pred_gain_Q24( /* O Returns inverse prediction gain in energy domain, Q30 */
137 const opus_int32 *A_Q24, /* I Prediction coefficients [order] */
138 const opus_intint order /* I Prediction order */
139)
140{
141 opus_intint k;
142 opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC16 ];
143 opus_int32 *Anew_QA;
144
145 Anew_QA = Atmp_QA[ order & 1 ];
146
147 /* Increase Q domain of the AR coefficients */
148 for( k = 0; k < order; k++ ) {
149 Anew_QA[ k ] = silk_RSHIFT32( A_Q24[ k ], 24 - QA )((A_Q24[ k ])>>(24 - 24));
150 }
151
152 return LPC_inverse_pred_gain_QA( Atmp_QA, order );
153}
154#endif