该问题是怎么引起的？

kernal_liteos_a/lib/libc/musl/src/string/strstr.c中
line 110: k = l-shift[h[l-1]];
The operand has undefined value. l - shift[h[l - 1]]；
存在执行路径使得 ，l=0 ，即shift[h[l-1]为不合法操作数；

重现步骤

1、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 33:static char *twoway_strstr(const unsigned char *h, const unsigned char *n)
Start Analysis；

2、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 41:for (l=0; n[l] && h[l]; l++)
if ( n[l]==0 || h[l]==0 ) Then Take the false branch;

3、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 43:if (n[l]) return 0;
n[l]==0 Then Take the false branch;

4、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 47:while (jp+k<l) {
jp = 0; k = p = 1; l=0 ;jp + k > l; Take the false branch;

5、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 67:while (jp+k<l) {
jp = 0; k = p = 1; l=0 ;jp + k > l; Take the false branch;

6、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 82:if (ip+1 > ms+1) ms = ip;
ip = -1;ms = ip;ip + 1 = ms + 1 Take the false branch;

7、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 86:if (memcmp(n, n+p, ms+1)) {
Call a function. memcmp(n, n + p, ms + 1);

8、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 86:if (memcmp(n, n+p, ms+1)) {
Take the true branch. memcmp(n, n + p, ms + 1);

9、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 88:p = MAX(ms, l-ms-1) + 1;
Take the false branch. (ms) < (l - ms - 1);

10、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 98:if (z-h < l) {
z = h; z-h = l; Take the false branch;

11、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 109:if (BITOP(byteset, h[l-1], &)) {
(byteset)[(size_t)(h[l - 1]) / (8 * sizeof (byteset))] & (size_t)1 << ((size_t)(h[l - 1]) % (8 * sizeof (byteset)));
** Take the true branch. ；

12、kernal_liteos_a/lib/libc/musl/src/string/strstr.c
line 110:k = l-shift[h[l-1]];
l = 0 ; The operand has undefined value. l - shift[h[l - 1]]

报错信息

kernal_liteos_a/lib/libc/musl/src/string/strstr.c中
line 110: k = l-shift[h[l-1]];
The operand has undefined value. l - shift[h[l - 1]]；
存在执行路径使得 ，l=0 ，即shift[h[l-1]为不合法操作数；