target/arm: Assert immh != 0 in disas_simd_shift_imm

Coverity raised a shed-load of errors cascading from inferring
that clz32(immh) might yield 32, from immh might be 0.

While immh cannot be 0 from encoding, it is not obvious even to
a human how we've checked that: via the filtering provided by
data_proc_simd[].

Backports commit 3944d58db3fc5bf131345a21a44013bc13849a12 from qemu
This commit is contained in:
Richard Henderson 2020-04-30 06:53:53 -04:00 committed by Lioncash
parent d5234c8b3d
commit fd4ce2cba0

View file

@ -10694,6 +10694,9 @@ static void disas_simd_shift_imm(DisasContext *s, uint32_t insn)
bool is_u = extract32(insn, 29, 1);
bool is_q = extract32(insn, 30, 1);
/* data_proc_simd[] has sent immh == 0 to disas_simd_mod_imm. */
assert(immh != 0);
switch (opcode) {
case 0x08: /* SRI */
if (!is_u) {