Xavier Bouchoux 5ab1854602 codegen/llvm: fix memset with vectors smaller than one byte
The special case to take advantage of llvm's intrinsic
was generating invalid llvm ir:

```
Invalid bitcast
  %60 = bitcast <2 x i2> %59 to i8, !dbg !3122
thread 145453 panic: LLVM module verification failed
```
2023-07-25 18:14:10 -07:00
..
2023-06-25 14:51:03 -07:00