[Bug target/97521] [11 Regression] wrong code with -mno-sse2 since r11-3394

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97521

--- Comment #10 from Hongtao.liu <crazylht at gmail dot com> ---
Speaking about how to represent the V*BImode constants, i think we need to
extend attribute vector_size to handle something like
---
typedef bool v8bi __attribute__ ((vector_size (1)));
---

currently there would be an error as 

<source>:1:51: error: invalid vector type for attribute 'vector_size'

    1 | typedef bool v8qi __attribute__ ((vector_size (1)));


also we need to support type convert between vector boolean types and integer
in front end, since many users may use integer as a mask.