[Bug target/118828] LoongArch: #pragma GCC target should update __loongarch_asx and similar macros

[chenglulu at loongson dot cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118828

--- Comment #1 from chenglulu <chenglulu at loongson dot cn> ---
(In reply to Xi Ruoyao from comment #0)
> Test case:
> 
> /* { dg-do preprocess } */
> /* { dg-options "-mno-lasx" } */
> 
> #ifdef __loongarch_asx
> #error LASX shouldn't be available here
> #endif
> 
> #pragma GCC push_options
> #pragma GCC target("lasx")
> #ifndef __loongarch_asx
> #error LASX should be available here
> #endif
> #pragma GCC pop_options
> 
> #ifdef __loongarch_asx
> #error LASX should become unavailable again
> #endif
> 
> Note that a similar test case (c-c++-common/pragma-target-2.c) for x86 works
> as expected.

This issue indeed hasn't been addressed. I've already fixed a patch for it, and
the tests came back fine. I'll commit it tonight.