[llvm] [Memory] Call __clear_cache in InvalidateInstructionCache on LoongArch (PR #67285)

[WÁNG Xuěruì via llvm-commits]

xen0n wrote:

> > IIRC, `__clear_cache` is DBAR, and I think we need not only DBAR but also IBAR?
> 
> `__clear_cache` has different implementations:
> 
>     * gcc: `ibar 0`
> 
>     * libgcc: empty (I have reported this issue to gcc loongarch maintainers)
> 
>     * compiler-rt: `ibar 0`

Hmmm then I must have remembered it wrong (hence the "IIRC" prefix in my reply). No problem from my side then ;-)

https://github.com/llvm/llvm-project/pull/67285