[llvm] [LangRef] Cap maximum value of vscale at 2^31-1. (PR #144607)

[Craig Topper via llvm-commits]

topperc wrote:

> > runtime VF vscale x V generated by LoopVectorize won't wrap when using i64 index types
> 
> What about 32-bit targets?
> 
> (Not that I'm objecting to this... you'd need to be doing something really unusual with your target to end up with vscales above 1000.)

If it helps, the maximum vscale for RISC-V is currently 1024. If we ever fix some other issues that prevent us from supporting the smallest vector length of 32, then the maximum vscale will be 2048.

https://github.com/llvm/llvm-project/pull/144607