[llvm] [X86] For inline memset with minsize, use stosb or stosd (PR #87003)

[Rose Silicon via llvm-commits]

RSilicon wrote:

> > > Your patch describes memset yet most of the changes appear to be for memcpy :/
> > 
> > 
> > Incorrect. The memset code was refactored to use the same method as the memcpy code for determining block size.
> 
> You changed the codegen for 2 memcpy tests, but do not mention that in the patch description.

Done!

https://github.com/llvm/llvm-project/pull/87003