[llvm] [SLPVectorizer][X86] Free load cost for stores with constant pointers (PR #118016)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

FWIW, the load emitted by clang-15 (https://godbolt.org/z/nbofoe6zM) shouldn't be related with this, and in any cases, it just seems suboptimal codegen (GCC doesn't emit any load wrt to this instance).

https://github.com/llvm/llvm-project/pull/118016