LoadCombine pattern handling was added as a workaround for the cases,
where the SLP vectorizer could not vectorize the code effectively. With
the copyables support, it can handle it directly.
Also, patch adds support for scalar loads[ + bswap] pattern for byte
sized loads (+ reverse bytes for bswap)
Recommit after revert in 6377c86d718232fe60c548dfd7ab439f7ff84df7
Reviewers: RKSimon, hiraditya
Pull Request: https://github.com/llvm/llvm-project/pull/174205
fe754dff6d