[llvm] [NVPTX] Merge consecutive elements while buffering constant vectors with sub-byte datatype. (PR #183628)

[Artem Belevich via llvm-commits]

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Artem-B wrote:

Set default to 0, This way you do not need to add a comment when you don't need padding.

https://github.com/llvm/llvm-project/pull/183628