[llvm] [DAG] visitTRUNCATE - more aggressively fold trunc(add(x,x)) -> add(trunc(x),trunc(x)) (PR #164227)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

LGTM for AArch64 too, thanks.

https://github.com/llvm/llvm-project/pull/164227