[PATCH] D66805: [MIPS] For vectors, select `add %x, -1` as `sub %x, 1`

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

Forgot to mention, this `sub %X, C` -> `add %X, -C` transform is already always being performed
by InstCombine in middle-end, so such undo transform is needed regardless of what DAGCombine does.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D66805/new/

https://reviews.llvm.org/D66805