[PATCH] D158673: [SDAG][RISCV] Avoid neg instructions when lowering atomic_load_sub with a constant rhs

[Jessica Clarke via Phabricator via llvm-commits]

jrtc27 added a comment.

This seems like it would be better as a DAG->DAG transform pre-lowering? Or perhaps a more general peephole to merge the neg(w)+li? Or do it in TableGen? I don't think this warrants custom C++ //lowering//.


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https://reviews.llvm.org/D158673