[PATCH] D72015: DAG: Stop trying to fold FP -(x-y) -> y-x in getNode with nsz

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

The transform doesn't necessarily add an instruction (depends on the target), but I agree that we don't want to replace an fneg generically with an fsub - even if that reduces the dependency chain, the fneg might be cheap/free relative to an independent FP op. I've added an AArch64 test here that should wiggle with this patch:
rGe6bdecf1cd6b <https://reviews.llvm.org/rGe6bdecf1cd6b75222ef094371a514026d8aa0afa>

Please rebase (and would be better to have the baseline AMDGPU test as a preliminary commit too).


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https://reviews.llvm.org/D72015