[PATCH] D137655: Expand fminimum and fmaximum into a pair of selects

[Goran Flegar via Phabricator via llvm-commits]

gflegar added a comment.

In D137655#3917359 <https://reviews.llvm.org/D137655#3917359>, @nikic wrote:

> I don't think this is right either. LLVM defines minnum according to the old semantics, which don't specify an order between zeroes. We'd need a separate ISD opcode for minnum according to 2018 semantics.

Unfortunately, I don't have the bandwidth to chase this rabbit hole further, especially since our use case is insensitive to what happens for -0 and +0. I can add a TODO comment to fix this. Though I would still argue for submitting this, as it is correct modulo -0/+0, which is far preferable to the current state where we have a silent failure (and produce invalid code) for the backends that attempt to expand the op (like in NVPTX).


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https://reviews.llvm.org/D137655