[PATCH] D61331: [SelectionDAG] remove constant folding limitations based on FP exceptions

[Andy Kaylor via Phabricator via llvm-commits]

andrew.w.kaylor added a comment.

Rather than get rid of this, can we update it to handle strict FP nodes correctly? Or at least put a skeleton in place to prepare to handle it correctly?

Right now I think we're throwing away the rounding mode and exception semantics arguments when we convert constrained intrinsics to strict FP nodes, but if we still had that information here we could use it to make a smart decision. For instance, suppose we had an intrinsic like this:

  %t = call double @llvm.experimental.constrained.fadd.f64(double 4.3, double 6.5,
                                                           metadata !"round.upward",
                                                           metadata !"fpexcept.ignore")

If that got to the selection DAG we would be able to fold it.


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  https://reviews.llvm.org/D61331/new/

https://reviews.llvm.org/D61331