[llvm] [ConstantFolding] Add flag to disable call folding (PR #140270)
Eli Friedman via llvm-commits
llvm-commits at lists.llvm.org
Fri May 23 13:04:37 PDT 2025
efriedma-quic wrote:
I don't see why you'd use an inaccurate implementation to constant-fold something like nvvm.rsqrt.approx.f32. It maps to some exact formula; likely a small table lookup plus linear interpolation. (Unless it isn't consistent across targets?)
For the target-independent transcendental intrinsics, you can use a nobuiltin call to the actual implementation. For non-transcendental intrinsics, you can control lowering with fast-math flags. If you want to turn off optimizations for debugging, we have other tools for that, like opt-bisect-limit.
Disabling folding for everything, even cases where it's possible to fold deterministically, is a good indication to users that we don't expect them to use this flag in production. So maybe this is okay.
https://github.com/llvm/llvm-project/pull/140270
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