Optimize num_traits::Float::powi to use GLSL.std.450 Pow #518
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nazar-pc
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Jan 21, 2026
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| // Check for usage of `num_traits` intrinsics (like Float::powi) that we can optimize | ||
| if self.tcx.crate_name(def_id.krate) == self.sym.num_traits && !def_id.is_local() { | ||
| let item_name = self.tcx.item_name(def_id); | ||
| if let Some(&intrinsic) = self.sym.libm_intrinsics.get(&item_name) { | ||
| self.libm_intrinsics.borrow_mut().insert(def_id, intrinsic); | ||
| } | ||
| } |
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I have no idea how things work more generally, but why are things like this even necessary? I'd expect the generic machinery of the compiler to optimize it to some canonical form that the target would like the most.
So it shouldn't make any difference if one writes x.powi(2) or x * x or uses a few layers of zero-cost abstractions in the process, should all result in identical SPIR-V, just like it does with LLVM. What am I missing?
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Fixes #516.