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0d8a978e8a
Add intrinsics `fmuladd{f16,f32,f64,f128}`. This computes `(a * b) + c`, to be fused if the code generator determines that (i) the target instruction set has support for a fused operation, and (ii) that the fused operation is more efficient than the equivalent, separate pair of `mul` and `add` instructions. https://llvm.org/docs/LangRef.html#llvm-fmuladd-intrinsic MIRI support is included for f32 and f64. The codegen_cranelift uses the `fma` function from libc, which is a correct implementation, but without the desired performance semantic. I think this requires an update to cranelift to expose a suitable instruction in its IR. I have not tested with codegen_gcc, but it should behave the same way (using `fma` from libc). |
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Cargo.toml |