Create interfaces for testing against MPFR

Add a way to call MPFR versions of functions in a predictable way, using
the `MpOp` trait.

Everything new here is guarded by the feature `test-multiprecision`
since MPFR cannot easily build on Windows or any cross compiled targets.

Author: tgross35

crates/libm-test/Cargo.toml

@@ -10,18 +10,21 @@ default = []
 # Generate tests which are random inputs and the outputs are calculated with
 # musl libc.
 test-musl-serialized = ["rand"]
+test-multiprecision = ["dep:az", "dep:rug"]
 
 # Build our own musl for testing and benchmarks
 build-musl = ["dep:musl-math-sys"]
 
 [dependencies]
 anyhow = "1.0.90"
+az = { version = "1.2.1", optional = true }
 libm = { path = "../.." }
 libm-macros = { path = "../libm-macros" }
 musl-math-sys = { path = "../musl-math-sys", optional = true }
 paste = "1.0.15"
 rand = "0.8.5"
 rand_chacha = "0.3.1"
+rug = { version = "1.26.1", optional = true, default-features = false, features = ["float", "std"] }
 
 [target.'cfg(target_family = "wasm")'.dependencies]
 # Enable randomness on WASM

crates/libm-test/src/lib.rs

@@ -1,4 +1,6 @@
 pub mod gen;
+#[cfg(feature = "test-multiprecision")]
+pub mod mpfloat;
 mod num_traits;
 mod special_case;
 mod test_traits;