Add a test against MPFR using random inputs

Author: tgross35

crates/libm-test/build.rs

@@ -64,6 +64,11 @@ fn emit_cfg_shorthands(cfg: &Config) {
         // Shorthand to detect i586 targets
         println!("cargo::rustc-cfg=x86_no_sse");
     }
+
+    println!("cargo::rustc-check-cfg=cfg(x86_macos)");
+    if cfg.target_arch == "x86_64" && cfg.target_vendor == "apple" {
+        println!("cargo::rustc-cfg=x86_macos");
+    }
 }
 
 /// Create a list of all source files in an array. This can be used for making sure that

crates/libm-test/src/lib.rs

@@ -16,14 +16,18 @@ pub type TestResult<T = (), E = anyhow::Error> = Result<T, E>;
 // List of all files present in libm's source
 include!(concat!(env!("OUT_DIR"), "/all_files.rs"));
 
-/// ULP allowed to differ from musl (note that musl itself may not be accurate).
+/// Default ULP allowed to differ from musl (note that musl itself may not be accurate).
 const MUSL_DEFAULT_ULP: u32 = 2;
 
-/// Certain functions have different allowed ULP (consider these xfail).
+/// Default ULP allowed to differ from multiprecision (i.e. infinite) results.
+const MULTIPREC_DEFAULT_ULP: u32 = 1;
+
+/// ULP allowed to differ from muls results.
 ///
 /// Note that these results were obtained using 400,000,000 rounds of random inputs, which
 /// is not a value used by default.
 pub fn musl_allowed_ulp(name: &str) -> u32 {
+    // Consider overrides xfail
     match name {
         #[cfg(x86_no_sse)]
         "asinh" | "asinhf" => 6,
@@ -44,6 +48,22 @@ pub fn musl_allowed_ulp(name: &str) -> u32 {
     }
 }
 
+/// ULP allowed to differ from multiprecision results.
+pub fn multiprec_allowed_ulp(name: &str) -> u32 {
+    // Consider overrides xfail
+    match name {
+        "asinh" | "asinhf" => 2,
+        "atanh" | "atanhf" => 2,
+        "exp10" | "exp10f" => 3,
+        "j0" | "j0f" => 2,
+        "lgamma" | "lgammaf" | "lgamma_r" | "lgammaf_r" => 2,
+        "sinh" | "sinhf" => 2,
+        "tanh" | "tanhf" => 2,
+        "tgamma" => 6,
+        _ => MULTIPREC_DEFAULT_ULP,
+    }
+}
+
 /// Return the unsuffixed version of a function name; e.g. `abs` and `absf` both return `abs`,
 /// `lgamma_r` and `lgammaf_r` both return `lgamma_r`.
 pub fn canonical_name(name: &str) -> &str {

crates/libm-test/src/special_case.rs

@@ -91,6 +91,25 @@ impl MaybeOverride<(f32,)> for SpecialCase {
 
         maybe_check_nan_bits(actual, expected, ctx)
     }
+
+    fn check_int<I: Int>(
+        input: (f32,),
+        actual: I,
+        expected: I,
+        ctx: &CheckCtx,
+    ) -> Option<anyhow::Result<()>> {
+        // On MPFR for lgammaf_r, we set -1 as the integer result for negative infinity but MPFR
+        // sets +1
+        if ctx.basis == CheckBasis::MultiPrecision
+            && ctx.fname == "lgammaf_r"
+            && input.0 == f32::NEG_INFINITY
+            && actual.abs() == expected.abs()
+        {
+            XFAIL
+        } else {
+            None
+        }
+    }
 }
 
 impl MaybeOverride<(f64,)> for SpecialCase {
@@ -126,6 +145,25 @@ impl MaybeOverride<(f64,)> for SpecialCase {
 
         maybe_check_nan_bits(actual, expected, ctx)
     }
+
+    fn check_int<I: Int>(
+        input: (f64,),
+        actual: I,
+        expected: I,
+        ctx: &CheckCtx,
+    ) -> Option<anyhow::Result<()>> {
+        // On MPFR for lgamma_r, we set -1 as the integer result for negative infinity but MPFR
+        // sets +1
+        if ctx.basis == CheckBasis::MultiPrecision
+            && ctx.fname == "lgamma_r"
+            && input.0 == f64::NEG_INFINITY
+            && actual.abs() == expected.abs()
+        {
+            XFAIL
+        } else {
+            None
+        }
+    }
 }
 
 /// Check NaN bits if the function requires it
@@ -185,23 +223,51 @@ fn maybe_skip_min_max_nan<F1: Float, F2: Float>(
 impl MaybeOverride<(i32, f32)> for SpecialCase {
     fn check_float<F: Float>(
         input: (i32, f32),
-        _actual: F,
-        _expected: F,
+        actual: F,
+        expected: F,
         ulp: &mut u32,
         ctx: &CheckCtx,
     ) -> Option<TestResult> {
-        bessel_prec_dropoff(input, ulp, ctx)
+        match ctx.basis {
+            CheckBasis::Musl => bessel_prec_dropoff(input, ulp, ctx),
+            CheckBasis::MultiPrecision => {
+                // We return +0.0, MPFR returns -0.0
+                if ctx.fname == "jnf"
+                    && input.1 == f32::NEG_INFINITY
+                    && actual == F::ZERO
+                    && expected == F::ZERO
+                {
+                    XFAIL
+                } else {
+                    None
+                }
+            }
+        }
     }
 }
 impl MaybeOverride<(i32, f64)> for SpecialCase {
     fn check_float<F: Float>(
         input: (i32, f64),
-        _actual: F,
-        _expected: F,
+        actual: F,
+        expected: F,
         ulp: &mut u32,
         ctx: &CheckCtx,
     ) -> Option<TestResult> {
-        bessel_prec_dropoff(input, ulp, ctx)
+        match ctx.basis {
+            CheckBasis::Musl => bessel_prec_dropoff(input, ulp, ctx),
+            CheckBasis::MultiPrecision => {
+                // We return +0.0, MPFR returns -0.0
+                if ctx.fname == "jn"
+                    && input.1 == f64::NEG_INFINITY
+                    && actual == F::ZERO
+                    && expected == F::ZERO
+                {
+                    XFAIL
+                } else {
+                    None
+                }
+            }
+        }
     }
 }
 

crates/libm-test/src/test_traits.rs

@@ -52,6 +52,8 @@ impl CheckCtx {
 pub enum CheckBasis {
     /// Check against Musl's math sources.
     Musl,
+    /// Check against infinite precision (MPFR).
+    MultiPrecision,
 }
 
 /// A trait to implement on any output type so we can verify it in a generic way.

crates/libm-test/tests/multiprecision.rs

@@ -0,0 +1,62 @@
+//! Test with "infinite precision"
+
+#![cfg(feature = "test-multiprecision")]
+
+use libm_test::gen::random;
+use libm_test::mpfloat::{self, MpOp};
+use libm_test::{CheckBasis, CheckCtx, CheckOutput, TupleCall, multiprec_allowed_ulp};
+
+/// Implement a test against MPFR with random inputs.
+macro_rules! multiprec_rand_tests {
+    (
+        fn_name: $fn_name:ident,
+        CFn: $CFn:ty,
+        CArgs: $CArgs:ty,
+        CRet: $CRet:ty,
+        RustFn: $RustFn:ty,
+        RustArgs: $RustArgs:ty,
+        RustRet: $RustRet:ty,
+        attrs: [$($meta:meta)*]
+    ) => {
+        paste::paste! {
+            #[test]
+            $(#[$meta])*
+            fn [< multiprec_random_ $fn_name >]() {
+                type MpOpTy = mpfloat::$fn_name::Operation;
+
+                let fname = stringify!($fn_name);
+                let ulp = multiprec_allowed_ulp(fname);
+                let cases = random::get_test_cases::<$RustArgs>(fname);
+                let mut mp_vals = MpOpTy::new();
+                let ctx = CheckCtx::new(ulp, fname, CheckBasis::MultiPrecision);
+
+                for input in cases {
+                    let mp_res = mp_vals.run(input);
+                    let crate_res = input.call(libm::$fn_name as $RustFn);
+
+                    mp_res.validate(crate_res, input, &ctx).unwrap();
+                }
+            }
+        }
+    };
+}
+
+libm_macros::for_each_function! {
+    callback: multiprec_rand_tests,
+    attributes: [],
+    skip: [
+        // FIXME: MPFR tests needed
+        frexp,
+        frexpf,
+        ilogb,
+        ilogbf,
+        ldexp,
+        ldexpf,
+        modf,
+        modff,
+        remquo,
+        remquof,
+        scalbn,
+        scalbnf,
+    ],
+}