1 files changed, 82 insertions, 0 deletions
diff --git a/tests/ui/float/classify-runtime-const.rs b/tests/ui/float/classify-runtime-const.rs
new file mode 100644
index 00000000000..59a232c255e
--- /dev/null
+++ b/tests/ui/float/classify-runtime-const.rs
@@ -0,0 +1,82 @@
+//@ compile-flags: -Zmir-opt-level=0 -Znext-solver
+//@ run-pass
+// ignore-tidy-linelength
+
+// This tests the float classification functions, for regular runtime code and for const evaluation.
+
+#![feature(f16_const)]
+#![feature(f128_const)]
+#![feature(const_float_classify)]
+
+use std::hint::black_box;
+use std::num::FpCategory::*;
+
+macro_rules! both_assert {
+    ($a:expr, NonDet) => {
+        {
+            // Compute `a`, but do not compare with anything as the result is non-deterministic.
+            const _: () = { let _val = $a; };
+            // `black_box` prevents promotion, and MIR opts are disabled above, so this is truly
+            // going through LLVM.
+            let _val = black_box($a);
+        }
+    };
+    ($a:expr, $b:ident) => {
+        {
+            const _: () = assert!(matches!($a, $b));
+            assert!(black_box($a) == black_box($b));
+        }
+    };
+}
+
+macro_rules! suite {
+    ( $tyname:ident: $( $tt:tt )* ) => {
+        fn f32() {
+            type $tyname = f32;
+            suite_inner!(f32 $($tt)*);
+        }
+
+        fn f64() {
+            type $tyname = f64;
+            suite_inner!(f64 $($tt)*);
+        }
+    }
+}
+
+macro_rules! suite_inner {
+    (
+        $ty:ident [$( $fn:ident ),*]
+        $val:expr => [$($out:ident),*]
+
+        $( $tail:tt )*
+    ) => {
+        $( both_assert!($ty::$fn($val), $out); )*
+        suite_inner!($ty [$($fn),*] $($tail)*)
+    };
+
+    ( $ty:ident [$( $fn:ident ),*]) => {};
+}
+
+// The result of the `is_sign` methods are not checked for correctness, since we do not
+// guarantee anything about the signedness of NaNs. See
+// https://rust-lang.github.io/rfcs/3514-float-semantics.html.
+
+suite! { T: // type alias for the type we are testing
+                   [ classify, is_nan, is_infinite, is_finite, is_normal, is_sign_positive, is_sign_negative]
+     -0.0 / 0.0 => [      Nan,   true,       false,     false,     false,           NonDet,           NonDet]
+      0.0 / 0.0 => [      Nan,   true,       false,     false,     false,           NonDet,           NonDet]
+            1.0 => [   Normal,  false,       false,      true,      true,             true,            false]
+           -1.0 => [   Normal,  false,       false,      true,      true,            false,             true]
+            0.0 => [     Zero,  false,       false,      true,     false,             true,            false]
+           -0.0 => [     Zero,  false,       false,      true,     false,            false,             true]
+      1.0 / 0.0 => [ Infinite,  false,        true,     false,     false,             true,            false]
+     -1.0 / 0.0 => [ Infinite,  false,        true,     false,     false,            false,             true]
+   1.0 / T::MAX => [Subnormal,  false,       false,      true,     false,             true,            false]
+  -1.0 / T::MAX => [Subnormal,  false,       false,      true,     false,            false,             true]
+}
+
+fn main() {
+    f32();
+    f64();
+    // FIXME(f16_f128): also test f16 and f128
+}