Enable const-testing for the ported SIMD intrinsics

Author: sayantn

tests/auxiliary/minisimd.rs

@@ -10,6 +10,10 @@
 
 #![allow(unused)]
 #![allow(non_camel_case_types)]
+// FIXME: `cfg(minisimd_const)` is used to toggle use of const trait impls, which require a few
+// nightly features. Remove this when `const_trait_impls`, `const_cmp` and `const_index` are
+// stablilized.
+#![allow(unexpected_cfgs)]
 
 // The field is currently left `pub` for convenience in porting tests, many of
 // which attempt to just construct it directly. That still works; it's just the
@@ -24,39 +28,32 @@ impl<T: Copy, const N: usize> Clone for Simd<T, N> {
     }
 }
 
-impl<T: PartialEq, const N: usize> PartialEq for Simd<T, N> {
-    fn eq(&self, other: &Self) -> bool {
-        self.as_array() == other.as_array()
-    }
-}
-
 impl<T: core::fmt::Debug, const N: usize> core::fmt::Debug for Simd<T, N> {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> Result<(), core::fmt::Error> {
         <[T; N] as core::fmt::Debug>::fmt(self.as_array(), f)
     }
 }
 
-impl<T, const N: usize> core::ops::Index<usize> for Simd<T, N> {
-    type Output = T;
-    fn index(&self, i: usize) -> &T {
-        &self.as_array()[i]
-    }
-}
-
 impl<T, const N: usize> Simd<T, N> {
     pub const fn from_array(a: [T; N]) -> Self {
         Simd(a)
     }
-    pub fn as_array(&self) -> &[T; N] {
+    pub const fn as_array(&self) -> &[T; N] {
         let p: *const Self = self;
         unsafe { &*p.cast::<[T; N]>() }
     }
-    pub fn into_array(self) -> [T; N]
+    pub const fn into_array(self) -> [T; N]
     where
         T: Copy,
     {
         *self.as_array()
     }
+    pub const fn splat(a: T) -> Self
+    where
+        T: Copy,
+    {
+        Self([a; N])
+    }
 }
 
 pub type u8x2 = Simd<u8, 2>;
@@ -109,6 +106,14 @@ pub type i64x8 = Simd<i64, 8>;
 pub type i128x2 = Simd<i128, 2>;
 pub type i128x4 = Simd<i128, 4>;
 
+pub type usizex2 = Simd<usize, 2>;
+pub type usizex4 = Simd<usize, 4>;
+pub type usizex8 = Simd<usize, 8>;
+
+pub type isizex2 = Simd<isize, 2>;
+pub type isizex4 = Simd<isize, 4>;
+pub type isizex8 = Simd<isize, 8>;
+
 pub type f32x2 = Simd<f32, 2>;
 pub type f32x4 = Simd<f32, 4>;
 pub type f32x8 = Simd<f32, 8>;
@@ -122,7 +127,7 @@ pub type f64x8 = Simd<f64, 8>;
 // which attempt to just construct it directly. That still works; it's just the
 // `.0` projection that doesn't.
 #[repr(simd, packed)]
-#[derive(Copy)]
+#[derive(Copy, Eq)]
 pub struct PackedSimd<T, const N: usize>(pub [T; N]);
 
 impl<T: Copy, const N: usize> Clone for PackedSimd<T, N> {
@@ -131,12 +136,6 @@ impl<T: Copy, const N: usize> Clone for PackedSimd<T, N> {
     }
 }
 
-impl<T: PartialEq, const N: usize> PartialEq for PackedSimd<T, N> {
-    fn eq(&self, other: &Self) -> bool {
-        self.as_array() == other.as_array()
-    }
-}
-
 impl<T: core::fmt::Debug, const N: usize> core::fmt::Debug for PackedSimd<T, N> {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> Result<(), core::fmt::Error> {
         <[T; N] as core::fmt::Debug>::fmt(self.as_array(), f)
@@ -147,14 +146,80 @@ impl<T, const N: usize> PackedSimd<T, N> {
     pub const fn from_array(a: [T; N]) -> Self {
         PackedSimd(a)
     }
-    pub fn as_array(&self) -> &[T; N] {
+    pub const fn as_array(&self) -> &[T; N] {
         let p: *const Self = self;
         unsafe { &*p.cast::<[T; N]>() }
     }
-    pub fn into_array(self) -> [T; N]
+    pub const fn into_array(self) -> [T; N]
     where
         T: Copy,
     {
         *self.as_array()
     }
+    pub const fn splat(a: T) -> Self
+    where
+        T: Copy,
+    {
+        Self([a; N])
+    }
+}
+
+// As `const_trait_impl` is a language feature with specialized syntax, we have to use them in a way
+// such that it doesn't get parsed as Rust code unless `cfg(minisimd_const)` is on. The easiest way
+// for that is a macro
+
+macro_rules! impl_traits {
+    ($($const_:ident)?) => {
+        impl<T: $([$const_])? PartialEq, const N: usize> $($const_)? PartialEq for Simd<T, N> {
+            fn eq(&self, other: &Self) -> bool {
+                self.as_array() == other.as_array()
+            }
+        }
+
+        impl<T, const N: usize> $($const_)? core::ops::Index<usize> for Simd<T, N> {
+            type Output = T;
+            fn index(&self, i: usize) -> &T {
+                &self.as_array()[i]
+            }
+        }
+
+        impl<T: $([$const_])? PartialEq, const N: usize> $($const_)? PartialEq for PackedSimd<T, N>
+        {
+            fn eq(&self, other: &Self) -> bool {
+                self.as_array() == other.as_array()
+            }
+        }
+    };
 }
+
+#[cfg(minisimd_const)]
+impl_traits!(const);
+
+#[cfg(not(minisimd_const))]
+impl_traits!();
+
+/// Version of `assert_eq` that ignores fancy runtime printing in const context
+#[cfg(minisimd_const)]
+#[macro_export]
+macro_rules! assert_eq {
+    ($left:expr, $right:expr $(,)?) => {
+        assert_eq!(
+            $left,
+            $right,
+            concat!("`", stringify!($left), "` == `", stringify!($right), "`")
+        );
+    };
+    ($left:expr, $right:expr$(, $($arg:tt)+)?) => {
+        {
+            let left = $left;
+            let right = $right;
+            // type inference works better with the concrete type on the
+            // left, but humans work better with the expected on the
+            // right
+            assert!(right == left, $($($arg)*),*);
+        }
+    };
+}
+
+#[cfg(minisimd_const)]
+use assert_eq;

tests/ui/simd/intrinsic/float-math-pass.rs

@@ -1,14 +1,15 @@
 //@ run-pass
 //@ ignore-emscripten
 //@ ignore-android
+//@ compile-flags: --cfg minisimd_const
 
 // FIXME: this test fails on arm-android because the NDK version 14 is too old.
 // It needs at least version 18. We disable it on all android build bots because
 // there is no way in compile-test to disable it for an (arch,os) pair.
 
 // Test that the simd floating-point math intrinsics produce correct results.
 
-#![feature(repr_simd, intrinsics, core_intrinsics)]
+#![feature(repr_simd, core_intrinsics, const_trait_impl, const_cmp, const_index)]
 #![allow(non_camel_case_types)]
 
 #[path = "../../../auxiliary/minisimd.rs"]
@@ -20,7 +21,10 @@ use std::intrinsics::simd::*;
 macro_rules! assert_approx_eq_f32 {
     ($a:expr, $b:expr) => {{
         let (a, b) = (&$a, &$b);
-        assert!((*a - *b).abs() < 1.0e-6, "{} is not approximately equal to {}", *a, *b);
+        assert!(
+            (*a - *b).abs() < 1.0e-6,
+            concat!(stringify!($a), " is not approximately equal to ", stringify!($b))
+        );
     }};
 }
 macro_rules! assert_approx_eq {
@@ -34,7 +38,7 @@ macro_rules! assert_approx_eq {
     }};
 }
 
-fn main() {
+const fn simple_math() {
     let x = f32x4::from_array([1.0, 1.0, 1.0, 1.0]);
     let y = f32x4::from_array([-1.0, -1.0, -1.0, -1.0]);
     let z = f32x4::from_array([0.0, 0.0, 0.0, 0.0]);
@@ -43,21 +47,44 @@ fn main() {
 
     unsafe {
         let r = simd_fabs(y);
-        assert_approx_eq!(x, r);
+        assert_eq!(x, r);
 
-        let r = simd_fcos(z);
+        // rounding functions
+        let r = simd_floor(h);
+        assert_eq!(z, r);
+
+        let r = simd_ceil(h);
+        assert_eq!(x, r);
+
+        let r = simd_round(h);
+        assert_eq!(x, r);
+
+        let r = simd_round_ties_even(h);
+        assert_eq!(z, r);
+
+        let r = simd_trunc(h);
+        assert_eq!(z, r);
+
+        let r = simd_fma(x, h, h);
         assert_approx_eq!(x, r);
 
-        let r = simd_fexp(z);
+        let r = simd_relaxed_fma(x, h, h);
         assert_approx_eq!(x, r);
+    }
+}
 
-        let r = simd_fexp2(z);
+fn special_math() {
+    let x = f32x4::from_array([1.0, 1.0, 1.0, 1.0]);
+    let z = f32x4::from_array([0.0, 0.0, 0.0, 0.0]);
+
+    unsafe {
+        let r = simd_fcos(z);
         assert_approx_eq!(x, r);
 
-        let r = simd_fma(x, h, h);
+        let r = simd_fexp(z);
         assert_approx_eq!(x, r);
 
-        let r = simd_relaxed_fma(x, h, h);
+        let r = simd_fexp2(z);
         assert_approx_eq!(x, r);
 
         let r = simd_fsqrt(x);
@@ -74,21 +101,11 @@ fn main() {
 
         let r = simd_fsin(z);
         assert_approx_eq!(z, r);
-
-        // rounding functions
-        let r = simd_floor(h);
-        assert_eq!(z, r);
-
-        let r = simd_ceil(h);
-        assert_eq!(x, r);
-
-        let r = simd_round(h);
-        assert_eq!(x, r);
-
-        let r = simd_round_ties_even(h);
-        assert_eq!(z, r);
-
-        let r = simd_trunc(h);
-        assert_eq!(z, r);
     }
 }
+
+fn main() {
+    const { simple_math() };
+    simple_math();
+    special_math();
+}

tests/ui/simd/intrinsic/float-minmax-pass.rs

@@ -1,9 +1,10 @@
 //@ run-pass
 //@ ignore-emscripten
+//@ compile-flags: --cfg minisimd_const
 
 // Test that the simd_f{min,max} intrinsics produce the correct results.
 
-#![feature(repr_simd, core_intrinsics)]
+#![feature(repr_simd, core_intrinsics, const_trait_impl, const_cmp, const_index)]
 #![allow(non_camel_case_types)]
 
 #[path = "../../../auxiliary/minisimd.rs"]
@@ -12,7 +13,7 @@ use minisimd::*;
 
 use std::intrinsics::simd::*;
 
-fn main() {
+const fn minmax() {
     let x = f32x4::from_array([1.0, 2.0, 3.0, 4.0]);
     let y = f32x4::from_array([2.0, 1.0, 4.0, 3.0]);
 
@@ -47,3 +48,8 @@ fn main() {
         assert_eq!(maxn, y);
     }
 }
+
+fn main() {
+    const { minmax() };
+    minmax();
+}

tests/ui/simd/intrinsic/generic-arithmetic-pass.rs

@@ -1,8 +1,9 @@
 //@ run-pass
 //@ ignore-backends: gcc
+//@ compile-flags: --cfg minisimd_const
 
 #![allow(non_camel_case_types)]
-#![feature(repr_simd, core_intrinsics)]
+#![feature(repr_simd, core_intrinsics, const_trait_impl, const_cmp, const_index)]
 
 #[path = "../../../auxiliary/minisimd.rs"]
 mod minisimd;
@@ -20,7 +21,7 @@ macro_rules! all_eq {
 
 use std::intrinsics::simd::*;
 
-fn main() {
+const fn arithmetic() {
     let x1 = i32x4::from_array([1, 2, 3, 4]);
     let y1 = U32::<4>::from_array([1, 2, 3, 4]);
     let z1 = f32x4::from_array([1.0, 2.0, 3.0, 4.0]);
@@ -224,3 +225,8 @@ fn main() {
         all_eq!(simd_cttz(y1), U32::<4>::from_array([0, 1, 0, 2]));
     }
 }
+
+fn main() {
+    const { arithmetic() };
+    arithmetic();
+}

tests/ui/simd/intrinsic/generic-arithmetic-saturating-pass.rs

@@ -1,8 +1,9 @@
 //@ run-pass
 //@ ignore-emscripten
+//@ compile-flags: --cfg minisimd_const
 
 #![allow(non_camel_case_types)]
-#![feature(repr_simd, core_intrinsics)]
+#![feature(repr_simd, core_intrinsics, const_trait_impl, const_cmp, const_index)]
 
 #[path = "../../../auxiliary/minisimd.rs"]
 mod minisimd;
@@ -12,7 +13,7 @@ use std::intrinsics::simd::{simd_saturating_add, simd_saturating_sub};
 
 type I32<const N: usize> = Simd<i32, N>;
 
-fn main() {
+const fn saturating() {
     // unsigned
     {
         const M: u32 = u32::MAX;
@@ -84,3 +85,8 @@ fn main() {
         }
     }
 }
+
+fn main() {
+    const { saturating() };
+    saturating();
+}