add simd_select intrinsic

src/librustc_trans/intrinsic.rs

@@ -1153,6 +1153,27 @@ fn generic_simd_intrinsic<'a, 'tcx>(
         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()))
     }
 
+    if name == "simd_select" {
+        let m_elem_ty = in_elem;
+        let m_len = in_len;
+        let v_len = arg_tys[1].simd_size(tcx);
+        require!(m_len == v_len,
+                 "mismatched lengths: mask length `{}` != other vector length `{}`",
+                 m_len, v_len
+        );
+        match m_elem_ty.sty {
+            ty::TyInt(_) => {},
+            _ => {
+                return_error!("mask element type is `{}`, expected `i_`", m_elem_ty);
+            }
+        }
+        // truncate the mask to a vector of i1s
+        let i1 = Type::i1(bx.cx);
+        let i1xn = Type::vector(&i1, m_len as u64);
+        let m_i1s = bx.trunc(args[0].immediate(), i1xn);
+        return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
+    }
+
     macro_rules! arith_red {
         ($name:tt : $integer_reduce:ident, $float_reduce:ident, $ordered:expr) => {
             if name == $name {

src/librustc_typeck/check/intrinsic.rs

@@ -361,6 +361,7 @@ pub fn check_platform_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         "simd_insert" => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
         "simd_extract" => (2, vec![param(0), tcx.types.u32], param(1)),
         "simd_cast" => (2, vec![param(0)], param(1)),
+        "simd_select" => (2, vec![param(0), param(1), param(1)], param(1)),
         "simd_reduce_all" | "simd_reduce_any" => (1, vec![param(0)], tcx.types.bool),
         "simd_reduce_add_ordered" | "simd_reduce_mul_ordered"
             => (2, vec![param(0), param(1)], param(1)),

src/test/compile-fail/simd-intrinsic-generic-select.rs

@@ -0,0 +1,56 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test that the simd_select intrinsic produces ok-ish error
+// messages when misused.
+
+#![feature(repr_simd, platform_intrinsics)]
+#![allow(non_camel_case_types)]
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct f32x4(pub f32, pub f32, pub f32, pub f32);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct u32x4(pub u32, pub u32, pub u32, pub u32);
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq)]
+struct b8x4(pub i8, pub i8, pub i8, pub i8);
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq)]
+struct b8x8(pub i8, pub i8, pub i8, pub i8,
+            pub i8, pub i8, pub i8, pub i8);
+
+extern "platform-intrinsic" {
+    fn simd_select<T, U>(x: T, a: U, b: U) -> U;
+}
+
+fn main() {
+    let m4 = b8x4(0, 0, 0, 0);
+    let m8 = b8x8(0, 0, 0, 0, 0, 0, 0, 0);
+    let x = u32x4(0, 0, 0, 0);
+    let z = f32x4(0.0, 0.0, 0.0, 0.0);
+
+    unsafe {
+        simd_select(m4, x, x);
+
+        simd_select(m8, x, x);
+        //~^ ERROR mismatched lengths: mask length `8` != other vector length `4`
+
+        simd_select(x, x, x);
+        //~^ ERROR mask element type is `u32`, expected `i_`
+
+        simd_select(z, z, z);
+        //~^ ERROR mask element type is `f32`, expected `i_`
+    }
+}

src/test/run-pass/simd-intrinsic-generic-select.rs

@@ -0,0 +1,144 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test that the simd_select intrinsics produces correct results.
+
+#![feature(repr_simd, platform_intrinsics)]
+#[allow(non_camel_case_types)]
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct i32x4(pub i32, pub i32, pub i32, pub i32);
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct u32x4(pub u32, pub u32, pub u32, pub u32);
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct f32x4(pub f32, pub f32, pub f32, pub f32);
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct b8x4(pub i8, pub i8, pub i8, pub i8);
+
+extern "platform-intrinsic" {
+    fn simd_select<T, U>(x: T, a: U, b: U) -> U;
+}
+
+fn main() {
+    let m0 = b8x4(!0, !0, !0, !0);
+    let m1 = b8x4(0, 0, 0, 0);
+    let m2 = b8x4(!0, !0, 0, 0);
+    let m3 = b8x4(0, 0, !0, !0);
+    let m4 = b8x4(!0, 0, !0, 0);
+
+    unsafe {
+        let a = i32x4(1, -2, 3, 4);
+        let b = i32x4(5, 6, -7, 8);
+
+        let r: i32x4 = simd_select(m0, a, b);
+        let e = a;
+        assert_eq!(r, e);
+
+        let r: i32x4 = simd_select(m1, a, b);
+        let e = b;
+        assert_eq!(r, e);
+
+        let r: i32x4 = simd_select(m2, a, b);
+        let e = i32x4(1, -2, -7, 8);
+        assert_eq!(r, e);
+
+        let r: i32x4 = simd_select(m3, a, b);
+        let e = i32x4(5, 6, 3, 4);
+        assert_eq!(r, e);
+
+        let r: i32x4 = simd_select(m4, a, b);
+        let e = i32x4(1, 6, 3, 8);
+        assert_eq!(r, e);
+    }
+
+    unsafe {
+        let a = u32x4(1, 2, 3, 4);
+        let b = u32x4(5, 6, 7, 8);
+
+        let r: u32x4 = simd_select(m0, a, b);
+        let e = a;
+        assert_eq!(r, e);
+
+        let r: u32x4 = simd_select(m1, a, b);
+        let e = b;
+        assert_eq!(r, e);
+
+        let r: u32x4 = simd_select(m2, a, b);
+        let e = u32x4(1, 2, 7, 8);
+        assert_eq!(r, e);
+
+        let r: u32x4 = simd_select(m3, a, b);
+        let e = u32x4(5, 6, 3, 4);
+        assert_eq!(r, e);
+
+        let r: u32x4 = simd_select(m4, a, b);
+        let e = u32x4(1, 6, 3, 8);
+        assert_eq!(r, e);
+    }
+
+    unsafe {
+        let a = f32x4(1., 2., 3., 4.);
+        let b = f32x4(5., 6., 7., 8.);
+
+        let r: f32x4 = simd_select(m0, a, b);
+        let e = a;
+        assert_eq!(r, e);
+
+        let r: f32x4 = simd_select(m1, a, b);
+        let e = b;
+        assert_eq!(r, e);
+
+        let r: f32x4 = simd_select(m2, a, b);
+        let e = f32x4(1., 2., 7., 8.);
+        assert_eq!(r, e);
+
+        let r: f32x4 = simd_select(m3, a, b);
+        let e = f32x4(5., 6., 3., 4.);
+        assert_eq!(r, e);
+
+        let r: f32x4 = simd_select(m4, a, b);
+        let e = f32x4(1., 6., 3., 8.);
+        assert_eq!(r, e);
+    }
+
+    unsafe {
+        let t = !0 as i8;
+        let f = 0 as i8;
+        let a = b8x4(t, f, t, f);
+        let b = b8x4(f, f, f, t);
+
+        let r: b8x4 = simd_select(m0, a, b);
+        let e = a;
+        assert_eq!(r, e);
+
+        let r: b8x4 = simd_select(m1, a, b);
+        let e = b;
+        assert_eq!(r, e);
+
+        let r: b8x4 = simd_select(m2, a, b);
+        let e = b8x4(t, f, f, t);
+        assert_eq!(r, e);
+
+        let r: b8x4 = simd_select(m3, a, b);
+        let e = b8x4(f, f, t, f);
+        assert_eq!(r, e);
+
+        let r: b8x4 = simd_select(m4, a, b);
+        let e = b8x4(t, f, t, t);
+        assert_eq!(r, e);
+    }
+}