Add a codegen test

tests/codegen/simd/packed-simd-alignment.rs

@@ -0,0 +1,44 @@
+//@ compile-flags: -Cno-prepopulate-passes
+
+#![crate_type = "lib"]
+#![feature(repr_simd, core_intrinsics)]
+// We want to make sure that codegen emits correctly-aligned loads and stores for repr(packed, simd) types
+// The alignment of a given load should be no less than T, and no more than the size of the vector type
+use std::intrinsics::simd as intrinsics;
+
+#[derive(Copy, Clone)]
+#[repr(packed, simd)]
+struct f32x3([f32; 3]);
+
+#[derive(Copy, Clone)]
+#[repr(packed, simd)]
+struct f32x4([f32; 4]);
+
+// CHECK-LABEL: load_f32x3
+#[no_mangle]
+pub fn load_f32x3(floats: &f32x3) -> f32x3 {
+    // FIXME: Is a memcpy really the best we can do?
+    // CHECK: @llvm.memcpy.{{.*}}ptr align 4 {{.*}}ptr align 4
+    *floats
+}
+
+// CHECK-LABEL: load_f32x4
+#[no_mangle]
+pub fn load_f32x4(floats: &f32x4) -> f32x4 {
+    // CHECK: load <4 x float>, ptr %{{[a-z0-9_]*}}, align 16
+    *floats
+}
+
+// CHECK-LABEL: add_f32x3
+#[no_mangle]
+pub fn add_f32x3(x: f32x3, y: f32x3) -> f32x3 {
+    // CHECK: load <3 x float>, ptr %{{[a-z0-9_]*}}, align 4
+    unsafe { intrinsics::simd_add(x, y) }
+}
+
+// CHECK-LABEL: add_f32x4
+#[no_mangle]
+pub fn add_f32x4(x: f32x4, y: f32x4) -> f32x4 {
+    // CHECK: load <4 x float>, ptr %{{[a-z0-9_]*}}, align 16
+    unsafe { intrinsics::simd_add(x, y) }
+}