Rollup merge of #128537 - Jamesbarford:118980-const-vector, r=RalfJung,nikic

const vector passed through to codegen

This allows constant vectors using a repr(simd) type to be propagated
through to the backend by reusing the functionality used to do a similar
thing for the simd_shuffle intrinsic

#118209

r​? RalfJung

1 files changed, 107 insertions, 0 deletions

diff --git a/tests/codegen/const-vector.rs b/tests/codegen/const-vector.rs
new file mode 100644
index 00000000000..d368838201e
--- /dev/null
+++ b/tests/codegen/const-vector.rs
@@ -0,0 +1,107 @@
+//@ compile-flags: -C no-prepopulate-passes -Copt-level=0
+
+// This test checks that constants of SIMD type are passed as immediate vectors.
+// We ensure that both vector representations (struct with fields and struct wrapping array) work.
+#![crate_type = "lib"]
+#![feature(abi_unadjusted)]
+#![feature(const_trait_impl)]
+#![feature(repr_simd)]
+#![feature(rustc_attrs)]
+#![feature(simd_ffi)]
+#![allow(non_camel_case_types)]
+
+// Setting up structs that can be used as const vectors
+#[repr(simd)]
+#[derive(Clone)]
+pub struct i8x2(i8, i8);
+
+#[repr(simd)]
+#[derive(Clone)]
+pub struct i8x2_arr([i8; 2]);
+
+#[repr(simd)]
+#[derive(Clone)]
+pub struct f32x2(f32, f32);
+
+#[repr(simd)]
+#[derive(Clone)]
+pub struct f32x2_arr([f32; 2]);
+
+#[repr(simd, packed)]
+#[derive(Copy, Clone)]
+pub struct Simd<T, const N: usize>([T; N]);
+
+// The following functions are required for the tests to ensure
+// that they are called with a const vector
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_i8x2(a: i8x2);
+}
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_i8x2_two_args(a: i8x2, b: i8x2);
+}
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_i8x2_mixed_args(a: i8x2, c: i32, b: i8x2);
+}
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_i8x2_arr(a: i8x2_arr);
+}
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_f32x2(a: f32x2);
+}
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_f32x2_arr(a: f32x2_arr);
+}
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_simd(a: Simd<i32, 4>);
+}
+
+extern "unadjusted" {
+    #[no_mangle]
+    fn test_simd_unaligned(a: Simd<i32, 3>);
+}
+
+// Ensure the packed variant of the simd struct does not become a const vector
+// if the size is not a power of 2
+// CHECK: %"Simd<i32, 3>" = type { [3 x i32] }
+
+pub fn do_call() {
+    unsafe {
+        // CHECK: call void @test_i8x2(<2 x i8> <i8 32, i8 64>
+        test_i8x2(const { i8x2(32, 64) });
+
+        // CHECK: call void @test_i8x2_two_args(<2 x i8> <i8 32, i8 64>, <2 x i8> <i8 8, i8 16>
+        test_i8x2_two_args(const { i8x2(32, 64) }, const { i8x2(8, 16) });
+
+        // CHECK: call void @test_i8x2_mixed_args(<2 x i8> <i8 32, i8 64>, i32 43, <2 x i8> <i8 8, i8 16>
+        test_i8x2_mixed_args(const { i8x2(32, 64) }, 43, const { i8x2(8, 16) });
+
+        // CHECK: call void @test_i8x2_arr(<2 x i8> <i8 32, i8 64>
+        test_i8x2_arr(const { i8x2_arr([32, 64]) });
+
+        // CHECK: call void @test_f32x2(<2 x float> <float 0x3FD47AE140000000, float 0x3FE47AE140000000>
+        test_f32x2(const { f32x2(0.32, 0.64) });
+
+        // CHECK: void @test_f32x2_arr(<2 x float> <float 0x3FD47AE140000000, float 0x3FE47AE140000000>
+        test_f32x2_arr(const { f32x2_arr([0.32, 0.64]) });
+
+        // CHECK: call void @test_simd(<4 x i32> <i32 2, i32 4, i32 6, i32 8>
+        test_simd(const { Simd::<i32, 4>([2, 4, 6, 8]) });
+
+        // CHECK: call void @test_simd_unaligned(%"Simd<i32, 3>" %1
+        test_simd_unaligned(const { Simd::<i32, 3>([2, 4, 6]) });
+    }
+}