interpret: make sure we accept transparent newtypes as ABI-compatible

also we were missing the case for Vector arguments, so handle those as well

Author: RalfJung

tests/pass/function_calls/abi_compat.rs

@@ -1,5 +1,7 @@
+#![feature(portable_simd)]
 use std::num;
 use std::mem;
+use std::simd;
 
 fn test_abi_compat<T, U>(t: T, u: U) {
     fn id<T>(x: T) -> T { x }
@@ -15,13 +17,33 @@ fn test_abi_compat<T, U>(t: T, u: U) {
     drop(f(t));
 }
 
+/// Ensure that `T` is compatible with various repr(transparent) wrappers around `T`.
+fn test_abi_newtype<T: Copy>(t: T) {
+    #[repr(transparent)]
+    struct Wrapper1<T>(T);
+    #[repr(transparent)]
+    struct Wrapper2<T>(T, ());
+    #[repr(transparent)]
+    struct Wrapper3<T>(T, [u8; 0]);
+
+    test_abi_compat(t, Wrapper1(t));
+    test_abi_compat(t, Wrapper2(t, ()));
+    test_abi_compat(t, Wrapper3(t, []));
+}
+
 fn main() {
     test_abi_compat(0u32, 'x');
     test_abi_compat(&0u32, &([true; 4], [0u32; 0]));
     test_abi_compat(0u32, mem::MaybeUninit::new(0u32));
     test_abi_compat(42u32, num::NonZeroU32::new(1).unwrap());
     test_abi_compat(0u32, Some(num::NonZeroU32::new(1).unwrap()));
     test_abi_compat(0u32, 0i32);
-    // Note that `bool` and `u8` are *not* compatible!
+    test_abi_compat(simd::u32x8::splat(1), simd::i32x8::splat(1));
+    // Note that `bool` and `u8` are *not* compatible, at least on x86-64!
     // One of them has `arg_ext: Zext`, the other does not.
+
+    test_abi_newtype(0u32);
+    test_abi_newtype(0f32);
+    test_abi_newtype((0u32, 1u32, 2u32));
+    test_abi_newtype([0u32, 1u32, 2u32]);
 }