sve: add addl. passing test for field projection

tests/ui/scalable-vectors/project-into-field-okay.rs

@@ -0,0 +1,95 @@
+//@ build-pass
+//@ compile-flags: -Copt-level=3 --test -Cdebuginfo=2
+//@ only-aarch64
+#![allow(internal_features, unused, improper_ctypes_definitions, nonstandard_style)]
+#![feature(
+    abi_unadjusted,
+    link_llvm_intrinsics,
+    rustc_attrs,
+    min_adt_const_params
+)]
+
+// This snippet is reduced from stdarch and previously failed prior to preventing projection into
+// fields during MIR validation in rust#160642.
+
+use std::{marker::ConstParamTy, mem::transmute};
+
+#[derive(Copy, Clone)]
+#[rustc_scalable_vector(4)]
+pub struct svfloat32_t(f32);
+
+#[repr(i32)]
+#[allow(non_camel_case_types)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, ConstParamTy)]
+#[non_exhaustive]
+pub enum svpattern {
+    SV_ALL = 31,
+}
+
+#[inline]
+#[target_feature(enable = "sve")]
+pub fn svlen_f32(_op: svfloat32_t) -> u64 {
+    svcntw()
+}
+
+#[test]
+#[allow(non_snake_case)]
+fn assert_svlen_f32_cntw() {
+    #[target_feature(enable = "sve")]
+    #[unsafe(no_mangle)]
+    #[inline(never)]
+    pub unsafe extern "C" fn stdarch_test_shim_svlen_f32_cntw(_op: svfloat32_t) -> u64 {
+        svlen_f32(_op)
+    }
+    std::hint::black_box(stdarch_test_shim_svlen_f32_cntw as usize);
+    //~^ WARN: direct cast of function item into an integer
+}
+
+#[inline]
+#[target_feature(enable = "sve")]
+pub fn svcntw() -> u64 {
+    svcntw_pat::<{ svpattern::SV_ALL }>()
+}
+
+#[test]
+#[allow(non_snake_case)]
+fn assert_svcntw_cntw() {
+    #[target_feature(enable = "sve")]
+    #[unsafe(no_mangle)]
+    #[inline(never)]
+    pub unsafe extern "C" fn stdarch_test_shim_svcntw_cntw() -> u64 {
+        svcntw()
+    }
+    std::hint::black_box(stdarch_test_shim_svcntw_cntw as usize);
+    //~^ WARN: direct cast of function item into an integer
+}
+
+#[inline]
+#[target_feature(enable = "sve")]
+pub fn svcntw_pat<const PATTERN: svpattern>() -> u64 {
+    unsafe extern "unadjusted" {
+        #[cfg_attr(target_arch = "aarch64", link_name = "llvm.aarch64.sve.cntw")]
+        fn _svcntw_pat(pattern: svpattern) -> i64;
+    }
+    unsafe { transmute(_svcntw_pat(PATTERN)) }
+    //~^ WARN: unnecessary transmute
+}
+
+#[test]
+#[allow(non_snake_case)]
+fn assert_svcntw_pat_cntw() {
+    #[target_feature(enable = "sve")]
+    #[unsafe(no_mangle)]
+    #[inline(never)]
+    pub unsafe extern "C" fn stdarch_test_shim_svcntw_pat_cntw() -> u64 {
+        svcntw_pat::<{ svpattern::SV_ALL }>()
+    }
+    std::hint::black_box(stdarch_test_shim_svcntw_pat_cntw as usize);
+    //~^ WARN: direct cast of function item into an integer
+}
+
+fn main() {
+    unsafe {
+        let _ = svlen_f32(unimplemented!());
+    }
+}

tests/ui/scalable-vectors/project-into-field-okay.stderr

@@ -0,0 +1,49 @@
+warning: direct cast of function item into an integer
+  --> $DIR/project-into-field-okay.rs:44:59
+   |
+LL |     std::hint::black_box(stdarch_test_shim_svlen_f32_cntw as usize);
+   |                                                           ^^^^^^^^
+   |
+   = note: `#[warn(function_casts_as_integer)]` on by default
+help: first cast to a pointer `as *const ()`
+   |
+LL |     std::hint::black_box(stdarch_test_shim_svlen_f32_cntw as *const () as usize);
+   |                                                           ++++++++++++
+
+warning: direct cast of function item into an integer
+  --> $DIR/project-into-field-okay.rs:63:56
+   |
+LL |     std::hint::black_box(stdarch_test_shim_svcntw_cntw as usize);
+   |                                                        ^^^^^^^^
+   |
+help: first cast to a pointer `as *const ()`
+   |
+LL |     std::hint::black_box(stdarch_test_shim_svcntw_cntw as *const () as usize);
+   |                                                        ++++++++++++
+
+warning: unnecessary transmute
+  --> $DIR/project-into-field-okay.rs:74:14
+   |
+LL |     unsafe { transmute(_svcntw_pat(PATTERN)) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(unnecessary_transmutes)]` on by default
+help: replace this with
+   |
+LL -     unsafe { transmute(_svcntw_pat(PATTERN)) }
+LL +     unsafe { i64::cast_unsigned(_svcntw_pat(PATTERN)) }
+   |
+
+warning: direct cast of function item into an integer
+  --> $DIR/project-into-field-okay.rs:87:60
+   |
+LL |     std::hint::black_box(stdarch_test_shim_svcntw_pat_cntw as usize);
+   |                                                            ^^^^^^^^
+   |
+help: first cast to a pointer `as *const ()`
+   |
+LL |     std::hint::black_box(stdarch_test_shim_svcntw_pat_cntw as *const () as usize);
+   |                                                            ++++++++++++
+
+warning: 4 warnings emitted
+