Rollup merge of #143300 - Kivooeo:tf25, r=tgross35

`tests/ui`: A New Order [25/N]

> [!NOTE]
>
> Intermediate commits are intended to help review, but will be squashed prior to merge.

Some `tests/ui/` housekeeping, to trim down number of tests directly under `tests/ui/`. Part of rust-lang/rust#133895.

r? `@tgross35`

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/ui/target-feature/target-feature-detection.rs b/tests/ui/target-feature/target-feature-detection.rs
new file mode 100644
index 00000000000..3404bfbe782
--- /dev/null
+++ b/tests/ui/target-feature/target-feature-detection.rs
@@ -0,0 +1,35 @@
+//! Check that `cfg!(target_feature = "...")` correctly detects available CPU features,
+//! specifically `sse2` on x86/x86_64 platforms, and correctly reports absent features.
+
+//@ run-pass
+
+#![allow(stable_features)]
+#![feature(cfg_target_feature)]
+
+use std::env;
+
+fn main() {
+    match env::var("TARGET") {
+        Ok(s) => {
+            // Skip this tests on i586-unknown-linux-gnu where sse2 is disabled
+            if s.contains("i586") {
+                return;
+            }
+        }
+        Err(_) => return,
+    }
+    if cfg!(any(target_arch = "x86", target_arch = "x86_64")) {
+        assert!(
+            cfg!(target_feature = "sse2"),
+            "SSE2 was not detected as available on an x86 platform"
+        );
+    }
+    // check a negative case too -- certainly not enabled by default
+    #[expect(unexpected_cfgs)]
+    {
+        assert!(
+            cfg!(not(target_feature = "ferris_wheel")),
+            "🎡 shouldn't be detected as available by default on any platform"
+        )
+    };
+}