Auto merge of #95223 - Dylan-DPC:rollup-idpb7ka, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #91608 (Fold aarch64 feature +fp into +neon)
 - #92955 (add perf side effect docs to `Iterator::cloned()`)
 - #94713 (Add u16::is_utf16_surrogate)
 - #95212 (Replace `this.clone()` with `this.create_snapshot_for_diagnostic()`)
 - #95219 (Modernize `alloc-no-oom-handling` test)
 - #95222 (interpret/validity: improve clarity)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

6 files changed, 148 insertions, 3 deletions

diff --git a/src/test/run-make-fulldeps/alloc-no-oom-handling/Makefile b/src/test/run-make-fulldeps/alloc-no-oom-handling/Makefile
index c68ae40eb94..6e25eb7e459 100644
--- a/src/test/run-make-fulldeps/alloc-no-oom-handling/Makefile
+++ b/src/test/run-make-fulldeps/alloc-no-oom-handling/Makefile
@@ -1,4 +1,4 @@
 -include ../tools.mk
 
 all:
-	$(RUSTC) --edition=2018 --crate-type=rlib ../../../../library/alloc/src/lib.rs --cfg feature=\"external_crate\" --cfg no_global_oom_handling
+	$(RUSTC) --edition=2021 --crate-type=rlib ../../../../library/alloc/src/lib.rs --cfg no_global_oom_handling
diff --git a/src/test/run-make-fulldeps/simd-ffi/Makefile b/src/test/run-make-fulldeps/simd-ffi/Makefile
index 38f2fcd18c5..e9c974a0137 100644
--- a/src/test/run-make-fulldeps/simd-ffi/Makefile
+++ b/src/test/run-make-fulldeps/simd-ffi/Makefile
@@ -41,7 +41,7 @@ define MK_TARGETS
 # now.
 $(1): simd.rs
 	$$(RUSTC) --target=$(1) --emit=llvm-ir,asm simd.rs \
-                -C target-feature='+fp,+neon,+sse2' -C extra-filename=-$(1)
+                -C target-feature='+neon,+sse2' -C extra-filename=-$(1)
 endef
 
 $(foreach targetxxx,$(TARGETS),$(eval $(call MK_TARGETS,$(targetxxx))))
diff --git a/src/test/ui/asm/aarch64/bad-reg.rs b/src/test/ui/asm/aarch64/bad-reg.rs
index 8619b3960a6..1a314101916 100644
--- a/src/test/ui/asm/aarch64/bad-reg.rs
+++ b/src/test/ui/asm/aarch64/bad-reg.rs
@@ -1,5 +1,5 @@
 // only-aarch64
-// compile-flags: -C target-feature=+fp
+// compile-flags: -C target-feature=+neon
 
 #![feature(asm_const, asm_sym)]
 
diff --git a/src/test/ui/target-feature/aarch64-neon-works.rs b/src/test/ui/target-feature/aarch64-neon-works.rs
new file mode 100644
index 00000000000..3878806fd02
--- /dev/null
+++ b/src/test/ui/target-feature/aarch64-neon-works.rs
@@ -0,0 +1,23 @@
+// only-aarch64
+// run-pass
+#![allow(dead_code)]
+use std::arch::*;
+use std::arch::aarch64::*;
+
+// Smoke test to verify aarch64 code that enables NEON compiles.
+fn main() {
+    let _zero = if is_aarch64_feature_detected!("neon") {
+        unsafe {
+            let zeros = zero_vector();
+            vgetq_lane_u8::<1>(zeros)
+        }
+    } else {
+        0
+    };
+}
+
+
+#[target_feature(enable = "neon")]
+unsafe fn zero_vector() -> uint8x16_t {
+    vmovq_n_u8(0)
+}
diff --git a/src/test/ui/target-feature/feature-hierarchy.rs b/src/test/ui/target-feature/feature-hierarchy.rs
new file mode 100644
index 00000000000..5fbd5e8a28d
--- /dev/null
+++ b/src/test/ui/target-feature/feature-hierarchy.rs
@@ -0,0 +1,58 @@
+// revisions: aarch64-neon aarch64-sve2
+// [aarch64-neon] compile-flags: -Ctarget-feature=+neon --target=aarch64-unknown-linux-gnu
+// [aarch64-neon] needs-llvm-components: aarch64
+// [aarch64-sve2] compile-flags: -Ctarget-feature=-neon,+sve2 --target=aarch64-unknown-linux-gnu
+// [aarch64-sve2] needs-llvm-components: aarch64
+// build-pass
+#![no_core]
+#![crate_type = "rlib"]
+#![feature(intrinsics, rustc_attrs, no_core, lang_items, staged_api)]
+#![stable(feature = "test", since = "1.0.0")]
+
+// Tests vetting "feature hierarchies" in the cases where we impose them.
+
+// Supporting minimal rust core code
+#[lang = "sized"]
+trait Sized {}
+#[lang = "copy"]
+trait Copy {}
+impl Copy for bool {}
+
+extern "rust-intrinsic" {
+    #[rustc_const_stable(feature = "test", since = "1.0.0")]
+    fn unreachable() -> !;
+}
+
+#[rustc_builtin_macro]
+macro_rules! cfg {
+    ($($cfg:tt)*) => {};
+}
+
+// Test code
+const fn do_or_die(cond: bool) {
+    if cond {
+    } else {
+        unsafe { unreachable() }
+    }
+}
+
+macro_rules! assert {
+    ($x:expr $(,)?) => {
+        const _: () = do_or_die($x);
+    };
+}
+
+
+#[cfg(aarch64_neon)]
+fn check_neon_not_sve2() {
+    // This checks that a normal aarch64 target doesn't suddenly jump up the feature hierarchy.
+    assert!(cfg!(target_feature = "neon"));
+    assert!(cfg!(not(target_feature = "sve2")));
+}
+
+#[cfg(aarch64_sve2)]
+fn check_sve2_includes_neon() {
+    // This checks that aarch64's sve2 includes neon
+    assert!(cfg!(target_feature = "neon"));
+    assert!(cfg!(target_feature = "sve2"));
+}
diff --git a/src/test/ui/target-feature/no-llvm-leaks.rs b/src/test/ui/target-feature/no-llvm-leaks.rs
new file mode 100644
index 00000000000..5a71b2166c3
--- /dev/null
+++ b/src/test/ui/target-feature/no-llvm-leaks.rs
@@ -0,0 +1,64 @@
+// revisions: aarch64 x86-64
+// [aarch64] compile-flags: -Ctarget-feature=+neon,+fp16,+fhm --target=aarch64-unknown-linux-gnu
+// [aarch64] needs-llvm-components: aarch64
+// [x86-64] compile-flags: -Ctarget-feature=+sse4.2,+rdrand --target=x86_64-unknown-linux-gnu
+// [x86-64] needs-llvm-components: x86
+// build-pass
+#![no_core]
+#![crate_type = "rlib"]
+#![feature(intrinsics, rustc_attrs, no_core, lang_items, staged_api)]
+#![stable(feature = "test", since = "1.0.0")]
+
+// Supporting minimal rust core code
+#[lang = "sized"]
+trait Sized {}
+#[lang = "copy"]
+trait Copy {}
+impl Copy for bool {}
+
+extern "rust-intrinsic" {
+    #[rustc_const_stable(feature = "test", since = "1.0.0")]
+    fn unreachable() -> !;
+}
+
+#[rustc_builtin_macro]
+macro_rules! cfg {
+    ($($cfg:tt)*) => {};
+}
+
+// Test code
+const fn do_or_die(cond: bool) {
+    if cond {
+    } else {
+        unsafe { unreachable() }
+    }
+}
+
+macro_rules! assert {
+    ($x:expr $(,)?) => {
+        const _: () = do_or_die($x);
+    };
+}
+
+
+#[cfg(target_arch = "aarch64")]
+fn check_aarch64() {
+    // This checks that the rustc feature name is used, not the LLVM feature.
+    assert!(cfg!(target_feature = "neon"));
+    assert!(cfg!(not(target_feature = "fp-armv8")));
+    assert!(cfg!(target_feature = "fhm"));
+    assert!(cfg!(not(target_feature = "fp16fml")));
+    assert!(cfg!(target_feature = "fp16"));
+    assert!(cfg!(not(target_feature = "fullfp16")));
+}
+
+#[cfg(target_arch = "x86_64")]
+fn check_x86_64() {
+    // This checks that the rustc feature name is used, not the LLVM feature.
+    assert!(cfg!(target_feature = "rdrand"));
+    assert!(cfg!(not(target_feature = "rdrnd")));
+
+    // Likewise: We enable LLVM's crc32 feature with SSE4.2, but Rust says it's just SSE4.2
+    assert!(cfg!(target_feature = "sse4.2"));
+    assert!(cfg!(not(target_feature = "crc32")));
+}