rustc_target: Add various aarch64 features

Add various aarch64 features already supported by LLVM and Linux.

The features are marked as unstable using a newly added symbol, i.e.
aarch64_unstable_target_feature.

Additionally include some comment fixes to ensure consistency of
feature names with the Arm ARM and support for architecture version
target features up to v9.5a.

This commit adds compiler support for the following features:

- FEAT_CSSC
- FEAT_ECV
- FEAT_FAMINMAX
- FEAT_FLAGM2
- FEAT_FP8
- FEAT_FP8DOT2
- FEAT_FP8DOT4
- FEAT_FP8FMA
- FEAT_FPMR
- FEAT_HBC
- FEAT_LSE128
- FEAT_LSE2
- FEAT_LUT
- FEAT_MOPS
- FEAT_LRCPC3
- FEAT_SVE_B16B16
- FEAT_SVE2p1
- FEAT_WFxT

6 files changed, 75 insertions, 5 deletions

diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index 7af5eb9278f..a0ef6483ed6 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -234,6 +234,8 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> LLVMFeature<'a
         ("aarch64", "pmuv3") => LLVMFeature::new("perfmon"),
         ("aarch64", "paca") => LLVMFeature::new("pauth"),
         ("aarch64", "pacg") => LLVMFeature::new("pauth"),
+        ("aarch64", "sve-b16b16") => LLVMFeature::new("b16b16"),
+        ("aarch64", "flagm2") => LLVMFeature::new("altnzcv"),
         // Rust ties fp and neon together.
         ("aarch64", "neon") => {
             LLVMFeature::with_dependency("neon", TargetFeatureFoldStrength::Both("fp-armv8"))
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index 4524458023d..1ec1990d2c5 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -302,6 +302,7 @@ declare_features! (
     // FIXME: Document these and merge with the list below.
 
     // Unstable `#[target_feature]` directives.
+    (unstable, aarch64_unstable_target_feature, "CURRENT_RUSTC_VERSION", Some(44839)),
     (unstable, aarch64_ver_target_feature, "1.27.0", Some(44839)),
     (unstable, arm_target_feature, "1.27.0", Some(44839)),
     (unstable, avx512_target_feature, "1.27.0", Some(44839)),
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 2957105288b..e691d1cfcb5 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -356,6 +356,7 @@ symbols! {
         _task_context,
         a32,
         aarch64_target_feature,
+        aarch64_unstable_target_feature,
         aarch64_ver_target_feature,
         abi,
         abi_amdgpu_kernel,
diff --git a/compiler/rustc_target/src/target_features.rs b/compiler/rustc_target/src/target_features.rs
index da66ba270b3..d4b5a5ff675 100644
--- a/compiler/rustc_target/src/target_features.rs
+++ b/compiler/rustc_target/src/target_features.rs
@@ -99,6 +99,8 @@ const AARCH64_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("bti", Stable, &[]),
     // FEAT_CRC
     ("crc", Stable, &[]),
+    // FEAT_CSSC
+    ("cssc", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // FEAT_DIT
     ("dit", Stable, &[]),
     // FEAT_DotProd
@@ -107,21 +109,39 @@ const AARCH64_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("dpb", Stable, &[]),
     // FEAT_DPB2
     ("dpb2", Stable, &["dpb"]),
+    // FEAT_ECV
+    ("ecv", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // FEAT_F32MM
     ("f32mm", Stable, &["sve"]),
     // FEAT_F64MM
     ("f64mm", Stable, &["sve"]),
+    // FEAT_FAMINMAX
+    ("faminmax", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // FEAT_FCMA
     ("fcma", Stable, &["neon"]),
     // FEAT_FHM
     ("fhm", Stable, &["fp16"]),
     // FEAT_FLAGM
     ("flagm", Stable, &[]),
+    // FEAT_FLAGM2
+    ("flagm2", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // FEAT_FP16
     // Rust ties FP and Neon: https://github.com/rust-lang/rust/pull/91608
     ("fp16", Stable, &["neon"]),
+    // FEAT_FP8
+    ("fp8", Unstable(sym::aarch64_unstable_target_feature), &["faminmax", "lut", "bf16"]),
+    // FEAT_FP8DOT2
+    ("fp8dot2", Unstable(sym::aarch64_unstable_target_feature), &["fp8dot4"]),
+    // FEAT_FP8DOT4
+    ("fp8dot4", Unstable(sym::aarch64_unstable_target_feature), &["fp8fma"]),
+    // FEAT_FP8FMA
+    ("fp8fma", Unstable(sym::aarch64_unstable_target_feature), &["fp8"]),
+    // FEAT_FPMR
+    ("fpmr", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // FEAT_FRINTTS
     ("frintts", Stable, &[]),
+    // FEAT_HBC
+    ("hbc", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // FEAT_I8MM
     ("i8mm", Stable, &[]),
     // FEAT_JSCVT
@@ -131,6 +151,14 @@ const AARCH64_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("lor", Stable, &[]),
     // FEAT_LSE
     ("lse", Stable, &[]),
+    // FEAT_LSE128
+    ("lse128", Unstable(sym::aarch64_unstable_target_feature), &["lse"]),
+    // FEAT_LSE2
+    ("lse2", Unstable(sym::aarch64_unstable_target_feature), &[]),
+    // FEAT_LUT
+    ("lut", Unstable(sym::aarch64_unstable_target_feature), &[]),
+    // FEAT_MOPS
+    ("mops", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // FEAT_MTE & FEAT_MTE2
     ("mte", Stable, &[]),
     // FEAT_AdvSimd & FEAT_FP
@@ -143,14 +171,16 @@ const AARCH64_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("pan", Stable, &[]),
     // FEAT_PMUv3
     ("pmuv3", Stable, &[]),
-    // FEAT_RAND
+    // FEAT_RNG
     ("rand", Stable, &[]),
     // FEAT_RAS & FEAT_RASv1p1
     ("ras", Stable, &[]),
-    // FEAT_RCPC
+    // FEAT_LRCPC
     ("rcpc", Stable, &[]),
-    // FEAT_RCPC2
+    // FEAT_LRCPC2
     ("rcpc2", Stable, &["rcpc"]),
+    // FEAT_LRCPC3
+    ("rcpc3", Unstable(sym::aarch64_unstable_target_feature), &["rcpc2"]),
     // FEAT_RDM
     ("rdm", Stable, &["neon"]),
     // FEAT_SB
@@ -173,9 +203,11 @@ const AARCH64_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     //
     // "For backwards compatibility, Neon and VFP are required in the latest architectures."
     ("sve", Stable, &["neon"]),
+    // FEAT_SVE_B16B16 (SVE or SME Instructions)
+    ("sve-b16b16", Unstable(sym::aarch64_unstable_target_feature), &["bf16"]),
     // FEAT_SVE2
     ("sve2", Stable, &["sve"]),
-    // FEAT_SVE2_AES
+    // FEAT_SVE_AES & FEAT_SVE_PMULL128
     ("sve2-aes", Stable, &["sve2", "aes"]),
     // FEAT_SVE2_BitPerm
     ("sve2-bitperm", Stable, &["sve2"]),
@@ -183,6 +215,8 @@ const AARCH64_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("sve2-sha3", Stable, &["sve2", "sha3"]),
     // FEAT_SVE2_SM4
     ("sve2-sm4", Stable, &["sve2", "sm4"]),
+    // FEAT_SVE2p1
+    ("sve2p1", Unstable(sym::aarch64_unstable_target_feature), &["sve2"]),
     // FEAT_TME
     ("tme", Stable, &[]),
     (
@@ -199,9 +233,19 @@ const AARCH64_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("v8.4a", Unstable(sym::aarch64_ver_target_feature), &["v8.3a", "dotprod", "dit", "flagm"]),
     ("v8.5a", Unstable(sym::aarch64_ver_target_feature), &["v8.4a", "ssbs", "sb", "dpb2", "bti"]),
     ("v8.6a", Unstable(sym::aarch64_ver_target_feature), &["v8.5a", "bf16", "i8mm"]),
-    ("v8.7a", Unstable(sym::aarch64_ver_target_feature), &[]),
+    ("v8.7a", Unstable(sym::aarch64_ver_target_feature), &["v8.6a", "wfxt"]),
+    ("v8.8a", Unstable(sym::aarch64_ver_target_feature), &["v8.7a", "hbc", "mops"]),
+    ("v8.9a", Unstable(sym::aarch64_ver_target_feature), &["v8.8a", "cssc"]),
+    ("v9.1a", Unstable(sym::aarch64_ver_target_feature), &["v9a", "v8.6a"]),
+    ("v9.2a", Unstable(sym::aarch64_ver_target_feature), &["v9.1a", "v8.7a"]),
+    ("v9.3a", Unstable(sym::aarch64_ver_target_feature), &["v9.2a", "v8.8a"]),
+    ("v9.4a", Unstable(sym::aarch64_ver_target_feature), &["v9.3a", "v8.9a"]),
+    ("v9.5a", Unstable(sym::aarch64_ver_target_feature), &["v9.4a"]),
+    ("v9a", Unstable(sym::aarch64_ver_target_feature), &["v8.5a", "sve2"]),
     // FEAT_VHE
     ("vh", Stable, &[]),
+    // FEAT_WFxT
+    ("wfxt", Unstable(sym::aarch64_unstable_target_feature), &[]),
     // tidy-alphabetical-end
 ];
 
diff --git a/library/std/tests/run-time-detect.rs b/library/std/tests/run-time-detect.rs
index 69486705656..779f0d1a9b8 100644
--- a/library/std/tests/run-time-detect.rs
+++ b/library/std/tests/run-time-detect.rs
@@ -5,6 +5,10 @@
     feature(stdarch_arm_feature_detection)
 )]
 #![cfg_attr(
+    all(target_arch = "aarch64", any(target_os = "linux", target_os = "android")),
+    feature(stdarch_aarch64_feature_detection)
+)]
+#![cfg_attr(
     all(target_arch = "powerpc", target_os = "linux"),
     feature(stdarch_powerpc_feature_detection)
 )]
@@ -36,21 +40,34 @@ fn aarch64_linux() {
     println!("bf16: {}", is_aarch64_feature_detected!("bf16"));
     println!("bti: {}", is_aarch64_feature_detected!("bti"));
     println!("crc: {}", is_aarch64_feature_detected!("crc"));
+    println!("cssc: {}", is_aarch64_feature_detected!("cssc"));
     println!("dit: {}", is_aarch64_feature_detected!("dit"));
     println!("dotprod: {}", is_aarch64_feature_detected!("dotprod"));
     println!("dpb2: {}", is_aarch64_feature_detected!("dpb2"));
     println!("dpb: {}", is_aarch64_feature_detected!("dpb"));
+    println!("ecv: {}", is_aarch64_feature_detected!("ecv"));
     println!("f32mm: {}", is_aarch64_feature_detected!("f32mm"));
     println!("f64mm: {}", is_aarch64_feature_detected!("f64mm"));
+    println!("faminmax: {}", is_aarch64_feature_detected!("faminmax"));
     println!("fcma: {}", is_aarch64_feature_detected!("fcma"));
     println!("fhm: {}", is_aarch64_feature_detected!("fhm"));
+    println!("flagm2: {}", is_aarch64_feature_detected!("flagm2"));
     println!("flagm: {}", is_aarch64_feature_detected!("flagm"));
     println!("fp16: {}", is_aarch64_feature_detected!("fp16"));
+    println!("fp8: {}", is_aarch64_feature_detected!("fp8"));
+    println!("fp8dot2: {}", is_aarch64_feature_detected!("fp8dot2"));
+    println!("fp8dot4: {}", is_aarch64_feature_detected!("fp8dot4"));
+    println!("fp8fma: {}", is_aarch64_feature_detected!("fp8fma"));
+    println!("fpmr: {}", is_aarch64_feature_detected!("fpmr"));
     println!("frintts: {}", is_aarch64_feature_detected!("frintts"));
+    println!("hbc: {}", is_aarch64_feature_detected!("hbc"));
     println!("i8mm: {}", is_aarch64_feature_detected!("i8mm"));
     println!("jsconv: {}", is_aarch64_feature_detected!("jsconv"));
+    println!("lse128: {}", is_aarch64_feature_detected!("lse128"));
     println!("lse2: {}", is_aarch64_feature_detected!("lse2"));
     println!("lse: {}", is_aarch64_feature_detected!("lse"));
+    println!("lut: {}", is_aarch64_feature_detected!("lut"));
+    println!("mops: {}", is_aarch64_feature_detected!("mops"));
     println!("mte: {}", is_aarch64_feature_detected!("mte"));
     println!("neon: {}", is_aarch64_feature_detected!("neon"));
     println!("paca: {}", is_aarch64_feature_detected!("paca"));
@@ -58,6 +75,7 @@ fn aarch64_linux() {
     println!("pmull: {}", is_aarch64_feature_detected!("pmull"));
     println!("rand: {}", is_aarch64_feature_detected!("rand"));
     println!("rcpc2: {}", is_aarch64_feature_detected!("rcpc2"));
+    println!("rcpc3: {}", is_aarch64_feature_detected!("rcpc3"));
     println!("rcpc: {}", is_aarch64_feature_detected!("rcpc"));
     println!("rdm: {}", is_aarch64_feature_detected!("rdm"));
     println!("sb: {}", is_aarch64_feature_detected!("sb"));
@@ -65,13 +83,16 @@ fn aarch64_linux() {
     println!("sha3: {}", is_aarch64_feature_detected!("sha3"));
     println!("sm4: {}", is_aarch64_feature_detected!("sm4"));
     println!("ssbs: {}", is_aarch64_feature_detected!("ssbs"));
+    println!("sve-b16b16: {}", is_aarch64_feature_detected!("sve-b16b16"));
     println!("sve2-aes: {}", is_aarch64_feature_detected!("sve2-aes"));
     println!("sve2-bitperm: {}", is_aarch64_feature_detected!("sve2-bitperm"));
     println!("sve2-sha3: {}", is_aarch64_feature_detected!("sve2-sha3"));
     println!("sve2-sm4: {}", is_aarch64_feature_detected!("sve2-sm4"));
     println!("sve2: {}", is_aarch64_feature_detected!("sve2"));
+    println!("sve2p1: {}", is_aarch64_feature_detected!("sve2p1"));
     println!("sve: {}", is_aarch64_feature_detected!("sve"));
     println!("tme: {}", is_aarch64_feature_detected!("tme"));
+    println!("wfxt: {}", is_aarch64_feature_detected!("wfxt"));
     // tidy-alphabetical-end
 }
 
diff --git a/tests/ui/target-feature/gate.rs b/tests/ui/target-feature/gate.rs
index 94d79d56c59..5c4fb847932 100644
--- a/tests/ui/target-feature/gate.rs
+++ b/tests/ui/target-feature/gate.rs
@@ -17,6 +17,7 @@
 // gate-test-ermsb_target_feature
 // gate-test-bpf_target_feature
 // gate-test-aarch64_ver_target_feature
+// gate-test-aarch64_unstable_target_feature
 // gate-test-csky_target_feature
 // gate-test-loongarch_target_feature
 // gate-test-lahfsahf_target_feature