Rollup merge of #139675 - sayantn:avx10, r=Amanieu

Add the AVX10 target features

Parent #138843

Adds the `avx10_target_feature` feature gate, and `avx10.1` and `avx10.2` target features.

It is confirmed that Intel is dropping AVX10/256 (see [this comment](https://github.com/rust-lang/rust/issues/111137#issuecomment-2795442288)), so this should be safe to implement now.

The LLVM fix for llvm/llvm-project#135394 was merged, and has been backported to LLVM20, and the patch has also been propagated to rustc in #140502

`@rustbot` label O-x86_64 O-x86_32 A-target-feature A-SIMD

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -301,6 +301,9 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
             None
         }
         ("x86", "movrs") if get_version().0 < 20 => None,
+        ("x86", "avx10.1") => Some(LLVMFeature::new("avx10.1-512")),
+        ("x86", "avx10.2") if get_version().0 < 20 => None,
+        ("x86", "avx10.2") if get_version().0 >= 20 => Some(LLVMFeature::new("avx10.2-512")),
         (_, s) => Some(LLVMFeature::new(s)),
     }
 }

compiler/rustc_feature/src/unstable.rs

@@ -393,6 +393,8 @@ declare_features! (
     (unstable, async_for_loop, "1.77.0", Some(118898)),
     /// Allows `async` trait bound modifier.
     (unstable, async_trait_bounds, "1.85.0", Some(62290)),
+    /// Allows using Intel AVX10 target features and intrinsics
+    (unstable, avx10_target_feature, "CURRENT_RUSTC_VERSION", Some(138843)),
     /// Allows using C-variadics.
     (unstable, c_variadic, "1.34.0", Some(44930)),
     /// Allows the use of `#[cfg(contract_checks)` to check if contract checks are enabled.

compiler/rustc_span/src/symbol.rs

@@ -531,6 +531,7 @@ symbols! {
         autodiff,
         automatically_derived,
         avx,
+        avx10_target_feature,
         avx512_target_feature,
         avx512bw,
         avx512f,

compiler/rustc_target/src/target_features.rs

@@ -394,6 +394,26 @@ static X86_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("amx-tile", Unstable(sym::x86_amx_intrinsics), &[]),
     ("amx-transpose", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
     ("avx", Stable, &["sse4.2"]),
+    (
+        "avx10.1",
+        Unstable(sym::avx10_target_feature),
+        &[
+            "avx512bf16",
+            "avx512bitalg",
+            "avx512bw",
+            "avx512cd",
+            "avx512dq",
+            "avx512f",
+            "avx512fp16",
+            "avx512ifma",
+            "avx512vbmi",
+            "avx512vbmi2",
+            "avx512vl",
+            "avx512vnni",
+            "avx512vpopcntdq",
+        ],
+    ),
+    ("avx10.2", Unstable(sym::avx10_target_feature), &["avx10.1"]),
     ("avx2", Stable, &["avx"]),
     ("avx512bf16", Unstable(sym::avx512_target_feature), &["avx512bw"]),
     ("avx512bitalg", Unstable(sym::avx512_target_feature), &["avx512bw"]),