Add the new amx target features

Author: sayantn

Diff for: compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -298,6 +298,12 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("sparc", "v8plus") if get_version().0 == 19 => Some(LLVMFeature::new("v9")),
         ("sparc", "v8plus") if get_version().0 < 19 => None,
         ("powerpc", "power8-crypto") => Some(LLVMFeature::new("crypto")),
+        // These new `amx` variants and `movrs` were introduced in LLVM20
+        ("x86", "amx-avx512" | "amx-fp8" | "amx-movrs" | "amx-tf32" | "amx-transpose")
+            if get_version().0 < 20 =>
+        {
+            None
+        }
         (_, s) => Some(LLVMFeature::new(s)),
     }
 }

Diff for: compiler/rustc_target/src/target_features.rs

@@ -380,11 +380,16 @@ static X86_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     // tidy-alphabetical-start
     ("adx", Stable, &[]),
     ("aes", Stable, &["sse2"]),
+    ("amx-avx512", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
     ("amx-bf16", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
     ("amx-complex", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
     ("amx-fp16", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
+    ("amx-fp8", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
     ("amx-int8", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
+    ("amx-movrs", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
+    ("amx-tf32", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
     ("amx-tile", Unstable(sym::x86_amx_intrinsics), &[]),
+    ("amx-transpose", Unstable(sym::x86_amx_intrinsics), &["amx-tile"]),
     ("avx", Stable, &["sse4.2"]),
     ("avx2", Stable, &["avx"]),
     ("avx512bf16", Unstable(sym::avx512_target_feature), &["avx512bw"]),

Diff for: tests/ui/check-cfg/target_feature.stderr

@@ -17,11 +17,16 @@ LL |     cfg!(target_feature = "_UNEXPECTED_VALUE");
 `aes`
 `altivec`
 `alu32`
+`amx-avx512`
 `amx-bf16`
 `amx-complex`
 `amx-fp16`
+`amx-fp8`
 `amx-int8`
+`amx-movrs`
+`amx-tf32`
 `amx-tile`
+`amx-transpose`
 `atomics`
 `avx`
 `avx2`