Rollup merge of rust-lang#148338 - durin42:llvm-22-amx-transpose, r=workingjubilee

cleanup: upstream dropped amx-transpose functionality

See also LLVM change 5322fb626820. Looks like this was just removed entirely.
It seems a little bad to just drop it, but I don't see an easy way to conditionalize
this and if it's really just Gone and we marked it as unstable (which it looks like
we did?) I guess we should just dump it.

```@rustbot``` label llvm-main

Author: matthiaskrgr

compiler/rustc_target/src/target_features.rs

@@ -386,7 +386,6 @@ static X86_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("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"]),
     ("apxf", Unstable(sym::apx_target_feature), &[]),
     ("avx", Stable, &["sse4.2"]),
     ("avx2", Stable, &["avx"]),

library/std_detect/src/detect/arch/x86.rs

@@ -93,7 +93,6 @@ features! {
     /// * `"amx-fp8"`
     /// * `"amx-movrs"`
     /// * `"amx-tf32"`
-    /// * `"amx-transpose"`
     /// * `"f16c"`
     /// * `"fma"`
     /// * `"bmi1"`
@@ -231,8 +230,6 @@ features! {
     /// AMX-MOVRS (Matrix MOVERS operations)
     @FEATURE: #[unstable(feature = "x86_amx_intrinsics", issue = "126622")] amx_tf32: "amx-tf32";
     /// AMX-TF32 (TensorFloat32 Operations)
-    @FEATURE: #[unstable(feature = "x86_amx_intrinsics", issue = "126622")] amx_transpose: "amx-transpose";
-    /// AMX-TRANSPOSE (Matrix Transpose Operations)
     @FEATURE: #[unstable(feature = "apx_target_feature", issue = "139284")] apxf: "apxf";
     /// APX-F (Advanced Performance Extensions - Foundation)
     @FEATURE: #[unstable(feature = "avx10_target_feature", issue = "138843")] avx10_1: "avx10.1";

library/std_detect/src/detect/os/x86.rs

@@ -285,7 +285,6 @@ pub(crate) fn detect_features() -> cache::Initializer {
                             unsafe { __cpuid_count(0x1e_u32, 1) };
 
                         enable(amx_feature_flags_eax, 4, Feature::amx_fp8);
-                        enable(amx_feature_flags_eax, 5, Feature::amx_transpose);
                         enable(amx_feature_flags_eax, 6, Feature::amx_tf32);
                         enable(amx_feature_flags_eax, 7, Feature::amx_avx512);
                         enable(amx_feature_flags_eax, 8, Feature::amx_movrs);

library/std_detect/tests/x86-specific.rs

@@ -76,7 +76,6 @@ fn dump() {
     println!("widekl: {:?}", is_x86_feature_detected!("widekl"));
     println!("movrs: {:?}", is_x86_feature_detected!("movrs"));
     println!("amx-fp8: {:?}", is_x86_feature_detected!("amx-fp8"));
-    println!("amx-transpose: {:?}", is_x86_feature_detected!("amx-transpose"));
     println!("amx-tf32: {:?}", is_x86_feature_detected!("amx-tf32"));
     println!("amx-avx512: {:?}", is_x86_feature_detected!("amx-avx512"));
     println!("amx-movrs: {:?}", is_x86_feature_detected!("amx-movrs"));

tests/ui/check-cfg/target_feature.stderr

@@ -27,7 +27,6 @@ LL |     cfg!(target_feature = "_UNEXPECTED_VALUE");
 `amx-movrs`
 `amx-tf32`
 `amx-tile`
-`amx-transpose`
 `apxf`
 `atomics`
 `avx`