Auto merge of #144542 - sayantn:stabilize-sse4a-tbm, r=Amanieu,traviscross

Stabilize `sse4a` and `tbm` target features

This PR stabilizes the feature flag `sse4a_target_feature` and `tbm_target_feature` (tracking issue rust-lang/rust#44839).

# Public API
The 2 `x86` target features `sse4a` and `tbm`

Also, these were added in LLVM2.6 and LLVM3.4-rc1, respectively, and as the minimum LLVM required for rustc is LLVM19, we are safe in that front too!

As all of the required tasks have been done (adding the target features to rustc, implementing their runtime detection in std_detect and implementing the associated intrinsics in core_arch), these target features can be stabilized now. The intrinsics were stabilized *long* ago, in 1.27.0

Reference PR:

- https://github.com/rust-lang/reference/pull/1949

cc `@rust-lang/lang`

`@rustbot` label I-lang-nominated
r? lang

compiler/rustc_feature/src/accepted.rs

@@ -396,6 +396,8 @@ declare_features! (
     (accepted, slice_patterns, "1.42.0", Some(62254)),
     /// Allows use of `&foo[a..b]` as a slicing syntax.
     (accepted, slicing_syntax, "1.0.0", None),
+    /// Allows use of `sse4a` target feature.
+    (accepted, sse4a_target_feature, "CURRENT_RUSTC_VERSION", Some(44839)),
     /// Allows elision of `'static` lifetimes in `static`s and `const`s.
     (accepted, static_in_const, "1.17.0", Some(35897)),
     /// Allows the definition recursive static items.
@@ -408,6 +410,8 @@ declare_features! (
     (accepted, target_feature, "1.27.0", None),
     /// Allows the use of `#[target_feature]` on safe functions.
     (accepted, target_feature_11, "1.86.0", Some(69098)),
+    /// Allows use of `tbm` target feature.
+    (accepted, tbm_target_feature, "CURRENT_RUSTC_VERSION", Some(44839)),
     /// Allows `fn main()` with return types which implements `Termination` (RFC 1937).
     (accepted, termination_trait, "1.26.0", Some(43301)),
     /// Allows `#[test]` functions where the return type implements `Termination` (RFC 1937).

compiler/rustc_feature/src/unstable.rs

@@ -334,8 +334,6 @@ declare_features! (
     (unstable, rtm_target_feature, "1.35.0", Some(44839)),
     (unstable, s390x_target_feature, "1.82.0", Some(44839)),
     (unstable, sparc_target_feature, "1.84.0", Some(132783)),
-    (unstable, sse4a_target_feature, "1.27.0", Some(44839)),
-    (unstable, tbm_target_feature, "1.27.0", Some(44839)),
     (unstable, wasm_target_feature, "1.30.0", Some(44839)),
     (unstable, x87_target_feature, "1.85.0", Some(44839)),
     // !!!!    !!!!    !!!!    !!!!   !!!!    !!!!    !!!!    !!!!    !!!!    !!!!    !!!!

compiler/rustc_target/src/target_features.rs

@@ -475,9 +475,9 @@ static X86_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("sse3", Stable, &["sse2"]),
     ("sse4.1", Stable, &["ssse3"]),
     ("sse4.2", Stable, &["sse4.1"]),
-    ("sse4a", Unstable(sym::sse4a_target_feature), &["sse3"]),
+    ("sse4a", Stable, &["sse3"]),
     ("ssse3", Stable, &["sse3"]),
-    ("tbm", Unstable(sym::tbm_target_feature), &[]),
+    ("tbm", Stable, &[]),
     ("vaes", Stable, &["avx2", "aes"]),
     ("vpclmulqdq", Stable, &["avx", "pclmulqdq"]),
     ("widekl", Stable, &["kl"]),

library/core/src/lib.rs

@@ -200,8 +200,6 @@
 #![feature(riscv_target_feature)]
 #![feature(rtm_target_feature)]
 #![feature(s390x_target_feature)]
-#![feature(sse4a_target_feature)]
-#![feature(tbm_target_feature)]
 #![feature(wasm_target_feature)]
 #![feature(x86_amx_intrinsics)]
 // tidy-alphabetical-end

library/stdarch/crates/core_arch/src/lib.rs

@@ -18,8 +18,6 @@
     rustc_attrs,
     staged_api,
     doc_cfg,
-    tbm_target_feature,
-    sse4a_target_feature,
     riscv_target_feature,
     arm_target_feature,
     mips_target_feature,

tests/ui/target-feature/gate.rs

@@ -1,18 +1,12 @@
 //@ only-x86_64
 //
-// gate-test-sse4a_target_feature
 // gate-test-powerpc_target_feature
-// gate-test-tbm_target_feature
 // gate-test-arm_target_feature
 // gate-test-hexagon_target_feature
 // gate-test-mips_target_feature
 // gate-test-nvptx_target_feature
 // gate-test-wasm_target_feature
-// gate-test-adx_target_feature
-// gate-test-cmpxchg16b_target_feature
-// gate-test-movbe_target_feature
 // gate-test-rtm_target_feature
-// gate-test-f16c_target_feature
 // gate-test-riscv_target_feature
 // gate-test-ermsb_target_feature
 // gate-test-bpf_target_feature

tests/ui/target-feature/gate.stderr

@@ -1,5 +1,5 @@
 error[E0658]: the target feature `x87` is currently unstable
-  --> $DIR/gate.rs:30:18
+  --> $DIR/gate.rs:24:18
    |
 LL | #[target_feature(enable = "x87")]
    |                  ^^^^^^^^^^^^^^