stabilize optimize attribute (size, speed, and none)

This commit stabilizes the `#[optimize]` attribute, which allows for more fine-grained control
of optimization levels.

Author: veluca93

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -26,7 +26,7 @@ impl SingleAttributeParser for OptimizeParser {
         Allow(Target::Method(MethodKind::Inherent)),
     ]);
     const TEMPLATE: AttributeTemplate = template!(List: &["size", "speed", "none"]);
-    const STABILITY: AttributeStability = unstable!(optimize_attribute);
+    const STABILITY: AttributeStability = AttributeStability::Stable;
 
     fn convert(cx: &mut AcceptContext<'_, '_>, args: &ArgParser) -> Option<AttributeKind> {
         let single = cx.expect_single_element_list(args, cx.attr_span)?;

compiler/rustc_feature/src/accepted.rs

@@ -342,6 +342,8 @@ declare_features! (
     (accepted, non_modrs_mods, "1.30.0", Some(44660)),
     /// Allows using multiple nested field accesses in offset_of!
     (accepted, offset_of_nested, "1.82.0", Some(120140)),
+    /// Allows using `#[optimize(X)]`.
+    (accepted, optimize_attribute, "CURRENT_RUSTC_VERSION", Some(54882)),
     /// Allows the use of or-patterns (e.g., `0 | 1`).
     (accepted, or_patterns, "1.53.0", Some(54883)),
     /// Allows using `+bundle,+whole-archive` link modifiers with native libs.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -157,6 +157,7 @@ pub static BUILTIN_ATTRIBUTES: &[Symbol] = &[
     sym::force_target_feature,
     sym::sanitize,
     sym::coverage,
+    sym::optimize,
 
     sym::doc,
 
@@ -180,8 +181,6 @@ pub static BUILTIN_ATTRIBUTES: &[Symbol] = &[
     sym::marker,
     sym::thread_local,
     sym::no_core,
-    // RFC 2412
-    sym::optimize,
 
     sym::ffi_pure,
     sym::ffi_const,

compiler/rustc_feature/src/unstable.rs

@@ -690,8 +690,6 @@ declare_features! (
     (unstable, offset_of_enum, "1.75.0", Some(120141)),
     /// Allows using fields with slice type in offset_of!
     (unstable, offset_of_slice, "1.81.0", Some(126151)),
-    /// Allows using `#[optimize(X)]`.
-    (unstable, optimize_attribute, "1.34.0", Some(54882)),
     /// Allows specifying nop padding on functions for dynamic patching.
     (unstable, patchable_function_entry, "1.81.0", Some(123115)),
     /// Experimental features that make `Pin` more ergonomic.

library/alloc/src/lib.rs

@@ -209,7 +209,6 @@
 #![feature(multiple_supertrait_upcastable)]
 #![feature(negative_impls)]
 #![feature(never_type)]
-#![feature(optimize_attribute)]
 #![feature(rustc_attrs)]
 #![feature(slice_internals)]
 #![feature(staged_api)]

library/alloctests/lib.rs

@@ -63,7 +63,6 @@
 #![feature(dropck_eyepatch)]
 #![feature(min_specialization)]
 #![feature(never_type)]
-#![feature(optimize_attribute)]
 #![feature(prelude_import)]
 #![feature(rustc_attrs)]
 #![feature(staged_api)]

library/core/src/lib.rs

@@ -147,7 +147,6 @@
 #![feature(negative_impls)]
 #![feature(never_type)]
 #![feature(no_core)]
-#![feature(optimize_attribute)]
 #![feature(pattern_types)]
 #![feature(pin_macro_internals)]
 #![feature(prelude_import)]

library/std/src/lib.rs

@@ -303,7 +303,6 @@
 #![feature(needs_panic_runtime)]
 #![feature(negative_impls)]
 #![feature(never_type)]
-#![feature(optimize_attribute)]
 #![feature(prelude_import)]
 #![feature(rustc_attrs)]
 #![feature(rustdoc_internals)]

tests/codegen-llvm/issues/issue-136329-optnone-noinline.rs

@@ -2,8 +2,6 @@
 
 //@ compile-flags: -Copt-level=3
 
-#![feature(optimize_attribute)]
-
 #[optimize(none)]
 pub fn foo() {
     let _x = 123;

tests/codegen-llvm/optimize-attr-1.rs

@@ -3,7 +3,6 @@
 //@[SIZE-OPT] compile-flags: -Copt-level=s -Ccodegen-units=1
 //@[SPEED-OPT] compile-flags: -Copt-level=3 -Ccodegen-units=1
 
-#![feature(optimize_attribute)]
 #![crate_type = "rlib"]
 
 // CHECK-LABEL: define{{.*}}i32 @nothing