Sync rustc 2026-09-29

.github/workflows/stdarch.yml

@@ -32,6 +32,10 @@ jobs:
     - name: Setup rust toolchain
       run: rustup show
 
+    # The stdarch-gen-common tests run rustfmt.
+    - name: Install rustfmt
+      run: rustup component add rustfmt
+
     - name: Setup rust cache
       uses: Swatinem/rust-cache@v2
 

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2026-09-24"
+channel = "nightly-2026-09-29"
 components = ["rust-src", "rustc-dev", "llvm-tools-preview"]

src/attributes.rs

@@ -4,8 +4,8 @@ use gccjit::Function;
 #[cfg(feature = "master")]
 use rustc_abi::{CanonAbi, InterruptKind};
 #[cfg(feature = "master")]
-use rustc_hir::attrs::InlineAttr;
-use rustc_hir::attrs::InstructionSetAttr;
+use rustc_attr_ir::InlineAttr;
+use rustc_attr_ir::InstructionSetAttr;
 #[cfg(feature = "master")]
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 #[cfg(feature = "master")]

src/base.rs

@@ -4,11 +4,10 @@ use std::time::Instant;
 #[cfg(feature = "master")]
 use gccjit::VarAttribute;
 use gccjit::{CType, FunctionType, GlobalKind};
+use rustc_attr_ir::{AttributeKind, Linkage, find_attr};
 use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
-use rustc_hir::attrs::{AttributeKind, Linkage};
-use rustc_hir::find_attr;
 use rustc_middle::dep_graph;
 #[cfg(feature = "master")]
 use rustc_middle::mono::Visibility;

src/callee.rs

@@ -106,7 +106,7 @@ pub fn get_fn<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, instance: Instance<'tcx>)
                 // This is a monomorphization of a generic function.
                 if !(cx.tcx.sess.opts.share_generics()
                     || tcx.codegen_instance_attrs(instance.def).inline
-                        == rustc_hir::attrs::InlineAttr::Never)
+                        == rustc_attr_ir::InlineAttr::Never)
                 {
                     // When not sharing generics, all instances are in the same
                     // crate and have hidden visibility.

src/consts.rs

@@ -4,10 +4,10 @@ use std::ops::Range;
 use gccjit::{FnAttribute, VarAttribute, Visibility};
 use gccjit::{Function, GlobalKind, LValue, RValue, ToRValue, Type};
 use rustc_abi::{self as abi, Align, HasDataLayout, Primitive, Size, WrappingRange};
+use rustc_attr_ir::Linkage;
 use rustc_codegen_ssa::traits::{
     BaseTypeCodegenMethods, ConstCodegenMethods, StaticCodegenMethods,
 };
-use rustc_hir::attrs::Linkage;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_log::tracing::trace;

src/gcc_util.rs

@@ -9,7 +9,9 @@ use rustc_codegen_ssa::target_features;
 use rustc_data_structures::smallvec::{SmallVec, smallvec};
 use rustc_session::config::NATIVE_CPU;
 use rustc_session::{EarlySession, Session};
-use rustc_target::spec::{Arch, RelocModel, StackProbeType, StackProtector, Target};
+use rustc_target::spec::{
+    Arch, MergeFunctions, RelocModel, StackProbeType, StackProtector, Target,
+};
 
 fn gcc_features_by_flags(sess: &EarlySession, features: &mut Vec<String>) {
     target_features::retpoline_features_by_flags(sess, features);
@@ -220,6 +222,16 @@ pub fn new_context<'gcc>(sess: &Session) -> Context<'gcc> {
         StackProtector::None => (),
     }
 
+    match sess.merge_functions() {
+        MergeFunctions::Disabled => {
+            context.add_command_line_option("-fno-ipa-icf-functions");
+        }
+        // GCC always merges functions with trampolines rather than aliases, so we don't
+        // need to differentiate MergeFunctions::Trampolines and MergeFunctions::Aliases
+        // as trampolines are allowed either way.
+        MergeFunctions::Trampolines | MergeFunctions::Aliases => {}
+    }
+
     match sess.target.stack_probes {
         StackProbeType::None => (),
         StackProbeType::Inline | StackProbeType::InlineOrCall { .. } => {

src/int.rs

@@ -954,6 +954,10 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
 
         debug_assert!(value_type.dyncast_array().is_some());
         let name_suffix = match self.type_kind(dest_typ) {
+            TypeKind::Half if dest_typ.is_compatible_with(self.type_f16()) => {
+                let value = self.int_to_float_cast(signed, value, self.float_type);
+                return self.context.new_cast(None, value, dest_typ);
+            }
             // cSpell:disable
             TypeKind::Float => "tisf",
             TypeKind::Double => "tidf",

src/lib.rs

@@ -25,6 +25,7 @@
 extern crate rustc_abi;
 extern crate rustc_apfloat;
 extern crate rustc_ast;
+extern crate rustc_attr_ir;
 extern crate rustc_codegen_ssa;
 extern crate rustc_data_structures;
 extern crate rustc_errors;

src/mono_item.rs

@@ -1,8 +1,8 @@
 use gccjit::Function;
 #[cfg(feature = "master")]
 use gccjit::{FnAttribute, GlobalKind, ToRValue, Type, VarAttribute};
+use rustc_attr_ir::Linkage;
 use rustc_codegen_ssa::traits::PreDefineCodegenMethods;
-use rustc_hir::attrs::Linkage;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};