3 files changed, 43 insertions, 16 deletions
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index cd82894af18..e7669470026 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -6,7 +6,6 @@ use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, PatchableFuncti
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::config::{FunctionReturn, OptLevel};
 use rustc_span::symbol::sym;
-use rustc_target::spec::abi::Abi;
 use rustc_target::spec::{FramePointer, SanitizerSet, StackProbeType, StackProtector};
 use smallvec::SmallVec;
 
@@ -482,7 +481,7 @@ pub fn from_fn_attrs<'ll, 'tcx>(
         return;
     }
 
-    let mut function_features = function_features
+    let function_features = function_features
         .iter()
         .flat_map(|feat| {
             llvm_util::to_llvm_features(cx.tcx.sess, feat).into_iter().map(|f| format!("+{f}"))
@@ -504,17 +503,6 @@ pub fn from_fn_attrs<'ll, 'tcx>(
             let name = name.as_str();
             to_add.push(llvm::CreateAttrStringValue(cx.llcx, "wasm-import-name", name));
         }
-
-        // The `"wasm"` abi on wasm targets automatically enables the
-        // `+multivalue` feature because the purpose of the wasm abi is to match
-        // the WebAssembly specification, which has this feature. This won't be
-        // needed when LLVM enables this `multivalue` feature by default.
-        if !cx.tcx.is_closure_like(instance.def_id()) {
-            let abi = cx.tcx.fn_sig(instance.def_id()).skip_binder().abi();
-            if abi == Abi::Wasm {
-                function_features.push("+multivalue".to_string());
-            }
-        }
     }
 
     let global_features = cx.tcx.global_backend_features(()).iter().map(|s| s.as_str());
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index 742bfd76590..851a4c42e99 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -705,10 +705,12 @@ impl MsvcBasicName for ty::UintTy {
 
 impl MsvcBasicName for ty::FloatTy {
     fn msvc_basic_name(self) -> &'static str {
-        // FIXME: f16 and f128 have no MSVC representation. We could improve the debuginfo.
-        // See: <https://github.com/rust-lang/rust/pull/114607/files#r1454683264>
+        // FIXME(f16_f128): `f16` and `f128` have no MSVC representation. We could improve the
+        // debuginfo. See: <https://github.com/rust-lang/rust/issues/121837>
         match self {
-            ty::FloatTy::F16 => "half",
+            ty::FloatTy::F16 => {
+                bug!("`f16` should have been handled in `build_basic_type_di_node`")
+            }
             ty::FloatTy::F32 => "float",
             ty::FloatTy::F64 => "double",
             ty::FloatTy::F128 => "fp128",
@@ -716,6 +718,38 @@ impl MsvcBasicName for ty::FloatTy {
     }
 }
 
+fn build_cpp_f16_di_node<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) -> DINodeCreationResult<'ll> {
+    // MSVC has no native support for `f16`. Instead, emit `struct f16 { bits: u16 }` to allow the
+    // `f16`'s value to be displayed using a Natvis visualiser in `intrinsic.natvis`.
+    let float_ty = cx.tcx.types.f16;
+    let bits_ty = cx.tcx.types.u16;
+    type_map::build_type_with_children(
+        cx,
+        type_map::stub(
+            cx,
+            Stub::Struct,
+            UniqueTypeId::for_ty(cx.tcx, float_ty),
+            "f16",
+            cx.size_and_align_of(float_ty),
+            NO_SCOPE_METADATA,
+            DIFlags::FlagZero,
+        ),
+        // Fields:
+        |cx, float_di_node| {
+            smallvec![build_field_di_node(
+                cx,
+                float_di_node,
+                "bits",
+                cx.size_and_align_of(bits_ty),
+                Size::ZERO,
+                DIFlags::FlagZero,
+                type_di_node(cx, bits_ty),
+            )]
+        },
+        NO_GENERICS,
+    )
+}
+
 fn build_basic_type_di_node<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     t: Ty<'tcx>,
@@ -739,6 +773,9 @@ fn build_basic_type_di_node<'ll, 'tcx>(
         ty::Char => ("char", DW_ATE_UTF),
         ty::Int(int_ty) if cpp_like_debuginfo => (int_ty.msvc_basic_name(), DW_ATE_signed),
         ty::Uint(uint_ty) if cpp_like_debuginfo => (uint_ty.msvc_basic_name(), DW_ATE_unsigned),
+        ty::Float(ty::FloatTy::F16) if cpp_like_debuginfo => {
+            return build_cpp_f16_di_node(cx);
+        }
         ty::Float(float_ty) if cpp_like_debuginfo => (float_ty.msvc_basic_name(), DW_ATE_float),
         ty::Int(int_ty) => (int_ty.name_str(), DW_ATE_signed),
         ty::Uint(uint_ty) => (uint_ty.name_str(), DW_ATE_unsigned),
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index e02c61cd296..68c3d47e826 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -1469,8 +1469,10 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         let (elem_ty_str, elem_ty) = if let ty::Float(f) = in_elem.kind() {
             let elem_ty = bx.cx.type_float_from_ty(*f);
             match f.bit_width() {
+                16 => ("f16", elem_ty),
                 32 => ("f32", elem_ty),
                 64 => ("f64", elem_ty),
+                128 => ("f128", elem_ty),
                 _ => return_error!(InvalidMonomorphization::FloatingPointVector {
                     span,
                     name,