Remove fn/closure #[spirv(unroll_loops)] attribute.

CHANGELOG.md

@@ -5,12 +5,40 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+<!-- NOTE(eddyb) sections from the original template:
+
+### Added
+- New features go here in a bullet list
+
+### Changed
+- Changes to existing functionality go here in a bullet list
+
+### Deprecated
+- Mark features soon-to-be removed in a bullet list
+
+### Removed
+- Features that have been removed in a bullet list
+
+### Fixed
+- Bug fixes in a bullet list
+
+### Security
+- Changes/fixes related to security vulnerabilities in a bullet list
+
+-->
+
 ## [Unreleased]
 
 ### Changed 🛠️
 
 - Applied workspace inheritance to Cargo.toml files
 
+### Removed
+
+- Removed the `fn`/closure `#[spirv(unroll_loops)]` attribute, as it has no users,
+  is becoming non-trivial to support, and requires redesign for better ergonomics
+  (e.g. `#[spirv(unroll)]` applied to individual loops, not the whole `fn`/closure)
+
 ## [0.4.0-alpha.17]
 
 ### Changed 🛠️
@@ -29,6 +57,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - 🚨BREAKING🚨 Migrated from `register_attr` to `register_tool`. [More information](docs/src/migration-to-register-tool.md).
 - Updated toolchain to `nightly-2022-10-01`
 - Updated `glam` to `0.22`
+
+### Removed
+
 - Removed `glam::BVec` support (they are no longer `#[repl(simd)]` in `glam`, as Rust doesn't support SIMD vectors with `bool` elements)
 
 ## [0.4.0-alpha.15]

crates/rustc_codegen_spirv/src/attr.rs

@@ -89,7 +89,6 @@ pub enum SpirvAttribute {
     InputAttachmentIndex(u32),
 
     // `fn`/closure attributes:
-    UnrollLoops,
     BufferLoadIntrinsic,
     BufferStoreIntrinsic,
 }
@@ -124,7 +123,6 @@ pub struct AggregatedSpirvAttributes {
     pub input_attachment_index: Option<Spanned<u32>>,
 
     // `fn`/closure attributes:
-    pub unroll_loops: Option<Spanned<()>>,
     pub buffer_load_intrinsic: Option<Spanned<()>>,
     pub buffer_store_intrinsic: Option<Spanned<()>>,
 }
@@ -213,7 +211,6 @@ impl AggregatedSpirvAttributes {
                 span,
                 "#[spirv(attachment_index)]",
             ),
-            UnrollLoops => try_insert(&mut self.unroll_loops, (), span, "#[spirv(unroll_loops)]"),
             BufferLoadIntrinsic => try_insert(
                 &mut self.buffer_load_intrinsic,
                 (),
@@ -346,15 +343,6 @@ impl CheckSpirvAttrVisitor<'_> {
 
                     _ => Err(Expected("function parameter")),
                 },
-                SpirvAttribute::UnrollLoops => match target {
-                    Target::Fn
-                    | Target::Closure
-                    | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent) => {
-                        Ok(())
-                    }
-
-                    _ => Err(Expected("function or closure")),
-                },
                 SpirvAttribute::BufferLoadIntrinsic | SpirvAttribute::BufferStoreIntrinsic => {
                     match target {
                         Target::Fn => Ok(()),

crates/rustc_codegen_spirv/src/codegen_cx/declare.rs

@@ -117,9 +117,6 @@ impl<'tcx> CodegenCx<'tcx> {
                 .map_or_else(|| instance.to_string(), ToString::to_string);
             self.entry_stub(&instance, fn_abi, declared, entry_name, entry);
         }
-        if attrs.unroll_loops.is_some() {
-            self.unroll_loops_decorations.borrow_mut().insert(fn_id);
-        }
         if attrs.buffer_load_intrinsic.is_some() {
             let mode = &fn_abi.ret.mode;
             self.buffer_load_intrinsic_fn_id

crates/rustc_codegen_spirv/src/codegen_cx/mod.rs

@@ -5,9 +5,7 @@ mod type_;
 
 use crate::builder::{ExtInst, InstructionTable};
 use crate::builder_spirv::{BuilderCursor, BuilderSpirv, SpirvConst, SpirvValue, SpirvValueKind};
-use crate::decorations::{
-    CustomDecoration, SerializedSpan, UnrollLoopsDecoration, ZombieDecoration,
-};
+use crate::decorations::{CustomDecoration, SerializedSpan, ZombieDecoration};
 use crate::spirv_type::{SpirvType, SpirvTypePrinter, TypeCache};
 use crate::symbols::Symbols;
 use crate::target::SpirvTarget;
@@ -20,7 +18,7 @@ use rustc_codegen_ssa::traits::{
     AsmMethods, BackendTypes, CoverageInfoMethods, DebugInfoMethods, GlobalAsmOperandRef,
     MiscMethods,
 };
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::mir::mono::CodegenUnit;
 use rustc_middle::mir::Body;
 use rustc_middle::ty::layout::{HasParamEnv, HasTyCtxt};
@@ -55,10 +53,6 @@ pub struct CodegenCx<'tcx> {
     /// each with its own reason and span that should be used for reporting
     /// (in the event that the value is actually needed)
     zombie_decorations: RefCell<FxHashMap<Word, ZombieDecoration>>,
-    /// Functions that have `#[spirv(unroll_loops)]`, and therefore should
-    /// get `LoopControl::UNROLL` applied to all of their loops' `OpLoopMerge`
-    /// instructions, during structuralization.
-    unroll_loops_decorations: RefCell<FxHashSet<Word>>,
     /// Cache of all the builtin symbols we need
     pub sym: Rc<Symbols>,
     pub instruction_table: InstructionTable,
@@ -121,7 +115,6 @@ impl<'tcx> CodegenCx<'tcx> {
             vtables: Default::default(),
             ext_inst: Default::default(),
             zombie_decorations: Default::default(),
-            unroll_loops_decorations: Default::default(),
             target,
             sym,
             instruction_table: InstructionTable::new(),
@@ -208,13 +201,7 @@ impl<'tcx> CodegenCx<'tcx> {
             self.zombie_decorations
                 .into_inner()
                 .into_iter()
-                .map(|(id, zombie)| zombie.encode(id))
-                .chain(
-                    self.unroll_loops_decorations
-                        .into_inner()
-                        .into_iter()
-                        .map(|id| UnrollLoopsDecoration {}.encode(id)),
-                ),
+                .map(|(id, zombie)| zombie.encode(id)),
         );
         result
     }

crates/rustc_codegen_spirv/src/decorations.rs

@@ -99,16 +99,6 @@ impl<'a, D: Deserialize<'a>> LazilyDeserialized<'a, D> {
     }
 }
 
-/// An `OpFunction` with `#[spirv(unroll_loops)]` on the Rust `fn` definition,
-/// which should get `LoopControl::UNROLL` applied to all of its loops'
-/// `OpLoopMerge` instructions, during structuralization.
-#[derive(Deserialize, Serialize)]
-pub struct UnrollLoopsDecoration {}
-
-impl CustomDecoration for UnrollLoopsDecoration {
-    const ENCODING_PREFIX: &'static str = "U";
-}
-
 #[derive(Deserialize, Serialize)]
 pub struct ZombieDecoration {
     pub reason: String,

crates/rustc_codegen_spirv/src/linker/mod.rs

@@ -19,11 +19,10 @@ mod zombies;
 use std::borrow::Cow;
 
 use crate::codegen_cx::SpirvMetadata;
-use crate::decorations::{CustomDecoration, UnrollLoopsDecoration};
 use rspirv::binary::{Assemble, Consumer};
 use rspirv::dr::{Block, Instruction, Loader, Module, ModuleHeader, Operand};
 use rspirv::spirv::{Op, StorageClass, Word};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::ErrorGuaranteed;
 use rustc_session::Session;
 
@@ -226,14 +225,9 @@ pub fn link(sess: &Session, mut inputs: Vec<Module>, opts: &Options) -> Result<L
         dce::dce(&mut output);
     }
 
-    let unroll_loops_decorations = UnrollLoopsDecoration::decode_all(&output)
-        .map(|(id, _)| id)
-        .collect::<FxHashSet<_>>();
-    UnrollLoopsDecoration::remove_all(&mut output);
-
     let mut output = if opts.structurize {
         let _timer = sess.timer("link_structurize");
-        structurizer::structurize(output, unroll_loops_decorations)
+        structurizer::structurize(output)
     } else {
         output
     };

crates/rustc_codegen_spirv/src/linker/structurizer.rs

@@ -1,7 +1,7 @@
 use indexmap::{indexmap, IndexMap};
 use rspirv::dr::{Block, Builder, Function, InsertPoint, Module, Operand};
 use rspirv::spirv::{LoopControl, Op, SelectionControl, Word};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashMap;
 use std::{iter, mem};
 
 /// Cached IDs of `OpTypeBool`, `OpConstantFalse`, and `OpConstantTrue`.
@@ -37,7 +37,7 @@ impl FuncBuilder<'_> {
     }
 }
 
-pub fn structurize(module: Module, unroll_loops_decorations: FxHashSet<Word>) -> Module {
+pub fn structurize(module: Module) -> Module {
     let mut builder = Builder::new_from_module(module);
 
     // Get the `OpTypeBool` type (it will only be created if it's missing).
@@ -72,14 +72,6 @@ pub fn structurize(module: Module, unroll_loops_decorations: FxHashSet<Word>) ->
             builder: &mut builder,
         };
 
-        let func_id = func.function().def_id().unwrap();
-
-        let loop_control = if unroll_loops_decorations.contains(&func_id) {
-            LoopControl::UNROLL
-        } else {
-            LoopControl::NONE
-        };
-
         let block_id_to_idx = func
             .blocks()
             .iter()
@@ -95,7 +87,6 @@ pub fn structurize(module: Module, unroll_loops_decorations: FxHashSet<Word>) ->
             },
             func,
             block_id_to_idx,
-            loop_control,
             incoming_edge_count: vec![],
             regions: FxHashMap::default(),
         }
@@ -140,10 +131,6 @@ struct Structurizer<'a> {
     func: FuncBuilder<'a>,
     block_id_to_idx: FxHashMap<BlockId, BlockIdx>,
 
-    /// `LoopControl` to use in all loops' `OpLoopMerge` instruction.
-    /// Currently only affected by function-scoped `#[spirv(unroll_loops)]`.
-    loop_control: LoopControl,
-
     /// Number of edges pointing to each block.
     /// Computed by `post_order` and updated when structuring loops
     /// (backedge count is subtracted to hide them from outer regions).
@@ -390,7 +377,7 @@ impl Structurizer<'_> {
                     .loop_merge(
                         while_exit_block_id,
                         while_body_merge_id,
-                        self.loop_control,
+                        LoopControl::NONE,
                         iter::empty(),
                     )
                     .unwrap();

crates/rustc_codegen_spirv/src/symbols.rs

@@ -339,7 +339,6 @@ impl Symbols {
                 "matrix",
                 SpirvAttribute::IntrinsicType(IntrinsicType::Matrix),
             ),
-            ("unroll_loops", SpirvAttribute::UnrollLoops),
             ("buffer_load_intrinsic", SpirvAttribute::BufferLoadIntrinsic),
             (
                 "buffer_store_intrinsic",

tests/ui/dis/unroll_loops.rs

@@ -1,18 +0,0 @@
-// build-pass
-// compile-flags: -C llvm-args=--disassemble-fn=unroll_loops::java_hash_ten_times
-
-use spirv_std::spirv;
-
-#[spirv(unroll_loops)]
-fn java_hash_ten_times(mut x: u32, y: u32) -> u32 {
-    let mut i = 0;
-    while i < 10 {
-        x = 31 * x + y;
-        i += 1;
-    }
-    x
-}
-#[spirv(fragment)]
-pub fn main() {
-    java_hash_ten_times(7, 42);
-}

tests/ui/dis/unroll_loops.stderr

@@ -1,40 +0,0 @@
-%1 = OpFunction  %2  None %3
-%4 = OpFunctionParameter  %2
-%5 = OpFunctionParameter  %2
-%6 = OpLabel
-OpLine %7 9 4
-OpBranch %8
-%8 = OpLabel
-OpBranch %9
-%9 = OpLabel
-%10 = OpPhi  %11  %12 %8 %13 %14
-%15 = OpPhi  %2  %4 %8 %16 %14
-%17 = OpPhi  %18  %19 %8 %20 %14
-OpLoopMerge %21 %14 Unroll
-OpBranchConditional %17 %22 %21
-%22 = OpLabel
-OpLine %7 9 10
-%23 = OpSLessThan  %18  %10 %24
-OpLine %7 9 10
-OpSelectionMerge %25 None
-OpBranchConditional %23 %26 %27
-%26 = OpLabel
-OpLine %7 10 12
-%28 = OpIMul  %2  %29 %15
-OpLine %7 10 8
-%16 = OpIAdd  %2  %28 %5
-OpLine %7 11 8
-%13 = OpIAdd  %11  %10 %30
-OpLine %7 9 4
-OpBranch %25
-%27 = OpLabel
-OpLine %7 14 1
-OpReturnValue %15
-%25 = OpLabel
-%20 = OpPhi  %18  %19 %26
-OpBranch %14
-%14 = OpLabel
-OpBranch %9
-%21 = OpLabel
-OpUnreachable
-OpFunctionEnd

tests/ui/spirv-attr/invalid-target.rs

@@ -17,18 +17,17 @@
 // * builtin: `position`
 
 // NOTE(eddyb) accounting for the number of errors this test actually produces:
-// * 473 errors, all "attribute is only valid on" (see `invalid-target.stderr`)
+// * 437 errors, all "attribute is only valid on" (see `invalid-target.stderr`)
 // * 41 uses of `#[rust_gpu::spirv(...)]` in this test
-// * at most 12 attributes per `#[rust_gpu::spirv(...)]`, so an upper bound of `41*12 = 492`
-// * the difference between 492 and 473 is 19, i.e. valid attributes, made up of:
+// * at most 11 attributes per `#[rust_gpu::spirv(...)]`, so an upper bound of `41*11 = 451`
+// * the difference between 451 and 437 is 14, i.e. valid attributes, made up of:
 //   * 4 on `_Struct`
-//   * 8 on functions, i.e. 2 on each of:
+//   * 4 on functions, i.e. 1 on each of:
 //     * `_inherent_method`
 //     * `_trait_method_with_default`,
 //     * `_trait_method` (in `impl _Trait for ()`)
 //     * `_fn`
 //   * 6 on `_entry_param`
-//   * 1 on `_closure`
 
 // NOTE(shesp) Directly using `#[rust_gpu::spirv(...)]` because macro attributes are invalid in most contexts
 
@@ -36,7 +35,6 @@
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 macro_rules! _macro {
     () => {};
@@ -46,7 +44,6 @@ macro_rules! _macro {
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 extern crate spirv_std as _;
 
@@ -54,7 +51,6 @@ extern crate spirv_std as _;
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 use spirv_std as _;
 
@@ -62,7 +58,6 @@ use spirv_std as _;
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 mod _mod {}
 
@@ -70,14 +65,12 @@ mod _mod {}
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 extern "C" {
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     type _ForeignTy;
 
@@ -85,7 +78,6 @@ extern "C" {
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     static _FOREIGN_STATIC: ();
 
@@ -93,7 +85,6 @@ extern "C" {
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     fn _foreign_fn();
 }
@@ -102,7 +93,6 @@ extern "C" {
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 static _STATIC: () = ();
 
@@ -110,7 +100,6 @@ static _STATIC: () = ();
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 const _CONST: () = ();
 
@@ -118,7 +107,6 @@ const _CONST: () = ();
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 type _TyAlias = ();
 
@@ -126,7 +114,6 @@ type _TyAlias = ();
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 type _OpaqueTy = impl Copy;
 
@@ -138,21 +125,18 @@ fn _opaque_ty_definer() -> _OpaqueTy {
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 enum _Enum {
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     _Variant {
         #[rust_gpu::spirv(
             sampler, block, sampled_image, generic_image_type, // struct-only
             vertex, // fn-only
             uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-            unroll_loops, // fn/closure-only
         )]
         _field: (),
     },
@@ -162,14 +146,12 @@ enum _Enum {
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 union _Union {
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     _field: (),
 }
@@ -177,14 +159,12 @@ union _Union {
 #[rust_gpu::spirv(
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 struct _Struct {
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     _field: (),
 }
@@ -193,14 +173,12 @@ struct _Struct {
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 impl _Struct {
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     const _INHERENT_ASSOC_CONST: () = ();
 
@@ -215,7 +193,6 @@ impl _Struct {
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 trait _TraitAlias = Copy;
 
@@ -223,14 +200,12 @@ trait _TraitAlias = Copy;
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 trait _Trait {
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     type _AssocTy;
 
@@ -238,7 +213,6 @@ trait _Trait {
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     const _TRAIT_ASSOC_CONST: ();
 
@@ -246,7 +220,6 @@ trait _Trait {
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     fn _trait_method();
 
@@ -261,14 +234,12 @@ trait _Trait {
     sampler, block, sampled_image, generic_image_type, // struct-only
     vertex, // fn-only
     uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-    unroll_loops, // fn/closure-only
 )]
 impl _Trait for () {
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     type _AssocTy = ();
 
@@ -276,7 +247,6 @@ impl _Trait for () {
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     const _TRAIT_ASSOC_CONST: () = ();
 
@@ -295,7 +265,6 @@ fn _fn(
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
-        unroll_loops, // fn/closure-only
     )]
     _entry_param: (),
 ) {
@@ -303,7 +272,6 @@ fn _fn(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )]
     let _statement = ();
 
@@ -319,7 +287,6 @@ fn _fn(
             sampler, block, sampled_image, generic_image_type, // struct-only
             vertex, // fn-only
             uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-            unroll_loops, // fn/closure-only
         )]
         (1, 2, 3) // expression
     );
@@ -329,7 +296,6 @@ fn _fn(
             sampler, block, sampled_image, generic_image_type, // struct-only
             vertex, // fn-only
             uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-            unroll_loops, // fn/closure-only
         )]
         _arm => {}
     }
@@ -340,19 +306,16 @@ fn _fn_with_generics<
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )] '_lifetime_param,
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )] _TyParam,
     #[rust_gpu::spirv(
         sampler, block, sampled_image, generic_image_type, // struct-only
         vertex, // fn-only
         uniform, position, descriptor_set = 0, binding = 0, flat, invariant, // param-only
-        unroll_loops, // fn/closure-only
     )] const _CONST_PARAM: usize,
 >() {
 }

tests/ui/spirv-attr/multiple.rs

@@ -51,6 +51,3 @@ fn _entry(
     #[spirv(invariant, invariant)] _invariant: (),
 ) {
 }
-
-#[spirv(unroll_loops, unroll_loops)]
-fn _unroll_loops() {}

tests/ui/spirv-attr/multiple.stderr

@@ -208,17 +208,5 @@ note: previous #[spirv(invariant)] attribute
 51 |     #[spirv(invariant, invariant)] _invariant: (),
    |             ^^^^^^^^^
 
-error: only one #[spirv(unroll_loops)] attribute is allowed on a function
-  --> $DIR/multiple.rs:55:23
-   |
-55 | #[spirv(unroll_loops, unroll_loops)]
-   |                       ^^^^^^^^^^^^
-   |
-note: previous #[spirv(unroll_loops)] attribute
-  --> $DIR/multiple.rs:55:9
-   |
-55 | #[spirv(unroll_loops, unroll_loops)]
-   |         ^^^^^^^^^^^^
-
-error: aborting due to 18 previous errors; 1 warning emitted
+error: aborting due to 17 previous errors; 1 warning emitted