[mlir][llvm] Purge struct_attr

[Dinistro]

Summary

This commit removes the llvm.struct_attr which was used to bundle
result attributes that were previously attached to multiple results.
This extension isn't part of LLVM as result attribute semantics cannot
be supported on a struct field granularity.
Furthermore, many usages promoted result attributes to argument
attributes but this does not necessary preserve the semantics.

[gysit]

mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp

97

nit: I would use llvm::append_range.

mlir/test/Conversion/FuncToLLVM/emit-c-wrappers-for-external-functions.mlir

5–6

It may be more opaque pointer compatible if we use check-not

CHECK-NOT:    test.returnOne
CHECK-SAME:  -> ()

[Dinistro]

address review comments.

The tests should now already support opaque pointers

[Dinistro]

mlir/test/Conversion/FuncToLLVM/emit-c-wrappers-for-external-functions.mlir

5–6

It seems that the -> () is not produced for LLVMFuncOp operations so I had to change this a bit.

[gysit]

LGTM modulo possible further test improvements.

mlir/test/Conversion/FuncToLLVM/emit-c-wrappers-for-external-callers.mlir

47

ultra nit: could this be

// CHECK-SAME: !llvm.ptr
// CHECK-SAME: !llvm.ptr
// CHECK-SAME: {test.argOne = 1 : i64}

?

[Dinistro]

additional test cleanup

mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td

def LLVM_Dialect : Dialect {
 
   let extraClassDeclaration = [{
     /// Name of the data layout attributes.
     static StringRef getDataLayoutAttrName() { return "llvm.data_layout"; }
     static StringRef getNoAliasScopesAttrName() { return "noalias_scopes"; }
     static StringRef getAliasScopesAttrName() { return "alias_scopes"; }
     static StringRef getLoopAttrName() { return "llvm.loop"; }
     static StringRef getAccessGroupsAttrName() { return "access_groups"; }
-    static StringRef getStructAttrsAttrName() { return "llvm.struct_attrs"; }
     static StringRef getTBAAAttrName() { return "llvm.tbaa"; }
 
     /// Names of llvm parameter attributes.
     static StringRef getAlignAttrName() { return "llvm.align"; }
     static StringRef getAllocAlignAttrName() { return "llvm.allocalign"; }
     static StringRef getAllocatedPointerAttrName() { return "llvm.allocptr"; }
     static StringRef getByValAttrName() { return "llvm.byval"; }
     static StringRef getByRefAttrName() { return "llvm.byref"; }
let extraClassDeclaration = [{
     static StringRef getWriteOnlyAttrName() { return "llvm.writeonly"; }
     static StringRef getZExtAttrName() { return "llvm.zeroext"; }
     // TODO Restrict the usage of this to parameter attributes once there is an
     // alternative way of modeling memory effects on FunctionOpInterface.
     /// Name of the attribute that will cause the creation of a readnone memory
     /// effect when lowering to the LLVMDialect.
     static StringRef getReadnoneAttrName() { return "llvm.readnone"; }
 
-    /// Verifies if the attribute is a well-formed value for "llvm.struct_attrs"
-    static LogicalResult verifyStructAttr(
-        Operation *op, Attribute attr, Type annotatedType);
-
     /// Verifies if the given string is a well-formed data layout descriptor.
     /// Uses `reportError` to report errors.
     static LogicalResult verifyDataLayoutString(
         StringRef descr, llvm::function_ref<void (const Twine &)> reportError);
 
     /// Name of the target triple attribute.
     static StringRef getTargetTripleAttrName() { return "llvm.target_triple"; }
 

mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp

if (attr.getName() == SymbolTable::getSymbolAttrName() ||
         (filterArgAndResAttrs &&
          (attr.getName() == func.getArgAttrsAttrName() ||
           attr.getName() == func.getResAttrsAttrName())))
       continue;
     result.push_back(attr);
   }
 }
 
-/// Helper function for wrapping all attributes into a single DictionaryAttr
-static auto wrapAsStructAttrs(OpBuilder &b, ArrayAttr attrs) {
-  return DictionaryAttr::get(
-      b.getContext(),
-      b.getNamedAttr(LLVM::LLVMDialect::getStructAttrsAttrName(), attrs));
-}
-
-/// Combines all result attributes into a single DictionaryAttr
-/// and prepends to argument attrs.
-/// This is intended to be used to format the attributes for a C wrapper
-/// function when the result(s) is converted to the first function argument
-/// (in the multiple return case, all returns get wrapped into a single
-/// argument). The total number of argument attributes should be equal to
-/// (number of function arguments) + 1.
-static void
-prependResAttrsToArgAttrs(OpBuilder &builder,
-                          SmallVectorImpl<NamedAttribute> &attributes,
+/// Adds a an empty set of argument attributes for the newly added argument in
+/// front of the existing ones.
+static void prependEmptyArgAttr(OpBuilder &builder,
+                                SmallVectorImpl<NamedAttribute> &newFuncAttrs,
                                 func::FuncOp func) {
-  size_t numArguments = func.getNumArguments();
-  auto allAttrs = SmallVector<Attribute>(
-      numArguments + 1, DictionaryAttr::get(builder.getContext()));
-  NamedAttribute *argAttrs = nullptr;
-  for (auto *it = attributes.begin(); it != attributes.end();) {
-    if (it->getName() == func.getArgAttrsAttrName()) {
-      auto arrayAttrs = it->getValue().cast<ArrayAttr>();
-      assert(arrayAttrs.size() == numArguments &&
-             "Number of arg attrs and args should match");
-      std::copy(arrayAttrs.begin(), arrayAttrs.end(), allAttrs.begin() + 1);
-      argAttrs = it;
-    } else if (it->getName() == func.getResAttrsAttrName()) {
-      auto arrayAttrs = it->getValue().cast<ArrayAttr>();
-      assert(!arrayAttrs.empty() && "expected array to be non-empty");
-      allAttrs[0] = (arrayAttrs.size() == 1)
-                        ? arrayAttrs[0]
-                        : wrapAsStructAttrs(builder, arrayAttrs);
-      it = attributes.erase(it);
-      continue;
-    }
-    it++;
-  }
-
-  auto newArgAttrs = builder.getNamedAttr(func.getArgAttrsAttrName(),
-                                          builder.getArrayAttr(allAttrs));
-  if (!argAttrs) {
-    attributes.emplace_back(newArgAttrs);
+  auto argAttrs = func.getArgAttrs();
+  // Nothing to do when there were no arg attrs beforehand.
+  if (!argAttrs)
     return;
-  }
-  *argAttrs = newArgAttrs;
+
+  size_t numArguments = func.getNumArguments();
+  SmallVector<Attribute> newArgAttrs;
+  newArgAttrs.reserve(numArguments + 1);
+  // Insert empty dictionary for the new argument.
+  newArgAttrs.push_back(builder.getDictionaryAttr({}));
+
+  llvm::append_range(newArgAttrs, *argAttrs);
+  auto newNamedAttr = builder.getNamedAttr(func.getArgAttrsAttrName(),
+                                           builder.getArrayAttr(newArgAttrs));
+  newFuncAttrs.push_back(newNamedAttr);
 }
 
 /// Creates an auxiliary function with pointer-to-memref-descriptor-struct
 /// arguments instead of unpacked arguments. This function can be called from C
 /// by passing a pointer to a C struct corresponding to a memref descriptor.
 /// Similarly, returned memrefs are passed via pointers to a C struct that is
 /// passed as additional argument.
 /// Internally, the auxiliary function unpacks the descriptor into individual
 /// components and forwards them to `newFuncOp` and forwards the results to
 /// the extra arguments.
 static void wrapForExternalCallers(OpBuilder &rewriter, Location loc,
                                    LLVMTypeConverter &typeConverter,
                                    func::FuncOp funcOp,
                                    LLVM::LLVMFuncOp newFuncOp) {
   auto type = funcOp.getFunctionType();
-  SmallVector<NamedAttribute, 4> attributes;
-  filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/false, attributes);
   auto [wrapperFuncType, resultIsNowArg] =
       typeConverter.convertFunctionTypeCWrapper(type);
+
+  SmallVector<NamedAttribute, 4> attributes;
+  // Only modify the argument and result attributes when the result is now an
+  // argument.
   if (resultIsNowArg)
-    prependResAttrsToArgAttrs(rewriter, attributes, funcOp);
+    prependEmptyArgAttr(rewriter, attributes, funcOp);
+  filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/resultIsNowArg,
+                       attributes);
   auto wrapperFuncOp = rewriter.create<LLVM::LLVMFuncOp>(
       loc, llvm::formatv("_mlir_ciface_{0}", funcOp.getName()).str(),
       wrapperFuncType, LLVM::Linkage::External, /*dsoLocal*/ false,
       /*cconv*/ LLVM::CConv::C, attributes);
 
   OpBuilder::InsertionGuard guard(rewriter);
   rewriter.setInsertionPointToStart(wrapperFuncOp.addEntryBlock());
 
static void wrapExternalFunction(OpBuilder &builder, Location loc,
   auto [wrapperType, resultIsNowArg] =
       typeConverter.convertFunctionTypeCWrapper(funcOp.getFunctionType());
   // This conversion can only fail if it could not convert one of the argument
   // types. But since it has been applied to a non-wrapper function before, it
   // should have failed earlier and not reach this point at all.
   assert(wrapperType && "unexpected type conversion failure");
 
   SmallVector<NamedAttribute, 4> attributes;
-  filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/false, attributes);
-
+  // Only modify the argument and result attributes when the result is now an
+  // argument.
   if (resultIsNowArg)
-    prependResAttrsToArgAttrs(builder, attributes, funcOp);
+    prependEmptyArgAttr(builder, attributes, funcOp);
+  filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/resultIsNowArg,
+                       attributes);
+
   // Create the auxiliary function.
   auto wrapperFunc = builder.create<LLVM::LLVMFuncOp>(
       loc, llvm::formatv("_mlir_ciface_{0}", funcOp.getName()).str(),
       wrapperType, LLVM::Linkage::External, /*dsoLocal*/ false,
       /*cconv*/ LLVM::CConv::C, attributes);
 
   builder.setInsertionPointToStart(newFuncOp.addEntryBlock());
 
convertFuncOpToLLVMFuncOp(func::FuncOp funcOp,
     // obtained after converting a given original argument/result.
     SmallVector<NamedAttribute, 4> attributes;
     filterFuncAttributes(funcOp, /*filterArgAndResAttrs=*/true, attributes);
     if (ArrayAttr resAttrDicts = funcOp.getAllResultAttrs()) {
       assert(!resAttrDicts.empty() && "expected array to be non-empty");
       auto newResAttrDicts =
           (funcOp.getNumResults() == 1)
               ? resAttrDicts
-              : rewriter.getArrayAttr(
-                    {wrapAsStructAttrs(rewriter, resAttrDicts)});
+              : rewriter.getArrayAttr(rewriter.getDictionaryAttr({}));
       attributes.push_back(
           rewriter.getNamedAttr(funcOp.getResAttrsAttrName(), newResAttrDicts));
     }
     if (ArrayAttr argAttrDicts = funcOp.getAllArgAttrs()) {
       SmallVector<Attribute, 4> newArgAttrs(
           llvmType.cast<LLVM::LLVMFunctionType>().getNumParams());
       for (unsigned i = 0, e = funcOp.getNumArguments(); i < e; ++i) {
         // Some LLVM IR attribute have a type attached to them. During FuncOp ->

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

for (SymbolRefAttr accessGroupRef : parallelAccesses) {
       Operation *accessGroupOp =
           SymbolTable::lookupNearestSymbolFrom(metadataOp, accessGroupName);
       if (!accessGroupOp)
         return op->emitOpError() << "expected '" << accessGroupRef
                                  << "' to reference an access_group op";
     }
   }
 
-  if (attr.getName() == LLVMDialect::getStructAttrsAttrName()) {
-    return op->emitOpError()
-           << "'" << LLVM::LLVMDialect::getStructAttrsAttrName()
-           << "' is permitted only in argument or result attributes";
-  }
-
   // If the data layout attribute is present, it must use the LLVM data layout
   // syntax. Try parsing it and report errors in case of failure. Users of this
   // attribute may assume it is well-formed and can pass it to the (asserting)
   // llvm::DataLayout constructor.
   if (attr.getName() != LLVM::LLVMDialect::getDataLayoutAttrName())
     return success();
   if (auto stringAttr = attr.getValue().dyn_cast<StringAttr>())
     return verifyDataLayoutString(
         stringAttr.getValue(),
         [op](const Twine &message) { op->emitOpError() << message.str(); });
 
   return op->emitOpError() << "expected '"
                            << LLVM::LLVMDialect::getDataLayoutAttrName()
                            << "' to be a string attributes";
 }
 
-LogicalResult LLVMDialect::verifyStructAttr(Operation *op, Attribute attr,
-                                            Type annotatedType) {
-  auto structType = annotatedType.dyn_cast<LLVMStructType>();
-  if (!structType) {
-    const auto emitIncorrectAnnotatedType = [&op]() {
-      return op->emitError()
-             << "expected '" << LLVMDialect::getStructAttrsAttrName()
-             << "' to annotate '!llvm.struct' or '!llvm.ptr<struct<...>>'";
-    };
-    const auto ptrType = annotatedType.dyn_cast<LLVMPointerType>();
-    if (!ptrType)
-      return emitIncorrectAnnotatedType();
-    structType = ptrType.getElementType().dyn_cast<LLVMStructType>();
-    if (!structType)
-      return emitIncorrectAnnotatedType();
-  }
-
-  const auto arrAttrs = attr.dyn_cast<ArrayAttr>();
-  if (!arrAttrs)
-    return op->emitError() << "expected '"
-                           << LLVMDialect::getStructAttrsAttrName()
-                           << "' to be an array attribute";
-
-  if (structType.getBody().size() != arrAttrs.size())
-    return op->emitError()
-           << "size of '" << LLVMDialect::getStructAttrsAttrName()
-           << "' must match the size of the annotated '!llvm.struct'";
-  return success();
-}
-
-static LogicalResult verifyFuncOpInterfaceStructAttr(Operation *op,
-                                                     Attribute attr,
-                                                     Type annotatedType) {
-  if (isa<FunctionOpInterface>(op))
-    return LLVMDialect::verifyStructAttr(op, attr, annotatedType);
-  return op->emitError() << "expected '"
-                         << LLVMDialect::getStructAttrsAttrName()
-                         << "' to be used on function-like operations";
-}
-
 LogicalResult LLVMDialect::verifyParameterAttribute(Operation *op,
                                                     Type paramType,
                                                     NamedAttribute paramAttr) {
   // LLVM attribute may be attached to a result of operation that has not been
   // converted to LLVM dialect yet, so the result may have a type with unknown
   // representation in LLVM dialect type space. In this case we cannot verify
   // whether the attribute may be
   bool verifyValueType = isCompatibleType(paramType);
auto checkPointerTypeMatches = [&]() -> LogicalResult {
     if (!ptrType.isOpaque() && ptrType.getElementType() != typeAttr.getValue())
       return op->emitError()
              << name
              << " attribute attached to LLVM pointer argument of "
                 "different type";
     return success();
   };
 
-  // Note: The struct parameter attributes are not lowered to LLVM IR.
-  if (name == LLVMDialect::getStructAttrsAttrName())
-    return verifyFuncOpInterfaceStructAttr(op, paramAttr.getValue(), paramType);
-
   // Check a unit attribute that is attached to a pointer value.
   if (name == LLVMDialect::getNoAliasAttrName() ||
       name == LLVMDialect::getReadonlyAttrName() ||
       name == LLVMDialect::getReadnoneAttrName() ||
       name == LLVMDialect::getWriteOnlyAttrName() ||
       name == LLVMDialect::getNestAttrName() ||
       name == LLVMDialect::getNoCaptureAttrName() ||
       name == LLVMDialect::getNoFreeAttrName() ||

mlir/test/Conversion/FuncToLLVM/emit-c-wrappers-for-external-callers.mlir

 // RUN: mlir-opt -llvm-request-c-wrappers -convert-func-to-llvm %s | FileCheck %s
 
 // CHECK: llvm.func @res_attrs_with_memref_return() -> (!llvm.struct{{.*}} {test.returnOne})
 // CHECK-LABEL: llvm.func @_mlir_ciface_res_attrs_with_memref_return
-// CHECK: %{{.*}}: !llvm.ptr{{.*}} {test.returnOne}
+// CHECK-NOT: test.returnOne
 func.func @res_attrs_with_memref_return() -> (memref<f32> {test.returnOne}) {
   %0 = memref.alloc() : memref<f32>
   return %0 : memref<f32>
 }
 
 // CHECK: llvm.func @res_attrs_with_value_return() -> (f32 {test.returnOne = 1 : i64})
 // CHECK-LABEL: llvm.func @_mlir_ciface_res_attrs_with_value_return
-// CHECK: -> (f32 {test.returnOne = 1 : i64})
+// CHECK-SAME: -> (f32 {test.returnOne = 1 : i64})
 func.func @res_attrs_with_value_return() -> (f32 {test.returnOne = 1}) {
   %0 = arith.constant 1.00 : f32
   return %0 : f32
 }
 
-// CHECK: llvm.func @multiple_return() -> (!llvm.struct<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK: llvm.func @multiple_return() -> !llvm.struct<{{.*}}>
 // CHECK-LABEL: llvm.func @_mlir_ciface_multiple_return
-// CHECK: (%{{.*}}: !llvm.ptr<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK-SAME: !llvm.ptr
+// CHECK-NOT: test.returnOne
+// CHECK-NOT: test.returnTwo
+// CHECK-NOT: test.returnThree
 func.func @multiple_return() -> (memref<f32> {test.returnOne = 1}, f32 {test.returnTwo = 2, test.returnThree = 3}) {
   %0 = memref.alloc() : memref<f32>
   %1 = arith.constant 1.00 : f32
   return %0, %1 : memref<f32>, f32
 }
 
-// CHECK: llvm.func @multiple_return_missing_res_attr() -> (!llvm.struct<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK: llvm.func @multiple_return_missing_res_attr() -> !llvm.struct<{{.*}}>
 // CHECK-LABEL: llvm.func @_mlir_ciface_multiple_return_missing_res_attr
-// CHECK: (%{{.*}}: !llvm.ptr<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK-SAME: !llvm.ptr
+// CHECK-NOT: test.returnOne
+// CHECK-NOT: test.returnTwo
+// CHECK-NOT: test.returnThree
 func.func @multiple_return_missing_res_attr() -> (memref<f32> {test.returnOne = 1}, i64, f32 {test.returnTwo = 2, test.returnThree = 3}) {
   %0 = memref.alloc() : memref<f32>
   %1 = arith.constant 2 : i64
   %2 = arith.constant 1.00 : f32
   return %0, %1, %2 : memref<f32>, i64, f32
 }
 
 // CHECK: llvm.func @one_arg_attr_no_res_attrs_with_memref_return({{.*}}) -> !llvm.struct{{.*}}
 // CHECK-LABEL: llvm.func @_mlir_ciface_one_arg_attr_no_res_attrs_with_memref_return
-// CHECK: %{{.*}}: !llvm.ptr<{{.*}}>, %{{.*}}: !llvm.ptr<{{.*}}> {test.argOne = 1 : i64}
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argOne = 1 : i64})
 func.func @one_arg_attr_no_res_attrs_with_memref_return(%arg0: memref<f32> {test.argOne = 1}) -> memref<f32> {
   %0 = memref.alloc() : memref<f32>
   return %0 : memref<f32>
 }
 
 // CHECK: llvm.func @one_arg_attr_one_res_attr_with_memref_return({{.*}}) -> (!llvm.struct<{{.*}}> {test.returnOne = 1 : i64})
 // CHECK-LABEL: llvm.func @_mlir_ciface_one_arg_attr_one_res_attr_with_memref_return
-// CHECK: (%{{.*}}: !llvm.ptr<{{.*}}> {test.returnOne = 1 : i64}, %{{.*}}: !llvm.ptr<{{.*}}> {test.argOne = 1 : i64}
+// CHECK-SAME: !llvm.ptr
+// CHECK-NOT: test.returnOne
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argOne = 1 : i64})
 func.func @one_arg_attr_one_res_attr_with_memref_return(%arg0: memref<f32> {test.argOne = 1}) -> (memref<f32> {test.returnOne = 1}) {
   %0 = memref.alloc() : memref<f32>
   return %0 : memref<f32>
 }
 
 // CHECK: llvm.func @one_arg_attr_one_res_attr_with_value_return({{.*}}) -> (f32 {test.returnOne = 1 : i64})
 // CHECK-LABEL: llvm.func @_mlir_ciface_one_arg_attr_one_res_attr_with_value_return
-// CHECK: (%{{.*}}: !llvm.ptr<{{.*}}> {test.argOne = 1 : i64}) -> (f32 {test.returnOne = 1 : i64})
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argOne = 1 : i64})
+// CHECK-SAME: -> (f32 {test.returnOne = 1 : i64})
 func.func @one_arg_attr_one_res_attr_with_value_return(%arg0: memref<f32> {test.argOne = 1}) -> (f32 {test.returnOne = 1}) {
   %0 = arith.constant 1.00 : f32
   return %0 : f32
 }
 
-// CHECK: llvm.func @multiple_arg_attr_multiple_res_attr({{.*}}) -> (!llvm.struct<{{.*}}> {llvm.struct_attrs = [{}, {test.returnOne = 1 : i64}, {test.returnTwo = 2 : i64}]})
+// CHECK: llvm.func @multiple_arg_attr_multiple_res_attr({{.*}}) -> !llvm.struct<{{.*}}>
 // CHECK-LABEL: llvm.func @_mlir_ciface_multiple_arg_attr_multiple_res_attr
-// CHECK: (%{{.*}}: !llvm.ptr<{{.*}}> {llvm.struct_attrs = [{}, {test.returnOne = 1 : i64}, {test.returnTwo = 2 : i64}]}, %{{.*}}: !llvm.ptr<{{.*}}> {test.argZero = 0 : i64}, %{{.*}}: f32, %{{.*}}: i32 {test.argTwo = 2 : i64}
+// CHECK-SAME: !llvm.ptr
+// CHECK-NOT: test.returnOne
+// CHECK-NOT: test.returnTwo
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argZero = 0 : i64}
+// CHECK-SAME: f32
+// CHECK-SAME: i32 {test.argTwo = 2 : i64})
 func.func @multiple_arg_attr_multiple_res_attr(%arg0: memref<f32> {test.argZero = 0}, %arg1: f32, %arg2: i32 {test.argTwo = 2}) -> (f32, memref<i32> {test.returnOne = 1}, i32 {test.returnTwo = 2}) {
   %0 = arith.constant 1.00 : f32
   %1 = memref.alloc() : memref<i32>
   %2 = arith.constant 2 : i32
   return %0, %1, %2 : f32, memref<i32>, i32
 }
 
 // CHECK: llvm.func @drop_linkage_attr() -> (!llvm.struct{{.*}} {test.returnOne})
 // CHECK-LABEL: llvm.func @_mlir_ciface_drop_linkage_attr
+// CHECK-SAME: !llvm.ptr
 // CHECK-NOT: llvm.linkage
-// CHECK: %{{.*}}: !llvm.ptr{{.*}} {test.returnOne}
 func.func @drop_linkage_attr() -> (memref<f32> {test.returnOne}) attributes { llvm.linkage = #llvm.linkage<external> } {
   %0 = memref.alloc() : memref<f32>
   return %0 : memref<f32>
 }

mlir/test/Conversion/FuncToLLVM/emit-c-wrappers-for-external-functions.mlir

 // RUN: mlir-opt -llvm-request-c-wrappers -convert-func-to-llvm %s | FileCheck %s
 
 // CHECK: llvm.func @res_attrs_with_memref_return() -> (!llvm.struct{{.*}} {test.returnOne})
 // CHECK-LABEL: llvm.func @_mlir_ciface_res_attrs_with_memref_return
-// CHECK: !llvm.ptr{{.*}} {test.returnOne}
+// CHECK-SAME: !llvm.ptr
+// CHECK-NOT: test.returnOne
 func.func private @res_attrs_with_memref_return() -> (memref<f32> {test.returnOne})
 
 // CHECK: llvm.func @res_attrs_with_value_return() -> (f32 {test.returnOne = 1 : i64})
 // CHECK-LABEL: llvm.func @_mlir_ciface_res_attrs_with_value_return
-// CHECK: -> (f32 {test.returnOne = 1 : i64})
+// CHECK-SAME: -> (f32 {test.returnOne = 1 : i64})
 func.func private @res_attrs_with_value_return() -> (f32 {test.returnOne = 1})
 
-// CHECK: llvm.func @multiple_return() -> (!llvm.struct<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK: llvm.func @multiple_return() -> !llvm.struct<{{.*}}>
 // CHECK-LABEL: llvm.func @_mlir_ciface_multiple_return
-// CHECK: (!llvm.ptr<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK-NOT: test.returnOne
+// CHECK-NOT: test.returnTwo
+// CHECK-NOT: test.returnThree
 func.func private @multiple_return() -> (memref<f32> {test.returnOne = 1}, f32 {test.returnTwo = 2, test.returnThree = 3})
 
-// CHECK: llvm.func @multiple_return_missing_res_attr() -> (!llvm.struct<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK: llvm.func @multiple_return_missing_res_attr() -> !llvm.struct<{{.*}}>
 // CHECK-LABEL: llvm.func @_mlir_ciface_multiple_return_missing_res_attr
-// CHECK: (!llvm.ptr<{{.*}}> {llvm.struct_attrs = [{test.returnOne = 1 : i64}, {}, {test.returnThree = 3 : i64, test.returnTwo = 2 : i64}]})
+// CHECK-NOT: test.returnOne
+// CHECK-NOT: test.returnTwo
+// CHECK-NOT: test.returnThree
 func.func private @multiple_return_missing_res_attr() -> (memref<f32> {test.returnOne = 1}, i64, f32 {test.returnTwo = 2, test.returnThree = 3})
 
 // CHECK: llvm.func @one_arg_attr_no_res_attrs_with_memref_return({{.*}}) -> !llvm.struct{{.*}}
 // CHECK-LABEL: llvm.func @_mlir_ciface_one_arg_attr_no_res_attrs_with_memref_return
-// CHECK: !llvm.ptr<{{.*}}>, !llvm.ptr<{{.*}}> {test.argOne = 1 : i64}
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argOne = 1 : i64})
 func.func private @one_arg_attr_no_res_attrs_with_memref_return(%arg0: memref<f32> {test.argOne = 1}) -> memref<f32>
 
 // CHECK: llvm.func @one_arg_attr_one_res_attr_with_memref_return({{.*}}) -> (!llvm.struct<{{.*}}> {test.returnOne = 1 : i64})
 // CHECK-LABEL: llvm.func @_mlir_ciface_one_arg_attr_one_res_attr_with_memref_return
-// CHECK: (!llvm.ptr<{{.*}}> {test.returnOne = 1 : i64}, !llvm.ptr<{{.*}}> {test.argOne = 1 : i64}
+// CHECK-SAME: !llvm.ptr
+// CHECK-NOT: test.returnOne
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argOne = 1 : i64})
 func.func private @one_arg_attr_one_res_attr_with_memref_return(%arg0: memref<f32> {test.argOne = 1}) -> (memref<f32> {test.returnOne = 1})
 
 // CHECK: llvm.func @one_arg_attr_one_res_attr_with_value_return({{.*}}) -> (f32 {test.returnOne = 1 : i64})
 // CHECK-LABEL: llvm.func @_mlir_ciface_one_arg_attr_one_res_attr_with_value_return
-// CHECK: (!llvm.ptr<{{.*}}> {test.argOne = 1 : i64}) -> (f32 {test.returnOne = 1 : i64})
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argOne = 1 : i64}
+// CHECK-SAME: -> (f32 {test.returnOne = 1 : i64})
 func.func private @one_arg_attr_one_res_attr_with_value_return(%arg0: memref<f32> {test.argOne = 1}) -> (f32 {test.returnOne = 1})
 
-// CHECK: llvm.func @multiple_arg_attr_multiple_res_attr({{.*}}) -> (!llvm.struct<{{.*}}> {llvm.struct_attrs = [{}, {test.returnOne = 1 : i64}, {test.returnTwo = 2 : i64}]})
+// CHECK: llvm.func @multiple_arg_attr_multiple_res_attr({{.*}}) -> !llvm.struct<{{.*}}>
 // CHECK-LABEL: llvm.func @_mlir_ciface_multiple_arg_attr_multiple_res_attr
-// CHECK: (!llvm.ptr<{{.*}}> {llvm.struct_attrs = [{}, {test.returnOne = 1 : i64}, {test.returnTwo = 2 : i64}]}, !llvm.ptr<{{.*}}> {test.argZero = 0 : i64}, f32, i32 {test.argTwo = 2 : i64}
+// CHECK-SAME: !llvm.ptr
+// CHECK-NOT: test.returnOne
+// CHECK-NOT: test.returnTwo
+// CHECK-SAME: !llvm.ptr
+// CHECK-SAME: {test.argZero = 0 : i64}
+// CHECK-SAME: f32
+// CHECK-SAME: i32 {test.argTwo = 2 : i64})
 func.func private @multiple_arg_attr_multiple_res_attr(%arg0: memref<f32> {test.argZero = 0}, %arg1: f32, %arg2: i32 {test.argTwo = 2}) -> (f32, memref<i32> {test.returnOne = 1}, i32 {test.returnTwo = 2})
 
 // CHECK: llvm.func weak @drop_linkage_attr() -> (!llvm.struct{{.*}} {test.returnOne})
 // CHECK-LABEL: llvm.func @_mlir_ciface_drop_linkage_attr
+// CHECK-SAME: !llvm.ptr
 // CHECK-NOT: llvm.linkage
-// CHECK: !llvm.ptr{{.*}} {test.returnOne}
 func.func private @drop_linkage_attr() -> (memref<f32> {test.returnOne}) attributes { llvm.linkage = #llvm.linkage<weak> }

mlir/test/Dialect/LLVMIR/invalid.mlir

llvm.mlir.global internal @side_effecting_global() : !llvm.struct<(i8)> {
   // expected-error@below {{ops with side effects not allowed in global initializers}}
   %1 = llvm.alloca %0 x !llvm.struct<(i8)> : (i64) -> !llvm.ptr<struct<(i8)>>
   %2 = llvm.load %1 : !llvm.ptr<struct<(i8)>>
   llvm.return %2 : !llvm.struct<(i8)>
 }
 
 // -----
 
-// expected-error@+1 {{'llvm.struct_attrs' is permitted only in argument or result attributes}}
-func.func @struct_attrs_in_op() attributes {llvm.struct_attrs = []} {
-  return
-}
-
-// -----
-
-// expected-error@+1 {{expected 'llvm.struct_attrs' to annotate '!llvm.struct' or '!llvm.ptr<struct<...>>'}}
-func.func @invalid_struct_attr_arg_type(%arg0 : i32 {llvm.struct_attrs = []}) {
-    return
-}
-
-// -----
-
-// expected-error@+1 {{expected 'llvm.struct_attrs' to annotate '!llvm.struct' or '!llvm.ptr<struct<...>>'}}
-func.func @invalid_struct_attr_pointer_arg_type(%arg0 : !llvm.ptr<i32> {llvm.struct_attrs = []}) {
-    return
-}
-
-// -----
-
-// expected-error@+1 {{expected 'llvm.struct_attrs' to be an array attribute}}
-func.func @invalid_arg_struct_attr_value(%arg0 : !llvm.struct<(i32)> {llvm.struct_attrs = {}}) {
-    return
-}
-
-// -----
-
-// expected-error@+1 {{size of 'llvm.struct_attrs' must match the size of the annotated '!llvm.struct'}}
-func.func @invalid_arg_struct_attr_size(%arg0 : !llvm.struct<(i32)> {llvm.struct_attrs = []}) {
-    return
-}
-
-// -----
-
-// expected-error@+1 {{expected 'llvm.struct_attrs' to annotate '!llvm.struct' or '!llvm.ptr<struct<...>>'}}
-func.func @invalid_struct_attr_res_type(%arg0 : i32) -> (i32 {llvm.struct_attrs = []}) {
-  return %arg0 : i32
-}
-
-// -----
-
-// expected-error@+1 {{expected 'llvm.struct_attrs' to annotate '!llvm.struct' or '!llvm.ptr<struct<...>>'}}
-func.func @invalid_struct_attr_pointer_res_type(%arg0 : !llvm.ptr<i32>) -> (!llvm.ptr<i32> {llvm.struct_attrs = []}) {
-    return %arg0 : !llvm.ptr<i32>
-}
-
-// -----
-
-// expected-error@+1 {{expected 'llvm.struct_attrs' to be an array attribute}}
-func.func @invalid_res_struct_attr_value(%arg0 : !llvm.struct<(i32)>) -> (!llvm.struct<(i32)> {llvm.struct_attrs = {}}) {
-    return %arg0 : !llvm.struct<(i32)>
-}
-
-// -----
-
-// expected-error@+1 {{size of 'llvm.struct_attrs' must match the size of the annotated '!llvm.struct'}}
-func.func @invalid_res_struct_attr_size(%arg0 : !llvm.struct<(i32)>) -> (!llvm.struct<(i32)> {llvm.struct_attrs = []}) {
-    return %arg0 : !llvm.struct<(i32)>
-}
-
-// -----
-
 func.func @insert_vector_invalid_source_vector_size(%arg0 : vector<16385xi8>, %arg1 : vector<[16]xi8>) {
   // expected-error@+1 {{op failed to verify that vectors are not bigger than 2^17 bits.}}
   %0 = llvm.intr.vector.insert %arg0, %arg1[0] : vector<16385xi8> into vector<[16]xi8>
 }
 
 // -----
 
 func.func @insert_vector_invalid_dest_vector_size(%arg0 : vector<16xi8>, %arg1 : vector<[16385]xi8>) {