r288866 - [c++17] P0135R1: Guaranteed copy elision.
Adrian Prantl via cfe-commits
cfe-commits at lists.llvm.org
Thu Dec 8 18:00:58 PST 2016
Hi Richard,
at this point this is more a heads-up than anything actionable, but I wanted to let you know that I bisected this bot failure (http://lab.llvm.org:8080/green/job/clang-stage2-cmake-RgSan_check/2721/consoleFull#10584592348254eaf0-7326-4999-85b0-388101f2d404) of std/input.output/stream.buffers/streambuf/streambuf.cons/copy.fail.cpp down to this commit.
I will follow up once I have a better understanding what is going on there.
-- adrian
> On Dec 6, 2016, at 3:52 PM, Richard Smith via cfe-commits <cfe-commits at lists.llvm.org> wrote:
>
> Author: rsmith
> Date: Tue Dec 6 17:52:28 2016
> New Revision: 288866
>
> URL: http://llvm.org/viewvc/llvm-project?rev=288866&view=rev
> Log:
> [c++17] P0135R1: Guaranteed copy elision.
>
> When an object of class type is initialized from a prvalue of the same type
> (ignoring cv qualifications), use the prvalue to initialize the object directly
> instead of inserting a redundant elidable call to a copy constructor.
>
> Added:
> cfe/trunk/test/CodeGenCXX/cxx1z-copy-omission.cpp
> cfe/trunk/test/SemaCXX/cxx1z-copy-omission.cpp
> Modified:
> cfe/trunk/include/clang/AST/Expr.h
> cfe/trunk/lib/AST/Expr.cpp
> cfe/trunk/lib/AST/ExprConstant.cpp
> cfe/trunk/lib/CodeGen/CGExpr.cpp
> cfe/trunk/lib/CodeGen/CGExprAgg.cpp
> cfe/trunk/lib/CodeGen/CGExprConstant.cpp
> cfe/trunk/lib/Sema/SemaExprCXX.cpp
> cfe/trunk/lib/Sema/SemaInit.cpp
> cfe/trunk/lib/Sema/SemaOverload.cpp
> cfe/trunk/test/CXX/drs/dr0xx.cpp
> cfe/trunk/test/CXX/drs/dr10xx.cpp
> cfe/trunk/test/CXX/drs/dr1xx.cpp
> cfe/trunk/test/CXX/drs/dr4xx.cpp
> cfe/trunk/test/SemaCXX/aggregate-initialization.cpp
> cfe/trunk/www/cxx_dr_status.html
> cfe/trunk/www/cxx_status.html
>
> Modified: cfe/trunk/include/clang/AST/Expr.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Expr.h?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/Expr.h (original)
> +++ cfe/trunk/include/clang/AST/Expr.h Tue Dec 6 17:52:28 2016
> @@ -3786,7 +3786,7 @@ public:
>
> /// \brief Build an empty initializer list.
> explicit InitListExpr(EmptyShell Empty)
> - : Expr(InitListExprClass, Empty) { }
> + : Expr(InitListExprClass, Empty), AltForm(nullptr, true) { }
>
> unsigned getNumInits() const { return InitExprs.size(); }
>
> @@ -3894,6 +3894,11 @@ public:
> // literal or an @encode?
> bool isStringLiteralInit() const;
>
> + /// Is this a transparent initializer list (that is, an InitListExpr that is
> + /// purely syntactic, and whose semantics are that of the sole contained
> + /// initializer)?
> + bool isTransparent() const;
> +
> SourceLocation getLBraceLoc() const { return LBraceLoc; }
> void setLBraceLoc(SourceLocation Loc) { LBraceLoc = Loc; }
> SourceLocation getRBraceLoc() const { return RBraceLoc; }
>
> Modified: cfe/trunk/lib/AST/Expr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/Expr.cpp (original)
> +++ cfe/trunk/lib/AST/Expr.cpp Tue Dec 6 17:52:28 2016
> @@ -1864,6 +1864,24 @@ bool InitListExpr::isStringLiteralInit()
> return isa<StringLiteral>(Init) || isa<ObjCEncodeExpr>(Init);
> }
>
> +bool InitListExpr::isTransparent() const {
> + assert(isSemanticForm() && "syntactic form never semantically transparent");
> +
> + // A glvalue InitListExpr is always just sugar.
> + if (isGLValue()) {
> + assert(getNumInits() == 1 && "multiple inits in glvalue init list");
> + return true;
> + }
> +
> + // Otherwise, we're sugar if and only if we have exactly one initializer that
> + // is of the same type.
> + if (getNumInits() != 1 || !getInit(0))
> + return false;
> +
> + return getType().getCanonicalType() ==
> + getInit(0)->getType().getCanonicalType();
> +}
> +
> SourceLocation InitListExpr::getLocStart() const {
> if (InitListExpr *SyntacticForm = getSyntacticForm())
> return SyntacticForm->getLocStart();
> @@ -2246,12 +2264,15 @@ bool Expr::isUnusedResultAWarning(const
> // effects (e.g. a placement new with an uninitialized POD).
> case CXXDeleteExprClass:
> return false;
> + case MaterializeTemporaryExprClass:
> + return cast<MaterializeTemporaryExpr>(this)->GetTemporaryExpr()
> + ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
> case CXXBindTemporaryExprClass:
> - return (cast<CXXBindTemporaryExpr>(this)
> - ->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx));
> + return cast<CXXBindTemporaryExpr>(this)->getSubExpr()
> + ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
> case ExprWithCleanupsClass:
> - return (cast<ExprWithCleanups>(this)
> - ->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx));
> + return cast<ExprWithCleanups>(this)->getSubExpr()
> + ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
> }
> }
>
>
> Modified: cfe/trunk/lib/AST/ExprConstant.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/ExprConstant.cpp (original)
> +++ cfe/trunk/lib/AST/ExprConstant.cpp Tue Dec 6 17:52:28 2016
> @@ -5670,6 +5670,9 @@ bool RecordExprEvaluator::VisitCastExpr(
> }
>
> bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
> + if (E->isTransparent())
> + return Visit(E->getInit(0));
> +
> const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
> if (RD->isInvalidDecl()) return false;
> const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
>
> Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExpr.cpp Tue Dec 6 17:52:28 2016
> @@ -3522,7 +3522,7 @@ LValue CodeGenFunction::EmitInitListLVal
> return EmitAggExprToLValue(E);
>
> // An lvalue initializer list must be initializing a reference.
> - assert(E->getNumInits() == 1 && "reference init with multiple values");
> + assert(E->isTransparent() && "non-transparent glvalue init list");
> return EmitLValue(E->getInit(0));
> }
>
>
> Modified: cfe/trunk/lib/CodeGen/CGExprAgg.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprAgg.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGExprAgg.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExprAgg.cpp Tue Dec 6 17:52:28 2016
> @@ -1145,15 +1145,15 @@ void AggExprEmitter::VisitInitListExpr(I
> if (E->hadArrayRangeDesignator())
> CGF.ErrorUnsupported(E, "GNU array range designator extension");
>
> + if (E->isTransparent())
> + return Visit(E->getInit(0));
> +
> AggValueSlot Dest = EnsureSlot(E->getType());
>
> LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType());
>
> // Handle initialization of an array.
> if (E->getType()->isArrayType()) {
> - if (E->isStringLiteralInit())
> - return Visit(E->getInit(0));
> -
> QualType elementType =
> CGF.getContext().getAsArrayType(E->getType())->getElementType();
>
> @@ -1162,16 +1162,6 @@ void AggExprEmitter::VisitInitListExpr(I
> return;
> }
>
> - if (E->getType()->isAtomicType()) {
> - // An _Atomic(T) object can be list-initialized from an expression
> - // of the same type.
> - assert(E->getNumInits() == 1 &&
> - CGF.getContext().hasSameUnqualifiedType(E->getInit(0)->getType(),
> - E->getType()) &&
> - "unexpected list initialization for atomic object");
> - return Visit(E->getInit(0));
> - }
> -
> assert(E->getType()->isRecordType() && "Only support structs/unions here!");
>
> // Do struct initialization; this code just sets each individual member
>
> Modified: cfe/trunk/lib/CodeGen/CGExprConstant.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprConstant.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGExprConstant.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp Tue Dec 6 17:52:28 2016
> @@ -778,9 +778,6 @@ public:
> }
>
> llvm::Constant *EmitArrayInitialization(InitListExpr *ILE) {
> - if (ILE->isStringLiteralInit())
> - return Visit(ILE->getInit(0));
> -
> llvm::ArrayType *AType =
> cast<llvm::ArrayType>(ConvertType(ILE->getType()));
> llvm::Type *ElemTy = AType->getElementType();
> @@ -845,6 +842,9 @@ public:
> }
>
> llvm::Constant *VisitInitListExpr(InitListExpr *ILE) {
> + if (ILE->isTransparent())
> + return Visit(ILE->getInit(0));
> +
> if (ILE->getType()->isArrayType())
> return EmitArrayInitialization(ILE);
>
>
> Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Tue Dec 6 17:52:28 2016
> @@ -6836,6 +6836,16 @@ ExprResult Sema::IgnoredValueConversions
> return E;
> E = Res.get();
> }
> +
> + // C++1z:
> + // If the expression is a prvalue after this optional conversion, the
> + // temporary materialization conversion is applied.
> + //
> + // We skip this step: IR generation is able to synthesize the storage for
> + // itself in the aggregate case, and adding the extra node to the AST is
> + // just clutter.
> + // FIXME: We don't emit lifetime markers for the temporaries due to this.
> + // FIXME: Do any other AST consumers care about this?
> return E;
> }
>
>
> Modified: cfe/trunk/lib/Sema/SemaInit.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaInit.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaInit.cpp Tue Dec 6 17:52:28 2016
> @@ -3546,8 +3546,14 @@ static void TryConstructorInitialization
> InitializationSequence &Sequence,
> bool IsListInit = false,
> bool IsInitListCopy = false) {
> - assert((!IsListInit || (Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
> - "IsListInit must come with a single initializer list argument.");
> + assert(((!IsListInit && !IsInitListCopy) ||
> + (Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
> + "IsListInit/IsInitListCopy must come with a single initializer list "
> + "argument.");
> + InitListExpr *ILE =
> + (IsListInit || IsInitListCopy) ? cast<InitListExpr>(Args[0]) : nullptr;
> + MultiExprArg UnwrappedArgs =
> + ILE ? MultiExprArg(ILE->getInits(), ILE->getNumInits()) : Args;
>
> // The type we're constructing needs to be complete.
> if (!S.isCompleteType(Kind.getLocation(), DestType)) {
> @@ -3555,6 +3561,35 @@ static void TryConstructorInitialization
> return;
> }
>
> + // C++1z [dcl.init]p17:
> + // - If the initializer expression is a prvalue and the cv-unqualified
> + // version of the source type is the same class as the class of the
> + // destination, the initializer expression is used to initialize the
> + // destination object.
> + // Per DR (no number yet), this does not apply when initializing a base
> + // class or delegating to another constructor from a mem-initializer.
> + if (S.getLangOpts().CPlusPlus1z &&
> + Entity.getKind() != InitializedEntity::EK_Base &&
> + Entity.getKind() != InitializedEntity::EK_Delegating &&
> + UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isRValue() &&
> + S.Context.hasSameUnqualifiedType(UnwrappedArgs[0]->getType(), DestType)) {
> + // Convert qualifications if necessary.
> + QualType InitType = UnwrappedArgs[0]->getType();
> + ImplicitConversionSequence ICS;
> + ICS.setStandard();
> + ICS.Standard.setAsIdentityConversion();
> + ICS.Standard.setFromType(InitType);
> + ICS.Standard.setAllToTypes(InitType);
> + if (!S.Context.hasSameType(InitType, DestType)) {
> + ICS.Standard.Third = ICK_Qualification;
> + ICS.Standard.setToType(2, DestType);
> + }
> + Sequence.AddConversionSequenceStep(ICS, DestType);
> + if (ILE)
> + Sequence.RewrapReferenceInitList(DestType, ILE);
> + return;
> + }
> +
> const RecordType *DestRecordType = DestType->getAs<RecordType>();
> assert(DestRecordType && "Constructor initialization requires record type");
> CXXRecordDecl *DestRecordDecl
> @@ -3588,20 +3623,16 @@ static void TryConstructorInitialization
> // constructors of the class T and the argument list consists of the
> // initializer list as a single argument.
> if (IsListInit) {
> - InitListExpr *ILE = cast<InitListExpr>(Args[0]);
> AsInitializerList = true;
>
> // If the initializer list has no elements and T has a default constructor,
> // the first phase is omitted.
> - if (ILE->getNumInits() != 0 || !DestRecordDecl->hasDefaultConstructor())
> + if (!(UnwrappedArgs.empty() && DestRecordDecl->hasDefaultConstructor()))
> Result = ResolveConstructorOverload(S, Kind.getLocation(), Args,
> CandidateSet, Ctors, Best,
> CopyInitialization, AllowExplicit,
> /*OnlyListConstructor=*/true,
> IsListInit);
> -
> - // Time to unwrap the init list.
> - Args = MultiExprArg(ILE->getInits(), ILE->getNumInits());
> }
>
> // C++11 [over.match.list]p1:
> @@ -3611,7 +3642,7 @@ static void TryConstructorInitialization
> // elements of the initializer list.
> if (Result == OR_No_Viable_Function) {
> AsInitializerList = false;
> - Result = ResolveConstructorOverload(S, Kind.getLocation(), Args,
> + Result = ResolveConstructorOverload(S, Kind.getLocation(), UnwrappedArgs,
> CandidateSet, Ctors, Best,
> CopyInitialization, AllowExplicit,
> /*OnlyListConstructors=*/false,
> @@ -3821,8 +3852,8 @@ static void TryListInitialization(Sema &
> QualType InitType = InitList->getInit(0)->getType();
> if (S.Context.hasSameUnqualifiedType(InitType, DestType) ||
> S.IsDerivedFrom(InitList->getLocStart(), InitType, DestType)) {
> - Expr *InitAsExpr = InitList->getInit(0);
> - TryConstructorInitialization(S, Entity, Kind, InitAsExpr, DestType,
> + Expr *InitListAsExpr = InitList;
> + TryConstructorInitialization(S, Entity, Kind, InitListAsExpr, DestType,
> Sequence, /*InitListSyntax*/ false,
> /*IsInitListCopy*/ true);
> return;
> @@ -4332,16 +4363,21 @@ static void TryReferenceInitializationCo
> }
>
> // - If the initializer expression
> + // C++14-and-before:
> // - is an xvalue, class prvalue, array prvalue, or function lvalue and
> // "cv1 T1" is reference-compatible with "cv2 T2"
> + // C++1z:
> + // - is an rvalue or function lvalue and "cv1 T1" is reference-compatible
> + // with "cv2 T2"
> // Note: functions are handled below.
> if (!T1Function &&
> (RefRelationship == Sema::Ref_Compatible ||
> (Kind.isCStyleOrFunctionalCast() &&
> RefRelationship == Sema::Ref_Related)) &&
> (InitCategory.isXValue() ||
> - (InitCategory.isPRValue() && T2->isRecordType()) ||
> - (InitCategory.isPRValue() && T2->isArrayType()))) {
> + (InitCategory.isPRValue() &&
> + (S.getLangOpts().CPlusPlus1z || T2->isRecordType() ||
> + T2->isArrayType())))) {
> ExprValueKind ValueKind = InitCategory.isXValue()? VK_XValue : VK_RValue;
> if (InitCategory.isPRValue() && T2->isRecordType()) {
> // The corresponding bullet in C++03 [dcl.init.ref]p5 gives the
> @@ -6604,7 +6640,26 @@ InitializationSequence::Perform(Sema &S,
> CreatedObject = Conversion->getReturnType()->isRecordType();
> }
>
> + // C++14 and before:
> + // - if the function is a constructor, the call initializes a temporary
> + // of the cv-unqualified version of the destination type [...]
> + // C++1z:
> + // - if the function is a constructor, the call is a prvalue of the
> + // cv-unqualified version of the destination type whose return object
> + // is initialized by the constructor [...]
> + // Both:
> + // The [..] call is used to direct-initialize, according to the rules
> + // above, the object that is the destination of the
> + // copy-initialization.
> + // In C++14 and before, that always means the "constructors are
> + // considered" bullet, because we have arrived at a reference-related
> + // type. In C++1z, it only means that if the types are different or we
> + // didn't produce a prvalue, so just check for that case here.
> bool RequiresCopy = !IsCopy && !isReferenceBinding(Steps.back());
> + if (S.getLangOpts().CPlusPlus1z && CurInit.get()->isRValue() &&
> + S.Context.hasSameUnqualifiedType(
> + Entity.getType().getNonReferenceType(), CurInit.get()->getType()))
> + RequiresCopy = false;
> bool MaybeBindToTemp = RequiresCopy || shouldBindAsTemporary(Entity);
>
> if (!MaybeBindToTemp && CreatedObject && shouldDestroyTemporary(Entity)) {
>
> Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaOverload.cpp Tue Dec 6 17:52:28 2016
> @@ -4979,7 +4979,7 @@ TryObjectArgumentInitialization(Sema &S,
> // cv-qualification on the member function declaration.
> //
> // However, when finding an implicit conversion sequence for the argument, we
> - // are not allowed to create temporaries or perform user-defined conversions
> + // are not allowed to perform user-defined conversions
> // (C++ [over.match.funcs]p5). We perform a simplified version of
> // reference binding here, that allows class rvalues to bind to
> // non-constant references.
>
> Modified: cfe/trunk/test/CXX/drs/dr0xx.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/drs/dr0xx.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/test/CXX/drs/dr0xx.cpp (original)
> +++ cfe/trunk/test/CXX/drs/dr0xx.cpp Tue Dec 6 17:52:28 2016
> @@ -248,7 +248,7 @@ namespace dr20 { // dr20: yes
> private:
> X(const X&); // expected-note {{here}}
> };
> - X f();
> + X &f();
> X x = f(); // expected-error {{private}}
> }
>
> @@ -316,8 +316,15 @@ namespace dr25 { // dr25: yes
> namespace dr26 { // dr26: yes
> struct A { A(A, const A & = A()); }; // expected-error {{must pass its first argument by reference}}
> struct B {
> - B(); // expected-note {{candidate}}
> - B(const B &, B = B()); // expected-error {{no matching constructor}} expected-note {{candidate}} expected-note {{here}}
> + B(); // expected-note 0-1{{candidate}}
> + B(const B &, B = B());
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{no matching constructor}} expected-note at -2 {{candidate}} expected-note at -2 {{here}}
> +#endif
> + };
> + struct C {
> + static C &f();
> + C(const C &, C = f()); // expected-error {{no matching constructor}} expected-note {{candidate}} expected-note {{here}}
> };
> }
>
> @@ -662,25 +669,33 @@ namespace dr58 { // dr58: yes
>
> namespace dr59 { // dr59: yes
> template<typename T> struct convert_to { operator T() const; };
> - struct A {}; // expected-note 2{{volatile qualifier}} expected-note 2{{requires 0 arguments}}
> - struct B : A {}; // expected-note 2{{volatile qualifier}} expected-note 2{{requires 0 arguments}}
> -#if __cplusplus >= 201103L // move constructors
> - // expected-note at -3 2{{volatile qualifier}}
> - // expected-note at -3 2{{volatile qualifier}}
> -#endif
> + struct A {}; // expected-note 5+{{candidate}}
> + struct B : A {}; // expected-note 0+{{candidate}}
>
> A a1 = convert_to<A>();
> A a2 = convert_to<A&>();
> A a3 = convert_to<const A>();
> - A a4 = convert_to<const volatile A>(); // expected-error {{no viable}}
> + A a4 = convert_to<const volatile A>();
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{no viable}}
> +#endif
> A a5 = convert_to<const volatile A&>(); // expected-error {{no viable}}
>
> B b1 = convert_to<B>();
> B b2 = convert_to<B&>();
> B b3 = convert_to<const B>();
> - B b4 = convert_to<const volatile B>(); // expected-error {{no viable}}
> + B b4 = convert_to<const volatile B>();
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{no viable}}
> +#endif
> B b5 = convert_to<const volatile B&>(); // expected-error {{no viable}}
>
> + A c1 = convert_to<B>();
> + A c2 = convert_to<B&>();
> + A c3 = convert_to<const B>();
> + A c4 = convert_to<const volatile B>(); // expected-error {{no viable}}
> + A c5 = convert_to<const volatile B&>(); // expected-error {{no viable}}
> +
> int n1 = convert_to<int>();
> int n2 = convert_to<int&>();
> int n3 = convert_to<const int>();
> @@ -920,14 +935,17 @@ namespace dr84 { // dr84: yes
> struct A { operator B() const; };
> struct C {};
> struct B {
> - B(B&); // expected-note {{candidate}}
> - B(C); // expected-note {{no known conversion from 'dr84::B' to 'dr84::C'}}
> + B(B&); // expected-note 0-1{{candidate}}
> + B(C); // expected-note 0-1{{no known conversion from 'dr84::B' to 'dr84::C'}}
> operator C() const;
> };
> A a;
> // Cannot use B(C) / operator C() pair to construct the B from the B temporary
> - // here.
> - B b = a; // expected-error {{no viable}}
> + // here. In C++1z, we initialize the B object directly using 'A::operator B()'.
> + B b = a;
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{no viable}}
> +#endif
> }
>
> namespace dr85 { // dr85: yes
>
> Modified: cfe/trunk/test/CXX/drs/dr10xx.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/drs/dr10xx.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/test/CXX/drs/dr10xx.cpp (original)
> +++ cfe/trunk/test/CXX/drs/dr10xx.cpp Tue Dec 6 17:52:28 2016
> @@ -3,8 +3,6 @@
> // RUN: %clang_cc1 -std=c++14 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
> // RUN: %clang_cc1 -std=c++1z %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
>
> -// expected-no-diagnostics
> -
> namespace std {
> __extension__ typedef __SIZE_TYPE__ size_t;
>
> @@ -32,6 +30,18 @@ namespace dr1048 { // dr1048: 3.6
> #endif
> }
>
> +namespace dr1054 { // dr1054: no
> + // FIXME: Test is incomplete.
> + struct A {} volatile a;
> + void f() {
> + // FIXME: This is wrong: an lvalue-to-rvalue conversion is applied here,
> + // which copy-initializes a temporary from 'a'. Therefore this is
> + // ill-formed because A does not have a volatile copy constructor.
> + // (We might want to track this aspect under dr1383 instead?)
> + a; // expected-warning {{assign into a variable to force a volatile load}}
> + }
> +}
> +
> namespace dr1070 { // dr1070: 3.5
> #if __cplusplus >= 201103L
> struct A {
>
> Modified: cfe/trunk/test/CXX/drs/dr1xx.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/drs/dr1xx.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/test/CXX/drs/dr1xx.cpp (original)
> +++ cfe/trunk/test/CXX/drs/dr1xx.cpp Tue Dec 6 17:52:28 2016
> @@ -576,11 +576,18 @@ namespace dr151 { // dr151: yes
>
> namespace dr152 { // dr152: yes
> struct A {
> - A(); // expected-note {{not viable}}
> + A(); // expected-note 0-2{{not viable}}
> explicit A(const A&);
> };
> - A a1 = A(); // expected-error {{no matching constructor}}
> + A a1 = A();
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{no matching constructor}}
> +#endif
> A a2((A()));
> +
> + A &f();
> + A a3 = f(); // expected-error {{no matching constructor}}
> + A a4(f());
> }
>
> // dr153: na
> @@ -823,11 +830,20 @@ namespace dr176 { // dr176: yes
> namespace dr177 { // dr177: yes
> struct B {};
> struct A {
> - A(A &); // expected-note {{not viable: expects an l-value}}
> - A(const B &); // expected-note {{not viable: no known conversion from 'dr177::A' to}}
> + A(A &); // expected-note 0-1{{not viable: expects an l-value}}
> + A(const B &); // expected-note 0-1{{not viable: no known conversion from 'dr177::A' to}}
> };
> B b;
> - A a = b; // expected-error {{no viable constructor copying variable}}
> + A a = b;
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{no viable constructor copying variable}}
> +#endif
> +
> + struct C { C(C&); }; // expected-note {{not viable: no known conversion from 'dr177::D' to 'dr177::C &'}}
> + struct D : C {};
> + struct E { operator D(); };
> + E e;
> + C c = e; // expected-error {{no viable constructor copying variable of type 'dr177::D'}}
> }
>
> namespace dr178 { // dr178: yes
>
> Modified: cfe/trunk/test/CXX/drs/dr4xx.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/drs/dr4xx.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/test/CXX/drs/dr4xx.cpp (original)
> +++ cfe/trunk/test/CXX/drs/dr4xx.cpp Tue Dec 6 17:52:28 2016
> @@ -553,12 +553,21 @@ namespace dr446 { // dr446: yes
> void(b ? a : a);
> b ? A() : a; // expected-error {{deleted}}
> b ? a : A(); // expected-error {{deleted}}
> - b ? A() : A(); // expected-error {{deleted}}
> + b ? A() : A();
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{deleted}}
> +#endif
>
> void(b ? a : c);
> b ? a : C(); // expected-error {{deleted}}
> - b ? c : A(); // expected-error {{deleted}}
> - b ? A() : C(); // expected-error {{deleted}}
> + b ? c : A();
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{deleted}}
> +#endif
> + b ? A() : C();
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{deleted}}
> +#endif
> }
> }
>
> @@ -874,10 +883,12 @@ namespace dr479 { // dr479: yes
> void f() {
> throw S();
> // expected-error at -1 {{temporary of type 'dr479::S' has private destructor}}
> - // expected-error at -2 {{calling a private constructor}}
> - // expected-error at -3 {{exception object of type 'dr479::S' has private destructor}}
> + // expected-error at -2 {{exception object of type 'dr479::S' has private destructor}}
> #if __cplusplus < 201103L
> - // expected-error at -5 {{C++98 requires an accessible copy constructor}}
> + // expected-error at -4 {{C++98 requires an accessible copy constructor}}
> +#endif
> +#if __cplusplus <= 201402L
> + // expected-error at -7 {{calling a private constructor}} (copy ctor)
> #endif
> }
> void g() {
>
> Added: cfe/trunk/test/CodeGenCXX/cxx1z-copy-omission.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cxx1z-copy-omission.cpp?rev=288866&view=auto
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/cxx1z-copy-omission.cpp (added)
> +++ cfe/trunk/test/CodeGenCXX/cxx1z-copy-omission.cpp Tue Dec 6 17:52:28 2016
> @@ -0,0 +1,81 @@
> +// RUN: %clang_cc1 -std=c++1z -emit-llvm -triple x86_64-linux-gnu -o - %s | FileCheck %s
> +
> +struct A {
> + A(int);
> + A(A&&);
> + A(const A&);
> + ~A();
> +
> + int arr[10];
> +};
> +
> +A f();
> +void h();
> +
> +// CHECK-LABEL: define {{.*}} @_Z1gv(
> +void g() {
> + // CHECK: %[[A:.*]] = alloca
> + // CHECK-NOT: alloca
> + // CHECK-NOT: call
> + // CHECK: call {{.*}} @_Z1fv({{.*}}* sret %[[A]])
> + A a = A( A{ f() } );
> + // CHECK-NOT: call
> +
> + // CHECK: call void @_Z1hv(
> + h();
> + // CHECK-NOT: call
> +
> + // CHECK: call void @_ZN1AD1Ev({{.*}}* %[[A]])
> + // CHECK-NOT: call
> + // CHECK-LABEL: }
> +}
> +
> +void f(A);
> +
> +// CHECK-LABEL: define {{.*}} @_Z1hv(
> +void h() {
> + // CHECK: %[[A:.*]] = alloca
> + // CHECK-NOT: alloca
> + // CHECK-NOT: call
> +
> + // CHECK: call {{.*}} @_Z1fv({{.*}}* sret %[[A]])
> + // CHECK-NOT: call
> + // CHECK: call {{.*}} @_Z1f1A({{.*}}* %[[A]])
> + f(f());
> + // CHECK-NOT: call
> + // CHECK: call void @_ZN1AD1Ev({{.*}}* %[[A]])
> +
> + // CHECK: call void @_Z1hv(
> + h();
> +
> + // CHECK-NOT: call
> + // CHECK-LABEL: }
> +}
> +
> +// We still pass classes with trivial copy/move constructors and destructors in
> +// registers, even if the copy is formally omitted.
> +struct B {
> + B(int);
> + int n;
> +};
> +
> +B fB();
> +void fB(B);
> +
> +// CHECK-LABEL: define {{.*}} @_Z1iv(
> +void i() {
> + // CHECK: %[[B:.*]] = alloca
> + // CHECK-NOT: alloca
> + // CHECK-NOT: call
> +
> + // CHECK: %[[B_N:.*]] = call i32 @_Z2fBv()
> + // CHECK-NOT: call
> + // CHECK: store i32 %[[B_N]],
> + // CHECK-NOT: call
> + // CHECK: %[[B_N:.*]] = load i32
> + // CHECK-NOT: call
> + // CHECK: call void @_Z2fB1B(i32 %[[B_N]])
> + fB(fB());
> +
> + // CHECK-LABEL: }
> +}
>
> Modified: cfe/trunk/test/SemaCXX/aggregate-initialization.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/aggregate-initialization.cpp?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/aggregate-initialization.cpp (original)
> +++ cfe/trunk/test/SemaCXX/aggregate-initialization.cpp Tue Dec 6 17:52:28 2016
> @@ -57,7 +57,7 @@ struct A {
> A(int);
> ~A();
>
> - A(const A&) = delete; // expected-note 2 {{'A' has been explicitly marked deleted here}}
> + A(const A&) = delete; // expected-note 0-2{{'A' has been explicitly marked deleted here}}
> };
>
> struct B {
> @@ -70,10 +70,16 @@ struct C {
>
> void f() {
> A as1[1] = { };
> - A as2[1] = { 1 }; // expected-error {{copying array element of type 'A' invokes deleted constructor}}
> + A as2[1] = { 1 };
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{copying array element of type 'A' invokes deleted constructor}}
> +#endif
>
> B b1 = { };
> - B b2 = { 1 }; // expected-error {{copying member subobject of type 'A' invokes deleted constructor}}
> + B b2 = { 1 };
> +#if __cplusplus <= 201402L
> + // expected-error at -2 {{copying member subobject of type 'A' invokes deleted constructor}}
> +#endif
>
> C c1 = { 1 };
> }
>
> Added: cfe/trunk/test/SemaCXX/cxx1z-copy-omission.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1z-copy-omission.cpp?rev=288866&view=auto
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/cxx1z-copy-omission.cpp (added)
> +++ cfe/trunk/test/SemaCXX/cxx1z-copy-omission.cpp Tue Dec 6 17:52:28 2016
> @@ -0,0 +1,134 @@
> +// RUN: %clang_cc1 -std=c++1z -verify %s
> +
> +struct Noncopyable {
> + Noncopyable();
> + Noncopyable(const Noncopyable &) = delete; // expected-note 1+{{deleted}}
> + virtual ~Noncopyable();
> +};
> +struct Derived : Noncopyable {};
> +struct NoncopyableAggr {
> + Noncopyable nc;
> +};
> +struct Indestructible {
> + Indestructible();
> + ~Indestructible() = delete; // expected-note 1+{{deleted}}
> +};
> +struct Incomplete; // expected-note 1+{{declar}}
> +
> +Noncopyable make(int kind = 0) {
> + switch (kind) {
> + case 0: return {};
> + case 1: return Noncopyable();
> + case 2: return Noncopyable{};
> + case 3: return make();
> + }
> + __builtin_unreachable();
> +}
> +
> +Indestructible make_indestructible();
> +Incomplete make_incomplete(); // expected-note 1+{{here}}
> +
> +void take(Noncopyable nc) {}
> +
> +Noncopyable nrvo() {
> + Noncopyable nrvo;
> + return nrvo; // expected-error {{deleted constructor}}
> +}
> +
> +Noncopyable nc1 = make();
> +Noncopyable nc2 = Noncopyable();
> +Noncopyable nc3 = Derived(); // expected-error {{deleted constructor}}
> +
> +NoncopyableAggr nca1 = NoncopyableAggr{};
> +NoncopyableAggr nca2 = NoncopyableAggr{{}};
> +NoncopyableAggr nca3 = NoncopyableAggr{NoncopyableAggr{Noncopyable()}};
> +
> +void test_expressions(bool b) {
> + auto lambda = [a = make()] {};
> +
> + take({});
> + take(Noncopyable());
> + take(Noncopyable{});
> + take(make());
> +
> + Noncopyable &&dc1 = dynamic_cast<Noncopyable&&>(Noncopyable());
> + Noncopyable &&dc2 = dynamic_cast<Noncopyable&&>(nc1);
> + Noncopyable &&dc3 = dynamic_cast<Noncopyable&&>(Derived());
> +
> + Noncopyable sc1 = static_cast<Noncopyable>(Noncopyable());
> + Noncopyable sc2 = static_cast<Noncopyable>(nc1); // expected-error {{deleted}}
> + Noncopyable sc3 = static_cast<Noncopyable&&>(Noncopyable()); // expected-error {{deleted}}
> + Noncopyable sc4 = static_cast<Noncopyable>(static_cast<Noncopyable&&>(Noncopyable())); // expected-error {{deleted}}
> +
> + Noncopyable cc1 = (Noncopyable)Noncopyable();
> + Noncopyable cc2 = (Noncopyable)Derived(); // expected-error {{deleted}}
> +
> + Noncopyable fc1 = Noncopyable(Noncopyable());
> + Noncopyable fc2 = Noncopyable(Derived()); // expected-error {{deleted}}
> +
> + // We must check for a complete type for every materialized temporary. (Note
> + // that in the special case of the top level of a decltype, no temporary is
> + // materialized.)
> + make_incomplete(); // expected-error {{incomplete}}
> + make_incomplete().a; // expected-error {{incomplete}}
> + make_incomplete().*(int Incomplete::*)nullptr; // expected-error {{incomplete}}
> + dynamic_cast<Incomplete&&>(make_incomplete()); // expected-error {{incomplete}}
> + const_cast<Incomplete&&>(make_incomplete()); // expected-error {{incomplete}}
> +
> + sizeof(Indestructible{}); // expected-error {{deleted}}
> + sizeof(make_indestructible()); // expected-error {{deleted}}
> + sizeof(make_incomplete()); // expected-error {{incomplete}}
> + typeid(Indestructible{}); // expected-error {{deleted}}
> + typeid(make_indestructible()); // expected-error {{deleted}}
> + typeid(make_incomplete()); // expected-error {{incomplete}}
> +
> + // FIXME: The first two cases here are now also valid in C++17 onwards.
> + using I = decltype(Indestructible()); // expected-error {{deleted}}
> + using I = decltype(Indestructible{}); // expected-error {{deleted}}
> + using I = decltype(make_indestructible());
> + using J = decltype(make_incomplete());
> +
> + Noncopyable cond1 = b ? Noncopyable() : make();
> + Noncopyable cond2 = b ? Noncopyable() : Derived(); // expected-error {{incompatible}}
> + Noncopyable cond3 = b ? Derived() : Noncopyable(); // expected-error {{incompatible}}
> + Noncopyable cond4 = b ? Noncopyable() : nc1; // expected-error {{deleted}}
> + Noncopyable cond5 = b ? nc1 : Noncopyable(); // expected-error {{deleted}}
> + // Could convert both to an xvalue of type Noncopyable here, but we're not
> + // permitted to consider that.
> + Noncopyable &&cond6 = b ? Noncopyable() : Derived(); // expected-error {{incompatible}}
> + Noncopyable &&cond7 = b ? Derived() : Noncopyable(); // expected-error {{incompatible}}
> + // Could convert both to a const lvalue of type Noncopyable here, but we're
> + // not permitted to consider that, either.
> + const Noncopyable cnc;
> + const Noncopyable &cond8 = b ? cnc : Derived(); // expected-error {{incompatible}}
> + const Noncopyable &cond9 = b ? Derived() : cnc; // expected-error {{incompatible}}
> +
> + extern const volatile Noncopyable make_cv();
> + Noncopyable cv_difference1 = make_cv();
> + const volatile Noncopyable cv_difference2 = make();
> +}
> +
> +template<typename T> struct ConversionFunction { operator T(); };
> +Noncopyable cf1 = ConversionFunction<Noncopyable>();
> +Noncopyable cf2 = ConversionFunction<Noncopyable&&>(); // expected-error {{deleted}}
> +Noncopyable cf3 = ConversionFunction<const volatile Noncopyable>();
> +const volatile Noncopyable cf4 = ConversionFunction<Noncopyable>();
> +Noncopyable cf5 = ConversionFunction<Derived>(); // expected-error {{deleted}}
> +
> +struct AsMember {
> + Noncopyable member;
> + AsMember() : member(make()) {}
> +};
> +// FIXME: DR (no number yet): we still get a copy for base or delegating construction.
> +struct AsBase : Noncopyable {
> + AsBase() : Noncopyable(make()) {} // expected-error {{deleted}}
> +};
> +struct AsDelegating final {
> + AsDelegating(const AsDelegating &) = delete;
> + static AsDelegating make(int);
> +
> + // The base constructor version of this is problematic; the complete object
> + // version would be OK. Perhaps we could allow copy omission here for final
> + // classes?
> + AsDelegating(int n) : AsDelegating(make(n)) {} // expected-error {{deleted}}
> +};
>
> Modified: cfe/trunk/www/cxx_dr_status.html
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_dr_status.html?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/www/cxx_dr_status.html (original)
> +++ cfe/trunk/www/cxx_dr_status.html Tue Dec 6 17:52:28 2016
> @@ -6139,7 +6139,7 @@ and <I>POD class</I></td>
> <td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1054">1054</a></td>
> <td>C++11</td>
> <td>Lvalue-to-rvalue conversions in expression statements</td>
> - <td class="none" align="center">Unknown</td>
> + <td class="none" align="center">No</td>
> </tr>
> <tr id="1055">
> <td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1055">1055</a></td>
>
> Modified: cfe/trunk/www/cxx_status.html
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_status.html?rev=288866&r1=288865&r2=288866&view=diff
> ==============================================================================
> --- cfe/trunk/www/cxx_status.html (original)
> +++ cfe/trunk/www/cxx_status.html Tue Dec 6 17:52:28 2016
> @@ -694,7 +694,7 @@ as the draft C++1z standard evolves.
> <tr>
> <td>Guaranteed copy elision</td>
> <td><a href="http://wg21.link/p0135r1">P0135R1</a></td>
> - <td class="none" align="center">No</td>
> + <td class="svn" align="center">SVN</td>
> </tr>
> <tr>
> <td rowspan=2>Stricter expression evaluation order</td>
>
>
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