r273602 - Implement p0292r2 (constexpr if), a likely C++1z feature.
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Thu Jun 23 22:03:47 PDT 2016
On Thu, Jun 23, 2016 at 12:26 PM, Aaron Ballman via cfe-commits <
cfe-commits at lists.llvm.org> wrote:
> On Thu, Jun 23, 2016 at 3:16 PM, Richard Smith via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
> > Author: rsmith
> > Date: Thu Jun 23 14:16:49 2016
> > New Revision: 273602
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=273602&view=rev
> > Log:
> > Implement p0292r2 (constexpr if), a likely C++1z feature.
>
> Is there a feature testing macro for this, or is one not required (or
> is one not determined by SG10 yet)?
>
The paper does not propose one. I expect we'll add one, though; I can
imagine reasonable use cases where you'd want to make an 'if' constexpr if
the feature is supported (and otherwise have a regular if).
> ~Aaron
>
> >
> > Added:
> > cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p2-1z.cpp
> > cfe/trunk/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp
> > cfe/trunk/test/CodeGenCXX/cxx1z-constexpr-if.cpp
> > Modified:
> > cfe/trunk/include/clang/AST/Stmt.h
> > cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
> > cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> > cfe/trunk/include/clang/Sema/Sema.h
> > cfe/trunk/lib/AST/ASTImporter.cpp
> > cfe/trunk/lib/AST/Stmt.cpp
> > cfe/trunk/lib/Analysis/BodyFarm.cpp
> > cfe/trunk/lib/CodeGen/CGStmt.cpp
> > cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
> > cfe/trunk/lib/CodeGen/CodeGenFunction.h
> > cfe/trunk/lib/Parse/ParseStmt.cpp
> > cfe/trunk/lib/Sema/JumpDiagnostics.cpp
> > cfe/trunk/lib/Sema/SemaExpr.cpp
> > cfe/trunk/lib/Sema/SemaExprCXX.cpp
> > cfe/trunk/lib/Sema/SemaExprMember.cpp
> > cfe/trunk/lib/Sema/SemaLambda.cpp
> > cfe/trunk/lib/Sema/SemaStmt.cpp
> > cfe/trunk/lib/Sema/TreeTransform.h
> > cfe/trunk/lib/Serialization/ASTReaderStmt.cpp
> > cfe/trunk/lib/Serialization/ASTWriterStmt.cpp
> > cfe/trunk/www/cxx_status.html
> >
> > Modified: cfe/trunk/include/clang/AST/Stmt.h
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Stmt.h?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/include/clang/AST/Stmt.h (original)
> > +++ cfe/trunk/include/clang/AST/Stmt.h Thu Jun 23 14:16:49 2016
> > @@ -93,6 +93,13 @@ protected:
> > unsigned NumStmts : 32 - NumStmtBits;
> > };
> >
> > + class IfStmtBitfields {
> > + friend class IfStmt;
> > + unsigned : NumStmtBits;
> > +
> > + unsigned IsConstexpr : 1;
> > + };
> > +
> > class ExprBitfields {
> > friend class Expr;
> > friend class DeclRefExpr; // computeDependence
> > @@ -248,6 +255,7 @@ protected:
> > union {
> > StmtBitfields StmtBits;
> > CompoundStmtBitfields CompoundStmtBits;
> > + IfStmtBitfields IfStmtBits;
> > ExprBitfields ExprBits;
> > CharacterLiteralBitfields CharacterLiteralBits;
> > FloatingLiteralBitfields FloatingLiteralBits;
> > @@ -878,7 +886,8 @@ class IfStmt : public Stmt {
> > SourceLocation ElseLoc;
> >
> > public:
> > - IfStmt(const ASTContext &C, SourceLocation IL, VarDecl *var, Expr
> *cond,
> > + IfStmt(const ASTContext &C, SourceLocation IL,
> > + bool IsConstexpr, VarDecl *var, Expr *cond,
> > Stmt *then, SourceLocation EL = SourceLocation(),
> > Stmt *elsev = nullptr);
> >
> > @@ -918,6 +927,9 @@ public:
> > SourceLocation getElseLoc() const { return ElseLoc; }
> > void setElseLoc(SourceLocation L) { ElseLoc = L; }
> >
> > + bool isConstexpr() const { return IfStmtBits.IsConstexpr; }
> > + void setConstexpr(bool C) { IfStmtBits.IsConstexpr = C; }
> > +
> > SourceLocation getLocStart() const LLVM_READONLY { return IfLoc; }
> > SourceLocation getLocEnd() const LLVM_READONLY {
> > if (SubExprs[ELSE])
> >
> > Modified: cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td (original)
> > +++ cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td Thu Jun 23
> 14:16:49 2016
> > @@ -512,6 +512,11 @@ def err_function_is_not_record : Error<
> > "unexpected %0 in function call; perhaps remove the %0?">;
> > def err_super_in_using_declaration : Error<
> > "'__super' cannot be used with a using declaration">;
> > +def ext_constexpr_if : ExtWarn<
> > + "constexpr if is a C++1z extension">, InGroup<CXX1z>;
> > +def warn_cxx14_compat_constexpr_if : Warning<
> > + "constexpr if is incompatible with C++ standards before C++1z">,
> > + DefaultIgnore, InGroup<CXXPre1zCompat>;
> >
> > // C++ derived classes
> > def err_dup_virtual : Error<"duplicate 'virtual' in base specifier">;
> >
> > Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
> > +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Jun 23
> 14:16:49 2016
> > @@ -75,10 +75,12 @@ def err_typecheck_converted_constant_exp
> > "conversion from %0 to %1 in converted constant expression would "
> > "bind reference to a temporary">;
> > def err_expr_not_cce : Error<
> > - "%select{case value|enumerator value|non-type template argument|array
> size}0 "
> > + "%select{case value|enumerator value|non-type template argument|"
> > + "array size|constexpr if condition}0 "
> > "is not a constant expression">;
> > def ext_cce_narrowing : ExtWarn<
> > - "%select{case value|enumerator value|non-type template argument|array
> size}0 "
> > + "%select{case value|enumerator value|non-type template argument|"
> > + "array size|constexpr if condition}0 "
> > "%select{cannot be narrowed from type %2 to %3|"
> > "evaluates to %2, which cannot be narrowed to type %3}1">,
> > InGroup<CXX11Narrowing>, DefaultError, SFINAEFailure;
> > @@ -4641,6 +4643,8 @@ def note_protected_by_vla_typedef : Note
> > "jump bypasses initialization of VLA typedef">;
> > def note_protected_by_vla_type_alias : Note<
> > "jump bypasses initialization of VLA type alias">;
> > +def note_protected_by_constexpr_if : Note<
> > + "jump enters controlled statement of constexpr if">;
> > def note_protected_by_vla : Note<
> > "jump bypasses initialization of variable length array">;
> > def note_protected_by_objc_try : Note<
> >
> > Modified: cfe/trunk/include/clang/Sema/Sema.h
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/include/clang/Sema/Sema.h (original)
> > +++ cfe/trunk/include/clang/Sema/Sema.h Thu Jun 23 14:16:49 2016
> > @@ -797,6 +797,11 @@ public:
> > /// run time.
> > Unevaluated,
> >
> > + /// \brief The current expression occurs within a discarded
> statement.
> > + /// This behaves largely similarly to an unevaluated operand in
> preventing
> > + /// definitions from being required, but not in other ways.
> > + DiscardedStatement,
> > +
> > /// \brief The current expression occurs within an unevaluated
> > /// operand that unconditionally permits abstract references to
> > /// fields, such as a SIZE operator in MS-style inline assembly.
> > @@ -2329,7 +2334,8 @@ public:
> > CCEK_CaseValue, ///< Expression in a case label.
> > CCEK_Enumerator, ///< Enumerator value with fixed underlying type.
> > CCEK_TemplateArg, ///< Value of a non-type template parameter.
> > - CCEK_NewExpr ///< Constant expression in a
> noptr-new-declarator.
> > + CCEK_NewExpr, ///< Constant expression in a
> noptr-new-declarator.
> > + CCEK_ConstexprIf ///< Condition in a constexpr if statement.
> > };
> > ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
> > llvm::APSInt &Value,
> CCEKind CCE);
> > @@ -3393,8 +3399,12 @@ public:
> > Stmt *SubStmt);
> >
> > class ConditionResult;
> > - StmtResult ActOnIfStmt(SourceLocation IfLoc, ConditionResult Cond,
> > - Stmt *ThenVal, SourceLocation ElseLoc, Stmt
> *ElseVal);
> > + StmtResult ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
> > + ConditionResult Cond, Stmt *ThenVal,
> > + SourceLocation ElseLoc, Stmt *ElseVal);
> > + StmtResult BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
> > + ConditionResult Cond, Stmt *ThenVal,
> > + SourceLocation ElseLoc, Stmt *ElseVal);
> > StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
> > ConditionResult Cond);
> > StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
> > @@ -8919,12 +8929,20 @@ public:
> > Decl *ConditionVar;
> > FullExprArg Condition;
> > bool Invalid;
> > + bool HasKnownValue;
> > + bool KnownValue;
> >
> > friend class Sema;
> > - ConditionResult(Decl *ConditionVar, FullExprArg Condition)
> > - : ConditionVar(ConditionVar), Condition(Condition),
> Invalid(false) {}
> > + ConditionResult(Sema &S, Decl *ConditionVar, FullExprArg Condition,
> > + bool IsConstexpr)
> > + : ConditionVar(ConditionVar), Condition(Condition),
> Invalid(false),
> > + HasKnownValue(IsConstexpr && Condition.get() &&
> > + !Condition.get()->isValueDependent()),
> > + KnownValue(HasKnownValue &&
> > +
> !!Condition.get()->EvaluateKnownConstInt(S.Context)) {}
> > explicit ConditionResult(bool Invalid)
> > - : ConditionVar(nullptr), Condition(nullptr), Invalid(Invalid) {}
> > + : ConditionVar(nullptr), Condition(nullptr), Invalid(Invalid),
> > + HasKnownValue(false), KnownValue(false) {}
> >
> > public:
> > ConditionResult() : ConditionResult(false) {}
> > @@ -8933,12 +8951,18 @@ public:
> > return std::make_pair(cast_or_null<VarDecl>(ConditionVar),
> > Condition.get());
> > }
> > + llvm::Optional<bool> getKnownValue() const {
> > + if (!HasKnownValue)
> > + return None;
> > + return KnownValue;
> > + }
> > };
> > static ConditionResult ConditionError() { return
> ConditionResult(true); }
> >
> > enum class ConditionKind {
> > - Boolean, ///< A boolean condition, from 'if', 'while', 'for', or
> 'do'.
> > - Switch ///< An integral condition for a 'switch' statement.
> > + Boolean, ///< A boolean condition, from 'if', 'while', 'for',
> or 'do'.
> > + ConstexprIf, ///< A constant boolean condition from 'if constexpr'.
> > + Switch ///< An integral condition for a 'switch' statement.
> > };
> >
> > ConditionResult ActOnCondition(Scope *S, SourceLocation Loc,
> > @@ -8963,7 +8987,8 @@ public:
> > /// \param Loc - A location associated with the condition, e.g. the
> > /// 'if' keyword.
> > /// \return true iff there were any errors
> > - ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E);
> > + ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E,
> > + bool IsConstexpr = false);
> >
> > /// DiagnoseAssignmentAsCondition - Given that an expression is
> > /// being used as a boolean condition, warn if it's an assignment.
> > @@ -8974,7 +8999,7 @@ public:
> > void DiagnoseEqualityWithExtraParens(ParenExpr *ParenE);
> >
> > /// CheckCXXBooleanCondition - Returns true if conversion to bool is
> invalid.
> > - ExprResult CheckCXXBooleanCondition(Expr *CondExpr);
> > + ExprResult CheckCXXBooleanCondition(Expr *CondExpr, bool IsConstexpr
> = false);
> >
> > /// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt
> to have
> > /// the specified width and sign. If an overflow occurs, detect it
> and emit
> > @@ -9533,15 +9558,18 @@ public:
> > /// \brief RAII object that enters a new expression evaluation context.
> > class EnterExpressionEvaluationContext {
> > Sema &Actions;
> > + bool Entered = true;
> >
> > public:
> > EnterExpressionEvaluationContext(Sema &Actions,
> > Sema::ExpressionEvaluationContext
> NewContext,
> > Decl *LambdaContextDecl = nullptr,
> > - bool IsDecltype = false)
> > - : Actions(Actions) {
> > - Actions.PushExpressionEvaluationContext(NewContext,
> LambdaContextDecl,
> > - IsDecltype);
> > + bool IsDecltype = false,
> > + bool ShouldEnter = true)
> > + : Actions(Actions), Entered(ShouldEnter) {
> > + if (Entered)
> > + Actions.PushExpressionEvaluationContext(NewContext,
> LambdaContextDecl,
> > + IsDecltype);
> > }
> > EnterExpressionEvaluationContext(Sema &Actions,
> > Sema::ExpressionEvaluationContext
> NewContext,
> > @@ -9554,7 +9582,8 @@ public:
> > }
> >
> > ~EnterExpressionEvaluationContext() {
> > - Actions.PopExpressionEvaluationContext();
> > + if (Entered)
> > + Actions.PopExpressionEvaluationContext();
> > }
> > };
> >
> >
> > Modified: cfe/trunk/lib/AST/ASTImporter.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTImporter.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/AST/ASTImporter.cpp (original)
> > +++ cfe/trunk/lib/AST/ASTImporter.cpp Thu Jun 23 14:16:49 2016
> > @@ -4981,7 +4981,8 @@ Stmt *ASTNodeImporter::VisitIfStmt(IfStm
> > if (!ToElseStmt && S->getElse())
> > return nullptr;
> > return new (Importer.getToContext()) IfStmt(Importer.getToContext(),
> > - ToIfLoc,
> ToConditionVariable,
> > + ToIfLoc, S->isConstexpr(),
> > + ToConditionVariable,
> > ToCondition, ToThenStmt,
> > ToElseLoc, ToElseStmt);
> > }
> >
> > Modified: cfe/trunk/lib/AST/Stmt.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Stmt.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/AST/Stmt.cpp (original)
> > +++ cfe/trunk/lib/AST/Stmt.cpp Thu Jun 23 14:16:49 2016
> > @@ -763,10 +763,11 @@ void MSAsmStmt::initialize(const ASTCont
> > });
> > }
> >
> > -IfStmt::IfStmt(const ASTContext &C, SourceLocation IL, VarDecl *var,
> Expr *cond,
> > - Stmt *then, SourceLocation EL, Stmt *elsev)
> > - : Stmt(IfStmtClass), IfLoc(IL), ElseLoc(EL)
> > -{
> > +IfStmt::IfStmt(const ASTContext &C, SourceLocation IL, bool IsConstexpr,
> > + VarDecl *var, Expr *cond, Stmt *then, SourceLocation EL,
> > + Stmt *elsev)
> > + : Stmt(IfStmtClass), IfLoc(IL), ElseLoc(EL) {
> > + setConstexpr(IsConstexpr);
> > setConditionVariable(C, var);
> > SubExprs[COND] = cond;
> > SubExprs[THEN] = then;
> >
> > Modified: cfe/trunk/lib/Analysis/BodyFarm.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/BodyFarm.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Analysis/BodyFarm.cpp (original)
> > +++ cfe/trunk/lib/Analysis/BodyFarm.cpp Thu Jun 23 14:16:49 2016
> > @@ -239,7 +239,7 @@ static Stmt *create_dispatch_once(ASTCon
> > SourceLocation());
> >
> > // (5) Create the 'if' statement.
> > - IfStmt *If = new (C) IfStmt(C, SourceLocation(), nullptr, UO, CS);
> > + IfStmt *If = new (C) IfStmt(C, SourceLocation(), false, nullptr, UO,
> CS);
> > return If;
> > }
> >
> > @@ -343,7 +343,7 @@ static Stmt *create_OSAtomicCompareAndSw
> >
> > /// Construct the If.
> > Stmt *If =
> > - new (C) IfStmt(C, SourceLocation(), nullptr, Comparison, Body,
> > + new (C) IfStmt(C, SourceLocation(), false, nullptr, Comparison,
> Body,
> > SourceLocation(), Else);
> >
> > return If;
> >
> > Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGStmt.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGStmt.cpp Thu Jun 23 14:16:49 2016
> > @@ -563,7 +563,8 @@ void CodeGenFunction::EmitIfStmt(const I
> > // If the condition constant folds and can be elided, try to avoid
> emitting
> > // the condition and the dead arm of the if/else.
> > bool CondConstant;
> > - if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant)) {
> > + if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant,
> > + S.isConstexpr())) {
> > // Figure out which block (then or else) is executed.
> > const Stmt *Executed = S.getThen();
> > const Stmt *Skipped = S.getElse();
> > @@ -572,7 +573,7 @@ void CodeGenFunction::EmitIfStmt(const I
> >
> > // If the skipped block has no labels in it, just emit the executed
> block.
> > // This avoids emitting dead code and simplifies the CFG
> substantially.
> > - if (!ContainsLabel(Skipped)) {
> > + if (S.isConstexpr() || !ContainsLabel(Skipped)) {
> > if (CondConstant)
> > incrementProfileCounter(&S);
> > if (Executed) {
> >
> > Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Thu Jun 23 14:16:49 2016
> > @@ -1107,9 +1107,10 @@ bool CodeGenFunction::containsBreak(cons
> > /// to a constant, or if it does but contains a label, return false.
> If it
> > /// constant folds return true and set the boolean result in Result.
> > bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
> > - bool &ResultBool) {
> > + bool &ResultBool,
> > + bool AllowLabels) {
> > llvm::APSInt ResultInt;
> > - if (!ConstantFoldsToSimpleInteger(Cond, ResultInt))
> > + if (!ConstantFoldsToSimpleInteger(Cond, ResultInt, AllowLabels))
> > return false;
> >
> > ResultBool = ResultInt.getBoolValue();
> > @@ -1119,15 +1120,16 @@ bool CodeGenFunction::ConstantFoldsToSim
> > /// ConstantFoldsToSimpleInteger - If the specified expression does not
> fold
> > /// to a constant, or if it does but contains a label, return false.
> If it
> > /// constant folds return true and set the folded value.
> > -bool CodeGenFunction::
> > -ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt &ResultInt)
> {
> > +bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
> > + llvm::APSInt
> &ResultInt,
> > + bool AllowLabels) {
> > // FIXME: Rename and handle conversion of other evaluatable things
> > // to bool.
> > llvm::APSInt Int;
> > if (!Cond->EvaluateAsInt(Int, getContext()))
> > return false; // Not foldable, not integer or not fully
> evaluatable.
> >
> > - if (CodeGenFunction::ContainsLabel(Cond))
> > + if (!AllowLabels && CodeGenFunction::ContainsLabel(Cond))
> > return false; // Contains a label.
> >
> > ResultInt = Int;
> >
> > Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
> > +++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Thu Jun 23 14:16:49 2016
> > @@ -3051,13 +3051,15 @@ public:
> > /// ConstantFoldsToSimpleInteger - If the specified expression does
> not fold
> > /// to a constant, or if it does but contains a label, return false.
> If it
> > /// constant folds return true and set the boolean result in Result.
> > - bool ConstantFoldsToSimpleInteger(const Expr *Cond, bool &Result);
> > + bool ConstantFoldsToSimpleInteger(const Expr *Cond, bool &Result,
> > + bool AllowLabels = false);
> >
> > /// ConstantFoldsToSimpleInteger - If the specified expression does
> not fold
> > /// to a constant, or if it does but contains a label, return false.
> If it
> > /// constant folds return true and set the folded value.
> > - bool ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt
> &Result);
> > -
> > + bool ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt
> &Result,
> > + bool AllowLabels = false);
> > +
> > /// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g.
> for an
> > /// if statement) to the specified blocks. Based on the condition,
> this might
> > /// try to simplify the codegen of the conditional based on the
> branch.
> >
> > Modified: cfe/trunk/lib/Parse/ParseStmt.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseStmt.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Parse/ParseStmt.cpp (original)
> > +++ cfe/trunk/lib/Parse/ParseStmt.cpp Thu Jun 23 14:16:49 2016
> > @@ -1108,6 +1108,14 @@ StmtResult Parser::ParseIfStatement(Sour
> > assert(Tok.is(tok::kw_if) && "Not an if stmt!");
> > SourceLocation IfLoc = ConsumeToken(); // eat the 'if'.
> >
> > + bool IsConstexpr = false;
> > + if (Tok.is(tok::kw_constexpr)) {
> > + Diag(Tok, getLangOpts().CPlusPlus1z ?
> diag::warn_cxx14_compat_constexpr_if
> > + : diag::ext_constexpr_if);
> > + IsConstexpr = true;
> > + ConsumeToken();
> > + }
> > +
> > if (Tok.isNot(tok::l_paren)) {
> > Diag(Tok, diag::err_expected_lparen_after) << "if";
> > SkipUntil(tok::semi);
> > @@ -1132,9 +1140,15 @@ StmtResult Parser::ParseIfStatement(Sour
> >
> > // Parse the condition.
> > Sema::ConditionResult Cond;
> > - if (ParseParenExprOrCondition(Cond, IfLoc,
> Sema::ConditionKind::Boolean))
> > + if (ParseParenExprOrCondition(Cond, IfLoc,
> > + IsConstexpr ?
> Sema::ConditionKind::ConstexprIf
> > + :
> Sema::ConditionKind::Boolean))
> > return StmtError();
> >
> > + llvm::Optional<bool> ConstexprCondition;
> > + if (IsConstexpr)
> > + ConstexprCondition = Cond.getKnownValue();
> > +
> > // C99 6.8.4p3 - In C99, the body of the if statement is a scope,
> even if
> > // there is no compound stmt. C90 does not have this clause. We
> only do this
> > // if the body isn't a compound statement to avoid push/pop in common
> cases.
> > @@ -1159,7 +1173,13 @@ StmtResult Parser::ParseIfStatement(Sour
> > SourceLocation ThenStmtLoc = Tok.getLocation();
> >
> > SourceLocation InnerStatementTrailingElseLoc;
> > - StmtResult ThenStmt(ParseStatement(&InnerStatementTrailingElseLoc));
> > + StmtResult ThenStmt;
> > + {
> > + EnterExpressionEvaluationContext PotentiallyDiscarded(
> > + Actions, Sema::DiscardedStatement, nullptr, false,
> > + /*ShouldEnter=*/ConstexprCondition && !*ConstexprCondition);
> > + ThenStmt = ParseStatement(&InnerStatementTrailingElseLoc);
> > + }
> >
> > // Pop the 'if' scope if needed.
> > InnerScope.Exit();
> > @@ -1185,8 +1205,12 @@ StmtResult Parser::ParseIfStatement(Sour
> > // The substatement in a selection-statement (each substatement, in
> the else
> > // form of the if statement) implicitly defines a local scope.
> > //
> > - ParseScope InnerScope(this, Scope::DeclScope, C99orCXX,
> Tok.is(tok::l_brace));
> > + ParseScope InnerScope(this, Scope::DeclScope, C99orCXX,
> > + Tok.is(tok::l_brace));
> >
> > + EnterExpressionEvaluationContext PotentiallyDiscarded(
> > + Actions, Sema::DiscardedStatement, nullptr, false,
> > + /*ShouldEnter=*/ConstexprCondition && *ConstexprCondition);
> > ElseStmt = ParseStatement();
> >
> > // Pop the 'else' scope if needed.
> > @@ -1217,7 +1241,7 @@ StmtResult Parser::ParseIfStatement(Sour
> > if (ElseStmt.isInvalid())
> > ElseStmt = Actions.ActOnNullStmt(ElseStmtLoc);
> >
> > - return Actions.ActOnIfStmt(IfLoc, Cond, ThenStmt.get(), ElseLoc,
> > + return Actions.ActOnIfStmt(IfLoc, IsConstexpr, Cond, ThenStmt.get(),
> ElseLoc,
> > ElseStmt.get());
> > }
> >
> >
> > Modified: cfe/trunk/lib/Sema/JumpDiagnostics.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/JumpDiagnostics.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Sema/JumpDiagnostics.cpp (original)
> > +++ cfe/trunk/lib/Sema/JumpDiagnostics.cpp Thu Jun 23 14:16:49 2016
> > @@ -319,6 +319,37 @@ void JumpScopeChecker::BuildScopeInforma
> > Jumps.push_back(S);
> > break;
> >
> > + case Stmt::IfStmtClass: {
> > + IfStmt *IS = cast<IfStmt>(S);
> > + if (!IS->isConstexpr())
> > + break;
> > +
> > + if (VarDecl *Var = IS->getConditionVariable())
> > + BuildScopeInformation(Var, ParentScope);
> > +
> > + // Cannot jump into the middle of the condition.
> > + unsigned NewParentScope = Scopes.size();
> > + Scopes.push_back(GotoScope(ParentScope,
> > + diag::note_protected_by_constexpr_if, 0,
> > + IS->getLocStart()));
> > + BuildScopeInformation(IS->getCond(), NewParentScope);
> > +
> > + // Jumps into either arm of an 'if constexpr' are not allowed.
> > + NewParentScope = Scopes.size();
> > + Scopes.push_back(GotoScope(ParentScope,
> > + diag::note_protected_by_constexpr_if, 0,
> > + IS->getLocStart()));
> > + BuildScopeInformation(IS->getThen(), NewParentScope);
> > + if (Stmt *Else = IS->getElse()) {
> > + NewParentScope = Scopes.size();
> > + Scopes.push_back(GotoScope(ParentScope,
> > + diag::note_protected_by_constexpr_if,
> 0,
> > + IS->getLocStart()));
> > + BuildScopeInformation(Else, NewParentScope);
> > + }
> > + return;
> > + }
> > +
> > case Stmt::CXXTryStmtClass: {
> > CXXTryStmt *TS = cast<CXXTryStmt>(S);
> > {
> >
> > Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> > +++ cfe/trunk/lib/Sema/SemaExpr.cpp Thu Jun 23 14:16:49 2016
> > @@ -12903,6 +12903,11 @@ static bool IsPotentiallyEvaluatedContex
> > // definition of a null pointer constant is completely crazy.)
> > return false;
> >
> > + case Sema::DiscardedStatement:
> > + // These are technically a potentially evaluated but they have
> the effect
> > + // of suppressing use marking.
> > + return false;
> > +
> > case Sema::ConstantEvaluated:
> > case Sema::PotentiallyEvaluated:
> > // We are in a potentially evaluated expression (or a
> constant-expression
> > @@ -14192,6 +14197,7 @@ bool Sema::DiagRuntimeBehavior(SourceLoc
> > switch (ExprEvalContexts.back().Context) {
> > case Unevaluated:
> > case UnevaluatedAbstract:
> > + case DiscardedStatement:
> > // The argument will never be evaluated, so don't complain.
> > break;
> >
> > @@ -14341,7 +14347,8 @@ void Sema::DiagnoseEqualityWithExtraPare
> > }
> > }
> >
> > -ExprResult Sema::CheckBooleanCondition(SourceLocation Loc, Expr *E) {
> > +ExprResult Sema::CheckBooleanCondition(SourceLocation Loc, Expr *E,
> > + bool IsConstexpr) {
> > DiagnoseAssignmentAsCondition(E);
> > if (ParenExpr *parenE = dyn_cast<ParenExpr>(E))
> > DiagnoseEqualityWithExtraParens(parenE);
> > @@ -14352,7 +14359,7 @@ ExprResult Sema::CheckBooleanCondition(S
> >
> > if (!E->isTypeDependent()) {
> > if (getLangOpts().CPlusPlus)
> > - return CheckCXXBooleanCondition(E); // C++ 6.4p4
> > + return CheckCXXBooleanCondition(E, IsConstexpr); // C++ 6.4p4
> >
> > ExprResult ERes = DefaultFunctionArrayLvalueConversion(E);
> > if (ERes.isInvalid())
> > @@ -14383,6 +14390,10 @@ Sema::ConditionResult Sema::ActOnConditi
> > Cond = CheckBooleanCondition(Loc, SubExpr);
> > break;
> >
> > + case ConditionKind::ConstexprIf:
> > + Cond = CheckBooleanCondition(Loc, SubExpr, true);
> > + break;
> > +
> > case ConditionKind::Switch:
> > Cond = CheckSwitchCondition(Loc, SubExpr);
> > break;
> > @@ -14390,7 +14401,8 @@ Sema::ConditionResult Sema::ActOnConditi
> > if (Cond.isInvalid())
> > return ConditionError();
> >
> > - return ConditionResult(nullptr, MakeFullExpr(Cond.get(), Loc));
> > + return ConditionResult(*this, nullptr, MakeFullExpr(Cond.get(), Loc),
> > + CK == ConditionKind::ConstexprIf);
> > }
> >
> > namespace {
> >
> > Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
> > +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Thu Jun 23 14:16:49 2016
> > @@ -3061,7 +3061,8 @@ Sema::ConditionResult Sema::ActOnConditi
> > CheckConditionVariable(cast<VarDecl>(ConditionVar), StmtLoc, CK);
> > if (E.isInvalid())
> > return ConditionError();
> > - return ConditionResult(ConditionVar, MakeFullExpr(E.get(), StmtLoc));
> > + return ConditionResult(*this, ConditionVar, MakeFullExpr(E.get(),
> StmtLoc),
> > + CK == ConditionKind::ConstexprIf);
> > }
> >
> > /// \brief Check the use of the given variable as a C++ condition in an
> if,
> > @@ -3096,6 +3097,9 @@ ExprResult Sema::CheckConditionVariable(
> > case ConditionKind::Boolean:
> > return CheckBooleanCondition(StmtLoc, Condition.get());
> >
> > + case ConditionKind::ConstexprIf:
> > + return CheckBooleanCondition(StmtLoc, Condition.get(), true);
> > +
> > case ConditionKind::Switch:
> > return CheckSwitchCondition(StmtLoc, Condition.get());
> > }
> > @@ -3104,7 +3108,7 @@ ExprResult Sema::CheckConditionVariable(
> > }
> >
> > /// CheckCXXBooleanCondition - Returns true if a conversion to bool is
> invalid.
> > -ExprResult Sema::CheckCXXBooleanCondition(Expr *CondExpr) {
> > +ExprResult Sema::CheckCXXBooleanCondition(Expr *CondExpr, bool
> IsConstexpr) {
> > // C++ 6.4p4:
> > // The value of a condition that is an initialized declaration in a
> statement
> > // other than a switch statement is the value of the declared variable
> > @@ -3113,7 +3117,12 @@ ExprResult Sema::CheckCXXBooleanConditio
> > // The value of a condition that is an expression is the value of the
> > // expression, implicitly converted to bool.
> > //
> > - return PerformContextuallyConvertToBool(CondExpr);
> > + // FIXME: Return this value to the caller so they don't need to
> recompute it.
> > + llvm::APSInt Value(/*BitWidth*/1);
> > + return (IsConstexpr && !CondExpr->isValueDependent())
> > + ? CheckConvertedConstantExpression(CondExpr,
> Context.BoolTy, Value,
> > + CCEK_ConstexprIf)
> > + : PerformContextuallyConvertToBool(CondExpr);
> > }
> >
> > /// Helper function to determine whether this is the (deprecated) C++
> >
> > Modified: cfe/trunk/lib/Sema/SemaExprMember.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprMember.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Sema/SemaExprMember.cpp (original)
> > +++ cfe/trunk/lib/Sema/SemaExprMember.cpp Thu Jun 23 14:16:49 2016
> > @@ -142,6 +142,7 @@ static IMAKind ClassifyImplicitMemberAcc
> > AbstractInstanceResult = IMA_Abstract;
> > break;
> >
> > + case Sema::DiscardedStatement:
> > case Sema::ConstantEvaluated:
> > case Sema::PotentiallyEvaluated:
> > case Sema::PotentiallyEvaluatedIfUsed:
> >
> > Modified: cfe/trunk/lib/Sema/SemaLambda.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLambda.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Sema/SemaLambda.cpp (original)
> > +++ cfe/trunk/lib/Sema/SemaLambda.cpp Thu Jun 23 14:16:49 2016
> > @@ -1635,6 +1635,7 @@ ExprResult Sema::BuildLambdaExpr(SourceL
> > ExprEvalContexts.back().Lambdas.push_back(Lambda);
> > break;
> >
> > + case DiscardedStatement:
> > case PotentiallyEvaluated:
> > case PotentiallyEvaluatedIfUsed:
> > break;
> >
> > Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
> > +++ cfe/trunk/lib/Sema/SemaStmt.cpp Thu Jun 23 14:16:49 2016
> > @@ -504,31 +504,43 @@ public:
> > }
> >
> > StmtResult
> > -Sema::ActOnIfStmt(SourceLocation IfLoc, ConditionResult Cond,
> > +Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr,
> ConditionResult Cond,
> > Stmt *thenStmt, SourceLocation ElseLoc,
> > Stmt *elseStmt) {
> > - auto CondVal = Cond.get();
> > - if (Cond.isInvalid()) {
> > - CondVal.first = nullptr;
> > - CondVal.second = new (Context)
> > - OpaqueValueExpr(SourceLocation(), Context.BoolTy, VK_RValue);
> > - }
> > + if (Cond.isInvalid())
> > + Cond = ConditionResult(
> > + *this, nullptr,
> > + MakeFullExpr(new (Context) OpaqueValueExpr(SourceLocation(),
> > + Context.BoolTy,
> VK_RValue),
> > + IfLoc),
> > + false);
> >
> > + Expr *CondExpr = Cond.get().second;
> > if (!Diags.isIgnored(diag::warn_comma_operator,
> > - CondVal.second->getExprLoc()))
> > - CommaVisitor(*this).Visit(CondVal.second);
> > -
> > - DiagnoseUnusedExprResult(thenStmt);
> > + CondExpr->getExprLoc()))
> > + CommaVisitor(*this).Visit(CondExpr);
> >
> > - if (!elseStmt) {
> > - DiagnoseEmptyStmtBody(CondVal.second->getLocEnd(), thenStmt,
> > + if (!elseStmt)
> > + DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), thenStmt,
> > diag::warn_empty_if_body);
> > - }
> >
> > + return BuildIfStmt(IfLoc, IsConstexpr, Cond, thenStmt, ElseLoc,
> elseStmt);
> > +}
> > +
> > +StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
> > + ConditionResult Cond, Stmt *thenStmt,
> > + SourceLocation ElseLoc, Stmt *elseStmt) {
> > + if (Cond.isInvalid())
> > + return StmtError();
> > +
> > + if (IsConstexpr)
> > + getCurFunction()->setHasBranchProtectedScope();
> > +
> > + DiagnoseUnusedExprResult(thenStmt);
> > DiagnoseUnusedExprResult(elseStmt);
> >
> > - return new (Context) IfStmt(Context, IfLoc, CondVal.first,
> CondVal.second,
> > - thenStmt, ElseLoc, elseStmt);
> > + return new (Context) IfStmt(Context, IfLoc, IsConstexpr,
> Cond.get().first,
> > + Cond.get().second, thenStmt, ElseLoc,
> elseStmt);
> > }
> >
> > namespace {
> > @@ -2836,8 +2848,21 @@ Sema::ActOnCapScopeReturnStmt(SourceLoca
> > CapturingScopeInfo *CurCap =
> cast<CapturingScopeInfo>(getCurFunction());
> > QualType FnRetType = CurCap->ReturnType;
> > LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(CurCap);
> > + bool HasDeducedReturnType =
> > + CurLambda && hasDeducedReturnType(CurLambda->CallOperator);
> > +
> > + if (ExprEvalContexts.back().Context == DiscardedStatement &&
> > + (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
> > + if (RetValExp) {
> > + ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
> > + if (ER.isInvalid())
> > + return StmtError();
> > + RetValExp = ER.get();
> > + }
> > + return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
> > + }
> >
> > - if (CurLambda && hasDeducedReturnType(CurLambda->CallOperator)) {
> > + if (HasDeducedReturnType) {
> > // In C++1y, the return type may involve 'auto'.
> > // FIXME: Blocks might have a return type of 'auto' explicitly
> specified.
> > FunctionDecl *FD = CurLambda->CallOperator;
> > @@ -3118,9 +3143,8 @@ StmtResult
> > Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
> > Scope *CurScope) {
> > StmtResult R = BuildReturnStmt(ReturnLoc, RetValExp);
> > - if (R.isInvalid()) {
> > + if (R.isInvalid() || ExprEvalContexts.back().Context ==
> DiscardedStatement)
> > return R;
> > - }
> >
> > if (VarDecl *VD =
> >
> const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
> > @@ -3169,6 +3193,19 @@ StmtResult Sema::BuildReturnStmt(SourceL
> > } else // If we don't have a function/method context, bail.
> > return StmtError();
> >
> > + // C++1z: discarded return statements are not considered when
> deducing a
> > + // return type.
> > + if (ExprEvalContexts.back().Context == DiscardedStatement &&
> > + FnRetType->getContainedAutoType()) {
> > + if (RetValExp) {
> > + ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
> > + if (ER.isInvalid())
> > + return StmtError();
> > + RetValExp = ER.get();
> > + }
> > + return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
> > + }
> > +
> > // FIXME: Add a flag to the ScopeInfo to indicate whether we're
> performing
> > // deduction.
> > if (getLangOpts().CPlusPlus14) {
> >
> > Modified: cfe/trunk/lib/Sema/TreeTransform.h
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/TreeTransform.h?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Sema/TreeTransform.h (original)
> > +++ cfe/trunk/lib/Sema/TreeTransform.h Thu Jun 23 14:16:49 2016
> > @@ -1174,9 +1174,10 @@ public:
> > ///
> > /// By default, performs semantic analysis to build the new statement.
> > /// Subclasses may override this routine to provide different
> behavior.
> > - StmtResult RebuildIfStmt(SourceLocation IfLoc, Sema::ConditionResult
> Cond,
> > - Stmt *Then, SourceLocation ElseLoc, Stmt
> *Else) {
> > - return getSema().ActOnIfStmt(IfLoc, Cond, Then, ElseLoc, Else);
> > + StmtResult RebuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
> > + Sema::ConditionResult Cond, Stmt *Then,
> > + SourceLocation ElseLoc, Stmt *Else) {
> > + return getSema().ActOnIfStmt(IfLoc, IsConstexpr, Cond, Then,
> ElseLoc, Else);
> > }
> >
> > /// \brief Start building a new switch statement.
> > @@ -6228,19 +6229,33 @@ TreeTransform<Derived>::TransformIfStmt(
> > // Transform the condition
> > Sema::ConditionResult Cond = getDerived().TransformCondition(
> > S->getIfLoc(), S->getConditionVariable(), S->getCond(),
> > - Sema::ConditionKind::Boolean);
> > + S->isConstexpr() ? Sema::ConditionKind::ConstexprIf
> > + : Sema::ConditionKind::Boolean);
> > if (Cond.isInvalid())
> > return StmtError();
> >
> > + // If this is a constexpr if, determine which arm we should
> instantiate.
> > + llvm::Optional<bool> ConstexprConditionValue;
> > + if (S->isConstexpr())
> > + ConstexprConditionValue = Cond.getKnownValue();
> > +
> > // Transform the "then" branch.
> > - StmtResult Then = getDerived().TransformStmt(S->getThen());
> > - if (Then.isInvalid())
> > - return StmtError();
> > + StmtResult Then;
> > + if (!ConstexprConditionValue || *ConstexprConditionValue) {
> > + Then = getDerived().TransformStmt(S->getThen());
> > + if (Then.isInvalid())
> > + return StmtError();
> > + } else {
> > + Then = new (getSema().Context)
> NullStmt(S->getThen()->getLocStart());
> > + }
> >
> > // Transform the "else" branch.
> > - StmtResult Else = getDerived().TransformStmt(S->getElse());
> > - if (Else.isInvalid())
> > - return StmtError();
> > + StmtResult Else;
> > + if (!ConstexprConditionValue || !*ConstexprConditionValue) {
> > + Else = getDerived().TransformStmt(S->getElse());
> > + if (Else.isInvalid())
> > + return StmtError();
> > + }
> >
> > if (!getDerived().AlwaysRebuild() &&
> > Cond.get() == std::make_pair(S->getConditionVariable(),
> S->getCond()) &&
> > @@ -6248,8 +6263,8 @@ TreeTransform<Derived>::TransformIfStmt(
> > Else.get() == S->getElse())
> > return S;
> >
> > - return getDerived().RebuildIfStmt(S->getIfLoc(), Cond, Then.get(),
> > - S->getElseLoc(), Else.get());
> > + return getDerived().RebuildIfStmt(S->getIfLoc(), S->isConstexpr(),
> Cond,
> > + Then.get(), S->getElseLoc(),
> Else.get());
> > }
> >
> > template<typename Derived>
> >
> > Modified: cfe/trunk/lib/Serialization/ASTReaderStmt.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderStmt.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Serialization/ASTReaderStmt.cpp (original)
> > +++ cfe/trunk/lib/Serialization/ASTReaderStmt.cpp Thu Jun 23 14:16:49
> 2016
> > @@ -184,6 +184,7 @@ void ASTStmtReader::VisitAttributedStmt(
> >
> > void ASTStmtReader::VisitIfStmt(IfStmt *S) {
> > VisitStmt(S);
> > + S->setConstexpr(Record[Idx++]);
> > S->setConditionVariable(Reader.getContext(),
> > ReadDeclAs<VarDecl>(Record, Idx));
> > S->setCond(Reader.ReadSubExpr());
> >
> > Modified: cfe/trunk/lib/Serialization/ASTWriterStmt.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriterStmt.cpp?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/Serialization/ASTWriterStmt.cpp (original)
> > +++ cfe/trunk/lib/Serialization/ASTWriterStmt.cpp Thu Jun 23 14:16:49
> 2016
> > @@ -128,6 +128,7 @@ void ASTStmtWriter::VisitAttributedStmt(
> >
> > void ASTStmtWriter::VisitIfStmt(IfStmt *S) {
> > VisitStmt(S);
> > + Record.push_back(S->isConstexpr());
> > Record.AddDeclRef(S->getConditionVariable());
> > Record.AddStmt(S->getCond());
> > Record.AddStmt(S->getThen());
> >
> > Added:
> cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p2-1z.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p2-1z.cpp?rev=273602&view=auto
> >
> ==============================================================================
> > --- cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p2-1z.cpp
> (added)
> > +++ cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p2-1z.cpp
> Thu Jun 23 14:16:49 2016
> > @@ -0,0 +1,47 @@
> > +// RUN: %clang_cc1 -std=c++1z -verify %s
> > +
> > +template<typename T, typename U> constexpr bool same = false;
> > +template<typename T> constexpr bool same<T, T> = true;
> > +
> > +auto a() {
> > + if constexpr (false)
> > + return 0;
> > +}
> > +static_assert(same<decltype(a()), void>);
> > +
> > +auto b() {
> > + if constexpr (false)
> > + return 0;
> > + else
> > + return 0.0;
> > +}
> > +static_assert(same<decltype(b()), double>);
> > +
> > +auto c() {
> > + if constexpr (true)
> > + return "foo";
> > + else
> > + return 'x';
> > + if constexpr (false)
> > + return 7.6;
> > + else
> > + return 5; // expected-error {{deduced as 'int' here but deduced as
> 'const char *' in earlier}}
> > +}
> > +
> > +template<int k> auto d() {
> > + if constexpr(k == 0)
> > + return 0;
> > + if constexpr(k == 1)
> > + return "foo";
> > + else if constexpr (k == 2)
> > + return 1.0;
> > +}
> > +static_assert(same<decltype(d<0>()), int>);
> > +static_assert(same<decltype(d<1>()), const char *>);
> > +static_assert(same<decltype(d<2>()), double>);
> > +static_assert(same<decltype(d<3>()), void>);
> > +
> > +auto e = []{ if constexpr (false) return 0; }(); // expected-error
> {{variable has incomplete type 'void'}}
> > +
> > +auto f = []{ if constexpr (true) return 0; }();
> > +static_assert(same<decltype(e), int>);
> >
> > Added: cfe/trunk/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp?rev=273602&view=auto
> >
> ==============================================================================
> > --- cfe/trunk/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp (added)
> > +++ cfe/trunk/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp Thu Jun 23
> 14:16:49 2016
> > @@ -0,0 +1,137 @@
> > +// RUN: %clang_cc1 -std=c++1z -verify %s
> > +// RUN: %clang_cc1 -std=c++1z -verify %s -DUNDEFINED
> > +
> > +#ifdef UNDEFINED
> > +// "used but not defined" errors don't get produced if we have more
> interesting
> > +// errors.
> > +namespace std_example {
> > + template <typename T, typename... Rest> void g(T &&p, Rest &&... rs) {
> > + // use p
> > + if constexpr(sizeof...(rs) > 0)
> > + g(rs...);
> > + }
> > + void use_g() {
> > + g(1, 2, 3);
> > + }
> > +
> > + static int x(); // no definition of x required
> > + int f() {
> > + if constexpr (true)
> > + return 0;
> > + else if (x())
> > + return x();
> > + else
> > + return -x();
> > + }
> > +}
> > +
> > +namespace odr_use_in_selected_arm {
> > + static int x(); // expected-warning {{is not defined}}
> > + int f() {
> > + if constexpr (false)
> > + return 0;
> > + else if (x()) // expected-note {{here}}
> > + return x();
> > + else
> > + return -x();
> > + }
> > +}
> > +#else
> > +namespace ccce {
> > + void f() {
> > + if (5) {}
> > + if constexpr (5) {} // expected-error {{cannot be narrowed}}
> > + }
> > + template<int N> void g() {
> > + if constexpr (N) {} // expected-error {{cannot be narrowed}}
> > + }
> > + template void g<5>(); // expected-note {{instantiation of}}
> > +}
> > +
> > +namespace generic_lambda {
> > + // Substituting for T produces a hard error here, even if
> substituting for
> > + // the type of x would remove the error.
> > + template<typename T> void f() {
> > + [](auto x) {
> > + if constexpr (sizeof(T) == 1 && sizeof(x) == 1)
> > + T::error(); // expected-error 2{{'::'}}
> > + } (0);
> > + }
> > +
> > + template<typename T> void g() {
> > + [](auto x) {
> > + if constexpr (sizeof(T) == 1)
> > + if constexpr (sizeof(x) == 1)
> > + T::error(); // expected-error {{'::'}}
> > + } (0);
> > + }
> > +
> > + void use() {
> > + f<int>(); // expected-note {{instantiation of}}
> > + f<char>(); // expected-note {{instantiation of}}
> > + g<int>(); // ok
> > + g<char>(); // expected-note {{instantiation of}}
> > + }
> > +}
> > +
> > +namespace potentially_discarded_branch_target {
> > + void in_switch(int n) {
> > + switch (n)
> > + case 4: if constexpr(sizeof(n) == 4) return;
> > + if constexpr(sizeof(n) == 4)
> > + switch (n) case 4: return;
> > + switch (n) {
> > + if constexpr (sizeof(n) == 4) // expected-note 2{{constexpr if}}
> > + case 4: return; // expected-error {{cannot jump}}
> > + else
> > + default: break; // expected-error {{cannot jump}}
> > + }
> > + }
> > +
> > + template<typename T>
> > + void in_switch_tmpl(int n) {
> > + switch (n) {
> > + if constexpr (sizeof(T) == 4) // expected-note 2{{constexpr if}}
> > + case 4: return; // expected-error {{cannot jump}}
> > + else
> > + default: break; // expected-error {{cannot jump}}
> > + }
> > + }
> > +
> > + void goto_scope(int n) {
> > + goto foo; // expected-error {{cannot jump}}
> > + if constexpr(sizeof(n) == 4) // expected-note {{constexpr if}}
> > + foo: return;
> > +bar:
> > + if constexpr(sizeof(n) == 4)
> > + goto bar; // ok
> > + }
> > +
> > + template<typename T>
> > + void goto_scope(int n) {
> > + goto foo; // expected-error {{cannot jump}}
> > + if constexpr(sizeof(n) == 4) // expected-note {{constexpr if}}
> > + foo: return;
> > +bar:
> > + if constexpr(sizeof(n) == 4)
> > + goto bar; // ok
> > + }
> > +
> > + void goto_redef(int n) {
> > +a: if constexpr(sizeof(n) == 4) // expected-error {{redefinition}}
> expected-note {{constexpr if}}
> > + a: goto a; // expected-note 2{{previous}}
> > + else
> > + a: goto a; // expected-error {{redefinition}} expected-error
> {{cannot jump}}
> > + }
> > +
> > + void evil_things() {
> > + goto evil_label; // expected-error {{cannot jump}}
> > + if constexpr (true || ({evil_label: false;})) {} // expected-note
> {{constexpr if}}
> > +
> > + if constexpr (true) // expected-note {{constexpr if}}
> > + goto surprise; // expected-error {{cannot jump}}
> > + else
> > + surprise: {}
> > + }
> > +}
> > +#endif
> >
> > Added: cfe/trunk/test/CodeGenCXX/cxx1z-constexpr-if.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cxx1z-constexpr-if.cpp?rev=273602&view=auto
> >
> ==============================================================================
> > --- cfe/trunk/test/CodeGenCXX/cxx1z-constexpr-if.cpp (added)
> > +++ cfe/trunk/test/CodeGenCXX/cxx1z-constexpr-if.cpp Thu Jun 23 14:16:49
> 2016
> > @@ -0,0 +1,21 @@
> > +// RUN: %clang_cc1 -std=c++1z %s -emit-llvm -o - | FileCheck %s
> --implicit-check-not=should_not_be_used
> > +
> > +void should_be_used_1();
> > +void should_be_used_2();
> > +void should_not_be_used();
> > +void f() {
> > + if constexpr (false)
> > + should_not_be_used();
> > + else
> > + should_be_used_1();
> > +
> > + if constexpr (true || ({ label: false; }))
> > + should_be_used_2();
> > + else {
> > + goto foo;
> > +foo: should_not_be_used();
> > + }
> > +}
> > +
> > +// CHECK: should_be_used_1
> > +// CHECK: should_be_used_2
> >
> > Modified: cfe/trunk/www/cxx_status.html
> > URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_status.html?rev=273602&r1=273601&r2=273602&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/www/cxx_status.html (original)
> > +++ cfe/trunk/www/cxx_status.html Thu Jun 23 14:16:49 2016
> > @@ -671,6 +671,12 @@ as the draft C++1z standard evolves.</p>
> > <td><a href="http://wg21.link/p0245r1">P0245R1</a></td>
> > <td class="full" align="center">Yes</td>
> > </tr>
> > + <!-- Oulu papers -->
> > + <tr>
> > + <td><tt>constexpr</tt> <em>if-statement</em>s</td>
> > + <td><a href="http://wg21.link/p0292r2">P0292R2</a></td>
> > + <td class="svn" align="center">SVN</td>
> > + </tr>
> > </table>
> >
> > <p>
> >
> >
> > _______________________________________________
> > cfe-commits mailing list
> > cfe-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
> _______________________________________________
> cfe-commits mailing list
> cfe-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20160623/079c009c/attachment-0001.html>
More information about the cfe-commits
mailing list