r273602 - Implement p0292r2 (constexpr if), a likely C++1z feature.
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Thu Jun 23 12:16:50 PDT 2016
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.
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>
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