Allow constant-folding of references which were formed in a manner not permitted
in a constant expression, for compatibility with g++. llvm-svn: 148020
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@ -832,7 +832,8 @@ static bool IsGlobalLValue(APValue::LValueBase B) {
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/// Check that this reference or pointer core constant expression is a valid
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/// value for an address or reference constant expression. Type T should be
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/// either LValue or CCValue.
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/// either LValue or CCValue. Return true if we can fold this expression,
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/// whether or not it's a constant expression.
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template<typename T>
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static bool CheckLValueConstantExpression(EvalInfo &Info, const Expr *E,
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const T &LVal, APValue &Value,
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@ -854,19 +855,15 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, const Expr *E,
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} else {
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Info.Diag(E->getExprLoc());
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}
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// Don't allow references to temporaries to escape.
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return false;
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}
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bool IsReferenceType = E->isGLValue();
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if (Designator.Invalid) {
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// This is not a core constant expression. A diagnostic will have already
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// been produced.
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if (IsReferenceType)
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return false;
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// Allow this for pointers, so we can fold things like integers cast to
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// pointers.
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// This is not a core constant expression. An appropriate diagnostic will
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// have already been produced.
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Value = APValue(LVal.getLValueBase(), LVal.getLValueOffset(),
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APValue::NoLValuePath());
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return true;
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@ -884,7 +881,7 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, const Expr *E,
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if (!Base) {
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// FIXME: diagnostic
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Info.CCEDiag(E->getExprLoc());
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return false;
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return true;
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}
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// Does this refer one past the end of some object?
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@ -897,7 +894,6 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, const Expr *E,
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else
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Info.Note(Base.dyn_cast<const Expr*>()->getExprLoc(),
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diag::note_constexpr_temporary_here);
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return false;
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}
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return true;
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@ -134,8 +134,9 @@ namespace UndefinedBehavior {
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constexpr const int &f(const int *q) {
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return q[0]; // expected-note {{dereferenced pointer past the end of subobject of 's' is not a constant expression}}
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}
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constexpr int n = (f(p), 0); // expected-error {{constant expression}} expected-note {{in call to 'f(&s.m + 1)'}}
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struct T {
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int n : f(p); // expected-error {{not an integer constant expression}} expected-note {{in call to 'f(&s.m + 1)'}}
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int n : f(p); // expected-error {{not an integer constant expression}} expected-note {{read of dereferenced one-past-the-end pointer}}
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};
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namespace Ptr {
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@ -69,3 +69,10 @@ void UnfoldableAddrLabelDiff() { static __int128_t x = (long)&&a-(long)&&b; a:b:
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// But make sure we do fold this.
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// CHECK: @_ZZ21FoldableAddrLabelDiffvE1x = internal global i64 sub (i64 ptrtoint (i8* blockaddress(@_Z21FoldableAddrLabelDiffv
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void FoldableAddrLabelDiff() { static long x = (long)&&a-(long)&&b; a:b:return;}
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// CHECK: @i = constant i32* bitcast (float* @PR9558 to i32*)
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int &i = reinterpret_cast<int&>(PR9558);
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int arr[2];
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// CHECK: @pastEnd = constant i32* bitcast (i8* getelementptr (i8* bitcast ([2 x i32]* @arr to i8*), i64 8) to i32*)
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int &pastEnd = arr[2];
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@ -8,7 +8,7 @@
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<link type="text/css" rel="stylesheet" href="content.css">
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<style type="text/css">
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.none { background-color: #FFCCCC }
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.partial { background-color: #FFFF99 }
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.svn { background-color: #FFFF99 }
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.full { background-color: #CCFF99 }
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th { background-color: #FFDDAA }
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</style>
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@ -156,7 +156,7 @@ with clang; other versions have not been tested.</p>
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<td>
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<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2764.pdf">N2764
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</a></td>
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<td class="none" align="center">No</td>
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<td class="svn" align="center">SVN</td>
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</tr>
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<tr>
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<td>Generalized attributes</td>
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@ -238,7 +238,7 @@ with clang; other versions have not been tested.</p>
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<tr>
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<td>Extending <code>sizeof</code></td>
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<td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2253.html">N2253</a></td>
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<td class="none" align="center">No</td>
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<td class="svn" align="center">SVN</td>
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</tr>
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<tr>
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<td>Inline namespaces</td>
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