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[clang] Fix C23 constexpr crashes #112708

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Merged
merged 2 commits into from
Oct 18, 2024
Merged

[clang] Fix C23 constexpr crashes #112708

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[clang] Fix C23 constexpr crashes
Fznamznon Oct 17, 2024
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Fznamznon Oct 17, 2024
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6 changes: 4 additions & 2 deletions clang/lib/AST/Decl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2512,7 +2512,8 @@ bool VarDecl::isUsableInConstantExpressions(const ASTContext &Context) const {
if (!DefVD->mightBeUsableInConstantExpressions(Context))
return false;
// ... and its initializer is a constant initializer.
if (Context.getLangOpts().CPlusPlus && !DefVD->hasConstantInitialization())
if ((Context.getLangOpts().CPlusPlus || getLangOpts().C23) &&
!DefVD->hasConstantInitialization())
return false;
// C++98 [expr.const]p1:
// An integral constant-expression can involve only [...] const variables
Expand Down Expand Up @@ -2620,7 +2621,8 @@ bool VarDecl::hasICEInitializer(const ASTContext &Context) const {

bool VarDecl::hasConstantInitialization() const {
// In C, all globals (and only globals) have constant initialization.
if (hasGlobalStorage() && !getASTContext().getLangOpts().CPlusPlus)
if (hasGlobalStorage() && !getASTContext().getLangOpts().CPlusPlus &&
!isConstexpr())
return true;

// In C++, it depends on whether the evaluation at the point of definition
Expand Down
17 changes: 17 additions & 0 deletions clang/test/Sema/constexpr.c
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Expand Up @@ -374,3 +374,20 @@ void constexprif() {
void constevalif() {
if consteval (300) {} //expected-error {{expected '(' after 'if'}}
}

struct S11 {
int len;
};
void ghissue112516() {
struct S11 *s11 = 0;
constexpr int num = s11->len; // expected-error {{constexpr variable 'num' must be initialized by a constant expression}}
void *Arr[num];
}

void ghissue109095() {
constexpr char c[] = { 'a' };
constexpr int i = c[1]; // expected-error {{constexpr variable 'i' must be initialized by a constant expression}}\
// expected-note {{declared here}}
_Static_assert(i == c[0]); // expected-error {{static assertion expression is not an integral constant expression}}\
// expected-note {{initializer of 'i' is not a constant expression}}
}
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