Author: Richard Smith Date: 2020-04-20T21:23:35-07:00 New Revision: 4b03dd7b849e8f5068dc8d72c6eab724c22a2805
URL: https://github.com/llvm/llvm-project/commit/4b03dd7b849e8f5068dc8d72c6eab724c22a2805 DIFF: https://github.com/llvm/llvm-project/commit/4b03dd7b849e8f5068dc8d72c6eab724c22a2805.diff LOG: PR45534: don't ignore unmodeled side-effects when constant-evaluating a call to __builtin_constant_p. Such side-effects should result in the call evaluating to 'false', even if we can still determine what value the argument expression will evaluate to. Added: Modified: clang/lib/AST/ExprConstant.cpp clang/test/SemaCXX/builtin-constant-p.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 8bc7a1128e7a..ad61221a6a91 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -10438,7 +10438,7 @@ static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) { ArgType->isAnyComplexType() || ArgType->isPointerType() || ArgType->isNullPtrType()) { APValue V; - if (!::EvaluateAsRValue(Info, Arg, V)) { + if (!::EvaluateAsRValue(Info, Arg, V) || Info.EvalStatus.HasSideEffects) { Fold.keepDiagnostics(); return false; } diff --git a/clang/test/SemaCXX/builtin-constant-p.cpp b/clang/test/SemaCXX/builtin-constant-p.cpp index f70676d250e0..1b8cf455ef27 100644 --- a/clang/test/SemaCXX/builtin-constant-p.cpp +++ b/clang/test/SemaCXX/builtin-constant-p.cpp @@ -1,4 +1,5 @@ // RUN: %clang_cc1 -std=c++17 -verify %s +// RUN: %clang_cc1 -std=c++20 -verify %s using intptr_t = __INTPTR_TYPE__; @@ -135,3 +136,33 @@ static_assert(mutate6(true) == 10); // not being a pointer to the start of a string literal. namespace std { struct type_info; } static_assert(__builtin_constant_p(&typeid(int))); + +void mutate_as_side_effect() { + int a; + static_assert(!__builtin_constant_p(((void)++a, 1))); +} + +namespace dtor_side_effect { + struct A { + constexpr A() {} + ~A(); + }; + static_assert(!__builtin_constant_p((A{}, 123))); +} + +#if __cplusplus >= 202002L +namespace constexpr_dtor { + struct A { + int *p; + constexpr ~A() { *p = 0; } + }; + struct Q { int n; constexpr int *get() { return &n; } }; + static_assert(!__builtin_constant_p((A{}, 123))); + // FIXME: We should probably accept this. GCC does. + // However, GCC appears to do so by running the destructors at the end of the + // enclosing full-expression, which seems broken; running them at the end of + // the evaluation of the __builtin_constant_p argument would be more + // defensible. + static_assert(!__builtin_constant_p((A{Q().get()}, 123))); +} +#endif _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
