SG; working on a follow-up now. Thanks! On Mon, Dec 26, 2016 at 8:26 PM, Richard Smith <rich...@metafoo.co.uk> wrote:
> On 26 December 2016 at 20:01, George Burgess IV via cfe-commits < > cfe-commits@lists.llvm.org> wrote: > >> Author: gbiv >> Date: Mon Dec 26 22:01:22 2016 >> New Revision: 290577 >> >> URL: http://llvm.org/viewvc/llvm-project?rev=290577&view=rev >> Log: >> Add a test for `const` folding introduced by r290297. NFC. >> >> AFAICT, we didn't add a test targeted at the new "const can sometimes >> act as constexpr" behavior introduced by r290297. >> >> Modified: >> cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp >> >> Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp >> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/c >> onstant-expression-cxx1y.cpp?rev=290577&r1=290576&r2=290577&view=diff >> ============================================================ >> ================== >> --- cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp (original) >> +++ cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp Mon Dec 26 >> 22:01:22 2016 >> @@ -957,3 +957,20 @@ namespace PR27989 { >> } >> static_assert(f(0) == 1, ""); >> } >> + >> +namespace const_char { >> +template <int M, int N> >> +constexpr int sum(const char (&Arr)[N]) { >> + static_assert(N >= M, ""); >> + int S = 0; >> + for (unsigned I = 0; I != M; ++I) >> + S += Arr[I]; >> + return S; >> +} >> + >> +// As an extension, we support evaluating some things that are `const` >> as though >> +// they were `constexpr`. >> +const char Cs[] = {'a', 'b', 'c'}; >> +const int N = 2; >> +static_assert(sum<N>(Cs) == 'a' + 'b', ""); >> +} > > > Hold on, this test should fail. It's OK to extend the set of things we can > constant-fold, but formal constant expression checking still needs to be > strict. (You should produce a CCEDiag from within the constant expression > evaluator to mark things that are not core constant expressions but are > permitted as an extension.) >
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