From c70f1d63f89258d1da24e7419b15fa58a61e6607 Mon Sep 17 00:00:00 2001 From: Richard Smith Date: Thu, 14 Dec 2017 15:16:18 +0000 Subject: [c++20] P0515R3: Parsing support and basic AST construction for operator <=>. Adding the new enumerator forced a bunch more changes into this patch than I would have liked. The -Wtautological-compare warning was extended to properly check the new comparison operator, clang-format needed updating because it uses precedence levels as weights for determining where to break lines (and several operators increased their precedence levels with this change), thread-safety analysis needed changes to build its own IL properly for the new operator. All "real" semantic checking for this operator has been deferred to a future patch. For now, we use the relational comparison rules and arbitrarily give the builtin form of the operator a return type of 'void'. llvm-svn: 320707 --- clang/test/SemaCXX/constant-expression-cxx2a.cpp | 27 ++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 clang/test/SemaCXX/constant-expression-cxx2a.cpp (limited to 'clang/test/SemaCXX/constant-expression-cxx2a.cpp') diff --git a/clang/test/SemaCXX/constant-expression-cxx2a.cpp b/clang/test/SemaCXX/constant-expression-cxx2a.cpp new file mode 100644 index 00000000000..935cbefc7cb --- /dev/null +++ b/clang/test/SemaCXX/constant-expression-cxx2a.cpp @@ -0,0 +1,27 @@ +// RUN: %clang_cc1 -std=c++2a -verify %s -fcxx-exceptions -triple=x86_64-linux-gnu + +namespace ThreeWayComparison { + struct A { + int n; + constexpr friend int operator<=>(const A &a, const A &b) { + return a.n < b.n ? -1 : a.n > b.n ? 1 : 0; + } + }; + static_assert(A{1} <=> A{2} < 0); + static_assert(A{2} <=> A{1} > 0); + static_assert(A{2} <=> A{2} == 0); + + // Note: not yet supported. + static_assert(1 <=> 2 < 0); // expected-error {{invalid operands}} + static_assert(2 <=> 1 > 0); // expected-error {{invalid operands}} + static_assert(1 <=> 1 == 0); // expected-error {{invalid operands}} + constexpr int k = (1 <=> 1, 0); + // expected-error@-1 {{constexpr variable 'k' must be initialized by a constant expression}} + // expected-warning@-2 {{three-way comparison result unused}} + + constexpr void f() { // expected-error {{constant expression}} + void(1 <=> 1); // expected-note {{constant expression}} + } + + // TODO: defaulted operator <=> +} -- cgit v1.2.3