PR12086, PR15117
Introduce CXXStdInitializerListExpr node, representing the implicit
construction of a std::initializer_list<T> object from its underlying array.
The AST representation of such an expression goes from an InitListExpr with a
flag set, to a CXXStdInitializerListExpr containing a MaterializeTemporaryExpr
containing an InitListExpr (possibly wrapped in a CXXBindTemporaryExpr).
This more detailed representation has several advantages, the most important of
which is that the new MaterializeTemporaryExpr allows us to directly model
lifetime extension of the underlying temporary array. Using that, this patch
*drastically* simplifies the IR generation of this construct, provides IR
generation support for nested global initializer_list objects, fixes several
bugs where the destructors for the underlying array would accidentally not get
invoked, and provides constant expression evaluation support for
std::initializer_list objects.
llvm-svn: 183872
diff --git a/clang/test/SemaCXX/constant-expression-cxx1y.cpp b/clang/test/SemaCXX/constant-expression-cxx1y.cpp
index 40a98d4..af44bf8 100644
--- a/clang/test/SemaCXX/constant-expression-cxx1y.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx1y.cpp
@@ -725,3 +725,43 @@
static_assert(a.y == 54, "");
constexpr int k = a.temporary++; // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}
}
+
+namespace std {
+ typedef decltype(sizeof(int)) size_t;
+
+ template <class _E>
+ class initializer_list
+ {
+ const _E* __begin_;
+ size_t __size_;
+
+ constexpr initializer_list(const _E* __b, size_t __s)
+ : __begin_(__b),
+ __size_(__s)
+ {}
+
+ public:
+ typedef _E value_type;
+ typedef const _E& reference;
+ typedef const _E& const_reference;
+ typedef size_t size_type;
+
+ typedef const _E* iterator;
+ typedef const _E* const_iterator;
+
+ constexpr initializer_list() : __begin_(nullptr), __size_(0) {}
+
+ constexpr size_t size() const {return __size_;}
+ constexpr const _E* begin() const {return __begin_;}
+ constexpr const _E* end() const {return __begin_ + __size_;}
+ };
+}
+
+namespace InitializerList {
+ constexpr int sum(std::initializer_list<int> ints) {
+ int total = 0;
+ for (int n : ints) total += n;
+ return total;
+ }
+ static_assert(sum({1, 2, 3, 4, 5}) == 15, "");
+}