Implement DR1454. This allows all intermediate results in constant expressions
to be core constant expressions (including pointers and references to
temporaries), and makes constexpr calculations Turing-complete. A Turing machine
simulator is included as a testcase.
This opens up the possibilty of removing CCValue entirely, and removing some
copies from the constant evaluator in the process, but that cleanup is not part
of this change.
llvm-svn: 150557
diff --git a/clang/test/CXX/expr/expr.const/p2-0x.cpp b/clang/test/CXX/expr/expr.const/p2-0x.cpp
index a22d1e4..8d3638f 100644
--- a/clang/test/CXX/expr/expr.const/p2-0x.cpp
+++ b/clang/test/CXX/expr/expr.const/p2-0x.cpp
@@ -49,25 +49,23 @@
};
// - an invocation of a constexpr function with arguments that, when substituted
-// by function invocation substitution (7.1.5), do not produce a constant
+// by function invocation substitution (7.1.5), do not produce a core constant
// expression;
namespace NonConstExprReturn {
static constexpr const int &id_ref(const int &n) {
- return n; // expected-note {{reference to temporary cannot be returned from a constexpr function}}
+ return n;
}
struct NonConstExprFunction {
- int n : id_ref( // expected-error {{constant expression}} expected-note {{in call to 'id_ref(16)'}}
- 16 // expected-note {{temporary created here}}
- );
+ int n : id_ref(16); // ok
};
constexpr const int *address_of(const int &a) {
- return &a; // expected-note {{pointer to 'n' cannot be returned from a constexpr function}}
+ return &a;
}
constexpr const int *return_param(int n) { // expected-note {{declared here}}
- return address_of(n); // expected-note {{in call to 'address_of(n)'}}
+ return address_of(n);
}
struct S {
- int n : *return_param(0); // expected-error {{constant expression}} expected-note {{in call to 'return_param(0)'}}
+ int n : *return_param(0); // expected-error {{constant expression}} expected-note {{read of variable whose lifetime has ended}}
};
}
@@ -78,16 +76,16 @@
namespace NonConstExprCtor {
struct T {
constexpr T(const int &r) :
- r(r) { // expected-note 2{{reference to temporary cannot be used to initialize a member in a constant expression}}
+ r(r) {
}
const int &r;
};
constexpr int n = 0;
constexpr T t1(n); // ok
- constexpr T t2(0); // expected-error {{must be initialized by a constant expression}} expected-note {{temporary created here}} expected-note {{in call to 'T(0)'}}
+ constexpr T t2(0); // expected-error {{must be initialized by a constant expression}} expected-note {{temporary created here}} expected-note {{reference to temporary is not a constant expression}}
struct S {
- int n : T(4).r; // expected-error {{constant expression}} expected-note {{temporary created here}} expected-note {{in call to 'T(4)'}}
+ int n : T(4).r; // ok
};
}
@@ -176,12 +174,12 @@
struct S {
int m;
};
- constexpr S s = { 5 }; // expected-note {{declared here}}
+ constexpr S s = { 5 };
constexpr const int *p = &s.m + 1;
constexpr const int &f(const int *q) {
- return q[0]; // expected-note {{dereferenced pointer past the end of subobject of 's' is not a constant expression}}
+ return q[0];
}
- constexpr int n = (f(p), 0); // expected-error {{constant expression}} expected-note {{in call to 'f(&s.m + 1)'}}
+ constexpr int n = (f(p), 0); // ok
struct T {
int n : f(p); // expected-error {{not an integral constant expression}} expected-note {{read of dereferenced one-past-the-end pointer}}
};