On Mon, Dec 02, 2019 at 12:09:17PM -0500, Jason Merrill wrote:
> On 12/1/19 8:09 PM, Marek Polacek wrote:
> > --- gcc/cp/constexpr.c
> > +++ gcc/cp/constexpr.c
> > @@ -779,7 +779,9 @@ cx_check_missing_mem_inits (tree ctype, tree body, bool
> > complain)
> > if (TREE_CODE (ctype) == UNION_TYPE)
> > {
> > - if (nelts == 0 && next_initializable_field (field))
> > + if (cxx_dialect < cxx2a
> > + && nelts == 0
> > + && next_initializable_field (field))
>
> Do we want cx_check_missing_mem_inits to do anything in C++20? Or can we
> return immediately at the beginning?
We can just return right away. Changed.
> > {
> > if (complain)
> > error ("%<constexpr%> constructor for union %qT must "
> > @@ -2153,15 +2157,27 @@ cxx_eval_call_expression (const constexpr_ctx *ctx,
> > tree t,
> > entry->result = result;
> > }
> > - /* The result of a constexpr function must be completely initialized. */
> > - if (TREE_CODE (result) == CONSTRUCTOR)
> > + /* The result of a constexpr function must be completely initialized.
> > +
> > + However, in C++20, a constexpr constructor doesn't necessarily have
> > + to initialize all the fields, so we don't clear
> > CONSTRUCTOR_NO_CLEARING
> > + in order to detect reading an unitialized object in constexpr instead
> > + of value-initializing it. (reduced_constant_expression_p is expected
> > to
> > + take care of clearing the flag.) */
> > + if (TREE_CODE (result) == CONSTRUCTOR
> > + && (cxx_dialect < cxx2a
> > + || !DECL_CONSTRUCTOR_P (fun)
> > + || !DECL_DECLARED_CONSTEXPR_P (fun)))
>
> How can we get here for a non-constexpr function?
We can't -- I was just being explicit. I dropped the DECL_DECLARED_CONSTEXPR_P
line.
> > clear_no_implicit_zero (result);
> > pop_cx_call_context ();
> > return result;
> > }
> > -/* FIXME speed this up, it's taking 16% of compile time on sieve testcase.
> > */
> > +/* Return true if T is a valid constant initializer. If a CONSTRUCTOR
> > + initializes all the members, the CONSTRUCTOR_NO_CLEARING flag will be
> > + cleared.
> > + FIXME speed this up, it's taking 16% of compile time on sieve testcase.
> > */
> > bool
> > reduced_constant_expression_p (tree t)
> > @@ -2183,8 +2199,17 @@ reduced_constant_expression_p (tree t)
> > if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
> > /* An initialized vector would have a VECTOR_CST. */
> > return false;
> > + else if (cxx_dialect >= cxx2a
> > + /* An ARRAY_TYPE doesn't have any TYPE_FIELDS. */
> > + && (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE
> > + /* A union only initializes one member. */
> > + || TREE_CODE (TREE_TYPE (t)) == UNION_TYPE))
> > + field = NULL_TREE;
> > else
> > - field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t)));
> > + /* In C++20, skip fields that don't actually need initializing,
> > + like empty bases. */
> > + field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t)),
> > + cxx_dialect >= cxx2a);
> > }
> > else
> > field = NULL_TREE;
> > @@ -2198,7 +2223,8 @@ reduced_constant_expression_p (tree t)
> > {
> > if (idx != field)
> > return false;
> > - field = next_initializable_field (DECL_CHAIN (field));
> > + field = next_initializable_field (DECL_CHAIN (field),
> > + cxx_dialect >= cxx2a);
> > }
> > }
> > if (field)
> > diff --git gcc/cp/cp-tree.h gcc/cp/cp-tree.h
> > index 7e810b8ee7b..35f3352bdff 100644
> > --- gcc/cp/cp-tree.h
> > +++ gcc/cp/cp-tree.h
> > @@ -6541,7 +6541,7 @@ extern bool is_direct_enum_init
> > (tree, tree);
> > extern void initialize_artificial_var (tree,
> > vec<constructor_elt, va_gc> *);
> > extern tree check_var_type (tree, tree,
> > location_t);
> > extern tree reshape_init (tree, tree,
> > tsubst_flags_t);
> > -extern tree next_initializable_field (tree);
> > +extern tree next_initializable_field (tree, bool = false);
> > extern tree fndecl_declared_return_type (tree);
> > extern bool undeduced_auto_decl (tree);
> > extern bool require_deduced_type (tree, tsubst_flags_t =
> > tf_warning_or_error);
> > diff --git gcc/cp/decl.c gcc/cp/decl.c
> > index 81d73433547..9feba7d5b54 100644
> > --- gcc/cp/decl.c
> > +++ gcc/cp/decl.c
> > +next_initializable_field (tree field, bool skip_empty /*=false*/)
> > {
> > while (field
> > && (TREE_CODE (field) != FIELD_DECL
> > || DECL_UNNAMED_BIT_FIELD (field)
> > || (DECL_ARTIFICIAL (field)
> > - && !(cxx_dialect >= cxx17 && DECL_FIELD_IS_BASE (field)))))
> > + /* In C++17, don't skip base class fields. */
> > + && !(cxx_dialect >= cxx17 && DECL_FIELD_IS_BASE (field))
> > + /* In C++20, don't skip vptr fields. */
> > + && !(cxx_dialect >= cxx2a && DECL_VIRTUAL_P (field)))
>
> I don't think this needs to be specific to C++20; in all language revisions
> a vptr makes a class non-aggregate, so we'd only get here for a use like
> that in reduced_constant_expression_p.
True enough, adjusted.
> > + || (skip_empty
> > + && is_really_empty_class (TREE_TYPE (field),
>
> This should probably check DECL_SIZE (field) == size_zero_node instead,
> since that will properly distinguish between overlapping and non-overlapping
> data members of empty class type. And please test how this works with data
> members of empty class type both with and without [[no_unique_address]].
I don't think that's possible -- empty classes in C++ have sizeof(char), unless
their only member is char[0], then their DECL_SIZE is 0.
I've added two testcases: constexpr-init13.C and constexpr-init14.C. Is there
another scenario regarding [[no_unique_address]] that you want me to test?
Bootstrapped/regtested on x86_64-linux, built Boost and cmcstl2.
2019-12-02 Marek Polacek <pola...@redhat.com>
Jakub Jelinek <ja...@redhat.com>
PR c++/91353 - P1331R2: Allow trivial default init in constexpr
contexts.
* c-cppbuiltin.c (c_cpp_builtins): Adjust the value of __cpp_constexpr.
* class.c (trivial_default_constructor_is_constexpr): Return true in
C++20.
* constexpr.c (cx_check_missing_mem_inits): Allow missing field
initializers in C++20.
(cxx_eval_call_expression): Don't clear CONSTRUCTOR_NO_CLEARING for
constexpr constructors in C++20.
(reduced_constant_expression_p): Don't set FIELD for union and array
types. Adjust calls to next_initializable_field.
* cp-tree.h (next_initializable_field): Adjust declaration.
* decl.c (check_for_uninitialized_const_var): Permit trivial default
initialization in constexpr.
(next_initializable_field): Add a bool parameter. Use it.
* method.c (walk_field_subobs): Still consider a constructor that
doesn't initialize all the members constexpr.
* g++.dg/cpp0x/constexpr-array6.C: Adjust dg-error.
* g++.dg/cpp0x/constexpr-ctor.C: Likewise.
* g++.dg/cpp0x/constexpr-diag3.C: Likewise.
* g++.dg/cpp0x/constexpr-diag4.C: Likewise.
* g++.dg/cpp0x/constexpr-ex3.C: Likewise.
* g++.dg/cpp0x/constexpr-template2.C: Likewise.
* g++.dg/cpp0x/constexpr-union2.C: Likewise.
* g++.dg/cpp0x/lambda/lambda-mangle.C: Rip out a piece of code ...
* g++.dg/cpp0x/lambda/lambda-mangle6.C: ... and put it here.
* g++.dg/cpp0x/pr79118.C: Adjust dg-error.
* g++.dg/cpp1y/constexpr-83921-3.C: Likewise.
* g++.dg/cpp1y/constexpr-neg1.C: Likewise.
* g++.dg/cpp1z/constexpr-lambda12.C: Likewise.
* g++.dg/cpp1z/feat-cxx1z.C: Use -std=c++17.
* g++.dg/cpp2a/constexpr-init1.C: New test.
* g++.dg/cpp2a/constexpr-init2.C: New test.
* g++.dg/cpp2a/constexpr-init3.C: New test.
* g++.dg/cpp2a/constexpr-init4.C: New test.
* g++.dg/cpp2a/constexpr-init5.C: New test.
* g++.dg/cpp2a/constexpr-init6.C: New test.
* g++.dg/cpp2a/constexpr-init7.C: New test.
* g++.dg/cpp2a/constexpr-init8.C: New test.
* g++.dg/cpp2a/constexpr-init9.C: New test.
* g++.dg/cpp2a/constexpr-init10.C: New test.
* g++.dg/cpp2a/constexpr-init11.C: New test.
* g++.dg/cpp2a/constexpr-init12.C: New test.
* g++.dg/cpp2a/constexpr-init13.C: New test.
* g++.dg/cpp2a/constexpr-init14.C: New test.
* g++.dg/cpp2a/constexpr-try5.C: Adjust dg-error.
* g++.dg/cpp2a/feat-cxx2a.C: Test __cpp_constexpr.
* g++.dg/cpp2a/lambda-mangle.C: New test.
* g++.dg/debug/dwarf2/pr44641.C: Skip for c++2a.
* g++.dg/ext/stmtexpr21.C: Adjust dg-error.
diff --git gcc/c-family/c-cppbuiltin.c gcc/c-family/c-cppbuiltin.c
index 6491545bc3b..680087cd254 100644
--- gcc/c-family/c-cppbuiltin.c
+++ gcc/c-family/c-cppbuiltin.c
@@ -975,7 +975,8 @@ c_cpp_builtins (cpp_reader *pfile)
cpp_define (pfile, "__cpp_fold_expressions=201603L");
cpp_define (pfile, "__cpp_nontype_template_args=201411L");
cpp_define (pfile, "__cpp_range_based_for=201603L");
- cpp_define (pfile, "__cpp_constexpr=201603L");
+ if (cxx_dialect <= cxx17)
+ cpp_define (pfile, "__cpp_constexpr=201603L");
cpp_define (pfile, "__cpp_if_constexpr=201606L");
cpp_define (pfile, "__cpp_capture_star_this=201603L");
cpp_define (pfile, "__cpp_inline_variables=201606L");
@@ -997,6 +998,7 @@ c_cpp_builtins (cpp_reader *pfile)
cpp_define (pfile, "__cpp_init_captures=201803L");
cpp_define (pfile, "__cpp_generic_lambdas=201707L");
cpp_define (pfile, "__cpp_designated_initializers=201707L");
+ cpp_define (pfile, "__cpp_constexpr=201907L");
cpp_define (pfile, "__cpp_constexpr_in_decltype=201711L");
cpp_define (pfile, "__cpp_conditional_explicit=201806L");
cpp_define (pfile, "__cpp_consteval=201811L");
diff --git gcc/cp/class.c gcc/cp/class.c
index f36f75fa0db..d8bb44990b7 100644
--- gcc/cp/class.c
+++ gcc/cp/class.c
@@ -5288,8 +5288,14 @@ trivial_default_constructor_is_constexpr (tree t)
/* A defaulted trivial default constructor is constexpr
if there is nothing to initialize. */
gcc_assert (!TYPE_HAS_COMPLEX_DFLT (t));
- /* A class with a vptr doesn't have a trivial default ctor. */
- return is_really_empty_class (t, /*ignore_vptr*/true);
+ /* A class with a vptr doesn't have a trivial default ctor.
+ In C++20, a class can have transient uninitialized members, e.g.:
+
+ struct S { int i; constexpr S() = default; };
+
+ should work. */
+ return (cxx_dialect >= cxx2a
+ || is_really_empty_class (t, /*ignore_vptr*/true));
}
/* Returns true iff class T has a constexpr default constructor. */
diff --git gcc/cp/constexpr.c gcc/cp/constexpr.c
index ee3ccb9691c..8952d09f19f 100644
--- gcc/cp/constexpr.c
+++ gcc/cp/constexpr.c
@@ -767,6 +767,10 @@ massage_constexpr_body (tree fun, tree body)
static bool
cx_check_missing_mem_inits (tree ctype, tree body, bool complain)
{
+ /* We allow uninitialized bases/fields in C++20. */
+ if (cxx_dialect >= cxx2a)
+ return false;
+
unsigned nelts = 0;
if (body)
@@ -815,7 +819,7 @@ cx_check_missing_mem_inits (tree ctype, tree body, bool
complain)
continue;
if (ANON_AGGR_TYPE_P (TREE_TYPE (field)))
{
- /* Recurse to check the anonummous aggregate member. */
+ /* Recurse to check the anonymous aggregate member. */
bad |= cx_check_missing_mem_inits
(TREE_TYPE (field), NULL_TREE, complain);
if (bad && !complain)
@@ -2153,15 +2157,26 @@ cxx_eval_call_expression (const constexpr_ctx *ctx,
tree t,
entry->result = result;
}
- /* The result of a constexpr function must be completely initialized. */
- if (TREE_CODE (result) == CONSTRUCTOR)
+ /* The result of a constexpr function must be completely initialized.
+
+ However, in C++20, a constexpr constructor doesn't necessarily have
+ to initialize all the fields, so we don't clear CONSTRUCTOR_NO_CLEARING
+ in order to detect reading an unitialized object in constexpr instead
+ of value-initializing it. (reduced_constant_expression_p is expected to
+ take care of clearing the flag.) */
+ if (TREE_CODE (result) == CONSTRUCTOR
+ && (cxx_dialect < cxx2a
+ || !DECL_CONSTRUCTOR_P (fun)))
clear_no_implicit_zero (result);
pop_cx_call_context ();
return result;
}
-/* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */
+/* Return true if T is a valid constant initializer. If a CONSTRUCTOR
+ initializes all the members, the CONSTRUCTOR_NO_CLEARING flag will be
+ cleared.
+ FIXME speed this up, it's taking 16% of compile time on sieve testcase. */
bool
reduced_constant_expression_p (tree t)
@@ -2183,8 +2198,17 @@ reduced_constant_expression_p (tree t)
if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
/* An initialized vector would have a VECTOR_CST. */
return false;
+ else if (cxx_dialect >= cxx2a
+ /* An ARRAY_TYPE doesn't have any TYPE_FIELDS. */
+ && (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE
+ /* A union only initializes one member. */
+ || TREE_CODE (TREE_TYPE (t)) == UNION_TYPE))
+ field = NULL_TREE;
else
- field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t)));
+ /* In C++20, skip fields that don't actually need initializing,
+ like empty bases. */
+ field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t)),
+ cxx_dialect >= cxx2a);
}
else
field = NULL_TREE;
@@ -2198,7 +2222,8 @@ reduced_constant_expression_p (tree t)
{
if (idx != field)
return false;
- field = next_initializable_field (DECL_CHAIN (field));
+ field = next_initializable_field (DECL_CHAIN (field),
+ cxx_dialect >= cxx2a);
}
}
if (field)
diff --git gcc/cp/cp-tree.h gcc/cp/cp-tree.h
index 7e810b8ee7b..35f3352bdff 100644
--- gcc/cp/cp-tree.h
+++ gcc/cp/cp-tree.h
@@ -6541,7 +6541,7 @@ extern bool is_direct_enum_init (tree,
tree);
extern void initialize_artificial_var (tree, vec<constructor_elt,
va_gc> *);
extern tree check_var_type (tree, tree, location_t);
extern tree reshape_init (tree, tree, tsubst_flags_t);
-extern tree next_initializable_field (tree);
+extern tree next_initializable_field (tree, bool = false);
extern tree fndecl_declared_return_type (tree);
extern bool undeduced_auto_decl (tree);
extern bool require_deduced_type (tree, tsubst_flags_t =
tf_warning_or_error);
diff --git gcc/cp/decl.c gcc/cp/decl.c
index 81d73433547..0ee68d3bf27 100644
--- gcc/cp/decl.c
+++ gcc/cp/decl.c
@@ -5835,8 +5835,12 @@ check_for_uninitialized_const_var (tree decl, bool
constexpr_context_p,
7.1.6 */
if (VAR_P (decl)
&& !TYPE_REF_P (type)
- && (constexpr_context_p
- || CP_TYPE_CONST_P (type) || var_in_constexpr_fn (decl))
+ && (CP_TYPE_CONST_P (type)
+ /* C++20 permits trivial default initialization in constexpr
+ context (P1331R2). */
+ || (cxx_dialect < cxx2a
+ && (constexpr_context_p
+ || var_in_constexpr_fn (decl))))
&& !DECL_NONTRIVIALLY_INITIALIZED_P (decl))
{
tree field = default_init_uninitialized_part (type);
@@ -5845,7 +5849,7 @@ check_for_uninitialized_const_var (tree decl, bool
constexpr_context_p,
bool show_notes = true;
- if (!constexpr_context_p)
+ if (!constexpr_context_p || cxx_dialect >= cxx2a)
{
if (CP_TYPE_CONST_P (type))
{
@@ -5906,16 +5910,23 @@ static tree reshape_init_r (tree, reshape_iter *, bool,
tsubst_flags_t);
/* FIELD is a FIELD_DECL or NULL. In the former case, the value
returned is the next FIELD_DECL (possibly FIELD itself) that can be
initialized. If there are no more such fields, the return value
- will be NULL. */
+ will be NULL. If SKIP_EMPTY, skips empty classes. */
tree
-next_initializable_field (tree field)
+next_initializable_field (tree field, bool skip_empty /*=false*/)
{
while (field
&& (TREE_CODE (field) != FIELD_DECL
|| DECL_UNNAMED_BIT_FIELD (field)
|| (DECL_ARTIFICIAL (field)
- && !(cxx_dialect >= cxx17 && DECL_FIELD_IS_BASE (field)))))
+ /* In C++17, don't skip base class fields. */
+ && !(cxx_dialect >= cxx17 && DECL_FIELD_IS_BASE (field))
+ /* Don't skip vptr fields. We might see them when we're
+ called from reduced_constant_expression_p. */
+ && !DECL_VIRTUAL_P (field))
+ || (skip_empty
+ && is_really_empty_class (TREE_TYPE (field),
+ /*ignore_vptr=*/false))))
field = DECL_CHAIN (field);
return field;
diff --git gcc/cp/method.c gcc/cp/method.c
index a707940cacc..d2aed473d77 100644
--- gcc/cp/method.c
+++ gcc/cp/method.c
@@ -1985,10 +1985,12 @@ walk_field_subobs (tree fields, special_function_kind
sfk, tree fnname,
if (bad && deleted_p)
*deleted_p = true;
- /* For an implicitly-defined default constructor to be constexpr,
- every member must have a user-provided default constructor or
- an explicit initializer. */
- if (constexpr_p && !CLASS_TYPE_P (mem_type)
+ /* Before C++20, for an implicitly-defined default constructor to
+ be constexpr, every member must have a user-provided default
+ constructor or an explicit initializer. */
+ if (constexpr_p
+ && cxx_dialect < cxx2a
+ && !CLASS_TYPE_P (mem_type)
&& TREE_CODE (DECL_CONTEXT (field)) != UNION_TYPE)
{
*constexpr_p = false;
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-array6.C
gcc/testsuite/g++.dg/cpp0x/constexpr-array6.C
index 16eacdde440..48dae5d9609 100644
--- gcc/testsuite/g++.dg/cpp0x/constexpr-array6.C
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-array6.C
@@ -4,7 +4,7 @@
struct A
{
int i;
- constexpr A() {} // { dg-error "A::i" }
+ constexpr A() {} // { dg-error "A::i" "" { target c++17_down } }
};
struct B
@@ -12,4 +12,5 @@ struct B
A a;
};
-constexpr B b[] = { {} }; // { dg-error "A::A" }
+constexpr B b[] = { {} }; // { dg-error "A::A" "" { target c++17_down } }
+// { dg-error "is not a constant expression" "" { target c++2a } .-1 }
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-ctor.C
gcc/testsuite/g++.dg/cpp0x/constexpr-ctor.C
index 55beda7c49f..1d0fa479cbc 100644
--- gcc/testsuite/g++.dg/cpp0x/constexpr-ctor.C
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-ctor.C
@@ -3,5 +3,5 @@
struct A
{
int i;
- constexpr A() { } // { dg-error "A::i" }
+ constexpr A() { } // { dg-error "A::i" "" { target c++17_down } }
};
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C
gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C
index e54b26c7f6a..1c43569615c 100644
--- gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-diag3.C
@@ -48,7 +48,7 @@ struct Def
{
int _M_i; // { dg-message "does not initialize" }
- constexpr Def() = default; // { dg-error "implicit declaration is not
.constexpr." }
+ constexpr Def() = default; // { dg-error "implicit declaration is not
.constexpr." "" { target c++17_down } }
};
constexpr Def defobj; // { dg-error "uninitialized" }
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-diag4.C
gcc/testsuite/g++.dg/cpp0x/constexpr-diag4.C
index 13ca6fa2390..c603bdd1a00 100644
--- gcc/testsuite/g++.dg/cpp0x/constexpr-diag4.C
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-diag4.C
@@ -21,5 +21,5 @@ struct A1
struct B1
{
A1 a1;
- constexpr B1() {} // { dg-error "B1::a1" }
+ constexpr B1() {} // { dg-error "B1::a1" "" { target c++17_down } }
};
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-ex3.C
gcc/testsuite/g++.dg/cpp0x/constexpr-ex3.C
index a5893563eec..9d6d5ff587c 100644
--- gcc/testsuite/g++.dg/cpp0x/constexpr-ex3.C
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-ex3.C
@@ -6,7 +6,7 @@
struct A
{
int i;
- constexpr A(int _i) { i = _i; } // { dg-error "empty body|A::i" }
+ constexpr A(int _i) { i = _i; } // { dg-error "empty body|A::i" "" { target
c++17_down } }
};
template <class T>
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-template2.C
gcc/testsuite/g++.dg/cpp0x/constexpr-template2.C
index 12a8d42b31f..71eb559a24c 100644
--- gcc/testsuite/g++.dg/cpp0x/constexpr-template2.C
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-template2.C
@@ -3,7 +3,7 @@
template <class T> struct A
{
T t;
- constexpr A() { } // { dg-error "::t" }
+ constexpr A() { } // { dg-error "::t" "" { target c++17_down } }
};
int main()
diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-union2.C
gcc/testsuite/g++.dg/cpp0x/constexpr-union2.C
index 1a5e832ac34..c22ecc99efb 100644
--- gcc/testsuite/g++.dg/cpp0x/constexpr-union2.C
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-union2.C
@@ -14,5 +14,5 @@ union bar
int x;
short y;
- constexpr bar() = default; // { dg-error "constexpr" }
+ constexpr bar() = default; // { dg-error "constexpr" "" { target
c++17_down } }
};
diff --git gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C
gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C
index 15b8b79ecbc..7894ef3051e 100644
--- gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C
+++ gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle.C
@@ -47,17 +47,6 @@ struct S {
[]{return 3;}());
};
-template<typename T> struct R {
- static int x;
-};
-// "int i;" makes the op() non-constexpr in C++17.
-template<typename T> int R<T>::x = []{int i; return 1;}();
-template int R<int>::x;
-// Type of lambda in intializer of R<int>::x: N1RIiE1xMUlvE_E
-// Corresponding operator(): _ZNK1RIiE1xMUlvE_clEv
-// { dg-final { scan-assembler "_ZNK1RIiE1xMUlvE_clEv" } }
-// { dg-final { scan-assembler "weak\[^\n\r\]*_?_ZNK1RIiE1xMUlvE_clEv" {
target { ! { *-*-mingw* *-*-cygwin } } } } }
-
void bar()
{
// lambdas in non-vague linkage functions have internal linkage.
diff --git gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle6.C
gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle6.C
new file mode 100644
index 00000000000..9ec13e79bbf
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp0x/lambda/lambda-mangle6.C
@@ -0,0 +1,15 @@
+// Test lambda mangling
+// { dg-do compile { target { c++11 && c++17_down } } }
+// { dg-require-weak "" }
+// { dg-options "-fno-inline" }
+
+template<typename T> struct R {
+ static int x;
+};
+// "int i;" makes the op() non-constexpr in C++17. In C++20, it does not.
+template<typename T> int R<T>::x = []{int i; return 1;}();
+template int R<int>::x;
+// Type of lambda in intializer of R<int>::x: N1RIiE1xMUlvE_E
+// Corresponding operator(): _ZNK1RIiE1xMUlvE_clEv
+// { dg-final { scan-assembler "_ZNK1RIiE1xMUlvE_clEv" } }
+// { dg-final { scan-assembler "weak\[^\n\r\]*_?_ZNK1RIiE1xMUlvE_clEv" {
target { ! { *-*-mingw* *-*-cygwin } } } } }
diff --git gcc/testsuite/g++.dg/cpp0x/pr79118.C
gcc/testsuite/g++.dg/cpp0x/pr79118.C
index 5db22a96dd4..616b51ea29a 100644
--- gcc/testsuite/g++.dg/cpp0x/pr79118.C
+++ gcc/testsuite/g++.dg/cpp0x/pr79118.C
@@ -13,7 +13,7 @@ struct One
constexpr One () : a(), b() {} // { dg-error "multiple" }
constexpr One (int) : a() {}
constexpr One (unsigned) : b () {}
- constexpr One (void *) {} // { dg-error "exactly one" }
+ constexpr One (void *) {} // { dg-error "exactly one" "" { target c++17_down
} }
};
One a ();
@@ -30,10 +30,10 @@ struct Two
};
constexpr Two () : a(), b() {}
- constexpr Two (int) : a() {} // { dg-error "b' must be initialized" }
- constexpr Two (unsigned) : b () {} // { dg-error "a' must be initialized" }
- constexpr Two (void *) {} // { dg-error "a' must be initialized" }
- // { dg-error "b' must be initialized" "" { target *-*-* } .-1 }
+ constexpr Two (int) : a() {} // { dg-error "b' must be initialized" "" {
target c++17_down } }
+ constexpr Two (unsigned) : b () {} // { dg-error "a' must be initialized" ""
{ target c++17_down } }
+ constexpr Two (void *) {} // { dg-error "a' must be initialized" "" { target
c++17_down } }
+ // { dg-error "b' must be initialized" "" { target c++17_down } .-1 }
};
Two e ();
diff --git gcc/testsuite/g++.dg/cpp1y/constexpr-83921-3.C
gcc/testsuite/g++.dg/cpp1y/constexpr-83921-3.C
index 4b1ed5c3a87..2f1218693e0 100644
--- gcc/testsuite/g++.dg/cpp1y/constexpr-83921-3.C
+++ gcc/testsuite/g++.dg/cpp1y/constexpr-83921-3.C
@@ -2,4 +2,4 @@
// { dg-do compile { target c++14 } }
struct Foo { int m; };
-constexpr void test() { Foo f; } // { dg-error "uninitialized" }
+constexpr void test() { Foo f; } // { dg-error "uninitialized" "" { target
c++17_down } }
diff --git gcc/testsuite/g++.dg/cpp1y/constexpr-neg1.C
gcc/testsuite/g++.dg/cpp1y/constexpr-neg1.C
index d82dbada1bf..53f0f1f7a2b 100644
--- gcc/testsuite/g++.dg/cpp1y/constexpr-neg1.C
+++ gcc/testsuite/g++.dg/cpp1y/constexpr-neg1.C
@@ -8,7 +8,7 @@ constexpr int f(int i) {
goto foo; // { dg-error "goto" }
foo:
asm("foo"); // { dg-error "asm" "" { target c++17_down } }
- int k; // { dg-error "uninitialized" }
+ int k; // { dg-error "uninitialized" "" { target
c++17_down } }
A a; // { dg-error "non-literal" }
return i;
}
diff --git gcc/testsuite/g++.dg/cpp1z/constexpr-lambda12.C
gcc/testsuite/g++.dg/cpp1z/constexpr-lambda12.C
index a59bf497b30..93b53273741 100644
--- gcc/testsuite/g++.dg/cpp1z/constexpr-lambda12.C
+++ gcc/testsuite/g++.dg/cpp1z/constexpr-lambda12.C
@@ -3,7 +3,7 @@
void f(int i)
{
[i]() constexpr {
- int j; // { dg-error "uninitialized" }
+ int j; // { dg-error "uninitialized" "" { target
c++17_down } }
j = i;
return j;
}();
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
new file mode 100644
index 00000000000..ab7b89da9e8
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
@@ -0,0 +1,99 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+// Test basic use.
+
+struct S {
+ int i;
+ constexpr S(bool b) {
+ if (b)
+ i = 42;
+ }
+};
+constexpr S s1(true);
+constexpr S s2(false); // { dg-error "not a constant expression" }
+
+constexpr int
+fn1 (int x)
+{
+ int a;
+ a = 5;
+ return x + a;
+}
+
+static_assert (fn1 (2) == 7);
+
+constexpr int
+fn2 (int x)
+{
+ const int a; // { dg-error "uninitialized .const a." }
+ constexpr int b; // { dg-error "uninitialized .const b." }
+ return x;
+}
+
+constexpr int
+fn3 (int x)
+{
+ int a; // { dg-message ".int a. is not const" }
+ return x + a; // { dg-error "the value of .a. is not usable in a constant
expression" }
+}
+
+constexpr int a = fn3 (5); // { dg-message "in .constexpr. expansion of" }
+
+constexpr int
+fn4 ()
+{
+ struct S { int a = -5; int b; } s;
+ return s.a;
+}
+
+static_assert (fn4 () == -5);
+
+constexpr int
+fn5 ()
+{
+ struct S { int a = 9; int b; } s;
+ return s.b;
+}
+
+constexpr int b = fn5 (); // { dg-error "accessing uninitialized member" }
+// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
+
+constexpr int
+fn6 ()
+{
+ int a;
+ return 42;
+}
+
+static_assert (fn6 () == 42);
+
+constexpr int
+fn7 (bool b)
+{
+ int a; // { dg-message ".int a. is not const" }
+ if (b)
+ a = 42;
+ return a;
+}
+
+static_assert (fn7 (true) == 42);
+static_assert (fn7 (false) == 42); // { dg-error "non-constant condition|the
value of .a. is not usable" }
+// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
+
+constexpr int
+fn8 (int n)
+{
+ int r;
+ switch (n)
+ {
+ case 1:
+ r = n;
+ return r;
+ case 42:
+ r = n;
+ return r;
+ }
+}
+
+static_assert (fn8 (1) == 1);
+static_assert (fn8 (42) == 42);
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init10.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init10.C
new file mode 100644
index 00000000000..74bf8e6677b
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init10.C
@@ -0,0 +1,11 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+// In c++2a we don't emit a call to _ZN3FooI3ArgEC1Ev.
+
+struct Arg;
+struct Base {
+ int i;
+ virtual ~Base();
+};
+template <class> struct Foo : Base { };
+Foo<Arg> a;
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init11.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init11.C
new file mode 100644
index 00000000000..1c7836a674a
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init11.C
@@ -0,0 +1,16 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct S {
+ int i;
+ constexpr S(int) : i(10) {}
+};
+
+struct W {
+ constexpr W(int) : s(8), p() {}
+
+ S s;
+ int *p;
+};
+
+constexpr auto a = W(42);
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init12.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init12.C
new file mode 100644
index 00000000000..7d3d3729b31
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init12.C
@@ -0,0 +1,16 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct S {
+ int uninit;
+ constexpr S(int) {}
+};
+
+struct W {
+ constexpr W(int) : s(8), p() {}
+
+ S s;
+ int *p;
+};
+
+constexpr auto a = W(42); // { dg-error "not a constant expression" }
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init13.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init13.C
new file mode 100644
index 00000000000..3d4460a0eb8
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init13.C
@@ -0,0 +1,37 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct E { };
+
+struct S {
+ E e;
+ constexpr S() {}
+};
+
+constexpr S s;
+constexpr S s2[4];
+
+struct W {
+ [[no_unique_address]] E e1, e2;
+ constexpr W() {}
+};
+
+constexpr W w;
+constexpr W w2[4];
+
+struct Y {
+ [[no_unique_address]] E e;
+ __extension__ char a[0];
+ constexpr Y() {}
+};
+
+constexpr Y y;
+constexpr Y y2[4];
+
+struct Z {
+ [[no_unique_address]] E e;
+ int i;
+ constexpr Z(int n) :i(n) { }
+};
+
+constexpr Z z(42);
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init14.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init14.C
new file mode 100644
index 00000000000..6ab6abf1505
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init14.C
@@ -0,0 +1,28 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct E {
+ constexpr E() = default;
+ constexpr E(int) {}
+};
+
+struct W {
+ [[no_unique_address]] E e;
+ constexpr W(int) : e(8) {}
+};
+
+constexpr W w = W(42);
+
+struct S {
+ E e;
+ constexpr S() : e{} { }
+};
+
+constexpr S s;
+
+struct S2 {
+ [[no_unique_address]] E e;
+ constexpr S2() : e{} { }
+};
+
+constexpr S2 s2;
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init2.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init2.C
new file mode 100644
index 00000000000..541da1c023f
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init2.C
@@ -0,0 +1,15 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct A
+{
+ int i;
+ constexpr A() : i{} {}
+};
+
+struct B
+{
+ A a;
+};
+
+constexpr B b[] = { {} };
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init3.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init3.C
new file mode 100644
index 00000000000..dd2735289cb
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init3.C
@@ -0,0 +1,16 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct A
+{
+ int i;
+ constexpr A() {}
+};
+
+struct B
+{
+ A a;
+};
+
+// A::i not initialized.
+constexpr B b[] = { {} }; // { dg-error "is not a constant expression" }
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init4.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init4.C
new file mode 100644
index 00000000000..dd614ede2c6
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init4.C
@@ -0,0 +1,61 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+// This bullet in [dcl.constexpr] is now gone:
+// - every non-static data member and base class sub-object shall be
initialized
+
+struct A {
+ int i;
+ constexpr A(int _i) { i = _i; }
+};
+
+struct B {
+ int i;
+ constexpr B() { }
+};
+
+// Anonymous members.
+struct E {
+ int a;
+ union {
+ char b;
+ __extension__ struct {
+ double c;
+ long d;
+ };
+ union {
+ char e;
+ void *f;
+ };
+ };
+ __extension__ struct {
+ long long g;
+ __extension__ struct {
+ int h;
+ double i;
+ };
+ union {
+ char *j;
+ E *k;
+ };
+ };
+
+ // Completely initialized.
+ constexpr E(int(&)[1]) : a(), b(), g(), h(), i(), j() {}
+ constexpr E(int(&)[3]) : a(), e(), g(), h(), i(), k() {}
+ constexpr E(int(&)[7]) : a(), b(), g(), h(), i(), j() {}
+ constexpr E(int(&)[8]) : a(), f(), g(), h(), i(), k() {}
+ constexpr E(int(&)[9]) : a(), c(), d(), g(), h(), i(), k() {}
+
+ // Missing d, i, j/k union init.
+ constexpr E(int(&)[2]) : a(), c(), g(), h() {}
+
+ // Missing h, j/k union init.
+ constexpr E(int(&)[4]) : a(), c(), d(), g(), i() {}
+
+ // Missing b/c/d/e/f union init.
+ constexpr E(int(&)[5]) : a(), g(), h(), i(), k() {}
+
+ // Missing a, b/c/d/e/f union, g/h/i/j/k struct init.
+ constexpr E(int(&)[6]) {}
+};
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init5.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init5.C
new file mode 100644
index 00000000000..0d21f26da0e
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init5.C
@@ -0,0 +1,22 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct S { int i; };
+
+constexpr void
+fn ()
+{
+ S s;
+
+ []() constexpr {
+ int i;
+ }();
+}
+
+constexpr int
+fn2 ()
+{
+ return __extension__ ({ int n; n; }); // { dg-error "not usable in a
constant expression" }
+}
+
+constexpr int i = fn2 (); // { dg-message "in .constexpr. expansion of" }
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init6.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init6.C
new file mode 100644
index 00000000000..a2994f5272c
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init6.C
@@ -0,0 +1,26 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+/* We used to get the "constexpr constructor for union S::<unnamed union>
+ must initialize exactly one non-static data member" error, but not anymore
+ in C++20. */
+
+struct S {
+ union {
+ int i;
+ double d;
+ };
+ constexpr S() { }
+};
+
+union U {
+ int a;
+ constexpr U() { }
+};
+
+struct W {
+ union {
+ int a;
+ };
+ constexpr W() { }
+};
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init7.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init7.C
new file mode 100644
index 00000000000..dd2741efa8c
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init7.C
@@ -0,0 +1,63 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct S {
+ int a = 1;
+ constexpr S() = default;
+};
+
+constexpr S s;
+
+union U {
+ int a = 1;
+ constexpr U() = default;
+};
+
+constexpr U u;
+
+struct S2 {
+ int a;
+ constexpr S2() = default;
+};
+
+constexpr S2 s2; // { dg-error "uninitialized .const s2." }
+
+union U2 {
+ int a;
+ constexpr U2() = default;
+};
+
+constexpr U2 u2; // { dg-error "uninitialized .const u2." }
+
+struct S3 {
+ // FIXME if it's anonymous union, we don't give the error below
+ union {
+ int a;
+ } u;
+ constexpr S3() = default;
+};
+
+constexpr S3 s3; // { dg-error "uninitialized .const s3." }
+
+struct S4 {
+ // FIXME if it's anonymous union, we don't give the error below
+ union {
+ int n;
+ } u;
+ constexpr S4() = default;
+};
+
+constexpr S4 s4; // { dg-error "uninitialized .const s4." }
+
+struct S5 {
+ union {
+ int n = 0;
+ };
+ // FIXME if it's anonymous union, we don't give the error below
+ union {
+ int m;
+ } u;
+ constexpr S5() = default;
+};
+
+constexpr S5 s5; // { dg-error "uninitialized .const s5.|not a constant
expression" }
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init8.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init8.C
new file mode 100644
index 00000000000..0d5a4a79c90
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init8.C
@@ -0,0 +1,15 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct S {
+ constexpr S(int) {}
+};
+
+struct W {
+ constexpr W(int) : s(8), p() {}
+
+ S s;
+ int *p;
+};
+
+constexpr auto a = W(42);
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init9.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init9.C
new file mode 100644
index 00000000000..b44098cc89b
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init9.C
@@ -0,0 +1,17 @@
+// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
+// { dg-do compile { target c++2a } }
+
+struct S {
+ constexpr S(int) {}
+};
+
+struct W {
+ constexpr W(int (&)[8]) : W(8) { }
+ constexpr W(int) : s(8), p() {}
+
+ S s;
+ int *p;
+};
+
+int arr[8];
+constexpr auto a = W(arr);
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-try5.C
gcc/testsuite/g++.dg/cpp2a/constexpr-try5.C
index 47cdce88e36..3b51bf7c901 100644
--- gcc/testsuite/g++.dg/cpp2a/constexpr-try5.C
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-try5.C
@@ -4,13 +4,13 @@
constexpr int foo ()
try { // { dg-warning "function-try-block body of 'constexpr'
function only available with" "" { target c++17_down } }
- int a; // { dg-error "uninitialized variable 'a' in
'constexpr' function" }
+ int a; // { dg-error "uninitialized variable 'a' in
'constexpr' function" "" { target c++17_down } }
static double b = 1.0;// { dg-error "'b' declared 'static' in 'constexpr'
function" }
goto l; // { dg-error "'goto' in 'constexpr' function" }
l:;
return 0;
} catch (...) {
- long int c; // { dg-error "uninitialized variable 'c' in
'constexpr' function" }
+ long int c; // { dg-error "uninitialized variable 'c' in
'constexpr' function" "" { target c++17_down } }
static float d = 2.0f;// { dg-error "'d' declared 'static' in 'constexpr'
function" }
goto l2; // { dg-error "'goto' in 'constexpr' function" }
l2:;
@@ -19,19 +19,19 @@ try { // { dg-warning
"function-try-block body of 'constexpr' function only av
constexpr int bar ()
{
- int a; // { dg-error "uninitialized variable 'a' in
'constexpr' function" }
+ int a; // { dg-error "uninitialized variable 'a' in
'constexpr' function" "" { target c++17_down } }
static long double b = 3.0;// { dg-error "'b' declared 'static' in
'constexpr' function" }
goto l; // { dg-error "'goto' in 'constexpr' function" }
l:;
try { // { dg-warning "'try' in 'constexpr' function
only available with" "" { target c++17_down } }
- short c; // { dg-error "uninitialized variable 'c' in
'constexpr' function" }
+ short c; // { dg-error "uninitialized variable 'c' in
'constexpr' function" "" { target c++17_down } }
static float d; // { dg-error "'d' declared 'static' in 'constexpr'
function" }
- // { dg-error "uninitialized variable 'd' in
'constexpr' function" "" { target *-*-* } .-1 }
+ // { dg-error "uninitialized variable 'd' in
'constexpr' function" "" { target c++17_down } .-1 }
goto l2; // { dg-error "'goto' in 'constexpr' function" }
l2:;
return 0;
} catch (int) {
- char e; // { dg-error "uninitialized variable 'e' in
'constexpr' function" }
+ char e; // { dg-error "uninitialized variable 'e' in
'constexpr' function" "" { target c++17_down } }
static int f = 5; // { dg-error "'f' declared 'static' in 'constexpr'
function" }
goto l3; // { dg-error "'goto' in 'constexpr' function" }
l3:;
diff --git gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C
gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C
index 9b6e2f59d2c..c5c16b6bcc7 100644
--- gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C
+++ gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C
@@ -134,8 +134,8 @@
#ifndef __cpp_constexpr
# error "__cpp_constexpr"
-#elif __cpp_constexpr != 201603
-# error "__cpp_constexpr != 201603"
+#elif __cpp_constexpr != 201907
+# error "__cpp_constexpr != 201907"
#endif
#ifndef __cpp_decltype_auto
diff --git gcc/testsuite/g++.dg/cpp2a/lambda-mangle.C
gcc/testsuite/g++.dg/cpp2a/lambda-mangle.C
new file mode 100644
index 00000000000..8ee9b0327a5
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/lambda-mangle.C
@@ -0,0 +1,15 @@
+// Test lambda mangling
+// { dg-do compile { target c++2a } }
+// { dg-require-weak "" }
+// { dg-options "-fno-inline" }
+
+template<typename T> struct R {
+ static int x;
+};
+// "int i;" makes the op() non-constexpr in C++17. In C++20, it does not.
+template<typename T> int R<T>::x = []{int i; return 1;}();
+template int R<int>::x;
+// Type of lambda in intializer of R<int>::x: N1RIiE1xMUlvE_E
+// Corresponding operator(): _ZNK1RIiE1xMUlvE_clEv
+// { dg-final { scan-assembler-not "_ZNK1RIiE1xMUlvE_clEv" } }
+// { dg-final { scan-assembler-not "weak\[^\n\r\]*_?_ZNK1RIiE1xMUlvE_clEv" } }
diff --git gcc/testsuite/g++.dg/debug/dwarf2/pr44641.C
gcc/testsuite/g++.dg/debug/dwarf2/pr44641.C
index d50df25f693..1139f412fda 100644
--- gcc/testsuite/g++.dg/debug/dwarf2/pr44641.C
+++ gcc/testsuite/g++.dg/debug/dwarf2/pr44641.C
@@ -1,5 +1,5 @@
// Origin: PR 44641
-// { dg-do compile }
+// { dg-do compile { target c++17_down } }
// { dg-options "-gdwarf-2 -O0 -dA" }
template <class A> struct MisplacedDbg;
@@ -40,3 +40,11 @@ struct MisplacedDbg // { dg-function-on-line
{_ZN12MisplacedDbgI3ArgEC[12]Ev} {
static MisplacedDbg<Arg> static_var1;
static MisplacedDbg<Arg*> static_var2;
static MisplacedDbg<Full> static_var3;
+
+// This test is skipped in C++20 because we consider the default constructor
+// MisplacedDbg() constexpr despite the uninitialized member "int i;". So
+// the calls to
+// MisplacedDbg<Arg>::MisplacedDbg()
+// MisplacedDbg<Full>::MisplacedDbg()
+// MisplacedDbg<Arg*>::MisplacedDbg()
+// are elided. (This comment is here not to mess up the line numbers.)
diff --git gcc/testsuite/g++.dg/ext/stmtexpr21.C
gcc/testsuite/g++.dg/ext/stmtexpr21.C
index 259cb2f1913..97052a117a7 100644
--- gcc/testsuite/g++.dg/ext/stmtexpr21.C
+++ gcc/testsuite/g++.dg/ext/stmtexpr21.C
@@ -7,7 +7,7 @@ struct test { const int *addr; };
const test* setup()
{
static constexpr test atest =
- { ({ int inner; (const int*)(0); }) }; // { dg-error "uninitialized" }
+ { ({ int inner; (const int*)(0); }) }; // { dg-error "uninitialized" "" {
target c++17_down } }
return &atest;
}
