[ Working virtually on Baker Island. ]
This patch implements C++20 P1331, allowing trivial default initialization in
constexpr contexts.
I used Jakub's patch from the PR which allowed uninitialized variables in
constexpr contexts. But the hard part was handling CONSTRUCTOR_NO_CLEARING
which is always cleared in cxx_eval_call_expression. We need to set it in
the case a constexpr constructor doesn't initialize all the members, so that
we can give proper diagnostic instead of value-initializing. A lot of my
attempts flopped but then I came up with this approach, which handles various
cases as tested in constexpr-init8.C, where S is initialized by a non-default
constexpr constructor, and constexpr-init9.C, using delegating constructors.
And the best part is that I didn't need any new cx_check_missing_mem_inits
calls! Just save the information whether a constructor is missing an init
into constexpr_fundef_table and retrieve it when needed.
constexpr-init10.C demonstrates that we can now elide a constructor call,
this is caused by the walk_field_subobs hunk. I hope that's OK.
(No attempts to fix DR 2256 were made.)
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2019-11-16 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 (constexpr_fundef): Add a bool member.
(retrieve_constexpr_fundef): Initialize it.
(cx_check_missing_mem_inits): New pointer-to-bool parameter, with a
default value NULL. Allow missing field initializers in C++20.
(register_constexpr_fundef): Adjust a call to
cx_check_missing_mem_inits. Set missing_init.
(cxx_eval_call_expression): Set CONSTRUCTOR_NO_CLEARING on a constexpr
constructor that doesn't initialize all the members.
* decl.c (check_for_uninitialized_const_var): Permit trivial default
initialization in constexpr.
* 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-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 76d1e4a380e..9766d7f96c4 100644
--- gcc/c-family/c-cppbuiltin.c
+++ gcc/c-family/c-cppbuiltin.c
@@ -972,7 +972,8 @@ 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");
@@ -991,6 +992,7 @@ c_cpp_builtins (cpp_reader *pfile)
{
/* Set feature test macros for C++2a. */
cpp_define (pfile, "__cpp_conditional_explicit=201806L");
+ cpp_define (pfile, "__cpp_constexpr=201907L");
cpp_define (pfile, "__cpp_constinit=201907L");
cpp_define (pfile, "__cpp_nontype_template_parameter_class=201806L");
cpp_define (pfile, "__cpp_impl_destroying_delete=201806L");
diff --git gcc/cp/class.c gcc/cp/class.c
index ef1d5136963..1fd5a7864e5 100644
--- gcc/cp/class.c
+++ gcc/cp/class.c
@@ -5234,8 +5234,14 @@ 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 8c79b0484fc..2161aa62d44 100644
--- gcc/cp/constexpr.c
+++ gcc/cp/constexpr.c
@@ -142,6 +142,7 @@ struct GTY((for_user)) constexpr_fundef {
tree body;
tree parms;
tree result;
+ bool missing_init;
};
struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef>
@@ -182,7 +183,7 @@ retrieve_constexpr_fundef (tree fun)
if (constexpr_fundef_table == NULL)
return NULL;
- constexpr_fundef fundef = { fun, NULL, NULL, NULL };
+ constexpr_fundef fundef = { fun, NULL, NULL, NULL, false };
return constexpr_fundef_table->find (&fundef);
}
@@ -762,10 +763,13 @@ massage_constexpr_body (tree fun, tree body)
}
/* CTYPE is a type constructed from BODY. Return true if some
- bases/fields are uninitialized, and complain if COMPLAIN. */
+ bases/fields are uninitialized, and complain if COMPLAIN.
+ In C++20, we allow missing field initializers. In such a case
+ record that in MISSING_INIT, if non-null. */
static bool
-cx_check_missing_mem_inits (tree ctype, tree body, bool complain)
+cx_check_missing_mem_inits (tree ctype, tree body, bool complain,
+ bool *missing_init = NULL)
{
unsigned nelts = 0;
@@ -779,7 +783,9 @@ 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))
{
if (complain)
error ("%<constexpr%> constructor for union %qT must "
@@ -815,13 +821,19 @@ 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);
+ (TREE_TYPE (field), NULL_TREE, complain, missing_init);
if (bad && !complain)
return true;
continue;
}
+ if (cxx_dialect >= cxx2a)
+ {
+ if (missing_init)
+ *missing_init = true;
+ continue;
+ }
ftype = strip_array_types (TREE_TYPE (field));
if (type_has_constexpr_default_constructor (ftype))
{
@@ -847,7 +859,8 @@ cx_check_missing_mem_inits (tree ctype, tree body, bool
complain)
{
/* Check the anonymous aggregate initializer is valid. */
bad |= cx_check_missing_mem_inits
- (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain);
+ (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain,
+ missing_init);
if (bad && !complain)
return true;
}
@@ -888,9 +901,11 @@ register_constexpr_fundef (tree fun, tree body)
return NULL;
}
+ bool missing_init = false;
if (DECL_CONSTRUCTOR_P (fun)
&& cx_check_missing_mem_inits (DECL_CONTEXT (fun),
- massaged, !DECL_GENERATED_P (fun)))
+ massaged, !DECL_GENERATED_P (fun),
+ &missing_init))
return NULL;
/* Create the constexpr function table if necessary. */
@@ -908,6 +923,7 @@ register_constexpr_fundef (tree fun, tree body)
DECL_CONTEXT (DECL_RESULT (fun)) = fun;
}
entry.body = copy_fn (fun, entry.parms, entry.result);
+ entry.missing_init = missing_init;
current_function_decl = saved_fn;
slot = constexpr_fundef_table->find_slot (&entry, INSERT);
if (clear_ctx)
@@ -2149,9 +2165,24 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree
t,
entry->result = result;
}
- /* The result of a constexpr function must be completely initialized. */
+ /* The result of a constexpr function must be completely initialized.
+ Except in C++20 where a constexpr constructor doesn't necessarily
+ have to initialize all the fields, so we set CONSTRUCTOR_NO_CLEARING
+ in order to detect reading an unitialized object in constexpr instead
+ of value-initializing it. */
if (TREE_CODE (result) == CONSTRUCTOR)
- clear_no_implicit_zero (result);
+ {
+ /* But do clear the flag in nested constructors. */
+ clear_no_implicit_zero (result);
+ if (cxx_dialect >= cxx2a
+ && DECL_CONSTRUCTOR_P (fun)
+ && DECL_DECLARED_CONSTEXPR_P (fun))
+ {
+ constexpr_fundef *f = retrieve_constexpr_fundef (fun);
+ if (f && f->missing_init)
+ CONSTRUCTOR_NO_CLEARING (result) = true;
+ }
+ }
pop_cx_call_context ();
return result;
diff --git gcc/cp/decl.c gcc/cp/decl.c
index 86e38f4af69..ab6da6080a5 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))
{
diff --git gcc/cp/method.c gcc/cp/method.c
index acba6c6da8c..39782970716 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/cpp1z/feat-cxx1z.C
gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C
index a18d6aea985..aee1d692a4e 100644
--- gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C
+++ gcc/testsuite/g++.dg/cpp1z/feat-cxx1z.C
@@ -1,5 +1,4 @@
-// { dg-do compile { target c++17 } }
-// { dg-options "-I${srcdir}/g++.dg/cpp1y -I${srcdir}/g++.dg/cpp1y/testinc" }
+// { dg-options "-std=c++17 -I${srcdir}/g++.dg/cpp1y
-I${srcdir}/g++.dg/cpp1y/testinc" }
// C++98 features:
diff --git gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
new file mode 100644
index 00000000000..b2248006c03
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
@@ -0,0 +1,100 @@
+// 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;
+}
+
+constexpr int a = fn3 (5); // { dg-error "the value of .a. is not usable in a
constant expression" }
+// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
+
+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..0d7b724a040
--- /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-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..5c2b545086c
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-init5.C
@@ -0,0 +1,23 @@
+// 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; });
+}
+
+constexpr int i = fn2 (); // { dg-error "not usable in a constant expression" }
+// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
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 95251c2f5c6..7b96b76a3f3 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;
}
