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* [gcc/devel/autopar_devel] c++: More P2002 operator<=> refinements.
@ 2020-08-22 22:50 Giuliano Belinassi
0 siblings, 0 replies; only message in thread
From: Giuliano Belinassi @ 2020-08-22 22:50 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:db8a93d61142936da8126078bc3e95fb221e002c
commit db8a93d61142936da8126078bc3e95fb221e002c
Author: Jason Merrill <jason@redhat.com>
Date: Wed Jun 17 16:22:33 2020 -0400
c++: More P2002 operator<=> refinements.
* Disallow && references.
* Allow empty unions.
* Improve diagnostics for a subobject comparison with
non-comparison-category type.
gcc/cp/ChangeLog:
* method.c (early_check_defaulted_comparison): Check for &&.
(build_comparison_op): Allow empty union. Diagnose non-category
type.
(common_comparison_type): Remove handling for non-category type.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/spaceship-ref1.C: New test.
* g++.dg/cpp2a/spaceship-synth-neg4.C: New test.
* g++.dg/cpp2a/spaceship-union1.C: New test.
Diff:
---
gcc/cp/method.c | 49 +++++++++++++++++------
gcc/testsuite/g++.dg/cpp2a/spaceship-ref1.C | 12 ++++++
gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg4.C | 20 +++++++++
gcc/testsuite/g++.dg/cpp2a/spaceship-union1.C | 12 ++++++
4 files changed, 81 insertions(+), 12 deletions(-)
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 1a819b29173..b23764b3d54 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -1134,6 +1134,11 @@ early_check_defaulted_comparison (tree fn)
error_at (loc, "defaulted %qD must be %<const%>", fn);
ok = false;
}
+ if (mem && type_memfn_rqual (TREE_TYPE (fn)) == REF_QUAL_RVALUE)
+ {
+ error_at (loc, "defaulted %qD must not have %<&&%> ref-qualifier", fn);
+ ok = false;
+ }
tree parmnode = FUNCTION_FIRST_USER_PARMTYPE (fn);
bool saw_byval = false;
bool saw_byref = mem;
@@ -1144,6 +1149,7 @@ early_check_defaulted_comparison (tree fn)
if (same_type_p (parmtype, ctx))
saw_byval = true;
else if (TREE_CODE (parmtype) != REFERENCE_TYPE
+ || TYPE_REF_IS_RVALUE (parmtype)
|| TYPE_QUALS (TREE_TYPE (parmtype)) != TYPE_QUAL_CONST
|| !(same_type_ignoring_top_level_qualifiers_p
(TREE_TYPE (parmtype), ctx)))
@@ -1186,11 +1192,9 @@ common_comparison_type (vec<tree> &comps)
tree comp = comps[i];
tree ctype = TREE_TYPE (comp);
comp_cat_tag tag = cat_tag_for (ctype);
- if (tag < cc_last)
- seen[tag] = ctype;
- else
- /* If any Ti is not a comparison category type, U is void. */
- return void_type_node;
+ /* build_comparison_op already checked this. */
+ gcc_checking_assert (tag < cc_last);
+ seen[tag] = ctype;
}
/* Otherwise, if at least one T i is std::partial_ordering, U is
@@ -1312,8 +1316,9 @@ build_comparison_op (tree fndecl, tsubst_flags_t complain)
iloc_sentinel ils (info.loc);
/* A defaulted comparison operator function for class C is defined as
- deleted if ... C is a union-like class. */
- if (TREE_CODE (ctype) == UNION_TYPE)
+ deleted if ... C has variant members. */
+ if (TREE_CODE (ctype) == UNION_TYPE
+ && next_initializable_field (TYPE_FIELDS (ctype)))
{
if (complain & tf_error)
inform (info.loc, "cannot default compare union %qT", ctype);
@@ -1336,6 +1341,7 @@ build_comparison_op (tree fndecl, tsubst_flags_t complain)
if (code == EQ_EXPR || code == SPACESHIP_EXPR)
{
+ bool bad = false;
auto_vec<tree> comps;
/* Compare each of the subobjects. Note that we get bases from
@@ -1348,21 +1354,22 @@ build_comparison_op (tree fndecl, tsubst_flags_t complain)
/* A defaulted comparison operator function for class C is defined as
deleted if any non-static data member of C is of reference type or
- C is a union-like class. */
+ C has variant members. */
if (TREE_CODE (expr_type) == REFERENCE_TYPE)
{
if (complain & tf_error)
inform (DECL_SOURCE_LOCATION (field), "cannot default compare "
"reference member %qD", field);
- DECL_DELETED_FN (fndecl) = true;
+ bad = true;
continue;
}
- else if (ANON_UNION_TYPE_P (expr_type))
+ else if (ANON_UNION_TYPE_P (expr_type)
+ && next_initializable_field (TYPE_FIELDS (expr_type)))
{
if (complain & tf_error)
inform (DECL_SOURCE_LOCATION (field), "cannot default compare "
"anonymous union member");
- DECL_DELETED_FN (fndecl) = true;
+ bad = true;
continue;
}
@@ -1374,7 +1381,19 @@ build_comparison_op (tree fndecl, tsubst_flags_t complain)
NULL_TREE, NULL, complain);
if (comp == error_mark_node)
{
- DECL_DELETED_FN (fndecl) = true;
+ bad = true;
+ continue;
+ }
+ if (code == SPACESHIP_EXPR
+ && cat_tag_for (TREE_TYPE (comp)) == cc_last)
+ {
+ /* The operator function is defined as deleted if ... Ri is not a
+ comparison category type. */
+ if (complain & tf_error)
+ inform (DECL_SOURCE_LOCATION (field),
+ "three-way comparison of %qD has type %qT, not a "
+ "comparison category type", field, TREE_TYPE (comp));
+ bad = true;
continue;
}
comps.safe_push (comp);
@@ -1384,6 +1403,11 @@ build_comparison_op (tree fndecl, tsubst_flags_t complain)
rettype = common_comparison_type (comps);
apply_deduced_return_type (fndecl, rettype);
}
+ if (bad)
+ {
+ DECL_DELETED_FN (fndecl) = true;
+ goto out;
+ }
for (unsigned i = 0; i < comps.length(); ++i)
{
tree comp = comps[i];
@@ -1468,6 +1492,7 @@ build_comparison_op (tree fndecl, tsubst_flags_t complain)
finish_return_stmt (comp2);
}
+ out:
if (info.defining)
finish_compound_stmt (compound_stmt);
else
diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-ref1.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-ref1.C
new file mode 100644
index 00000000000..5f888dfc3b4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-ref1.C
@@ -0,0 +1,12 @@
+// Reject &&.
+// { dg-do compile { target c++20 } }
+
+struct A
+{
+ bool operator==(const A&) const && = default; // { dg-error "ref-qualifier" }
+};
+
+struct B
+{
+ friend bool operator==(const B&&, const B&&) = default; // { dg-error "" }
+};
diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg4.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg4.C
new file mode 100644
index 00000000000..e99aa0a2041
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg4.C
@@ -0,0 +1,20 @@
+// P2002: deleted if a subobject <=> has non-category type.
+// { dg-do compile { target c++20 } }
+
+#include <compare>
+
+struct A
+{
+ bool operator<=>(const A&) const;
+};
+
+struct B
+{
+ A a; // { dg-message "bool" }
+ auto operator<=>(const B&) const = default;
+};
+
+int main()
+{
+ auto x = B() <=> B(); // { dg-error "deleted" }
+}
diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-union1.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-union1.C
new file mode 100644
index 00000000000..a08ba0de69c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-union1.C
@@ -0,0 +1,12 @@
+// P2002: Allow default comparison of unions with no members.
+// { dg-do compile { target c++20 } }
+
+union A
+{
+ bool operator==(const A&) const = default;
+};
+
+int main()
+{
+ A() == A();
+}
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