On Wed, Sep 29, 2021 at 02:14:36PM -0400, Jason Merrill wrote:
> On 9/28/21 16:34, Jakub Jelinek wrote:
> > On Tue, Sep 28, 2021 at 03:33:35PM -0400, Jason Merrill wrote:
> > > > > According to the function comment for defaulted_late_check, won't
> > > > > COMPLETE_TYPE_P (ctx) always be false here?
> > >
> > > Not for a function defaulted outside the class.
> > >
> > > > If so, I wonder if we could get away with moving this entire fragment
> > > > from defaulted_late_check to finish_struct_1 instead of calling
> > > > defaulted_late_check from finish_struct_1.
> > >
> > > The comment in check_bases_and_members says that we call it there so that
> > > it's before we clone [cd]tors. Probably better to leave the call there
> > > for
> > > other functions, just skip it for comparisons.
> >
> > So like this instead then? Just tested with dg.exp=*spaceship* so far.
>
> I was thinking to keep the checking/synthesis in defaulted_late_check, just
> change when it's called.
>
> That is, not to change defaulted_late_check at all, to keep the
> finish_struct_1 change you had in your first patch, and to change
> check_bases_and_members to not call defaulted_late_check for comparisons.
>
> We probably also want to assert COMPLETE_TYPE_P in build_comparison_op, at
> least when info.defining.
I've tried that, but the assertion in build_comparison_op ICEs on
spaceship-synth8.C testcase:
#0 fancy_abort (file=0x2d75b3c "../../gcc/cp/method.c", line=1387,
function=0x2d761c3 "build_comparison_op") at ../../gcc/diagnostic.c:1982
#1 0x0000000000c8dad0 in build_comparison_op (fndecl=<function_decl
0x7fffea195600 operator<=>>, complain=0) at ../../gcc/cp/method.c:1387
#2 0x0000000000c8fa7c in synthesize_method (fndecl=<function_decl
0x7fffea195600 operator<=>>) at ../../gcc/cp/method.c:1780
#3 0x0000000000e0ac55 in maybe_instantiate_noexcept (fn=<function_decl
0x7fffea195600 operator<=>>, complain=3) at ../../gcc/cp/pt.c:25769
#4 0x0000000000e33672 in maybe_check_overriding_exception_spec
(overrider=<function_decl 0x7fffea195600 operator<=>>, basefn=<function_decl
0x7fffea195500 operator<=>>)
at ../../gcc/cp/search.c:1897
#5 0x0000000000e33f5e in check_final_overrider (overrider=<function_decl
0x7fffea195600 operator<=>>, basefn=<function_decl 0x7fffea195500 operator<=>>)
at ../../gcc/cp/search.c:2015
#6 0x0000000000e35365 in look_for_overrides_r (type=<record_type
0x7fffea191dc8 D>, fndecl=<function_decl 0x7fffea195600 operator<=>>) at
../../gcc/cp/search.c:2183
#7 0x0000000000e34e60 in look_for_overrides (type=<record_type 0x7fffea191d20
E>, fndecl=<function_decl 0x7fffea195600 operator<=>>) at
../../gcc/cp/search.c:2127
#8 0x0000000000afc3ba in check_for_override (decl=<function_decl
0x7fffea195600 operator<=>>, ctype=<record_type 0x7fffea191d20 E>) at
../../gcc/cp/class.c:2934
#9 0x0000000000b047c2 in check_methods (t=<record_type 0x7fffea191d20 E>) at
../../gcc/cp/class.c:4720
#10 0x0000000000b0d25c in check_bases_and_members (t=<record_type
0x7fffea191d20 E>) at ../../gcc/cp/class.c:5990
#11 0x0000000000b141de in finish_struct_1 (t=<record_type 0x7fffea191d20 E>) at
../../gcc/cp/class.c:7373
#12 0x0000000000b15f16 in finish_struct (t=<record_type 0x7fffea191d20 E>,
attributes=<tree 0x0>) at ../../gcc/cp/class.c:7676
Do you think there is any hope to defer even that, or is that something
that has to be done before layout_class_type?
--- gcc/cp/method.c.jj 2021-09-29 10:07:28.791062239 +0200
+++ gcc/cp/method.c 2021-09-29 20:24:14.229131851 +0200
@@ -1384,6 +1384,7 @@ build_comparison_op (tree fndecl, tsubst
lhs = convert_from_reference (lhs);
rhs = convert_from_reference (rhs);
tree ctype = TYPE_MAIN_VARIANT (TREE_TYPE (lhs));
+ gcc_assert (COMPLETE_TYPE_P (ctype));
iloc_sentinel ils (info.loc);
--- gcc/cp/class.c.jj 2021-09-29 10:07:28.745062879 +0200
+++ gcc/cp/class.c 2021-09-29 20:23:13.117984089 +0200
@@ -6133,7 +6133,8 @@ check_bases_and_members (tree t)
no longer ill-formed, it is defined as deleted instead. */
DECL_DELETED_FN (fn) = true;
}
- defaulted_late_check (fn);
+ if (special_function_p (fn) != sfk_comparison)
+ defaulted_late_check (fn);
}
if (LAMBDA_TYPE_P (t))
@@ -7467,7 +7468,14 @@ finish_struct_1 (tree t)
for any static member objects of the type we're working on. */
for (x = TYPE_FIELDS (t); x; x = DECL_CHAIN (x))
if (DECL_DECLARES_FUNCTION_P (x))
- DECL_IN_AGGR_P (x) = false;
+ {
+ /* Synthetize constexpr defaulted comparisons. */
+ if (!DECL_ARTIFICIAL (x)
+ && DECL_DEFAULTED_IN_CLASS_P (x)
+ && special_function_p (x) == sfk_comparison)
+ defaulted_late_check (x);
+ DECL_IN_AGGR_P (x) = false;
+ }
else if (VAR_P (x) && TREE_STATIC (x)
&& TREE_TYPE (x) != error_mark_node
&& same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (x)), t))
--- gcc/testsuite/g++.dg/cpp2a/spaceship-eq11.C.jj 2021-09-29
20:21:49.861145165 +0200
+++ gcc/testsuite/g++.dg/cpp2a/spaceship-eq11.C 2021-09-29 20:21:49.861145165
+0200
@@ -0,0 +1,43 @@
+// PR c++/102490
+// { dg-do run { target c++20 } }
+
+struct A
+{
+ unsigned char a : 1;
+ unsigned char b : 1;
+ constexpr bool operator== (const A &) const = default;
+};
+
+struct B
+{
+ unsigned char a : 8;
+ int : 0;
+ unsigned char b : 7;
+ constexpr bool operator== (const B &) const = default;
+};
+
+struct C
+{
+ unsigned char a : 3;
+ unsigned char b : 1;
+ constexpr bool operator== (const C &) const = default;
+};
+
+void
+foo (C &x, int y)
+{
+ x.b = y;
+}
+
+int
+main ()
+{
+ A a{}, b{};
+ B c{}, d{};
+ C e{}, f{};
+ a.b = 1;
+ d.b = 1;
+ foo (e, 0);
+ foo (f, 1);
+ return a == b || c == d || e == f;
+}
--- gcc/testsuite/g++.dg/cpp2a/spaceship-eq12.C.jj 2021-09-29
20:21:49.861145165 +0200
+++ gcc/testsuite/g++.dg/cpp2a/spaceship-eq12.C 2021-09-29 20:21:49.861145165
+0200
@@ -0,0 +1,5 @@
+// PR c++/102490
+// { dg-do run { target c++20 } }
+// { dg-options "-O2" }
+
+#include "spaceship-eq11.C"
Jakub
