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* [Bug c++/102786] New: PMF constant evaluation bug
@ 2021-10-15 18:05 jakub at gcc dot gnu.org
2021-10-15 19:22 ` [Bug c++/102786] " pinskia at gcc dot gnu.org
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-10-15 18:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
Bug ID: 102786
Summary: PMF constant evaluation bug
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
In the following testcase:
// { dg-do compile { target c++20 } }
struct S {
virtual constexpr int foo () const { return 42; }
};
constexpr S s;
constexpr auto a = &S::foo;
constexpr auto b = (s.*a) ();
constexpr auto c = (s.*&S::foo) ();
we correctly accept b's initializer, but reject c's initializer with:
error: value ‘1’ of type ‘int (S::*)() const’ is not a constant expression
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] PMF constant evaluation bug
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
@ 2021-10-15 19:22 ` pinskia at gcc dot gnu.org
2021-10-15 20:32 ` pinskia at gcc dot gnu.org
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-15 19:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This might be a dup.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] PMF constant evaluation bug
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
2021-10-15 19:22 ` [Bug c++/102786] " pinskia at gcc dot gnu.org
@ 2021-10-15 20:32 ` pinskia at gcc dot gnu.org
2021-10-19 7:25 ` [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant cvs-commit at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-10-15 20:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2021-10-15
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
2021-10-15 19:22 ` [Bug c++/102786] " pinskia at gcc dot gnu.org
2021-10-15 20:32 ` pinskia at gcc dot gnu.org
@ 2021-10-19 7:25 ` cvs-commit at gcc dot gnu.org
2021-11-29 8:49 ` cvs-commit at gcc dot gnu.org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-10-19 7:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:f45610a45236e97616726ca042898d6ac46a082e
commit r12-4491-gf45610a45236e97616726ca042898d6ac46a082e
Author: Jakub Jelinek <jakub@redhat.com>
Date: Tue Oct 19 09:24:57 2021 +0200
c++: Don't reject calls through PMF during constant evaluation [PR102786]
The following testcase incorrectly rejects the c initializer,
while in the s.*a case cxx_eval_* sees .__pfn reads etc.,
in the s.*&S::foo case get_member_function_from_ptrfunc creates
expressions which use INTEGER_CSTs with type of pointer to METHOD_TYPE.
And cxx_eval_constant_expression rejects any INTEGER_CSTs with pointer
type if they aren't 0.
Either we'd need to make sure we defer such folding till cp_fold but the
function and pfn_from_ptrmemfunc is used from lots of places, or
the following patch just tries to reject only non-zero INTEGER_CSTs
with pointer types if they don't point to METHOD_TYPE in the hope that
all such INTEGER_CSTs with POINTER_TYPE to METHOD_TYPE are result of
folding valid pointer-to-member function expressions.
I don't immediately see how one could create such INTEGER_CSTs otherwise,
cast of integers to PMF is rejected and would have the PMF RECORD_TYPE
anyway, etc.
2021-10-19 Jakub Jelinek <jakub@redhat.com>
PR c++/102786
* constexpr.c (cxx_eval_constant_expression): Don't reject
INTEGER_CSTs with type POINTER_TYPE to METHOD_TYPE.
* g++.dg/cpp2a/constexpr-virtual19.C: New test.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
` (2 preceding siblings ...)
2021-10-19 7:25 ` [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant cvs-commit at gcc dot gnu.org
@ 2021-11-29 8:49 ` cvs-commit at gcc dot gnu.org
2021-11-29 9:08 ` jakub at gcc dot gnu.org
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-11-29 8:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:62e4f0e8977497e01d2c262a3bd459ab26a5aaca
commit r11-9326-g62e4f0e8977497e01d2c262a3bd459ab26a5aaca
Author: Jakub Jelinek <jakub@redhat.com>
Date: Tue Oct 19 09:24:57 2021 +0200
c++: Don't reject calls through PMF during constant evaluation [PR102786]
The following testcase incorrectly rejects the c initializer,
while in the s.*a case cxx_eval_* sees .__pfn reads etc.,
in the s.*&S::foo case get_member_function_from_ptrfunc creates
expressions which use INTEGER_CSTs with type of pointer to METHOD_TYPE.
And cxx_eval_constant_expression rejects any INTEGER_CSTs with pointer
type if they aren't 0.
Either we'd need to make sure we defer such folding till cp_fold but the
function and pfn_from_ptrmemfunc is used from lots of places, or
the following patch just tries to reject only non-zero INTEGER_CSTs
with pointer types if they don't point to METHOD_TYPE in the hope that
all such INTEGER_CSTs with POINTER_TYPE to METHOD_TYPE are result of
folding valid pointer-to-member function expressions.
I don't immediately see how one could create such INTEGER_CSTs otherwise,
cast of integers to PMF is rejected and would have the PMF RECORD_TYPE
anyway, etc.
2021-10-19 Jakub Jelinek <jakub@redhat.com>
PR c++/102786
* constexpr.c (cxx_eval_constant_expression): Don't reject
INTEGER_CSTs with type POINTER_TYPE to METHOD_TYPE.
* g++.dg/cpp2a/constexpr-virtual19.C: New test.
(cherry picked from commit f45610a45236e97616726ca042898d6ac46a082e)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
` (3 preceding siblings ...)
2021-11-29 8:49 ` cvs-commit at gcc dot gnu.org
@ 2021-11-29 9:08 ` jakub at gcc dot gnu.org
2022-05-10 8:21 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-11-29 9:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
` (4 preceding siblings ...)
2021-11-29 9:08 ` jakub at gcc dot gnu.org
@ 2022-05-10 8:21 ` cvs-commit at gcc dot gnu.org
2022-05-11 6:22 ` cvs-commit at gcc dot gnu.org
2022-10-28 23:28 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-05-10 8:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:536b03642ad1a32100f71d414e6bd6dc54fc208a
commit r10-10650-g536b03642ad1a32100f71d414e6bd6dc54fc208a
Author: Jakub Jelinek <jakub@redhat.com>
Date: Tue Oct 19 09:24:57 2021 +0200
c++: Don't reject calls through PMF during constant evaluation [PR102786]
The following testcase incorrectly rejects the c initializer,
while in the s.*a case cxx_eval_* sees .__pfn reads etc.,
in the s.*&S::foo case get_member_function_from_ptrfunc creates
expressions which use INTEGER_CSTs with type of pointer to METHOD_TYPE.
And cxx_eval_constant_expression rejects any INTEGER_CSTs with pointer
type if they aren't 0.
Either we'd need to make sure we defer such folding till cp_fold but the
function and pfn_from_ptrmemfunc is used from lots of places, or
the following patch just tries to reject only non-zero INTEGER_CSTs
with pointer types if they don't point to METHOD_TYPE in the hope that
all such INTEGER_CSTs with POINTER_TYPE to METHOD_TYPE are result of
folding valid pointer-to-member function expressions.
I don't immediately see how one could create such INTEGER_CSTs otherwise,
cast of integers to PMF is rejected and would have the PMF RECORD_TYPE
anyway, etc.
2021-10-19 Jakub Jelinek <jakub@redhat.com>
PR c++/102786
* constexpr.c (cxx_eval_constant_expression): Don't reject
INTEGER_CSTs with type POINTER_TYPE to METHOD_TYPE.
* g++.dg/cpp2a/constexpr-virtual19.C: New test.
(cherry picked from commit f45610a45236e97616726ca042898d6ac46a082e)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
` (5 preceding siblings ...)
2022-05-10 8:21 ` cvs-commit at gcc dot gnu.org
@ 2022-05-11 6:22 ` cvs-commit at gcc dot gnu.org
2022-10-28 23:28 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-05-11 6:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:662de049d63759b731bed62f9df60edb47120658
commit r9-10106-g662de049d63759b731bed62f9df60edb47120658
Author: Jakub Jelinek <jakub@redhat.com>
Date: Tue Oct 19 09:24:57 2021 +0200
c++: Don't reject calls through PMF during constant evaluation [PR102786]
The following testcase incorrectly rejects the c initializer,
while in the s.*a case cxx_eval_* sees .__pfn reads etc.,
in the s.*&S::foo case get_member_function_from_ptrfunc creates
expressions which use INTEGER_CSTs with type of pointer to METHOD_TYPE.
And cxx_eval_constant_expression rejects any INTEGER_CSTs with pointer
type if they aren't 0.
Either we'd need to make sure we defer such folding till cp_fold but the
function and pfn_from_ptrmemfunc is used from lots of places, or
the following patch just tries to reject only non-zero INTEGER_CSTs
with pointer types if they don't point to METHOD_TYPE in the hope that
all such INTEGER_CSTs with POINTER_TYPE to METHOD_TYPE are result of
folding valid pointer-to-member function expressions.
I don't immediately see how one could create such INTEGER_CSTs otherwise,
cast of integers to PMF is rejected and would have the PMF RECORD_TYPE
anyway, etc.
2021-10-19 Jakub Jelinek <jakub@redhat.com>
PR c++/102786
* constexpr.c (cxx_eval_constant_expression): Don't reject
INTEGER_CSTs with type POINTER_TYPE to METHOD_TYPE.
* g++.dg/cpp2a/constexpr-virtual19.C: New test.
(cherry picked from commit f45610a45236e97616726ca042898d6ac46a082e)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant
2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
` (6 preceding siblings ...)
2022-05-11 6:22 ` cvs-commit at gcc dot gnu.org
@ 2022-10-28 23:28 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-10-28 23:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102786
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to work| |10.4.0, 12.1.0, 9.5.0
Target Milestone|--- |9.5
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2022-10-28 23:28 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
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2021-10-15 18:05 [Bug c++/102786] New: PMF constant evaluation bug jakub at gcc dot gnu.org
2021-10-15 19:22 ` [Bug c++/102786] " pinskia at gcc dot gnu.org
2021-10-15 20:32 ` pinskia at gcc dot gnu.org
2021-10-19 7:25 ` [Bug c++/102786] [c++20] virtual pmf sometimes rejected as not a constant cvs-commit at gcc dot gnu.org
2021-11-29 8:49 ` cvs-commit at gcc dot gnu.org
2021-11-29 9:08 ` jakub at gcc dot gnu.org
2022-05-10 8:21 ` cvs-commit at gcc dot gnu.org
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