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* [Bug c++/83476] [8/9/10/11 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
@ 2021-04-13 20:04 ` ppalka at gcc dot gnu.org
  2021-04-13 20:04 ` ppalka at gcc dot gnu.org
                   ` (9 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-04-13 20:04 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
      Known to work|                            |4.8.1
            Summary|Template argument deduction |[8/9/10/11 Regression]
                   |fails with reference        |Template argument deduction
                   |template parameter          |fails with reference
                   |                            |template parameter
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org
      Known to fail|                            |10.3.0, 11.0, 8.4.0, 9.3.0
   Last reconfirmed|                            |2021-04-13
     Ever confirmed|0                           |1
   Target Milestone|---                         |8.5
             Blocks|                            |99885

--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed.  C++98 testcase (essentially equivalent to comment #2, but without
brace initialization) which exhibits a regression starting with r0-128511
(4.9.0):

template <int& V> struct A {};
template <int& V> void f(A<V>);
int n;
int main() {
  A<n> a;
  f(a);
}

GCC 4.8 compiles the testcase successfully.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99885
[Bug 99885] CTAD fails for auto const& NTTP

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [8/9/10/11 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
  2021-04-13 20:04 ` [Bug c++/83476] [8/9/10/11 Regression] Template argument deduction fails with reference template parameter ppalka at gcc dot gnu.org
@ 2021-04-13 20:04 ` ppalka at gcc dot gnu.org
  2021-04-14 12:55 ` cvs-commit at gcc dot gnu.org
                   ` (8 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-04-13 20:04 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
I am testing:

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index c2b581c0f82..0a7397b742f 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -21898,8 +21898,10 @@ static bool uses_deducible_template_parms (tree type);
 static bool
 deducible_expression (tree expr)
 {
-  /* Strip implicit conversions.  */
-  while (CONVERT_EXPR_P (expr) || TREE_CODE (expr) == VIEW_CONVERT_EXPR)
+  /* Strip implicit conversions and implicit INDIRECT_REFs.  */
+  while (CONVERT_EXPR_P (expr)
+        || TREE_CODE (expr) == VIEW_CONVERT_EXPR
+        || REFERENCE_REF_P (expr))
     expr = TREE_OPERAND (expr, 0);
   return (TREE_CODE (expr) == TEMPLATE_PARM_INDEX);
 }

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [8/9/10/11 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
  2021-04-13 20:04 ` [Bug c++/83476] [8/9/10/11 Regression] Template argument deduction fails with reference template parameter ppalka at gcc dot gnu.org
  2021-04-13 20:04 ` ppalka at gcc dot gnu.org
@ 2021-04-14 12:55 ` cvs-commit at gcc dot gnu.org
  2021-04-14 15:51 ` [Bug c++/83476] [8/9/10 " ppalka at gcc dot gnu.org
                   ` (7 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-04-14 12:55 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:2ccc05a5141506fde0e20dec702c717fd67bf6ee

commit r11-8175-g2ccc05a5141506fde0e20dec702c717fd67bf6ee
Author: Patrick Palka <ppalka@redhat.com>
Date:   Wed Apr 14 08:54:30 2021 -0400

    c++: Fix deduction with reference NTTP [PR83476]

    In the testcase ref11.C below, during deduction for the call f(a),
    uses_deducible_template_parms returns false for the dependent
    specialization A<V> because the generic template argument V here is
    wrapped in an implicit INDIRECT_REF (formed from template_parm_to_arg).
    Since uses_deducible_template_parms returns false, unify_one_argument
    exits early without ever attempting to deduce 'n' for 'V'.  This patch
    fixes this by making deducible_expression look through such implicit
    INDIRECT_REFs.

    gcc/cp/ChangeLog:

            PR c++/83476
            PR c++/99885
            * pt.c (deducible_expression): Look through implicit
            INDIRECT_REFs as well.

    gcc/testsuite/ChangeLog:

            PR c++/83476
            PR c++/99885
            * g++.dg/cpp1z/class-deduction85.C: New test.
            * g++.dg/template/ref11.C: New test.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [8/9/10 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (2 preceding siblings ...)
  2021-04-14 12:55 ` cvs-commit at gcc dot gnu.org
@ 2021-04-14 15:51 ` ppalka at gcc dot gnu.org
  2021-04-20 16:09 ` cvs-commit at gcc dot gnu.org
                   ` (6 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-04-14 15:51 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[8/9/10/11 Regression]      |[8/9/10 Regression]
                   |Template argument deduction |Template argument deduction
                   |fails with reference        |fails with reference
                   |template parameter          |template parameter

--- Comment #5 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 11 so far.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [8/9/10 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (3 preceding siblings ...)
  2021-04-14 15:51 ` [Bug c++/83476] [8/9/10 " ppalka at gcc dot gnu.org
@ 2021-04-20 16:09 ` cvs-commit at gcc dot gnu.org
  2021-04-30  7:43 ` [Bug c++/83476] [8/9 " rguenth at gcc dot gnu.org
                   ` (5 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-04-20 16:09 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:904cbf6ae2a1e45b3a272365cca19f9dd9a27fa2

commit r10-9733-g904cbf6ae2a1e45b3a272365cca19f9dd9a27fa2
Author: Patrick Palka <ppalka@redhat.com>
Date:   Tue Apr 20 12:06:24 2021 -0400

    c++: Fix deduction with reference NTTP [PR83476]

    In the testcase ref11.C below, during deduction for the call f(a),
    uses_deducible_template_parms returns false for the dependent
    specialization A<V> because the generic template argument V here is
    wrapped in an implicit INDIRECT_REF (formed from template_parm_to_arg).
    Since uses_deducible_template_parms returns false, unify_one_argument
    exits early without ever attempting to deduce 'n' for 'V'.  This patch
    fixes this by making deducible_expression look through such implicit
    INDIRECT_REFs.

    gcc/cp/ChangeLog:

            PR c++/83476
            PR c++/99885
            * pt.c (deducible_expression): Look through implicit
            INDIRECT_REFs as well.

    gcc/testsuite/ChangeLog:

            PR c++/83476
            PR c++/99885
            * g++.dg/cpp1z/class-deduction85.C: New test.
            * g++.dg/template/ref11.C: New test.

    (cherry picked from commit 2ccc05a5141506fde0e20dec702c717fd67bf6ee)

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [8/9 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (4 preceding siblings ...)
  2021-04-20 16:09 ` cvs-commit at gcc dot gnu.org
@ 2021-04-30  7:43 ` rguenth at gcc dot gnu.org
  2021-05-14  9:49 ` [Bug c++/83476] [9 " jakub at gcc dot gnu.org
                   ` (4 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-04-30  7:43 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [9 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (5 preceding siblings ...)
  2021-04-30  7:43 ` [Bug c++/83476] [8/9 " rguenth at gcc dot gnu.org
@ 2021-05-14  9:49 ` jakub at gcc dot gnu.org
  2021-06-01  8:09 ` rguenth at gcc dot gnu.org
                   ` (3 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-05-14  9:49 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|8.5                         |9.4

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 8 branch is being closed.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [9 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (6 preceding siblings ...)
  2021-05-14  9:49 ` [Bug c++/83476] [9 " jakub at gcc dot gnu.org
@ 2021-06-01  8:09 ` rguenth at gcc dot gnu.org
  2021-12-08 19:03 ` pinskia at gcc dot gnu.org
                   ` (2 subsequent siblings)
  10 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-06-01  8:09 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|9.4                         |9.5

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9.4 is being released, retargeting bugs to GCC 9.5.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [9 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (7 preceding siblings ...)
  2021-06-01  8:09 ` rguenth at gcc dot gnu.org
@ 2021-12-08 19:03 ` pinskia at gcc dot gnu.org
  2022-05-11 14:59 ` cvs-commit at gcc dot gnu.org
  2022-05-11 15:01 ` ppalka at gcc dot gnu.org
  10 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-08 19:03 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |vittorio.romeo at outlook dot com

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 80651 has been marked as a duplicate of this bug. ***

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [9 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (8 preceding siblings ...)
  2021-12-08 19:03 ` pinskia at gcc dot gnu.org
@ 2022-05-11 14:59 ` cvs-commit at gcc dot gnu.org
  2022-05-11 15:01 ` ppalka at gcc dot gnu.org
  10 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-05-11 14:59 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:c6432e17960799509c48df6b500a8d069110980b

commit r9-10154-gc6432e17960799509c48df6b500a8d069110980b
Author: Patrick Palka <ppalka@redhat.com>
Date:   Wed Apr 14 08:54:30 2021 -0400

    c++: Fix deduction with reference NTTP [PR83476]

    In the testcase ref11.C below, during deduction for the call f(a),
    uses_deducible_template_parms returns false for the dependent
    specialization A<V> because the generic template argument V here is
    wrapped in an implicit INDIRECT_REF (formed from template_parm_to_arg).
    Since uses_deducible_template_parms returns false, unify_one_argument
    exits early without ever attempting to deduce 'n' for 'V'.  This patch
    fixes this by making deducible_expression look through such implicit
    INDIRECT_REFs.

    gcc/cp/ChangeLog:

            PR c++/83476
            PR c++/99885
            * pt.c (deducible_expression): Look through implicit
            INDIRECT_REFs as well.

    gcc/testsuite/ChangeLog:

            PR c++/83476
            PR c++/99885
            * g++.dg/cpp1z/class-deduction85.C: New test.
            * g++.dg/template/ref11.C: New test.

    (cherry picked from commit 2ccc05a5141506fde0e20dec702c717fd67bf6ee)

^ permalink raw reply	[flat|nested] 11+ messages in thread

* [Bug c++/83476] [9 Regression] Template argument deduction fails with reference template parameter
       [not found] <bug-83476-4@http.gcc.gnu.org/bugzilla/>
                   ` (9 preceding siblings ...)
  2022-05-11 14:59 ` cvs-commit at gcc dot gnu.org
@ 2022-05-11 15:01 ` ppalka at gcc dot gnu.org
  10 siblings, 0 replies; 11+ messages in thread
From: ppalka at gcc dot gnu.org @ 2022-05-11 15:01 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83476

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #11 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Should be fixed for 9.5, 10.4, and 11/12.

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2022-05-11 15:01 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
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2021-04-13 20:04 ` [Bug c++/83476] [8/9/10/11 Regression] Template argument deduction fails with reference template parameter ppalka at gcc dot gnu.org
2021-04-13 20:04 ` ppalka at gcc dot gnu.org
2021-04-14 12:55 ` cvs-commit at gcc dot gnu.org
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2021-05-14  9:49 ` [Bug c++/83476] [9 " jakub at gcc dot gnu.org
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