[Bug c++/114013] New: [14 Regression] Specializations of var templates no longer emitted since r14-8987

[Bug c++/114013] New: [14 Regression] Specializations of var templates no longer emitted since r14-8987

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114013

            Bug ID: 114013
           Summary: [14 Regression] Specializations of var templates no
                    longer emitted since r14-8987
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
  Target Milestone: ---

struct S { int a, b; };

template <int N>
constexpr struct S var[16] = {};

template <>
constexpr inline struct S var<6>[8] = {
  { 1, 1 }, { 2, 0 }, { 3, 1 }, { 4, 0 },
  { 5, 1 }, { 6, 0 }, { 7, 1 }, { 8, 0 }
};

[[gnu::noipa]] void
foo (S)
{
}

template <int N>
void
bar (int x)
{
  foo (var<N>[x]);
}

volatile int x;

int
main ()
{
  bar <6> (x);
}

extracted from mesa no longer links starting with
r14-8987-gdd9d14f7d53de07beff06004922a2bff20ece671 (-O0 or -O2, doesn't
matter).
/usr/bin/ld: /tmp/cc4Mqq20.o: in function `void bar<6>(int)':
mesa.C:(.text._Z3barILi6EEvi[_Z3barILi6EEvi]+0x14): undefined reference to
`var<6>'
collect2: error: ld returned 1 exit status

[Bug c++/114013] [14 Regression] Specializations of var templates no longer emitted since r14-8987

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114013

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-02-20
   Target Milestone|---                         |14.0
           Priority|P3                          |P1
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |nshead at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW

[Bug c++/114013] [14 Regression] Specializations of var templates no longer emitted since r14-8987

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114013

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
s/16/8/, sorry for the leftover from earlier larger version.

[Bug c++/114013] [14 Regression] Specializations of var templates no longer emitted since r14-8987

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114013

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
And it behaves the same way even if there is
template <int N>
constexpr inline struct S var[8] = {};
instead.

[Bug c++/114013] [14 Regression] Specializations of var templates no longer emitted since r14-8987

[enrico.seiler+gccbugs at outlook dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114013

--- Comment #3 from Enrico Seiler <enrico.seiler+gccbugs at outlook dot com> ---
For -O0 and -O1, this also does not link:

template <int> int value;
template <> inline int value<1>;
void bar(int) { bar(value<1>); }

https://godbolt.org/z/Wxv7PE8ob

[Bug c++/114013] [14 Regression] Specializations of var templates no longer emitted since r14-8987

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114013

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathaniel Shead <nshead@gcc.gnu.org>:

https://gcc.gnu.org/g:615b62aada6cc42759e5c43e196dab6c524925d6

commit r14-9201-g615b62aada6cc42759e5c43e196dab6c524925d6
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Wed Feb 28 11:20:53 2024 +1100

    c++: Revert deferring emission of inline variables [PR114013]

    This is a (partial) reversion of r14-8987-gdd9d14f7d53 to return to
    eagerly emitting inline variables to the middle-end when they are
    declared. 'import_export_decl' will still continue to accept them, as
    allowing this is a pure extension and doesn't seem to cause issues with
    modules, but otherwise deferring the emission of inline variables
    appears to cause issues on some targets and prevents some code using
    inline variable templates from correctly linking.

    There might be a more targetted way to support this, but due to the
    complexity of handling linkage and emission I'd prefer to wait till
    GCC 15 to explore our options.

            PR c++/113970
            PR c++/114013

    gcc/cp/ChangeLog:

            * decl.cc (make_rtl_for_nonlocal_decl): Don't defer inline
            variables.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp1z/inline-var10.C: New test.

    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

[Bug c++/114013] [14 Regression] Specializations of var templates no longer emitted since r14-8987

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114013

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.