https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89144
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-02-01
CC| |jakub at gcc dot gnu.org,
| |jason at gcc dot gnu.org,
| |redi at gcc dot gnu.org
Target Milestone|--- |9.0
Summary|GCC emits undefined |[9 Regression] GCC emits
|references when a constexpr |undefined references when a
|initializer_list appears in |constexpr initializer_list
|a template function |appears in a template
| |function
Ever confirmed|0 |1
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
On the trunk this is rejected:
pr89144.C: In function ‘void foo()’:
pr89144.C:6:43: error: ‘std::initializer_list<int>{((const
int*)(&<anonymous>)), 0}’ is not a constant expression
6 | constexpr std::initializer_list <int>c {};
| ^
(but bisection points to r247793, so it is unclear why gcc 8.x doesn't reject
it either). The ._0 undefined references at -O0 appeared already in 4.7.
If constexpr std::initializer_list<int> c{}; doesn't appear in a template, then
older GCC releases compile it fine, with ._0 being actually defined:
.type ._0, @object
.size ._0, 0
._0:
or for say c{1, 2, 3}
.type ._0, @object
.size ._0, 12
._0:
.long 1
.long 2
.long 3
.align 16
.type c.2420, @object
.size c.2420, 16
c.2420:
.quad ._0
.quad 3
But trunk rejects it no matter if it is in a template or not (the (const int
*)&TARGET_EXPR ...) doesn't pass reduced_constant_expression_p).
