https://gcc.gnu.org/g:9694bb129c0dbf54138d94caa28d692842fdc233
commit r16-652-g9694bb129c0dbf54138d94caa28d692842fdc233
Author: Jason Merrill <ja...@redhat.com>
Date: Fri May 9 19:13:49 2025 -0400
c++: -fimplicit-constexpr and modules
Import didn't like differences in DECL_DECLARED_CONSTEXPR_P due to implicit
constexpr, breaking several g++.dg/modules tests; we should handle that
along with DECL_MAYBE_DELETED. For which we need to stream the bit.
gcc/cp/ChangeLog:
* module.cc (trees_out::lang_decl_bools): Stream implicit_constexpr.
(trees_in::lang_decl_bools): Likewise.
(trees_in::is_matching_decl): Check it.
Diff:
---
gcc/cp/module.cc | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index e7782627a492..4f9c3788380a 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -6024,7 +6024,7 @@ trees_out::lang_decl_bools (tree t, bits_out& bits)
WB (lang->u.fn.has_dependent_explicit_spec_p);
WB (lang->u.fn.immediate_fn_p);
WB (lang->u.fn.maybe_deleted);
- /* We do not stream lang->u.fn.implicit_constexpr. */
+ WB (lang->u.fn.implicit_constexpr);
WB (lang->u.fn.escalated_p);
WB (lang->u.fn.xobj_func);
goto lds_min;
@@ -6095,7 +6095,7 @@ trees_in::lang_decl_bools (tree t, bits_in& bits)
RB (lang->u.fn.has_dependent_explicit_spec_p);
RB (lang->u.fn.immediate_fn_p);
RB (lang->u.fn.maybe_deleted);
- /* We do not stream lang->u.fn.implicit_constexpr. */
+ RB (lang->u.fn.implicit_constexpr);
RB (lang->u.fn.escalated_p);
RB (lang->u.fn.xobj_func);
goto lds_min;
@@ -12193,13 +12193,23 @@ trees_in::is_matching_decl (tree existing, tree decl,
bool is_typedef)
/* Similarly if EXISTING has undeduced constexpr, but DECL's
is already deduced. */
- if (DECL_MAYBE_DELETED (e_inner) && !DECL_MAYBE_DELETED (d_inner)
- && DECL_DECLARED_CONSTEXPR_P (d_inner))
- DECL_DECLARED_CONSTEXPR_P (e_inner) = true;
- else if (!DECL_MAYBE_DELETED (e_inner) && DECL_MAYBE_DELETED (d_inner))
- /* Nothing to do. */;
+ if (DECL_DECLARED_CONSTEXPR_P (e_inner)
+ == DECL_DECLARED_CONSTEXPR_P (d_inner))
+ /* Already matches. */;
+ else if (DECL_DECLARED_CONSTEXPR_P (d_inner)
+ && (DECL_MAYBE_DELETED (e_inner)
+ || decl_implicit_constexpr_p (d_inner)))
+ /* DECL was deduced, copy to EXISTING. */
+ {
+ DECL_DECLARED_CONSTEXPR_P (e_inner) = true;
+ if (decl_implicit_constexpr_p (d_inner))
+ DECL_LANG_SPECIFIC (e_inner)->u.fn.implicit_constexpr = true;
+ }
else if (DECL_DECLARED_CONSTEXPR_P (e_inner)
- != DECL_DECLARED_CONSTEXPR_P (d_inner))
+ && (DECL_MAYBE_DELETED (d_inner)
+ || decl_implicit_constexpr_p (e_inner)))
+ /* EXISTING was deduced, leave it alone. */;
+ else
{
mismatch_msg = G_("conflicting %<constexpr%> for imported "
"declaration %#qD");
