https://gcc.gnu.org/g:1636e85270d918a84d57bb521c22c42abf42a47c
commit r15-8287-g1636e85270d918a84d57bb521c22c42abf42a47c
Author: Martin Uecker <uec...@tugraz.at>
Date: Sat Mar 1 21:32:21 2025 +0100
c: Fix bug in typedef redefinitions of tagged types [PR118765]
When we redefine a tagged type we incorrectly update TYPE_STUB_DECL
of the previously defined type instead of the new one. Because
TYPE_STUB_DECL is used when determining whether two such types are
the same, this can cause valid typedef redefinitions to be rejected
later. This is only a partial fix for PR118765.
PR c/118765
gcc/c/ChangeLog:
* c-decl.cc (finish_struct,finish_enum): Swap direction when
copying TYPE_STRUB_DECL in redefinitions.
gcc/testsuite/ChangeLog:
* gcc.dg/pr118765.c: New test.
Diff:
---
gcc/c/c-decl.cc | 4 ++--
gcc/testsuite/gcc.dg/pr118765.c | 7 +++++++
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index 0dcbae9b26f5..1ae520828c34 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -9846,7 +9846,7 @@ finish_struct (location_t loc, tree t, tree fieldlist,
tree attributes,
&& TREE_CODE (vistype) == TREE_CODE (t)
&& !C_TYPE_BEING_DEFINED (vistype))
{
- TYPE_STUB_DECL (vistype) = TYPE_STUB_DECL (t);
+ TYPE_STUB_DECL (t) = TYPE_STUB_DECL (vistype);
if (c_type_variably_modified_p (t))
{
error ("redefinition of struct or union %qT with variably "
@@ -10321,7 +10321,7 @@ finish_enum (tree enumtype, tree values, tree
attributes)
&& TREE_CODE (vistype) == TREE_CODE (enumtype)
&& !C_TYPE_BEING_DEFINED (vistype))
{
- TYPE_STUB_DECL (vistype) = TYPE_STUB_DECL (enumtype);
+ TYPE_STUB_DECL (enumtype) = TYPE_STUB_DECL (vistype);
if (!comptypes_same_p (enumtype, vistype))
error("conflicting redefinition of enum %qT", enumtype);
}
diff --git a/gcc/testsuite/gcc.dg/pr118765.c b/gcc/testsuite/gcc.dg/pr118765.c
new file mode 100644
index 000000000000..12d025979e3a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr118765.c
@@ -0,0 +1,7 @@
+/* { dg-do "compile" } */
+/* { dg-options "-std=gnu23" } */
+
+typedef struct q { int x; } q_t;
+struct q { int x; };
+typedef struct q { int x; } q_t;
+
