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* [gcc r11-10700] c++: Fix up handling of references to anon union members in initializers [PR53932]
@ 2023-05-02 20:13 Jakub Jelinek
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From: Jakub Jelinek @ 2023-05-02 20:13 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:bd34d694f4c060c92aee0e09edf4c7e1d83807e5
commit r11-10700-gbd34d694f4c060c92aee0e09edf4c7e1d83807e5
Author: Jakub Jelinek <jakub@redhat.com>
Date: Thu Jan 19 23:27:34 2023 +0100
c++: Fix up handling of references to anon union members in initializers [PR53932]
For anonymous union members we create artificial VAR_DECLs which
have DECL_VALUE_EXPR for the actual COMPONENT_REF. That works
just fine inside of functions (including global dynamic constructors),
because during gimplification such VAR_DECLs are gimplified as
their DECL_VALUE_EXPR. This is also done during regimplification.
But references to these artificial vars in DECL_INITIAL expressions
aren't ever replaced by the DECL_VALUE_EXPRs, so we end up either
with link failures like on the testcase below, or worse ICEs with
LTO.
The following patch fixes those during cp_fully_fold_init where we
already walk all the trees (!data->genericize means that
function rather than cp_fold_function).
2023-01-19 Jakub Jelinek <jakub@redhat.com>
PR c++/53932
* cp-gimplify.c (cp_fold_r): During cp_fully_fold_init replace
DECL_ANON_UNION_VAR_P VAR_DECLs with their corresponding
DECL_VALUE_EXPR.
* g++.dg/init/pr53932.C: New test.
(cherry picked from commit 9b9a989adc042b304572fd6d4ade46b47be6ccb8)
Diff:
---
gcc/cp/cp-gimplify.c | 45 ++++++++++++++++++++++++++++---------
gcc/testsuite/g++.dg/init/pr53932.C | 25 +++++++++++++++++++++
2 files changed, 60 insertions(+), 10 deletions(-)
diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index 4eee9ff6eb6..a929e9f83d4 100644
--- a/gcc/cp/cp-gimplify.c
+++ b/gcc/cp/cp-gimplify.c
@@ -42,6 +42,14 @@ along with GCC; see the file COPYING3. If not see
#include "cgraph.h"
#include "omp-general.h"
+struct cp_fold_data
+{
+ hash_set<tree> pset;
+ bool genericize; // called from cp_fold_function?
+
+ cp_fold_data (bool g): genericize (g) {}
+};
+
/* Forward declarations. */
static tree cp_genericize_r (tree *, int *, void *);
@@ -468,8 +476,8 @@ cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
init, VEC_INIT_EXPR_VALUE_INIT (*expr_p),
from_array,
tf_warning_or_error);
- hash_set<tree> pset;
- cp_walk_tree (expr_p, cp_fold_r, &pset, NULL);
+ cp_fold_data data (/*genericize*/true);
+ cp_walk_tree (expr_p, cp_fold_r, &data, NULL);
cp_genericize_tree (expr_p, false);
copy_if_shared (expr_p);
ret = GS_OK;
@@ -875,14 +883,31 @@ struct cp_genericize_data
GIMPLE-form. */
static tree
-cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data)
+cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data_)
{
- tree stmt;
- enum tree_code code;
+ cp_fold_data *data = (cp_fold_data*)data_;
+ tree stmt = *stmt_p;
+ enum tree_code code = TREE_CODE (stmt);
+
+ switch (code)
+ {
+ case VAR_DECL:
+ /* In initializers replace anon union artificial VAR_DECLs
+ with their DECL_VALUE_EXPRs, as nothing will do it later. */
+ if (DECL_ANON_UNION_VAR_P (stmt) && !data->genericize)
+ {
+ *stmt_p = stmt = unshare_expr (DECL_VALUE_EXPR (stmt));
+ break;
+ }
+ break;
+
+ default:
+ break;
+ }
*stmt_p = stmt = cp_fold (*stmt_p);
- if (((hash_set<tree> *) data)->add (stmt))
+ if (data->pset.add (stmt))
{
/* Don't walk subtrees of stmts we've already walked once, otherwise
we can have exponential complexity with e.g. lots of nested
@@ -949,8 +974,8 @@ cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data)
void
cp_fold_function (tree fndecl)
{
- hash_set<tree> pset;
- cp_walk_tree (&DECL_SAVED_TREE (fndecl), cp_fold_r, &pset, NULL);
+ cp_fold_data data (/*genericize*/true);
+ cp_walk_tree (&DECL_SAVED_TREE (fndecl), cp_fold_r, &data, NULL);
}
/* Turn SPACESHIP_EXPR EXPR into GENERIC. */
@@ -2218,8 +2243,8 @@ cp_fully_fold_init (tree x)
if (processing_template_decl)
return x;
x = cp_fully_fold (x);
- hash_set<tree> pset;
- cp_walk_tree (&x, cp_fold_r, &pset, NULL);
+ cp_fold_data data (/*genericize*/false);
+ cp_walk_tree (&x, cp_fold_r, &data, NULL);
return x;
}
diff --git a/gcc/testsuite/g++.dg/init/pr53932.C b/gcc/testsuite/g++.dg/init/pr53932.C
new file mode 100644
index 00000000000..3b129e7d68a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/pr53932.C
@@ -0,0 +1,25 @@
+// PR c++/53932
+// { dg-do link }
+
+static union { int i; };
+int &r = i;
+int s = i;
+int *t = &i;
+
+void
+foo (int **p, int *q)
+{
+ static int &u = i;
+ static int v = i;
+ static int *w = &i;
+ int &x = i;
+ int y = i;
+ int *z = &i;
+ *p = &i;
+ *q = i;
+}
+
+int
+main ()
+{
+}
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