From 04cf6b57c7c467f615a16b7bbda574671e3fb2df Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 19 Jan 2023 23:27:34 +0100 Subject: [PATCH] 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 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) --- gcc/cp/cp-gimplify.c | 45 ++++++++++++++++++++++------- gcc/testsuite/g++.dg/init/pr53932.C | 25 ++++++++++++++++ 2 files changed, 60 insertions(+), 10 deletions(-) create mode 100644 gcc/testsuite/g++.dg/init/pr53932.C diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c index 9d87ff42b2f3..7a8a4f101cbf 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 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 *); @@ -750,8 +758,8 @@ 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 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; @@ -1172,14 +1180,31 @@ 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 *) 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 @@ -1246,8 +1271,8 @@ cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data) void cp_fold_function (tree fndecl) { - hash_set 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. */ @@ -2525,8 +2550,8 @@ cp_fully_fold_init (tree x) if (processing_template_decl) return x; x = cp_fully_fold (x); - hash_set 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 000000000000..3b129e7d68a9 --- /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 () +{ +} -- 2.47.2