On 3/11/24 19:27, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/13?-- >8 -- This ICE started with the fairly complicated r13-765. We crash in gimplify_var_or_parm_decl because a stray VAR_DECL leaked there. The problem is ultimately that potential_prvalue_result_of wasn't correctly handling arrays and replace_placeholders_for_class_temp_r replaced a PLACEHOLDER_EXPR in a TARGET_EXPR which is used in the context of copy elision. If I have M m[2] = { M{""}, M{""} }; then we don't invoke the M(const M&) copy-ctor. I think the fix is to detect such a case in potential_prvalue_result_of. PR c++/109966 gcc/cp/ChangeLog: * typeck2.cc (potential_prvalue_result_of): Add walk_subtrees parameter. Handle initializing an array from a brace-enclosed-initializer. (replace_placeholders_for_class_temp_r): Pass walk_subtrees down to potential_prvalue_result_of. gcc/testsuite/ChangeLog: * g++.dg/cpp1y/nsdmi-aggr20.C: New test. * g++.dg/cpp1y/nsdmi-aggr21.C: New test. --- gcc/cp/typeck2.cc | 27 ++++++++--- gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr20.C | 17 +++++++ gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr21.C | 59 +++++++++++++++++++++++ 3 files changed, 96 insertions(+), 7 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr20.C create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr21.C diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc index 31198b2f9f5..8b99ce78e9a 100644 --- a/gcc/cp/typeck2.cc +++ b/gcc/cp/typeck2.cc @@ -1406,46 +1406,59 @@ digest_init_flags (tree type, tree init, int flags, tsubst_flags_t complain) A a = (A{}); // initializer A a = (1, A{}); // initializer A a = true ? A{} : A{}; // initializer + A arr[1] = { A{} }; // initializer auto x = A{}.x; // temporary materialization auto x = foo(A{}); // temporary materializationFULL_EXPR is the whole expression, SUBOB is its TARGET_EXPR subobject. */ static bool-potential_prvalue_result_of (tree subob, tree full_expr) +potential_prvalue_result_of (tree subob, tree full_expr, int *walk_subtrees) { +#define RECUR(t) potential_prvalue_result_of (subob, t, walk_subtrees) if (subob == full_expr) return true; else if (TREE_CODE (full_expr) == TARGET_EXPR) { tree init = TARGET_EXPR_INITIAL (full_expr); if (TREE_CODE (init) == COND_EXPR) - return (potential_prvalue_result_of (subob, TREE_OPERAND (init, 1)) - || potential_prvalue_result_of (subob, TREE_OPERAND (init, 2))); + return (RECUR (TREE_OPERAND (init, 1)) + || RECUR (TREE_OPERAND (init, 2))); else if (TREE_CODE (init) == COMPOUND_EXPR) - return potential_prvalue_result_of (subob, TREE_OPERAND (init, 1)); + return RECUR (TREE_OPERAND (init, 1)); /* ??? I don't know if this can be hit. */ else if (TREE_CODE (init) == PAREN_EXPR) { gcc_checking_assert (false); - return potential_prvalue_result_of (subob, TREE_OPERAND (init, 0)); + return RECUR (TREE_OPERAND (init, 0)); } } + /* The array case listed above. */ + else if (TREE_CODE (full_expr) == CONSTRUCTOR + && TREE_CODE (TREE_TYPE (full_expr)) == ARRAY_TYPE) + for (constructor_elt &e: CONSTRUCTOR_ELTS (full_expr)) + if (e.value == subob) + { + *walk_subtrees = 0;
Why clear walk_subtrees? Won't that mean we fail to replace any placeholders nested within an array element initializer?
Jason
