To work around it, I added a pset to
replace_placeholders_for_class_temp_r, but it would be best to just rely
on TARGET_EXPR_ELIDING_P.
This patch changes the diagnostic we emit in constexpr-diag1.C: instead
of:
constexpr-diag1.C:20:21: error: temporary of non-literal type 'B' in a constant
expression
we say:
constexpr-diag1.C:20:23: error: call to non-'constexpr' function 'B::B()'
PR c++/114707
gcc/cp/ChangeLog:
* call.cc (convert_for_arg_passing): Call set_target_expr_eliding.
* typeck2.cc (replace_placeholders_for_class_temp_r): Don't use pset.
(digest_nsdmi_init): Call cp_walk_tree_without_duplicates instead of
cp_walk_tree.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/constexpr-diag1.C: Adjust dg-error.
---
gcc/cp/call.cc | 3 +++
gcc/cp/typeck2.cc | 20 ++++----------------
gcc/testsuite/g++.dg/cpp0x/constexpr-diag1.C | 2 +-
3 files changed, 8 insertions(+), 17 deletions(-)
diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index ed68eb3c568..750ecf60fd9 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -9437,6 +9437,9 @@ convert_for_arg_passing (tree type, tree val,
tsubst_flags_t complain)
if (complain & tf_warning)
warn_for_address_of_packed_member (type, val);
+ /* gimplify_arg elides TARGET_EXPRs that initialize a function argument. */
+ set_target_expr_eliding (val);
+
return val;
}
diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
index 06bad4d3303..7782f38da43 100644
--- a/gcc/cp/typeck2.cc
+++ b/gcc/cp/typeck2.cc
@@ -1409,16 +1409,14 @@ digest_init_flags (tree type, tree init, int flags,
tsubst_flags_t complain)
in the context of guaranteed copy elision). */
static tree
-replace_placeholders_for_class_temp_r (tree *tp, int *, void *data)
+replace_placeholders_for_class_temp_r (tree *tp, int *, void *)
{
tree t = *tp;
- auto pset = static_cast<hash_set<tree> *>(data);
/* We're looking for a TARGET_EXPR nested in the whole expression. */
if (TREE_CODE (t) == TARGET_EXPR
/* That serves as temporary materialization, not an initializer. */
- && !TARGET_EXPR_ELIDING_P (t)
- && !pset->add (t))
+ && !TARGET_EXPR_ELIDING_P (t))
{
tree init = TARGET_EXPR_INITIAL (t);
while (TREE_CODE (init) == COMPOUND_EXPR)
@@ -1433,16 +1431,6 @@ replace_placeholders_for_class_temp_r (tree *tp, int *,
void *data)
gcc_checking_assert (!find_placeholders (init));
}
}
- /* TARGET_EXPRs initializing function arguments are not marked as eliding,
- even though gimplify_arg drops them on the floor. Don't go replacing
- placeholders in them. */
- else if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR)
- for (int i = 0; i < call_expr_nargs (t); ++i)
- {
- tree arg = get_nth_callarg (t, i);
- if (TREE_CODE (arg) == TARGET_EXPR && !TARGET_EXPR_ELIDING_P (arg))
- pset->add (arg);
- }
return NULL_TREE;
}
@@ -1490,8 +1478,8 @@ digest_nsdmi_init (tree decl, tree init, tsubst_flags_t
complain)
temporary materialization does not occur when initializing an object
from a prvalue of the same type, therefore we must not replace the
placeholder with a temporary object so that it can be elided. */
- hash_set<tree> pset;
- cp_walk_tree (&init, replace_placeholders_for_class_temp_r, &pset, nullptr);
+ cp_walk_tree_without_duplicates (&init,
replace_placeholders_for_class_temp_r,
+ nullptr);
return init;
}
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-diag1.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-diag1.C
index ccb8d81adca..da6fc2030bc 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-diag1.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-diag1.C
@@ -17,4 +17,4 @@ constexpr int b = A<B>().f(); // { dg-error "" }
template <class T>
constexpr int f (T t) { return 42; }
-constexpr int x = f(B()); // { dg-error "non-literal" }
+constexpr int x = f(B()); // { dg-error "call to non-.constexpr." }
base-commit: 2b2476d4d18c92b8aba3567ebccd2100c2f7c258
