On 3/9/23 14:32, Patrick Palka wrote:
On Mon, 6 Mar 2023, Marek Polacek via Gcc-patches wrote:
When processing a noexcept, constructors aren't elided: build_over_call
has
/* It's unsafe to elide the constructor when handling
a noexcept-expression, it may evaluate to the wrong
value (c++/53025). */
&& (force_elide || cp_noexcept_operand == 0))
so the assert I added recently needs to be relaxed a little bit.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR c++/109030
gcc/cp/ChangeLog:
* constexpr.cc (cxx_eval_call_expression): Relax assert.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/noexcept77.C: New test.
---
gcc/cp/constexpr.cc | 6 +++++-
gcc/testsuite/g++.dg/cpp0x/noexcept77.C | 9 +++++++++
2 files changed, 14 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept77.C
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index 364695b762c..5384d0e8e46 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -2869,7 +2869,11 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree
t,
/* We used to shortcut trivial constructor/op= here, but nowadays
we can only get a trivial function here with -fno-elide-constructors. */
- gcc_checking_assert (!trivial_fn_p (fun) || !flag_elide_constructors);
+ gcc_checking_assert (!trivial_fn_p (fun)
+ || !flag_elide_constructors
+ /* We don't elide constructors when processing
+ a noexcept-expression. */
+ || cp_noexcept_operand);
It seems weird that we're performing constant evaluation within an
unevaluated operand. Would it make sense to also fix this a second way
by avoiding constant evaluation from maybe_constant_init when
cp_unevaluated_operand && !manifestly_const_eval, like in maybe_constant_value?
Sounds good.
IIUC since we could still have an evaluated subexpression withis
noexcept, the two fixes would be complementary.
bool non_constant_args = false;
new_call.bindings
diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept77.C
b/gcc/testsuite/g++.dg/cpp0x/noexcept77.C
new file mode 100644
index 00000000000..16db8eb79ee
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept77.C
@@ -0,0 +1,9 @@
+// PR c++/109030
+// { dg-do compile { target c++11 } }
+
+struct foo { };
+
+struct __as_receiver {
+ foo empty_env;
+};
+void sched(foo __fun) noexcept(noexcept(__as_receiver{__fun})) { }
base-commit: dfb14cdd796ad9df6b5f2def047ef36b29385902
--
2.39.2
