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| author | Jakub Jelinek <jakub@redhat.com> | 2022-01-19 00:42:18 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2022-01-19 00:42:18 +0100 |
| commit | 1a5145f1e3adf8b2ba4ad416a5ddef59a1e34d48 (patch) | |
| tree | 88783f175903044a0c9e8e63b3c382d9c2a6d498 | |
| parent | fdd6d85bd75df9a97659220373b5c1e8b3019e26 (diff) | |
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c++: Fix handling of temporaries with consteval ctors and non-trivial dtors [PR104055]
The following testcase is miscompiled. We see the constructor is immediate,
in build_over_call we trigger:
if (obj_arg && is_dummy_object (obj_arg))
{
call = build_cplus_new (DECL_CONTEXT (fndecl), call, complain);
obj_arg = NULL_TREE;
}
which makes call a TARGET_EXPR with the dtor in TARGET_EXPR_CLEANUP,
but then call cxx_constant_value on it. In cxx_eval_outermost_constant_expr
it triggers the:
else if (TREE_CODE (t) != CONSTRUCTOR)
{
r = get_target_expr_sfinae (r, tf_warning_or_error | tf_no_cleanup);
TREE_CONSTANT (r) = true;
}
which wraps the CONSTRUCTOR r into a new TARGET_EXPR, but one without
dtors (I think we need e.g. the TREE_CONSTANT for the callers),
and finally build_over_call uses that.
The following patch fixes that by using get_target_expr instead
of get_target_expr_sfinae + TREE_CONSTANT (r) = true if t is
a TARGET_EXPR with non-NULL TARGET_EXPR_CLEANUP.
2022-01-19 Jakub Jelinek <jakub@redhat.com>
PR c++/104055
* constexpr.cc (cxx_eval_outermost_constant_expr): If t is a
TARGET_EXPR with TARGET_EXPR_CLEANUP, use get_target_expr rather
than get_target_expr_sfinae with tf_no_cleanup, and don't set
TREE_CONSTANT.
* g++.dg/cpp2a/consteval27.C: New test.
| -rw-r--r-- | gcc/cp/constexpr.cc | 6 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/consteval27.C | 18 |
2 files changed, 23 insertions, 1 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index f73496f..dcc1674 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -7821,7 +7821,11 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, if (TREE_CODE (t) == TARGET_EXPR && TARGET_EXPR_INITIAL (t) == r) return t; - else if (TREE_CODE (t) != CONSTRUCTOR) + else if (TREE_CODE (t) == CONSTRUCTOR) + ; + else if (TREE_CODE (t) == TARGET_EXPR && TARGET_EXPR_CLEANUP (t)) + r = get_target_expr (r); + else { r = get_target_expr_sfinae (r, tf_warning_or_error | tf_no_cleanup); TREE_CONSTANT (r) = true; diff --git a/gcc/testsuite/g++.dg/cpp2a/consteval27.C b/gcc/testsuite/g++.dg/cpp2a/consteval27.C new file mode 100644 index 0000000..72d56df --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/consteval27.C @@ -0,0 +1,18 @@ +// PR c++/104055 +// { dg-do run { target c++20 } } + +int g; + +struct A { + ~A () { if (a != 17 || b != 26) __builtin_abort (); g = 42; } + consteval A () : a (17), b (26) {} + int a, b; +}; + +int +main () +{ + A{}; + if (g != 42) + __builtin_abort (); +} |