Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
The recent r15-6369 unfortunately caused a bad wrong-code issue.
Here we have
TARGET_EXPR <D.2996, (void) (D.2996 = {.status=0, .data={._vptr.Foo=&_ZTV3Foo
+ 16}})>
and call cp_fold_r -> maybe_constant_init with object=D.2996. In
cxx_eval_outermost_constant_expr we now take the type of the object
if present. An object can't have type 'void' and so we continue to
evaluate the initializer. That evaluates into a VOID_CST, meaning
we disregard the whole initializer, and terrible things ensue.
I think the new prvalue optimization (r15-6052) should only be enabled
for simple TARGET_EXPRs -- ones that don't initialize the object via
a sequence of statement as the one above.
I also think we want an assert so that this doesn't happen again.
PR c++/118396
PR c++/118523
gcc/cp/ChangeLog:
* constexpr.cc (cxx_eval_outermost_constant_expr): Assert
that we don't throw away the initializer by evaluating it away.
* cp-gimplify.cc (cp_fold_r): Only attempt to evaluate the initializer
if the TARGET_EXPR is simple.
gcc/testsuite/ChangeLog:
* g++.dg/tree-ssa/pr78687.C: Revert r15-6052.
* g++.dg/tree-ssa/pr90883.C: Likewise.
* g++.dg/cpp0x/constexpr-prvalue4.C: New test.
* g++.dg/cpp1y/constexpr-prvalue3.C: New test.
---
gcc/cp/constexpr.cc | 14 ++++--
gcc/cp/cp-gimplify.cc | 4 +-
.../g++.dg/cpp0x/constexpr-prvalue4.C | 33 ++++++++++++++
.../g++.dg/cpp1y/constexpr-prvalue3.C | 45 +++++++++++++++++++
gcc/testsuite/g++.dg/tree-ssa/pr78687.C | 3 +-
gcc/testsuite/g++.dg/tree-ssa/pr90883.C | 3 +-
6 files changed, 94 insertions(+), 8 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-prvalue4.C
create mode 100644 gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue3.C
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index c898e3bfa6e..61b25277419 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -8876,9 +8876,17 @@ cxx_eval_outermost_constant_expr (tree t, bool
allow_non_constant,
/* Turn off -frounding-math for manifestly constant evaluation. */
warning_sentinel rm (flag_rounding_math,
ctx.manifestly_const_eval == mce_true);
- tree type = (object
- ? cv_unqualified (TREE_TYPE (object))
- : initialized_type (t));
+ tree type;
+ if (object)
+ {
+ type = cv_unqualified (TREE_TYPE (object));
+ /* If there is an object to initialize, make sure we don't throw
+ away the initializer. */
+ gcc_assert (!VOID_TYPE_P (initialized_type (t)) || constexpr_dtor);
+ }
+ else
+ type = initialized_type (t);
+
tree r = t;
bool is_consteval = false;
if (VOID_TYPE_P (type))
diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index c7074b00cef..283c0fa3e26 100644
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -1475,7 +1475,9 @@ cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data_)
cp_walk_tree (&init, cp_fold_r, data, NULL);
cp_walk_tree (&TARGET_EXPR_CLEANUP (stmt), cp_fold_r, data, NULL);
*walk_subtrees = 0;
- if (!flag_no_inline)
+ /* Only attempt to evaluate the initializer if we're inlining and
+ the TARGET_EXPR is simple. */
+ if (!flag_no_inline && !VOID_TYPE_P (TREE_TYPE (init)))
{
tree folded = maybe_constant_init (init, TARGET_EXPR_SLOT (stmt));
if (folded != init && TREE_CONSTANT (folded))
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-prvalue4.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-prvalue4.C
new file mode 100644
index 00000000000..afcee65f880
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-prvalue4.C
@@ -0,0 +1,33 @@
+// PR c++/118396
+// { dg-do run { target c++11 } }
+// { dg-options "-O" }
+
+void *operator new(__SIZE_TYPE__, void *__p) { return __p; }
+
+struct Foo {
+ virtual ~Foo() = default;
+};
+struct Data {
+ int status;
+ Foo data{};
+};
+
+Data *P, *Q;
+
+struct vector {
+ vector (const Data &__value) {
+ P = static_cast<Data *>(__builtin_operator_new(0));
+ new (P) Data (__value);
+ Q = P + 1;
+ }
+ Data *begin() { return P; }
+ Data *end() { return Q; }
+};
+
+int
+main ()
+{
+ vector items_(Data{});
+ for (auto item : items_)
+ item.status == 0 ? void() : __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue3.C
b/gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue3.C
new file mode 100644
index 00000000000..8ea86c60be5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue3.C
@@ -0,0 +1,45 @@
+// PR c++/118523
+// { dg-do compile { target c++14 } }
+// { dg-options "-O2 -Wall" }
+
+struct __new_allocator {
+ constexpr __new_allocator() {}
+ __new_allocator(__new_allocator &) {}
+};
+template <typename> using __allocator_base = __new_allocator;
+template <typename> struct allocator_traits;
+template <typename> struct allocator : __allocator_base<int> {};
+template <typename _Tp> struct allocator_traits<allocator<_Tp>> {
+ using pointer = _Tp *;
+ template <typename _Up> using rebind_alloc = allocator<_Up>;
+ static void deallocate(allocator<_Tp>, pointer, long);
+};
+struct __alloc_traits : allocator_traits<allocator<int>> {};
+struct _Vector_impl_data {
+ __alloc_traits::pointer _M_start;
+ __alloc_traits::pointer _M_end_of_storage;
+ constexpr _Vector_impl_data() : _M_start(), _M_end_of_storage() {}
+};
+struct _Vector_impl : __alloc_traits::rebind_alloc<int>, _Vector_impl_data {};
+struct _Vector_base {
+ ~_Vector_base() {
+ _M_deallocate(_M_impl._M_start,
+ _M_impl._M_end_of_storage - _M_impl._M_start);
+ }
+ _Vector_impl _M_impl;
+ void _M_deallocate(__alloc_traits::pointer __p, long __n) {
+ if (__p)
+ __alloc_traits::deallocate(_M_impl, __p, __n);
+ }
+};
+struct vector : protected _Vector_base {};
+struct S {
+ vector a{};
+};
+struct B2 {
+ B2(S);
+};
+struct E : B2 {
+ E(S opts = {}) : B2{opts} {}
+};
+void fun() { E{}; }
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr78687.C
b/gcc/testsuite/g++.dg/tree-ssa/pr78687.C
index 6e8a5b7efdf..698458f0e9a 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/pr78687.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr78687.C
@@ -480,5 +480,4 @@ int main(int argc, char* argv[])
f();
}
-// XFAILed due to PR116416
-/* { dg-final { scan-tree-dump "Removing load:.*ptr;" "sra" { xfail { *-*-* }
} } } */
+/* { dg-final { scan-tree-dump "Removing load:.*ptr;" "sra" } } */
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr90883.C
b/gcc/testsuite/g++.dg/tree-ssa/pr90883.C
index ad9231eaff2..f540e78fa00 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/pr90883.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr90883.C
@@ -16,5 +16,4 @@
// We want to match enough here to capture that we deleted an empty
// constructor store
// mips will expand to loop to clear because CLEAR_RATIO.
-// { dg-final { scan-tree-dump-not ".*\.a = {}" "dse1" { xfail { mips*-*-* } }
} }
-// { dg-final { scan-tree-dump-not ".*\.b = 0" "dse1" { xfail { mips*-*-* } }
} }
+// { dg-final { scan-tree-dump "Deleted redundant store: .*\.a = {}" "dse1" {
xfail { mips*-*-* } } } }
base-commit: 29da6a642402ac64002f5edeab268606b4637103
--
2.48.0
