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re PR c++/35878 ([LWG 2302] Useless NULL pointer check when constructing object) 

gcc/

PR c++/35878
* cp/init.c (std_placement_new_fn_p): New.
(build_new_1): Call it.

testsuite/

PR c++/35878
* g++.dg/init/pr35878_1.C: New.
* g++.dg/init/pr35878_2.C: Likewise.
* g++.dg/init/pr35878_3.C: Likewise.

From-SVN: r246301
This commit is contained in:
Ville Voutilainen 2017-03-21 08:36:22 +02:00 committed by Ville Voutilainen
parent 5b9e0383cc
commit ece3b7e65a
5 changed files with 86 additions and 1 deletions
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6
gcc/cp/ChangeLog
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@ -1,3 +1,9 @@
2017-03-21 Ville Voutilainen <ville.voutilainen@gmail.com>
PR c++/35878
* cp/init.c (std_placement_new_fn_p): New.
(build_new_1): Call it.
2017-03-20 Jason Merrill <jason@redhat.com>
PR c++/80096 - ICE with C++17 non-type auto.

18
gcc/cp/init.c
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@ -2707,6 +2707,21 @@ malloc_alignment ()
return MAX (max_align_t_align(), MALLOC_ABI_ALIGNMENT);
}
/* Determine whether an allocation function is a namespace-scope
non-replaceable placement new function. See DR 1748.
TODO: Enable in all standard modes. */
static bool std_placement_new_fn_p (tree alloc_fn)
{
if ((cxx_dialect > cxx14) && DECL_NAMESPACE_SCOPE_P (alloc_fn))
{
tree first_arg = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (alloc_fn)));
if ((TREE_VALUE (first_arg) == ptr_type_node)
&& TREE_CHAIN (first_arg) == void_list_node)
return true;
}
return false;
}
/* Generate code for a new-expression, including calling the "operator
new" function, initializing the object, and, if an exception occurs
during construction, cleaning up. The arguments are as for
@ -3185,7 +3200,8 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts,
So check for a null exception spec on the op new we just called. */
nothrow = TYPE_NOTHROW_P (TREE_TYPE (alloc_fn));
check_new = (flag_check_new || nothrow);
check_new = flag_check_new
|| (nothrow && !std_placement_new_fn_p (alloc_fn));
if (cookie_size)
{

21
gcc/testsuite/g++.dg/init/pr35878_1.C Normal file
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@ -0,0 +1,21 @@
// { dg-options "-O2 --std=gnu++11" }
// { dg-do compile }
// { dg-final { scan-assembler "test.*%rdi, %rdi" { target i?86-*-* x86_64-*-* } } }
#include <new>
#include <utility>
struct s1{
int a;
int b;
int c;
};
void f1 (s1 * v, s1&& s)
{
new (v) s1(std::move(s));
}
void f2 (s1 * v, s1&& s)
{
*v = std::move(s);
}

21
gcc/testsuite/g++.dg/init/pr35878_2.C Normal file
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@ -0,0 +1,21 @@
// { dg-options "-O2 --std=gnu++17 -fcheck-new" }
// { dg-do compile }
// { dg-final { scan-assembler "test.*%rdi, %rdi" { target i?86-*-* x86_64-*-* } } }
#include <new>
#include <utility>
struct s1{
int a;
int b;
int c;
};
void f1 (s1 * v, s1&& s)
{
new (v) s1(std::move(s));
}
void f2 (s1 * v, s1&& s)
{
*v = std::move(s);
}

21
gcc/testsuite/g++.dg/init/pr35878_3.C Normal file
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@ -0,0 +1,21 @@
// { dg-options "-O2 --std=gnu++17" }
// { dg-do compile }
// { dg-final { scan-assembler-not "test.*%rdi, %rdi" { target i?86-*-* x86_64-*-* } } }
#include <new>
#include <utility>
struct s1{
int a;
int b;
int c;
};
void f1 (s1 * v, s1&& s)
{
new (v) s1(std::move(s));
}
void f2 (s1 * v, s1&& s)
{
*v = std::move(s);
}