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| author | Jason Merrill <jason@redhat.com> | 2021-01-13 13:27:06 -0500 |
|---|---|---|
| committer | Jason Merrill <jason@redhat.com> | 2021-01-15 13:57:01 -0500 |
| commit | d75199f782348bfc401f925b60f33ffc9822b7cc (patch) | |
| tree | a1f67748fa7024d5816a2133f7e9310101d70f0a /gcc/cp/cp-tree.h | |
| parent | 424deca72b63e644cbc975cbc2fdda5248449bcb (diff) | |
| download | gcc-d75199f782348bfc401f925b60f33ffc9822b7cc.zip gcc-d75199f782348bfc401f925b60f33ffc9822b7cc.tar.gz gcc-d75199f782348bfc401f925b60f33ffc9822b7cc.tar.bz2 | |
c++: Avoid redundant copy in {} init [PR98642]
Here, initializing from { } implies a call to the default constructor for
base. We were then seeing that we're initializing a base subobject, so we
tried to copy the result of that call. This is clearly wrong; we should
initialize the base directly from its default constructor.
This patch does a lot of refactoring of unsafe_copy_elision_p and adds
make_safe_copy_elision that will also try to do the base constructor
rewriting from the last patch.
gcc/cp/ChangeLog:
PR c++/98642
* call.c (unsafe_return_slot_p): Return int.
(init_by_return_slot_p): Split out from...
(unsafe_copy_elision_p): ...here.
(unsafe_copy_elision_p_opt): New name for old meaning.
(build_over_call): Adjust.
(make_safe_copy_elision): New.
* typeck2.c (split_nonconstant_init_1): Elide copy from safe
list-initialization.
* cp-tree.h: Adjust.
gcc/testsuite/ChangeLog:
PR c++/98642
* g++.dg/cpp1z/elide5.C: New test.
Diffstat (limited to 'gcc/cp/cp-tree.h')
| -rw-r--r-- | gcc/cp/cp-tree.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index e7b46b7..51139f4 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -6471,7 +6471,8 @@ extern bool is_std_init_list (tree); extern bool is_list_ctor (tree); extern void validate_conversion_obstack (void); extern void mark_versions_used (tree); -extern bool unsafe_return_slot_p (tree); +extern int unsafe_return_slot_p (tree); +extern bool make_safe_copy_elision (tree, tree); extern bool cp_warn_deprecated_use (tree, tsubst_flags_t = tf_warning_or_error); extern void cp_warn_deprecated_use_scopes (tree); extern tree get_function_version_dispatcher (tree); |