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| author | Jason Merrill <jason@redhat.com> | 2016-10-05 18:59:02 -0400 |
|---|---|---|
| committer | Jason Merrill <jason@gcc.gnu.org> | 2016-10-05 18:59:02 -0400 |
| commit | bf9b09fbe23d4efb07eec21bbb3f73f1a075cb2b (patch) | |
| tree | 5a876d8698a058b630252e34bb1ce6e5df218eed /gcc | |
| parent | 5794b9f622dce668aa92ebabdf26abd0e799c665 (diff) | |
| download | gcc-bf9b09fbe23d4efb07eec21bbb3f73f1a075cb2b.zip gcc-bf9b09fbe23d4efb07eec21bbb3f73f1a075cb2b.tar.gz gcc-bf9b09fbe23d4efb07eec21bbb3f73f1a075cb2b.tar.bz2 | |
Implement P0135R1, Guaranteed copy elision.
* cvt.c (ocp_convert): Don't re-copy a TARGET_EXPR in C++17.
From-SVN: r240820
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/cp/ChangeLog | 3 | ||||
| -rw-r--r-- | gcc/cp/cvt.c | 7 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp1z/elide1.C | 16 |
3 files changed, 24 insertions, 2 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 569d696..7bd7db6 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,8 @@ 2016-10-05 Jason Merrill <jason@redhat.com> + Implement P0135R1, Guaranteed copy elision. + * cvt.c (ocp_convert): Don't re-copy a TARGET_EXPR in C++17. + PR c++/54293 * call.c (reference_binding): Fix binding to member of temporary. diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c index 2f5f15a..ecc8ef8 100644 --- a/gcc/cp/cvt.c +++ b/gcc/cp/cvt.c @@ -693,8 +693,11 @@ ocp_convert (tree type, tree expr, int convtype, int flags, if (error_operand_p (e)) return error_mark_node; - if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP)) - /* We need a new temporary; don't take this shortcut. */; + if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP) + && !(cxx_dialect >= cxx1z + && TREE_CODE (e) == TARGET_EXPR)) + /* We need a new temporary; don't take this shortcut. But in C++17, don't + force a temporary if we already have one. */; else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e))) { if (same_type_p (type, TREE_TYPE (e))) diff --git a/gcc/testsuite/g++.dg/cpp1z/elide1.C b/gcc/testsuite/g++.dg/cpp1z/elide1.C new file mode 100644 index 0000000..a0538bb --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/elide1.C @@ -0,0 +1,16 @@ +// { dg-options -std=c++1z } + +struct A +{ + A(); + A(const A&) = delete; +}; + +bool b; +A a = A(); +A a1 = b ? A() : A(); +A a2 = (42, A()); + +A f(); +A a3 = f(); +A a4 = b ? A() : f(); |