@@ -10172,28 +10172,31 @@ extend_ref_init_temps (tree decl, tree init, vec<tree, va_gc> **cleanups)
return init;
if (TREE_CODE (type) == REFERENCE_TYPE)
init = extend_ref_init_temps_1 (decl, init, cleanups);
- else if (is_std_init_list (type))
+ else
{
- /* The temporary array underlying a std::initializer_list
- is handled like a reference temporary. */
tree ctor = init;
if (TREE_CODE (ctor) == TARGET_EXPR)
ctor = TARGET_EXPR_INITIAL (ctor);
if (TREE_CODE (ctor) == CONSTRUCTOR)
{
- tree array = CONSTRUCTOR_ELT (ctor, 0)->value;
- array = extend_ref_init_temps_1 (decl, array, cleanups);
- CONSTRUCTOR_ELT (ctor, 0)->value = array;
+ if (is_std_init_list (type))
+ {
+ /* The temporary array underlying a std::initializer_list
+ is handled like a reference temporary. */
+ tree array = CONSTRUCTOR_ELT (ctor, 0)->value;
+ array = extend_ref_init_temps_1 (decl, array, cleanups);
+ CONSTRUCTOR_ELT (ctor, 0)->value = array;
+ }
+ else
+ {
+ unsigned i;
+ constructor_elt *p;
+ vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ctor);
+ FOR_EACH_VEC_SAFE_ELT (elts, i, p)
+ p->value = extend_ref_init_temps (decl, p->value, cleanups);
+ }
}
}
- else if (TREE_CODE (init) == CONSTRUCTOR)
- {
- unsigned i;
- constructor_elt *p;
- vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (init);
- FOR_EACH_VEC_SAFE_ELT (elts, i, p)
- p->value = extend_ref_init_temps (decl, p->value, cleanups);
- }
return init;
}
new file mode 100644
@@ -0,0 +1,25 @@
+// DR 1697
+// { dg-do run { target c++11 } }
+
+#define assert(X) do { if (!(X)) __builtin_abort(); } while(0)
+
+int i;
+struct S {
+ ~S() { assert (i++ == 2); }
+};
+struct X {
+ X() { assert (i++ == 0); }
+ X(const X&);
+};
+struct T {
+ S &&s;
+ X x;
+};
+void f() { assert (i++ == 1); }
+int main() {
+ {
+ T t = T{ {}, {} };
+ f();
+ }
+ assert (i == 3);
+}
While looking at guaranteed copy elision, I noticed some outstanding issues with temporary lifetime extension. In one case, we were failing to extend temporaries bound to references within another temporary. In another, we were failing to extend a temporary when we bind a reference to a scalar subobject. Tested x86_64-pc-linux-gnu, applying to trunk. commit 72052afef06d077e8061b974aff3c2910037b7a0 Author: Jason Merrill <jason@redhat.com> Date: Wed Oct 5 14:30:18 2016 -0400 * call.c (extend_ref_init_temps): Fix TARGET_EXPR handling. commit c9d1d33ded916cb7f0dbbf6b7b4673acc2af0244 Author: Jason Merrill <jason@redhat.com> Date: Wed Oct 5 16:24:33 2016 -0400 PR c++/54293 - binding reference to member of temporary * call.c (reference_binding): Fix binding to member of temporary. diff --git a/gcc/cp/call.c b/gcc/cp/call.c index c333418..dac1337 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -1539,15 +1539,20 @@ reference_binding (tree rto, tree rfrom, tree expr, bool c_cast_p, int flags, gl_kind = clk_rvalueref; } else if (expr) - { - gl_kind = lvalue_kind (expr); - if (gl_kind & clk_class) - /* A class prvalue is not a glvalue. */ - gl_kind = clk_none; - } + gl_kind = lvalue_kind (expr); + else if (CLASS_TYPE_P (from) + || TREE_CODE (from) == ARRAY_TYPE) + gl_kind = clk_class; else gl_kind = clk_none; - is_lvalue = gl_kind && !(gl_kind & clk_rvalueref); + + /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */ + if ((flags & LOOKUP_NO_TEMP_BIND) + && (gl_kind & clk_class)) + gl_kind = clk_none; + + /* Same mask as real_lvalue_p. */ + is_lvalue = gl_kind && !(gl_kind & (clk_rvalueref|clk_class)); tfrom = from; if ((gl_kind & clk_bitfield) != 0) @@ -1569,11 +1574,7 @@ reference_binding (tree rto, tree rfrom, tree expr, bool c_cast_p, int flags, [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for const and rvalue references to rvalues of compatible class type. We should also do direct bindings for non-class xvalues. */ - if (related_p - && (gl_kind - || (!(flags & LOOKUP_NO_TEMP_BIND) - && (CLASS_TYPE_P (from) - || TREE_CODE (from) == ARRAY_TYPE)))) + if (related_p && gl_kind) { /* [dcl.init.ref] diff --git a/gcc/testsuite/g++.dg/init/ref19.C b/gcc/testsuite/g++.dg/init/ref19.C index ed78c93..d583e93 100644 --- a/gcc/testsuite/g++.dg/init/ref19.C +++ b/gcc/testsuite/g++.dg/init/ref19.C @@ -11,7 +11,11 @@ struct A int main() { - const int &r = A().i; + { + const int &r = A().i; + if (d != 0) + return 1; + } if (d != 1) return 1; }