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-rw-r--r--gcc/cp/call.cc44
-rw-r--r--gcc/cp/cp-tree.h2
-rw-r--r--gcc/cp/method.cc2
-rw-r--r--gcc/cp/parser.cc5
-rw-r--r--gcc/testsuite/g++.dg/cpp0x/elision4.C15
-rw-r--r--gcc/testsuite/g++.dg/ext/reference_constructs_from_temporary1.C2
-rw-r--r--gcc/testsuite/g++.dg/ext/reference_converts_from_temporary1.C2
7 files changed, 60 insertions, 12 deletions
diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index bd04a1d..7771d80 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -9210,15 +9210,47 @@ conv_binds_ref_to_prvalue (conversion *c)
return conv_is_prvalue (next_conversion (c));
}
-/* Return tristate::TS_TRUE if converting EXPR to a reference type TYPE does
- not involve creating a temporary. Return tristate::TS_FALSE if converting
- EXPR to a reference type TYPE binds the reference to a temporary. If the
- conversion is invalid or bad, return tristate::TS_UNKNOWN. DIRECT_INIT_P
+/* True iff C is a conversion that binds a reference to a temporary.
+ This is a superset of conv_binds_ref_to_prvalue: here we're also
+ interested in xvalues. */
+
+static bool
+conv_binds_ref_to_temporary (conversion *c)
+{
+ if (conv_binds_ref_to_prvalue (c))
+ return true;
+ if (c->kind != ck_ref_bind)
+ return false;
+ c = next_conversion (c);
+ /* This is the case for
+ struct Base {};
+ struct Derived : Base {};
+ const Base& b(Derived{});
+ where we bind 'b' to the Base subobject of a temporary object of type
+ Derived. The subobject is an xvalue; the whole object is a prvalue. */
+ if (c->kind != ck_base)
+ return false;
+ c = next_conversion (c);
+ if (c->kind == ck_identity && c->u.expr)
+ {
+ tree expr = c->u.expr;
+ while (handled_component_p (expr))
+ expr = TREE_OPERAND (expr, 0);
+ if (TREE_CODE (expr) == TARGET_EXPR)
+ return true;
+ }
+ return false;
+}
+
+/* Return tristate::TS_TRUE if converting EXPR to a reference type TYPE binds
+ the reference to a temporary. Return tristate::TS_FALSE if converting
+ EXPR to a reference type TYPE doesn't bind the reference to a temporary. If
+ the conversion is invalid or bad, return tristate::TS_UNKNOWN. DIRECT_INIT_P
says whether the conversion should be done in direct- or copy-initialization
context. */
tristate
-ref_conv_binds_directly (tree type, tree expr, bool direct_init_p /*= false*/)
+ref_conv_binds_to_temporary (tree type, tree expr, bool direct_init_p/*=false*/)
{
gcc_assert (TYPE_REF_P (type));
@@ -9230,7 +9262,7 @@ ref_conv_binds_directly (tree type, tree expr, bool direct_init_p /*= false*/)
/*c_cast_p=*/false, flags, tf_none);
tristate ret (tristate::TS_UNKNOWN);
if (conv && !conv->bad_p)
- ret = tristate (!conv_binds_ref_to_prvalue (conv));
+ ret = tristate (conv_binds_ref_to_temporary (conv));
/* Free all the conversions we allocated. */
obstack_free (&conversion_obstack, p);
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 8bc1c2d..469eb2f 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6534,7 +6534,7 @@ extern bool sufficient_parms_p (const_tree);
extern tree type_decays_to (tree);
extern tree extract_call_expr (tree);
extern tree build_trivial_dtor_call (tree, bool = false);
-extern tristate ref_conv_binds_directly (tree, tree, bool = false);
+extern tristate ref_conv_binds_to_temporary (tree, tree, bool = false);
extern tree build_user_type_conversion (tree, tree, int,
tsubst_flags_t);
extern tree build_new_function_call (tree, vec<tree, va_gc> **,
diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
index 55af5c4..622e1b9 100644
--- a/gcc/cp/method.cc
+++ b/gcc/cp/method.cc
@@ -2233,7 +2233,7 @@ ref_xes_from_temporary (tree to, tree from, bool direct_init_p)
tree val = build_stub_object (from);
if (!TYPE_REF_P (from) && TREE_CODE (from) != FUNCTION_TYPE)
val = CLASS_TYPE_P (from) ? force_rvalue (val, tf_none) : rvalue (val);
- return ref_conv_binds_directly (to, val, direct_init_p).is_false ();
+ return ref_conv_binds_to_temporary (to, val, direct_init_p).is_true ();
}
/* Worker for is_{,nothrow_}convertible. Attempt to perform an implicit
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 555476e..dc3d17c 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -13731,7 +13731,8 @@ warn_for_range_copy (tree decl, tree expr)
if (TYPE_REF_P (type))
{
- if (glvalue_p (expr) && ref_conv_binds_directly (type, expr).is_false ())
+ if (glvalue_p (expr)
+ && ref_conv_binds_to_temporary (type, expr).is_true ())
{
auto_diagnostic_group d;
if (warning_at (loc, OPT_Wrange_loop_construct,
@@ -13762,7 +13763,7 @@ warn_for_range_copy (tree decl, tree expr)
/* If we can initialize a reference directly, suggest that to avoid the
copy. */
tree rtype = cp_build_reference_type (type, /*rval*/false);
- if (ref_conv_binds_directly (rtype, expr).is_true ())
+ if (ref_conv_binds_to_temporary (rtype, expr).is_false ())
{
auto_diagnostic_group d;
if (warning_at (loc, OPT_Wrange_loop_construct,
diff --git a/gcc/testsuite/g++.dg/cpp0x/elision4.C b/gcc/testsuite/g++.dg/cpp0x/elision4.C
new file mode 100644
index 0000000..3cc2e3a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/elision4.C
@@ -0,0 +1,15 @@
+// PR c++/107085
+// { dg-do compile { target c++11 } }
+
+struct X {
+ X();
+ X(X&&);
+};
+struct Z : X {};
+X x1 = Z();
+X x2 = X(Z());
+
+struct B { };
+struct D : B { };
+B b1 = D();
+B b2 = B(D());
diff --git a/gcc/testsuite/g++.dg/ext/reference_constructs_from_temporary1.C b/gcc/testsuite/g++.dg/ext/reference_constructs_from_temporary1.C
index 76de905..5354b1d 100644
--- a/gcc/testsuite/g++.dg/ext/reference_constructs_from_temporary1.C
+++ b/gcc/testsuite/g++.dg/ext/reference_constructs_from_temporary1.C
@@ -201,7 +201,7 @@ SA(!__reference_constructs_from_temporary(const int&, H));
SA(!__reference_constructs_from_temporary(int&&, G2));
SA(!__reference_constructs_from_temporary(const int&, H2));
-SA(!__reference_constructs_from_temporary(const Base&, Der));
+SA(__reference_constructs_from_temporary(const Base&, Der));
// This fails because std::is_constructible_v<int&&, id<int[3]>> is false.
SA(!__reference_constructs_from_temporary(int&&, id<int[3]>));
diff --git a/gcc/testsuite/g++.dg/ext/reference_converts_from_temporary1.C b/gcc/testsuite/g++.dg/ext/reference_converts_from_temporary1.C
index 90196c3..e6c159e 100644
--- a/gcc/testsuite/g++.dg/ext/reference_converts_from_temporary1.C
+++ b/gcc/testsuite/g++.dg/ext/reference_converts_from_temporary1.C
@@ -201,7 +201,7 @@ SA( __reference_converts_from_temporary(const int&, H));
SA(!__reference_converts_from_temporary(int&&, G2));
SA(!__reference_converts_from_temporary(const int&, H2));
-SA(!__reference_converts_from_temporary(const Base&, Der));
+SA(__reference_converts_from_temporary(const Base&, Der));
// This fails because std::is_constructible_v<int&&, id<int[3]>> is false.
SA(!__reference_converts_from_temporary(int&&, id<int[3]>));
generated by cgit v1.1 at 2025-01-18 23:33:31 +0000